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Boominator MINI (development thread)

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Topic: Boominator MINI (development thread)
Posted By: Saturnus
Subject: Boominator MINI (development thread)
Date Posted: 19 December 2012 at 8:18pm

Please note. This is a development thread that is expected to be complete in Autumn 2018.

Please read all responses to make sure you have noted all changes to the design before beginning construction.

Please note: the Aura NS6 this build was originally based on have sold out and will not be produced anymore. A new design based on Dayton Audio drivers and advanced DSP amplifiers is in the process of being completed during Autumn 2018.

As some of you might have noticed I've finally decided to expand on my original Boominator design with a few extra models. This is based on the many requests to make something lighter, smaller, larger and/or more versatile. So I'll make them all.

Firstly, I'd strongly emphasize that the original Boominator design should still be your preferred first choice for a DIY build. These extra versions just expands on the concept. 

There'll be a true mark II version which has a new flexible bracing structures which allows to incorporate almost any driver with suitable parameters into the Boominator design. The main result of this will be a LITE version with neodynium based drivers (Eminence Basslite S1020) making it possible to build a Boominator that weighs half the original at 10kg excluding batteries (the original weighs 19kg excluding batteries).

There'll also be a MEGA version with 4x 15" pro woofers (the PD.153ER to be exact) and a powerful Selenium DT220TI compression drivers combined with a compact bi-radial CD horn (the Eminence APT200S horn guide). It'll be massive mainly in terms of weight (estimated 70kg) as it will still be impressively compact and will sports 2x 300W amp for the woofers.

Back on topic though. The MINI. One of the most asked for designs was a cheaper and smaller version. In effect I tried to advice people to just build half a Boominator. But although good, it's not really what I wanted to offer as it's not a true bipolar speaker which is an absolute necessity for an outdoors speaker of this kind to sound good. I also wanted something that could be used indoors which ruled out the overtuned boombox BR tuning that I worked and experimented so long to perfect. One thing remains though: the higher than standard Q tuning at Q=1.207. With the ultra cheap Aura NS6 drivers this gives the same warm sound with exceptional vocal clarity as the original Boominator.

Aura NS6 is available from PE and Madisound. Both unfortunately US dealers but with a price that low and freight forwarder service used instead of direct delivery. It's still a very good deal.

To complement the Aura NS6, I've chosen a old favorite of ultra compact designs with drivers that go up to about 4.5-5Khz, the Dayton ND16FA-6. Available from PE and Europe-Audio. It's small, it's cheap, and crossed in above 4Khz it does it's job very well. It also have the desired very high dispersion.

Filter is a hybrid 2.-order with L-R LP and B-W HP at 4.6Khz. No extra attenuation or compensation circuits necessary. This is due to an L-R filter being 6dB down at x-o and a B-W being 3dB down at x-o. But a pure b-W also has a 1dB lift at x-o, the hybrid takes care of that while at the same time compensation for the 3dB spike in the woofers FR between 4Khz and 5Khz. Remember to invert phase on the tweeters. Use cheap as dirt components except the cap in series with the tweeters negative pole (it's inverted, remember) which should be at least an MKP type.

Amp is ideally the amp32 from 41hz but it might be a bit difficult to solder as it's really tiny and uses SMD components through out. Other than that only a "9800mah" li-ion battery, a recessed dish, grills, some cables bits, and some connectors are needed. The recessed dish functions as cooling plate for the amp as well the point where the connectors are mounted..

Not sure what other choices there are for amps but the TA2024 is generally ruled out as that doesn't work too well with 4 ohms loads that dips to 3.2 ohm. Also, it's a waste to put a TK2050 based amp in it as the drivers aren't really capable of handling that running 24V on full tilt for very long, as well as you'd need 10(!) times the battery capacity to get the same playing time. And a TK2050 uses too much power running 12V compared to a TA2020/TA2021 based amp.

If anyone got suggestions for an amp. I'd like to hear it. Though any ready built amp in a cabinet you can rule out right away as that will take up too much internal volume. It must be a bare bones circuit board.

Cabinet design will be up over the holidays but dimensions are 180x180x720mm built from 9mm plywood. A router and knowledge of how to use it is an absolute necessary tool in order to build this speaker.




Replies:
Posted By: bitSmasher
Date Posted: 19 December 2012 at 9:49pm
*You will now be notified by email of all Replies in this Topic.

interested in the boomeganator Thumbs Up


Posted By: lost eden
Date Posted: 19 December 2012 at 9:58pm
Interested. Still got a box of parts under my bed (incluidng a 10" Fane & Face CD) from a boombox project I was planning because I couldn't justify a full boominator, but never actually built anything because I knew it would pail in comparison to a boominator... This could be the answer ;D


Posted By: roubi
Date Posted: 20 December 2012 at 10:47am
Maybe I'm gonna say something stupid but why not keeping the Amp6 in replacement of the Amp32. It is easier to solder !


Posted By: Zuk4wd
Date Posted: 20 December 2012 at 3:03pm
good idea's ,
 
i would love somthing light with maybe 2 of these drivers:
http://www.eminence.com/speakers/speaker-detail/?model=LA8_CNMBA - http://www.eminence.com/speakers/speaker-detail/?model=LA8_CNMBA
 
why is the back to back design ? 360 degree sound seems not something that i would want.


Posted By: Saturnus
Date Posted: 20 December 2012 at 6:42pm
Originally posted by Zuk4wd Zuk4wd wrote:

why is the back to back design ? 360 degree sound seems not something that i would want.

I don't want to start with Adam and Eve of simple acoustics again. It's primarily an efficiency issue. In a bipolar design the bass output from the speaker on the "back" augments the output from the "front" with 6dB under the summing frequency. In the Boominator it's at 384Hz.

In principle you could just let the drivers on the "back" play bass, and nothing else. But so much would be lost. You cannot really comprehend why a bipolar design with 360 sound is so vastly preferable  for this type of speaker until you hear it. No one who has ever heard it has said: "Great, but could I just get the sound only from the front instead". No, they all say: "Great, can I get the same sound at home if I use bipolar speakers there as well?"



Posted By: Saturnus
Date Posted: 20 December 2012 at 10:09pm

Originally posted by roubi roubi wrote:

Maybe I'm gonna say something stupid but why not keeping the Amp6 in replacement of the Amp32. It is easier to solder !

Certainly also an option. And it would fit, so no problems there.



Posted By: Zuk4wd
Date Posted: 21 December 2012 at 8:24am
@ Saturnus :
 don't want to start with Adam and Eve of simple acoustics again. It's primarily an efficiency issue. In a bipolar design the bass output from the speaker on the "back" augments the output from the "front" with 6dB under the summing frequency. In the Boominator it's at 384Hz.
 
thanx for explaining !


Posted By: alphabetikal
Date Posted: 21 December 2012 at 3:07pm
maybe instead of batteries, use super-capacitors ?! ;-)
http://vimeo.com/51873011" rel="nofollow - http://vimeo.com/51873011


Posted By: Firemedic023
Date Posted: 22 December 2012 at 1:26am
I already built an 8" version of the boominator and now have almost all of the parts on order for an original version which should be complete by February. Now I am already imaginating the glory of the Mega Boominator! It will be perfect for us since we only need about 8 hours of run time for our football and country concert tailgating events. I can't wait to see the plans!


Posted By: tcourtneyvincent
Date Posted: 06 January 2013 at 1:20pm
so when is this going to be released?


Posted By: Saturnus
Date Posted: 11 January 2013 at 7:24am

I apologize for the delay. The first two tries had to be scrapped. The originally planned one simulated fine but wasn't DIY friendly enough in that it relied on some very fancy routing. The second try where the center brace was scrapped didn't simulate to well as there'd be too much vibration in the cabinet (power lost and different effective tuning due to lower Ql value).

I think I have solved most problems now, and will simulate it. It'll be slightly larger at 200x200x700mm (length is reduced though) but will be much easier to build and have a central compartment for electronics just as the original Boominator. And that'll be the same 66mm width as well so a 12v 7ah standard SLA can be used instead of it having to be a li-ion battery. This also means you can use any amp you like as getting sufficient cooling is no longer an issue either.

I should have it ready shortly (though not today). 



Posted By: bitSmasher
Date Posted: 11 January 2013 at 7:27am
Any more hints as to the Mega? Perhaps it deserves its own thread...


Posted By: Saturnus
Date Posted: 11 January 2013 at 8:13am

I'll finish this one first before starting on the MEGA but there's at least 2 versions possible as I see it right now. The ultimate in sound quality one with pd.153.er (4 ohms) drivers as originally intended but Eminence Kappalite 3015 will also work at a lower price and lower total weight. Perfect for a "light mega". It'll not go as deep (it will be 95% equal to the Boominator in output just with +6dB in sensitivity) or have the same sound quality as with the pd.153.er drivers though but you also don't have to have minimum 6 amp channels (8 preferred) and a digital dsp like mini-dsp to run it effectively with the Kappalites. You could in principle get by with a stereo amp and passive crossover, although I'd highly recommend a 4 channel amp and active cross-over.

And, yes, I'll make a separate thread for that one.



Posted By: Saturnus
Date Posted: 12 January 2013 at 1:46pm

Drawing completed. Please read the comment field.

It's basically a back to basics Boominator design just scaled down.

http://sketchup.google.com/3dwarehouse/details?mid=965927e4830845c72ef85ac2733ed8e5" rel="nofollow - http://sketchup.google.com/3dwarehouse/details?mid=965927e4830845c72ef85ac2733ed8e5



Posted By: Phaedras
Date Posted: 13 January 2013 at 10:41am
For some reason that links didnt work for me.. But this one does:
 
http://sketchup.google.com/3dwarehouse/details?mid=965927e4830845c72ef85ac2733ed8e5 - http://sketchup.google.com/3dwarehouse/details?mid=965927e4830845c72ef85ac2733ed8e5
 
Edit: Why on earth does the forum clone the link when its posted?


Posted By: Zuk4wd
Date Posted: 14 January 2013 at 10:23am
Nice looking design,
 
what 8" drivers will work, High sensitivity ?
and what's the polarity of the rear woofers ?
 
the last question may sound stupid. but i don't get the principle of the bipolar design.
 
cardioide sub doesn't work without delay and seperate amp channels


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More sound,Less noise


Posted By: tcourtneyvincent
Date Posted: 14 January 2013 at 11:54am
The woofers are only 91db and the tweeter only 89db, why not choice something more sensitive?


Posted By: Saturnus
Date Posted: 14 January 2013 at 12:45pm
Originally posted by Zuk4wd Zuk4wd wrote:

Nice looking design,
 
what 8" drivers will work, High sensitivity ?
and what's the polarity of the rear woofers ?
 
the last question may sound stupid. but i don't get the principle of the bipolar design.
 
cardioide sub doesn't work without delay and seperate amp channels

No 8" drivers have been found that adequately satisfies the requirements that the HP10W (10") or Aura NS6 (6") does. There will not be a 8" version as I regard it as redundant.

It's bipole, so both woofers are in phase.

Cardoid subs attampts to achieve the opposite of what is required for a bipole design, and that is to control dispersion in the sub frequencies by controlling phase of the individual drivers. That naturally requires delays and seperate amps. A bipolar design is opposite, it attempts to make the whole speaker omni-polar at all frequencies.

When used outdoors a bipolar system really equals setting up an infinite in height and width virtual wall down the middle of the speaker. So in effect each side is a 2pi enviroment instead of a 4pi enviroment. Each side will also in effect have a total experienced Qts that is half of the actual Qts of the speaker. These are effects of a bipolar speaker that only relates to outdoors free air/semi-free air enviroments.  


Posted By: Saturnus
Date Posted: 14 January 2013 at 12:56pm
Originally posted by tcourtneyvincent tcourtneyvincent wrote:

The woofers are only 91db and the tweeter only 89db, why not choice something more sensitive?

91 dB/w/m is actually quite good for a $6 6" woofer. You try finding something at $6 at has the same sensitivity, and not least sound as good. The Aura NS6 actually does sound much much much better the it's price point suggests. (The low price is only due to it be a clearance sale, so better get them while they're still sold. A similar driver will not be available again for under $20).

After filtering and in the used cabinet it's actually close to 90dB/w/m over the entire range. Keep in mind that high frequencies are boosted (slightly) by diffraction which is taken into account in the design.

Remember that it has 4 of these drivers so total sensitivity for the system is around 96dB/w/m.


Posted By: tcourtneyvincent
Date Posted: 14 January 2013 at 1:00pm
Do you have plans for the design? Or do i just guess the distance apart for the driver and the size of the gap in the middle?


Posted By: Saturnus
Date Posted: 14 January 2013 at 1:07pm
Originally posted by tcourtneyvincent tcourtneyvincent wrote:

Do you have plans for the design? Or do i just guess the distance apart for the driver and the size of the gap in the middle?

?
 
The plans are above, just download them.

(They are in sketch-up format which is a free 3D design software (or at least you can download a free version), all measurements and so on are done with the measurement tool. All elements are in components, so you can just move them around as you like.)


Posted By: Pawneira
Date Posted: 14 January 2013 at 1:41pm
So what's the estimated price for all this? 

I want to build this for Roskilde Smile

Edit: Sounds awesome though!


Posted By: Saturnus
Date Posted: 14 January 2013 at 1:49pm
Originally posted by Pawneira Pawneira wrote:

So what's the estimated price for all this? 

Edit: Sounds awesome though!

That really depends. It's just a bare bones design. I'm not selling anything, so it'll depend on what price you have to pay for the drivers used (depends on freight and customs fees), if you have the wood and tools lying around, what amplifier and battery you choose, and what bling you want to add. Bling is anything from just a handle to carry it with, up to LED lights, GPS tracker (so you/the police can track it if it's stolen), and so on.
 
If you live in the States (which I don't) it could be built for around $110 including everything.


Posted By: ravni
Date Posted: 14 January 2013 at 4:19pm
Originally posted by Saturnus Saturnus wrote:

Filter is a hybrid 2.-order with L-R LP and B-W HP at 4.6Khz. No extra attenuation or compensation circuits necessary. This is due to an L-R filter being 6dB down at x-o and a B-W being 3dB down at x-o. But a pure b-W also has a 1dB lift at x-o, the hybrid takes care of that while at the same time compensation for the 3dB spike in the woofers FR between 4Khz and 5Khz. Remember to invert phase on the tweeters. Use cheap as dirt components except the cap in series with the tweeters negative pole (it's inverted, remember) which should be at least an MKP type.


Hi, will there be a schematic of this filter made public? 

ps. can't wait to make my own!!


Posted By: Edd Jordan
Date Posted: 14 January 2013 at 4:22pm
i like it. has there been any developmental in LiFePO4 battery prices as these would make it lighter. last time i looked into them though still too expensive. 



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I do a sideline in ply wood wheels.


Posted By: Phaedras
Date Posted: 14 January 2013 at 4:35pm
I'm likely to do one, do you have more info on the filter Saturnus? The impedance of the woofers seem to be around 15 ohm at the crossover frequency.. What impedance did you use to calculate the filter?


Posted By: Saturnus
Date Posted: 14 January 2013 at 4:46pm

Originally posted by Phaedras Phaedras wrote:

I'm likely to do one, do you have more info on the filter Saturnus? The impedance of the woofers seem to be around 15 ohm at the crossover frequency.. What impedance did you use to calculate the filter?

8 ohm (2 in parallel) and 4 ohm for the tweeter which is half the impedance at x-o for one tweeter.

Yes. I'll post a schematics. However, it is likely that components needs slight tweaking in values after building and testing, so any schematics posted now will have to be taken with a grain of salt as it might not be perfectly adjusted from the start. I doubt many will notice the difference though.



Posted By: Edd Jordan
Date Posted: 14 January 2013 at 5:00pm
http://www.ebay.co.uk/itm/LithiumFerrumPhosphate-LiFePo4-cell-aluminiumCasing-8Ah-/290582322953#vi-content" rel="nofollow - http://www.ebay.co.uk/itm/LithiumFerrumPhosphate-LiFePo4-cell-aluminiumCasing-8Ah-/290582322953#vi-content

These look cheap (ish)


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I do a sideline in ply wood wheels.


Posted By: Saturnus
Date Posted: 14 January 2013 at 5:14pm
Originally posted by Edd Jordan Edd Jordan wrote:

http://www.ebay.co.uk/itm/LithiumFerrumPhosphate-LiFePo4-cell-aluminiumCasing-8Ah-/290582322953#vi-content" rel="nofollow - http://www.ebay.co.uk/itm/LithiumFerrumPhosphate-LiFePo4-cell-aluminiumCasing-8Ah-/290582322953#vi-content

These look cheap (ish)

I think I saw a LiFePO4  in a standard 12V 7Ah package with built-in BMS for as low as $60 excluding freight recently.



Posted By: Edd Jordan
Date Posted: 14 January 2013 at 5:19pm
Well that is a great price i wonder if there are any 24v packs around the same price.

i love the look of the mini boominator cant wait to hear one at a festival this year.




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I do a sideline in ply wood wheels.


Posted By: Saturnus
Date Posted: 14 January 2013 at 5:54pm
Originally posted by Edd Jordan Edd Jordan wrote:

Well that is a great price i wonder if there are any 24v packs around the same price.

i love the look of the mini boominator cant wait to hear one at a festival this year.


http://www.aliexpress.com/item/12V-6ah-lifepo4-battery-lifp-battery-for-12V-equipment-lithium-12v-6ah/532694245.html" rel="nofollow - http://www.aliexpress.com/item/12V-6ah-lifepo4-battery-lifp-battery-for-12V-equipment-lithium-12v-6ah/532694245.html

That's for the one I referred to earlier.

But dig around Aliexpress. A vast number of manufacturers/resellers have emerged in the last 2-3 months.


Posted By: Edd Jordan
Date Posted: 14 January 2013 at 6:16pm
£62 with shipping not a bad price getting cheaper any how. end of thread hijack. Smile

-------------
I do a sideline in ply wood wheels.


Posted By: Pepto
Date Posted: 17 January 2013 at 9:58am
Saturnus, thank's so much for the sketchup's and all the info.  I'm planning to build a mini during the winter.

I would however want to bring the price down just a bit more - If I were to swap the Dayton tweeters for piezo horns instead, would I compromise the integrity of the box in a way that would significantly hurt the sound?  I'm thinking about going for Goldwood piezos, available for under $2 at PE (compared to $12 for the Daytons).  Is this a terrible idea? 


Posted By: Saturnus
Date Posted: 17 January 2013 at 10:13am

Originally posted by Pepto Pepto wrote:

Is this a terrible idea?

Yes. I think it is but I can't stop you. Just note that you have to dampen the piezoes by several dB. (A series resistor does not dampen a piezo).

Btw, I just noticed that Intertechnik also has the Dayton tweeters in stock at a good price (€10 each) which is a good deal cheaper than buying them in the States when custom fees and VAT is considered.

http://https://www.intertechnik.de/Shop/Lautsprecher/Dayton/Dayton-Hochtoener/_70303_H28-ND16FA-6_1768,de,7054,53103" rel="nofollow - http://https://www.intertechnik.de/Shop/Lautsprecher/Dayton/Dayton-Hochtoener/_70303_H28-ND16FA-6_1768,de,7054,53103

Appearantly Loudspeakershop has them even cheaper at €8½ each. That's cheaper than PE even in retail.

http://lautsprechershop.de/index_hifi_en.htm?lautsprechershop.de/hifi/dayton_en.htm" rel="nofollow - http://lautsprechershop.de/index_hifi_en.htm?lautsprechershop.de/hifi/dayton_en.htm



Posted By: Pepto
Date Posted: 17 January 2013 at 11:07am
You saying its a terrible idea would definitely stop me :)  Piezos worked well in the original boominator, so i thought they might work for the mini as well. I will stay with the Daytons now tough.

Thanks for the shop tips. I will try and find cheap stores closer to Sweden (within EU at least).




Posted By: Saturnus
Date Posted: 17 January 2013 at 8:32pm

0.56mH inductor should be below 0.4 Ohm series resistance.
5.60uF capacitor should be MKP or MKT type



Posted By: Edd Jordan
Date Posted: 17 January 2013 at 11:29pm
How do you sum your signal to get mono? or is the mini run in stereo and this is just one channel? 



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I do a sideline in ply wood wheels.


Posted By: Saturnus
Date Posted: 17 January 2013 at 11:38pm
Originally posted by Edd Jordan Edd Jordan wrote:

How do you sum your signal to get mono? or is the mini run in stereo and this is just one channel? 

The latter.



Posted By: Saturnus
Date Posted: 18 January 2013 at 3:00pm
Originally posted by Pepto Pepto wrote:

Thanks for the shop tips. I will try and find cheap stores closer to Sweden (within EU at least).

europe-audio, intertechnik, and lautsprechershop as I have linked to are all German which last time I checked was in the EU. Intertechnik has an impeccable customer service. Haven't done business with the other two so I couldn't say for them.


Posted By: Kostecki
Date Posted: 20 January 2013 at 10:00pm
Great project - can wait to see what people come up with Clap

Holding on for the mega version.


Posted By: Brummiejon
Date Posted: 29 January 2013 at 10:11am
Hi
I know that this is a thread about the Boominator Mini, I am planning to build a full Boominator and as I am UK based, I'm having trouble sourcing the drivers.....
 
The following may be useful to any UK builders of either the mini or full boominator so I thought that it would be worth posting...... moderator can delete if you disagree..............
 

Hello All

I am a complete noob here, I'm not well versed with speaker enclosure design, I'm not well versed in electronics but I am perfectly capable of sound engineering, soldering and I can recone speaker drivers, so I'm a noob in some ways but OK in others.....

I'm based in the UK, I want to build a boominator and stay true to the original design because Saturnus, quite obviously knows more about enclosure design and electronics than I.

However, P.Audio may be based in the UK and “Blue Arran” are their UK distributor but you cannot get the HP10W here......

I wrote to Blue Arran for advice on potential replacements and I really helpful guy called Jon Harriman sent this reply...... I thought that some of the readers of this forum would find it useful.........

Thank you for your enquiry. Looking at the available info on the Boominator, the speaker selection doesn't actually seem to have been a particularly critical part of the design of the box - quoting from the original diyaudio thread, "I used 4 P.Audio HP10W woofers because they're cheap, sounds great, and not least because they had the perfect depth for magnet to magnet mounting". It looks less as if the box has been designed to work specifically on the back of a particular driver, and far more as if that driver has been chosen as a matter of convenience, and the lack of a wealth of other drivers listed on the website is more a case of low end-user feedback on the matter rather than other drivers being technically precluded.

The box has been tuned to 82Hz, and is functioning as a straightforward bass reflex enclosure, so realistically you will have successful results with any 10" driver of suitable size and power handling, with a resonant frequency lower than the tuning frequency of the box. P-Audio's SN-10MB, which is also listed as being suitable, has a mounting depth of 122mm, so I'll take that as the maximum depth (both the original choice and the Eminence S2010 have a depth of 109mm).

Regarding the loudspeaker options listed on the Boominator site - we can't, unfortunately, get hold of the Goldwood driver at all, I believe this is solely available in the US market.

HP-10W - P-Audio now only make this driver to order. Whilst we are P-Audio's UK importer and distributor, we would need an undertaking for an order of 12 off drivers, and would be on an lead time of approximately six months from point of order.

SN-10MB Series II - This is still available from P-Audio, but unfortunately we don't have any in stock at the moment, so again we'd be looking at quite an extensive lead time (probably 3-4 months absolute best).

Eminence Basslite S2010 - Again, not in stock on the shelf, but available on a shorter lead time than the P-Audio options, usually around 2 weeks or so.

 

Recommended options:

http://www.bluearan.co.uk/index.php?id=PAUE10200S - http://www.bluearan.co.uk/index.php?id=PAUE10200S P-Audio’s E10-200S performs extremely well – resonant frequency of 73Hz, around the same as the SN-10MB. The quoted sensitivity figure of 93dB is actually quite misleading, it performs significantly better than that, and will actually deliver 100dB-plus across almost everything from 100Hz right up to 5kHz. Checking out the spec sheet, the E10-200S significantly out-performs the SN-10MB in many respects, with the exception of the Xmax being a little lower and the fact that it’s a heavier driver. Depth 109mm. Available from stock.

 

http://www.bluearan.co.uk/index.php?id=EMIDEL10A - http://www.bluearan.co.uk/index.php?id=EMIDEL10A Eminence Delta 10 – 350W RMS will also work , resonance 66Hz, 98.8dB/W. Depth 108mm, available from stock.

 

Incidentally, for the tweeters: Motorola sold their piezo production line over a decade ago, and production has since passed through several hands. Currently available in the same profile as the KSN1001A is this:

http://www.bluearan.co.uk/index.php?id=SKT900298 - http://www.bluearan.co.uk/index.php?id=SKT900298

 

I note that Saturnus also recommend use of P-Audio’s PHT-407N tweeter. The sound of this high frequency horn and driver is significantly more refined than you’ll be able to achieve from piezo drivers, and if budget will allow, it’s definitely worth looking at. One caveat, though – it will need a crossover, whereas the piezo driver will not. Here’s the PHT-407N:

http://www.bluearan.co.uk/index.php?id=PAUPHT407N - http://www.bluearan.co.uk/index.php?id=PAUPHT407N

 

Obviously, this guy is at work and doesn’t have time to read all of the threads here, so I put him right about a couple of issues (ie, the drivers being an integral part of the box structure) and this was his reply back....

“Glad to help. Obviously I don’t have unlimited time, so hadn’t looked into the project as far as the construction details, and hence was unaware of the structural nature of the driver coupling. As you say, it’ll help make for a compact box, but that’s going to be a nightmare if you blow one! In light of the info, though, the SN-10MB doesn’t seem to make a lot of sense as it’s around half an inch deeper per driver. Not insuperable, but something to take into account when building.

Fortunately, both of the drivers I’ve recommended are around the 108-109mm region, as (or at least so it would appear) per the HP-10W. Interesting claim regarding the idea of the magnets coupling – not sure how effective that would actually be in practice, particularly with the pole pieces in place. Incidentally, indoors or outdoors is largely irrelevant – although setting up near walls/corners can reflect sound which would otherwise be disappearing in an unproductive direction.

 

You’re absolutely right, the E10-200S is heavier than your original choice, actually by 1.4kg. Frankly, I’d say for the extra 5.6kg per box, it’s well worth it, you’re getting better power handling and significantly better sensitivity (as I say, ignore the quoted 93dB, it’s wildly misleading at best). Delta 10 actually a little heavier; decent enough driver, but I think you’ll get more mileage from the E10-200S.

 

Eminence Gamma 10 should work too, and are at a pretty keen price: http://www.bluearan.co.uk/index.php?id=EMIGAM10A - http://www.bluearan.co.uk/index.php?id=EMIGAM10A 

 

And Fane’s Sovereign 10-125 is another option, although a little shallower, so you may need to rebate the driver into the baffle to compensate: http://www.bluearan.co.uk/index.php?id=FANSOV10-125 - http://www.bluearan.co.uk/index.php?id=FANSOV10-125

 

There are a LOT more drivers to choose from, what I’ve put forward here is really the budget end of the market. Budgetary constraints are realistically likely to rule out both the Eminence S2010 and the SN-10MB – this is a knock-on effect from the  automotive industry using a lot of neodymium in motors for hybrid vehicles, which has largely priced it out of the market fro speaker magnets unfortunately.

 

Tweeters – piezos are actually remarkably efficient, and as they don’t need a crossover they make for a very straightforward solution. As cheap drivers which need no other fittings except arguably a resistor, they’re extremely hard to beat on the cost-front. On the other hand though, with a suitable crossover in place a tweeter won’t affect the resistance of your box overall – your biggest hassle will be finding an off-the-shelf crossover designed for a 4 ohm woofer and an 8-ohm tweeter. Building your own is a lot less difficult than some people will make out, but of course this may well be an avenue you’re not keen to explore. Tonally, you’ll have a far nicer box with the PHT-407N, but whether it’s worth the expenditure and effort is entirely your call.”

 

So, this has given me plenty to consider, I still have to go for the budget option because a boominator lite or a signature boominator is going to be too pricy for me (Looking at £700+).  I may have to swallow the extra weight and try the P.Audio E10-200S. It may be well be worth a punt........

 

Comments more than welcome



Posted By: Phaedras
Date Posted: 29 January 2013 at 1:02pm
I have a few comments Brummiejon..

1. The HP10w is easy to come by, Intertechnik in Germany sells them and i'm sure they would be glad to ship them to you...

2. Taking advice on which drivers to use from a guy with absolutely no clue to the design, is silly.

3. You should post this in the Boominator thread on diyaudio or in a separate thread here as its not really relevant to the Boominator Mini thread :)

4. Ofcourse there are a lot of drivers that are louder and perhaps better sounding than the HP10w but they come with a much bigger price-tag.. The reason for using the HP10w is because, for the price, you get an excellent quality woofer which fits the design and constraints of the Boominator perfectly.. If you wanted to put a 2x300w amp in the Boominator, then forget about the HP10w as it will run out of xmax before you could put 100w into it.. However, as the boominator is designed around long battery life with small amps the limits of the HP10w fits perfect - as you dont need any more..

5. A lot more can be said, but I think you should bring the discussion elsewhere :)

Happy building!




Posted By: Brummiejon
Date Posted: 29 January 2013 at 1:49pm
OK, thanks


Posted By: markg
Date Posted: 29 January 2013 at 9:07pm
Has anyone built a boominator mini yet?   I just ordered the components today. I will use it outdoors but also in the hockey arena locker room. Any changes to the design advised for use indoors?


Posted By: Saturnus
Date Posted: 29 January 2013 at 9:53pm
Originally posted by markg markg wrote:

Has anyone built a boominator mini yet?   I just ordered the components today. I will use it outdoors but also in the hockey arena locker room. Any changes to the design advised for use indoors?

Not to my knowledge but 4-5 people are in the process of doing so. No change for indoors use. It's designed to be usable both indoors and outdoors. 



Posted By: markg
Date Posted: 29 January 2013 at 9:55pm
thanks. i'll post pictures of the build soon.


Posted By: EOM
Date Posted: 30 January 2013 at 6:03am
Saturnus, Thank you for  the work in putting this together.
I have ordered the drivers for a Mini Boominator and plan to get started on a build soon. Plan on using either a modded Lepai or YJ TA2020 for the Amp.

A couple of ideas have been rattling around after reading the Boominator thread.
1) Are there drivers out there that would make a completely waterproof version for VERY wet activities such as Kayaking, Rafting or Sailing where the box might get dunked? The Mini box seems to be a good candidate since it is a sealed box design and small enough.
2) Has anyone thought about making the halves separable? I did not see it on the boominator thread in DIY (may have missed it!). What effect does  the center box have on the acoustics of the speaker boxes and would this preclude the idea? Still a noob at this stuff.
 


Posted By: alphabetikal
Date Posted: 30 January 2013 at 9:42am
Saturnus - you should put this in a wiki ? This thread is going to get massive and then its very hard to find the info needed etc.
Unless you dont have time to do that, in which case i think some one should volunteer to do it who knows how to install the software and got a few hours a week to run it.
Or could it go into the boominator wiki some how?


Posted By: billyturf
Date Posted: 30 January 2013 at 10:25am
Saturnus,

Is there an alternative for the AURA NS6, because shipping to EU costs more than the actual speakers?

Thx.


Posted By: Phaedras
Date Posted: 31 January 2013 at 9:55am
Originally posted by billyturf billyturf wrote:

Saturnus,

Is there an alternative for the AURA NS6, because shipping to EU costs more than the actual speakers?

Thx.

No, and since the price of the speakers are so incredibly low, even with the shipping they are cheaper than alternatives in Europe :)


Posted By: Phaedras
Date Posted: 31 January 2013 at 9:59am
Originally posted by alphabetikal alphabetikal wrote:

Saturnus - you should put this in a wiki ? This thread is going to get massive and then its very hard to find the info needed etc.
Unless you dont have time to do that, in which case i think some one should volunteer to do it who knows how to install the software and got a few hours a week to run it.
Or could it go into the boominator wiki some how?

I'm actually running a WIKI over on boominator.dk aswell as the facebook page, so hop on over and add info if you like.. Ill update from time to time :)


Posted By: TIP220
Date Posted: 02 February 2013 at 9:57am
Hi Folks 
after lurking and thinking about a build for a while, the concept of a mini boominator fills all my criteria. So I have signed up especially to have a go at one myself. 
I ordered all drivers from PE and await their delivery. I would consider myself more than handy with the construction and build aspect of the project, however I will hold my hands up to be a complete edjut when it comes to the electrical side.
I will obviously upload pics as the project progresses but will be asking all sorts of newbie questions when it comes to wiring it all up.
looking forward to the adventure.


Posted By: TIP220
Date Posted: 11 February 2013 at 7:40pm
speakers have arrived from PE but I was a prat and managed to only order 2 tweeters.
so I will have to pay postage from Europe-audio, is it possible to buy the correct inductors and cap components from them? I can find the inductors but the 5.6 MKP cap seems elusive. can anybody point me in the correct direction.
I have 're-worked' the CAD model to make use of CNC equipment I have access to. I have kept the internal volumes identical, but have gone with 12mm Birch 9ply (kept the bracing 9mm). My concern is that once glued the will be no way of easily accessing the drivers. How reliable are components and how much should ease of access be considered ? Anybody suggestions or comments are welcome. I am very much an amateur when it comes to speakers. 
TIP220
 


Posted By: Saturnus
Date Posted: 11 February 2013 at 8:04pm

You can get tweeters, coils, capacitors etc from  http://www.intertechnik.com/" rel="nofollow - http://www.intertechnik.com/

Just use a MKT cap. They're fairly cheap.

According to CATIA simulations there's not much reason for using 12mm over 9mm with the suggested bracing structure. However, I suppose it wouldn't hurt to make the baffles 12mm.

Just make sure that everything is working before closing the box the last time. Triple check everything. There should be not reliability issues at all if everything is connected and soldered together correctly. It'll easily last years and years.

The weak point is the electronics compartment in the middle. Make sure you can access that and change the battery or amp if you're unlucky. I would not worry at all about the speakers.

One of the first prototypes of the Boominator still works perfectly, and is touring festivals, brought to beach parties, bbqs, company events etc every year, and have been so since 2005. Sure it's looks battered but it still works fine.



Posted By: Pepto
Date Posted: 12 February 2013 at 10:20am
Originally posted by TIP220 TIP220 wrote:

... I can find the inductors but the 5.6 MKP cap seems elusive. ...

I ended up ordering tweeters and cross over components from Europe-Audio.  I chose this cap for the 5,7uF  http://www.europe-audio.com/Product.asp?Product_ID=8951
Seeing as i'm a complete amateur myself, i simply hope this was a good choice :)


edit. what's up with the hyperlink?


Posted By: EOM
Date Posted: 12 February 2013 at 5:29pm
I have completed initial build out and have tested the basic set up before final paint and gluing up the box. Decided to use biscuits for ease of assembly. Only build observation I might make is to double check assembly order you want to use. Next time I would consider rearranging material to set the top and bottom as last pieces to put together.
It sounds pretty decent Thumbs Up. The center box is a little crowded with the crossovers, amp and wiring (I ran everything there in case I want to play later). Still trying to find a reasonable battery. There is a possibility of getting a friend to run a curve on it. I will let you know if it happens.
The forum will not allow me to post a photo directly. Its only a clamped up primer box at this point anyway. 
 


Posted By: menace
Date Posted: 13 February 2013 at 3:43am
As to waterproof speakers. I think you could spray them with something perhaps. Pretty sure i have seen some well respected names in the diy audio world spray speaker cones with coatings before........ Dunno if you could do a good enough job to take them scoober diving though;-)


Posted By: menace
Date Posted: 13 February 2013 at 6:40am
Great to see this project in the making Saturnus. As, for me the 10 inch format was never interesting, just too big for what I was ever gonna use it for. And i am in the process of doing one my self based around a set of 6 inch car audio components and some lifepo4 cells. Although I think I might give your suggested drivers ago now, I have seen both of them mentioned before but never really taken much notice until now. Great sensitivity in that aura for a six.

Also, about the 9800mah li-ion battery you mentioned in your initial post, did you have a particular battery in mind, if so can you link that? Also, what were you thnking amp wise when you were thinking about li-ion, doesn't 4s start to get high in voltage for these 12v tripath amps and 3s would be unproductive??? Just interested as to what you had in mind there.

Another thing actually. Whats made you not decide on the amp6 from the start? Seems to me to be the logical choice.

Cheers, Menace.


Posted By: Saturnus
Date Posted: 13 February 2013 at 7:57am

You can spray the cone very lightly with impregnating silicone for added resistance to the elements. However, it is far better just to avoid water/sand coming into contact with the driver in the first place. You can do that by using a grill, either a fine mesh grill which can be difficult to find in the right size, but I also very much favour using a standard punched grill where you first take the rubber ring off, spray the top side with contact glue, glue on a speaker cloth of your liking, cut away excess, and lastly put the rubber ring back on. Remember, the grill goes on the inside, between the woofer and the baffle.

While we're on the subject of the baffle. If you have the wood lying around, you can make the baffles of 12mm instead of 9mm without changing the outside dimensions. The result is a slightly improved stiffness, slightly higher weight, but most importantly it will make the drivers fit without any gaps between the magnet and the center brace. The grill with rubber ring will probably be slightly more than 1mm, usually about 1.2mm, but it easily compresses. It will not have any significant effect on tuning due to smaller cabinet volume (it's less than 1/3 of a liter smaller).

Baffles = 2x 12mm, brace = 9mm, grills with rubber ring = 2x 1mm, woofers 2x 82.5mm. Total = 200mm.

Please note. I think I forgot to mention this before but I advise the cabinet to stuffed medium hard with acoustic wool.

I didn't use the amp6 because the original idea called for an fully closed enclosure where all drivers shared the same volume. With the change to a design with a central electronic enclosure that is no longer applicable. Adjust the size of the electronic compartment as you see fit to suit whatever battery and amplifier you choose. Remember to keep the speaker cabinet volume roughly the same size so adjust overall length accordingly.

The 9800mah li-ion is one similar to this  http://www.aliexpress.com/store/product/New-DC-12V-Portable-9800mAh-Li-ion-Super-Rechargeable-li-on-Battery-Pack-for-wireless-transmitter/803611_564472693.html" rel="nofollow - http://www.aliexpress.com/store/product/New-DC-12V-Portable-9800mAh-Li-ion-Super-Rechargeable-li-on-Battery-Pack-for-wireless-transmitter/803611_564472693.html . It's 3 cell, so nominal voltage is between 10.8V and 11.4V. That works fine with any TA2020, TA2021, and (to some degree) TA2024 amp. The lower voltage of a 3-cell battery pack is actually a blessing in disguise as it makes a TA2024 amp capable of running a 4 ohms load which it would not do optimally on 12V or higher voltage. But you can use whatever battery you like. The electronic compartment is now sized so that it can host a standard 12V 7Ah SLA.

The amp I currently favour using for my own build is this  http://www.ebay.com/itm/TA2024-MKV-Bluetooth-Tripath-amplifier-2X-15-Watts-12V-fully-finished-/251221801085?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item3a7dfc787d" rel="nofollow - http://www.ebay.com/itm/TA2024-MKV-Bluetooth-Tripath-amplifier-2X-15-Watts-12V-fully-finished-/251221801085?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item3a7dfc787d . Combined with the battery above and laid on it's side I can cut 34mm of the width of the electronics compartment making the overall length 666mm. Please note that for that to fit, you need to replace the large input caps on that amp to something more suited for a class D amplifiers, like standard small WIMA or EPCOS MKP types (the large caps are passive loudspeaker filter caps, they're not suited for places where they can and will receive large amount of RF noise). I favour this amp primarily because of the built-in bluetooth audio module which naturally isn't terribly good for critical listening like all bluetooth audio recievers but for use as a portable audio player, it's an absolute gem as you can just stream the music directly from you phone instead of having to worry about cables.




Posted By: Larzman
Date Posted: 21 February 2013 at 3:14am
Thanks for the new design Saturnus. I've been lurking around the Boominator thread for awhile and always wanted something smaller. This 6" will travel very well :)

Only thing I'll add/change is the power system, a little "functional bling" if you will. It's convenient to have a light, USB phone charger jack or whatever when your away from AC power. A pair of small 5W solar panels and a charge controller might be handy. Hope I can fit what I want in the center section. That's where Aliexpress and/or eBay are handy sources for prebuilt small circuits & connectors.


Posted By: Larzman
Date Posted: 22 February 2013 at 3:37pm
For those considering the 9800mAH LiPo battery in Saturnus's link, here's one of the feedbacks about this seller:

"I ordered 3 batteries. One of the batteries arrived damaged. The packaging was flimsy, and there was a tear in packaging where the damage had occurred. They refunded 50% of the single damaged battery after I sent them photos of the damage. I tested the capacity of the other batteries. It was only around 3400mAH, around one third of the advertised rate. On contacting the seller on this second issue, at first they questioned my testing method (I discharged the battery through a known resistor to get the current, then measured how long til the voltage dropped below 9.5V, to get the hours, then multiplied them to get mAH. The battery lasted about 28 hours at a discharge current of 0.12A). After discussion they eventually admitted the capacity was much less than 9800mAH. However they refused any discussion on any further reimbursement. The seller is polite, but overall the experience was negative. The battery is not very quality in build and its capacity is way below its advertised rate."

Granted, it's only 1 review, but as with anything you get from Chinese sources, be wary of their claims. I have bought several items through Aliexpress from China and had very good luck, but do some research before you spend your cash, it may save you some grief. I have also seen several critical reviews about the Hittime store on Aliexpress. Proceed with caution.

When I do another order for a 9800mAH LiPo, I'll post results.


Posted By: Saturnus
Date Posted: 22 February 2013 at 4:08pm

It's not that relevant as you can't actually order them anymore.

The new international regulations prohibits the transport of lipo batteries of this size unless they are UN38.3 approved. Such an approval costs money, and none of those low-cost models we have usually bought will pass anyways so it's a dead-end I'm afraid.

Good thing I designed it to be able to hold a standard SLA size so I can get a proper lifepo4 battery instead.



Posted By: Larzman
Date Posted: 22 February 2013 at 4:36pm
Crap, you are correct Saturnus. I did some research and here's the link for USPS restrictions, effective January 1, 2013 - http://about.usps.com/postal-bulletin/2012/pb22336/html/updt_012.htm

Don't know where to source them now, but LiPo's are the best for portable devices and I'll see what I can find for new sources of inexpensive batteries.


Posted By: KWB75
Date Posted: 22 February 2013 at 5:08pm
I ordered one of those batteries (from the link Saturnus posted) last week, recieved an email today confirming my order has been shipped. Who knows what'll happen now!...


Posted By: slaz
Date Posted: 22 February 2013 at 5:10pm
Originally posted by Larzman Larzman wrote:

Crap, you are correct Saturnus. I did some research and here's the link for USPS restrictions, effective January 1, 2013 - http://about.usps.com/postal-bulletin/2012/pb22336/html/updt_012.htm

Don't know where to source them now, but LiPo's are the best for portable devices and I'll see what I can find for new sources of inexpensive batteries.


Yeah - and (at least some of) they haven't altered the ebay listing, and presumably are still taking orders. They had my money for a week or so ... and didn't give a reason for not being able to supply/ship.

There's an outfit in the UK that seems to have stock of the "6800mAh" cased ones - but double the price - so no longer such a bargain .... buying 2 would cost almost the same as a lifepo4 7Ah.

Even though the 7Ah lifepo4 is almost certainly superior quality, I might choose 2 x 6800mAh CCTV ones for pure convenience when it comes to highly portable "walk-with-it" systems.


-------------
REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON


Posted By: Svampan
Date Posted: 23 February 2013 at 6:46pm
Subscribed to the thread, very interested in seeing how the mini unfolds!


Posted By: MortenR
Date Posted: 25 February 2013 at 1:54am
..


Posted By: TIP220
Date Posted: 25 February 2013 at 7:52pm
well things are going well, all panels now cut and routed , and painted/ lacquered before assembly, Photos to follow!
a few questions/advise before I do assemble, would it better to mount the crossover components to a board and fix in the main speaker box or in the center section? (assuming they will fit with the SLA and amp???)..  Im still waiting on the amp arriving, I went for this  in the end
http://www.ebay.co.uk/itm/330549329451?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 - http://www.ebay.co.uk/itm/330549329451?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
 hopefully that will work.
I am working on a charge indicator light and usb socket. I will upload pics later in the week when I start assembly.
enjoying building thisSmile
edit - trying to get link to work, but still not ???


Posted By: Saturnus
Date Posted: 25 February 2013 at 7:58pm

Depends on whether you plan to do some tweaking of the filter as the design matures. Or if you trust my calculations and experience to have nailed the optimum filter.

I did earlier in this this thread warn that the filter may be tweaked slightly but in any case I expect it to be very minor tweaks, and that the filter, as is, will do it's job well enough for most people not to notice any difference at all.



Posted By: davey t
Date Posted: 25 February 2013 at 8:41pm
Next time you test a battery capacity, use a constant current load. this is simply a Lm317 device + resistor which can be bought from maplin. 

You can do it with a resistor if you graph the voltage and integrate the varying current... 

Finally, if you want a good lithium ion battery pack, just buy an RC pack and RC charger. Simple


I can't fnd the plans or any drawings anywhere on this thread. The link didn't work. Am I missing something? 



Originally posted by Larzman Larzman wrote:

For those considering the 9800mAH LiPo battery in Saturnus's link, here's one of the feedbacks about this seller:

"I ordered 3 batteries. One of the batteries arrived damaged. The packaging was flimsy, and there was a tear in packaging where the damage had occurred. They refunded 50% of the single damaged battery after I sent them photos of the damage. I tested the capacity of the other batteries. It was only around 3400mAH, around one third of the advertised rate. On contacting the seller on this second issue, at first they questioned my testing method (I discharged the battery through a known resistor to get the current, then measured how long til the voltage dropped below 9.5V, to get the hours, then multiplied them to get mAH. The battery lasted about 28 hours at a discharge current of 0.12A). After discussion they eventually admitted the capacity was much less than 9800mAH. However they refused any discussion on any further reimbursement. The seller is polite, but overall the experience was negative. The battery is not very quality in build and its capacity is way below its advertised rate."

Granted, it's only 1 review, but as with anything you get from Chinese sources, be wary of their claims. I have bought several items through Aliexpress from China and had very good luck, but do some research before you spend your cash, it may save you some grief. I have also seen several critical reviews about the Hittime store on Aliexpress. Proceed with caution.

When I do another order for a 9800mAH LiPo, I'll post results.


-------------
Minirig portable soundsystem movement


Posted By: TIP220
Date Posted: 25 February 2013 at 8:48pm
Originally posted by Saturnus Saturnus wrote:

Depends on whether you plan to do some tweaking of the filter as the design matures. Or if you trust my calculations and experience to have nailed the optimum filter.

I did earlier in this this thread warn that the filter may be tweaked slightly but in any case I expect it to be very minor tweaks, and that the filter, as is, will do it's job well enough for most people not to notice any difference at all.


it is not trust in you that is required (that is a given) but in my ability to purchase the correct bits .
this was my shopping list from intertechnik
1     2       1381920             ND16FA-6                                10,10 Euro      20,20 Euro
2     2       1500100             CO30/056/080                            5,70 Euro       11,40 Euro
3     2       1500058             LU25/022/050                            1,30 Euro       2,60 Euro
4     2       1341036             EGL/2.2/50/5                            0,95 Euro       1,90 Euro
5     2       1341190             MKTR/5.6/100                            2,50 Euro       5,00 Euro

are there any glaring errors there ??? if not if there is not space in the centre section, I'll seal them in.
thanks for the help
TIP


Posted By: Saturnus
Date Posted: 25 February 2013 at 9:02pm

Originally posted by davey t davey t wrote:

Finally, if you want a good lithium ion battery pack, just buy an RC pack and RC charger. Simple

I can't fnd the plans or any drawings anywhere on this thread. The link didn't work. Am I missing something?

This link's not working?  http://sketchup.google.com/3dwarehouse/details?mid=965927e4830845c72ef85ac2733ed8e5" rel="nofollow - http://sketchup.google.com/3dwarehouse/details?mid=965927e4830845c72ef85ac2733ed8e5 if not, then just google "boominator mini sketchup"

An RC li-ion pack however will probably set you back more than a lifepo4. And those are much better quality.


Posted By: Larzman
Date Posted: 26 February 2013 at 1:32am
I was about to say the same think Saturnus. If Davey knows of a source to supply 12.6V 6800mAH LiPo batteries for $16 (inc. shipping), then I hope he will post a link... or for the 9800mAH ones for under $25


Posted By: Larzman
Date Posted: 26 February 2013 at 2:06am
I'm tempted to order this and tear it apart to see what the batteries are, hoping it has 12V, but I doubt it. probably a pair of 3.7V LiPo's.

http://www.aliexpress.com/item/20000mAh-Universal-Backup-USB-Battery-Power-Bank-External-Battery-Pack-Charger-With-Retail-Package-1pc-Free/724947297.html?err_biz_type=null&url_type=wto_buyer360_title&biz_type=sitePromo_wto_buyer360_alert&crm_mtn_tracelog_plan_id=1320339828&crm_mtn_tracelog_task_id=22763967&crm_mtn_tracelog_log_id=3193975965


Posted By: enal
Date Posted: 26 February 2013 at 3:57am



[QUOTE=Saturnus

]You guys in the UK can benefit from HobbyKing prices on batteries. They have a really nice selection on lipo packs and even have lifepo4's now.
I fly Eletric RC Helis that pull some crazy loads(45-80C) all within 5-7 minutes of flight and get fast charged at 20amps and back in the air.  We punish these poor batteries and they last for a couple flight seasons or more so I'm thinking of putting something together off of some of my packs that the Internal Resistance has gotten worse.  

The question I have for Saturnas and the other Boomies is...Why just use 12vlt and not 18vlt or 24vlt ?  Since the amps can handle the high
er voltages and the output increase..? or is it just an efficiency item going with the 12vlt?  

A 3s(3cell) pack is 11.1vlt, 4s(4cell) pack is 14.4, 5s is 18.5vlt and 6s is 22.4 etc...The chargers available from HobbyKing are fairly cheap as well, but probably the SLA battery is the most economical.  One thing that I wouldn't recommend unless you really know what you are doing is using a solar charging source with the lipo's.  I've personally witnessed a couple disasters with one being a pilot burning down the brand new family mini van. Never saw him at the flying field again!  The solar charger with an SLA may be a safer choice.

Typicallly with the RC packs it is cheaper to go with a higher voltage pack with a little less capacity so it's a toss up some times, but the clearance sales would be good to check out.  The SLA's seem to be fairly cheap, but heavy and the lipo's are really light buy not cheap so it ends up being which is more important cost or weight. 

There is also the A123 cells that I've seen some pretty cool large power packs built from, but again can be expensive unless you go with a large quantity purchase.

I've even thought of retrofiting a 12-18vlt drill battery and charger in the mix, but wasn't sure if the capacity would really be worth it. ???

I'm anxious to get started on mine with the Mini ClassDAudio Amp, but still trying to plan it out without getting too tied up in the details...














Posted By: enal
Date Posted: 26 February 2013 at 4:05am
Sorry for the weird spacing on the post above...My tablet is acting up a bit..!


Posted By: Saturnus
Date Posted: 26 February 2013 at 7:16am

The Boominator MINI is relatively tiny compared to the Boominator. 5 times smaller to be exact.

The recommended amps runs 12V only. Naturally one could use an amp with which takes higher voltages but I'd recommend against it. If you do, you must insert a higher order high pass sub cut filter to ensure the driver excursion limits are not exceeded.

As for choosing battery, I strongly recommend using a lifepo4 battery if you can under any circumstance afford it.



Posted By: Saturnus
Date Posted: 26 February 2013 at 7:35am

Originally posted by Larzman Larzman wrote:

I'm tempted to order this and tear it apart to see what the batteries are, hoping it has 12V, but I doubt it. probably a pair of 3.7V LiPo's.

No point. Weight is 450g. That means you already know the maximum capacity it could have is far far less than what is advertised.

Let's assume the battery cells is 2/3rds of that weight. Li-Po energy density is on average 165Wh/kg for the actual battery without any electronics and packaging. That's means the maximum capacity it could have is 50Wh. Divide that with 3.7V for nominal cell voltage, and you end up with 13380mAh capacity. It's probably not even close to that in reality though.



Posted By: Larzman
Date Posted: 26 February 2013 at 1:45pm
Yep, you are correct Saturnus. I thought about it after posting, then figured the true WH would be much less than 20 when you consider they are rating it at 5V, not 12V. I checked on Alibaba last might and it looks like LiPo's price has gone up, wish I would have bought 10 of them when I got the great $16 deal. I've already used a few on other projects, and want to keep those alive. However, the MiniBoom is a really important project, so I might make them swappable into it until I can find some inexpensive ones again.


Posted By: TIP220
Date Posted: 26 February 2013 at 9:39pm

well my amp arrived today so managed a trial fit, mostly to make sure that all the bits fit.

So far so good , I still have a fair bit of thought to go into how to package the electronics.

 I am not really going for a festival sound-system but something that will see slightly lighter duties, therefore I don’t intend to fit grills to the drivers. I am really happy with the quality of finish I have got so far, the baffles paint job is gorgeous in direct sunshine (ford electric orange)

Anyway onto the pics








Posted By: Saturnus
Date Posted: 26 February 2013 at 10:26pm

Looks great. Gorgeous even.

Although I still think the 12mm plywood you have use may be a bit too think for this build but I don't see it have a negative effect, so why not?

Are the drivers excellent quality? Especially considering their price?

Those blue caps are huge Big smile 



Posted By: Larzman
Date Posted: 27 February 2013 at 1:40pm
Box looks great TIP. I'm wondering, what type of primer/paint did you use to get such a clean, glossy finish? Was it buffed out before application of a final clearcoat?


Posted By: Kostecki
Date Posted: 27 February 2013 at 4:29pm
I'm with Larzman on that one, and would also like to know some more about that paint job Big smile


Posted By: TIP220
Date Posted: 27 February 2013 at 5:58pm
the finish was all achieved using standard car paint in rattle cans.
first start with a high build 'filler' primer, after a couple of pretty heavy coats to fill the grain of the ply it was wet sanded with 1200 wet&dry paper, next was a couple of coats of white primer (this stage is only necessary because of the pearlescent orange colour) 
again a brief flatting back using 1200 grit paper. next was 3 coats of colour (because it was pearlescent you CANNOT sand this) then onto clear lacquer, again several coats let it dry for 48 hours then a gentle wet sand with 1200 grit and then a final coat of lacquer.
I sprayed in my shed but had a fan heater on to get the temperature in the shed up to about 40C.
I have used this technique for furniture I have made in the past and it does make for a hard wearing finish, but you MUST let the lacquer harden for several days before rough handling or you will leave finger prints in the surface.
glad people like itThumbs Up , more pics to follow when I get time to start assembling
TIP 


Posted By: lost eden
Date Posted: 27 February 2013 at 6:08pm
Would there be anything to stop me building a *half* mini boominator? Obviously the input would have to be summed to mono & the battery/electronics compartment would make it heavier at one end & non symmetrical, but it would be supremely portable & still probably put out a decent bit of noise?


Posted By: TIP220
Date Posted: 27 February 2013 at 8:38pm
Originally posted by Saturnus Saturnus wrote:

Looks great. Gorgeous even.

Although I still think the 12mm plywood you have use may be a bit too think for this build but I don't see it have a negative effect, so why not?

Are the drivers excellent quality? Especially considering their price?

Those blue caps are huge Big smile 


I will have to weigh it all at some point but going by the pick it up test it certainly does not feel 'heavy'
The drivers to look and feel like well put together items. I would have preferred a rubber surround rather than foam, but only because I have had too many go rotten but I'm sure there is a good reason.


Posted By: davey t
Date Posted: 27 February 2013 at 8:41pm
Originally posted by Larzman Larzman wrote:

I was about to say the same think Saturnus. If Davey knows of a source to supply 12.6V 6800mAH LiPo batteries for $16 (inc. shipping), then I hope he will post a link... or for the 9800mAH ones for under $25

I wouldn't risk paying this little for a lipo of that size... and as you have found out, the capacity isn't as high as stated. Plus lipo batteries can be very dangerous and short lived unless they are well matched and balanced with reliable wiring and good quality protection electronics... which costs money. 

buy cheap buy twice


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Minirig portable soundsystem movement


Posted By: davey t
Date Posted: 27 February 2013 at 9:03pm
Sorry I'm playing catchup a little here... 

I can't open the sketchup file cos my sketchup is out of date.. haven't used it in year. But from the online view and the photos, it looks like a sealed enclosure? Is that right? 

With 4 Aura 6" drivers to give you 360degree sound. and you are running a passive xover between the 6" and the hf. 

It's a cool design.. should be nice an compact to carry with 1 person. 

So the reason why you're not running at 24V is to make the battery last longer? Guess this makes sense.. The aura driver is 8ohms correct? so you're only putting in 10W.. This will give you around 100db with 1 driver, or around 110 with all 4 at 40W.... I guess that's pretty loud :)

Should sound really nice with those dayton tweeters. Is there any eq or custom bass filtering going on or are you just running things flat down to 30hz or whatever the natural response of the amp is? 

As I said, apologies if it's already been mentioned, I couldn't find this info easily. I love to see these 12V projects






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Minirig portable soundsystem movement


Posted By: Kostecki
Date Posted: 27 February 2013 at 9:17pm
Originally posted by TIP220 TIP220 wrote:

I have used this technique for furniture I have made in the past and it does make for a hard wearing finish, but you MUST let the lacquer harden for several days before rough handling or you will leave finger prints in the surface.

So by your judgement it should withstand "festival-use" fairly well? Big smile


Posted By: TIP220
Date Posted: 28 February 2013 at 6:02am
Originally posted by Kostecki Kostecki wrote:

Originally posted by TIP220 TIP220 wrote:

I have used this technique for furniture I have made in the past and it does make for a hard wearing finish, but you MUST let the lacquer harden for several days before rough handling or you will leave finger prints in the surface.

So by your judgement it should withstand "festival-use" fairly well? Big smile

its car paint, so its hard wearing but you cant get too precious about the finish as it will scratch just like a car.


Posted By: Larzman
Date Posted: 28 February 2013 at 1:28pm
Davey T - the 6800mAH LiPo's I bought last summer are working very well except for the one I fried. Don't know if they are up to stated capacity, but the advertised voltage is spot on, 12.6V. The 12V packs use 3 LiPo batteries, each producing 4.2V when fully charged. As far as 6800mAH, I don't have a reliable test method to qualify that, but they do seem to last long and charge in about 2 hours (from 11.1 to 12.6). I accidentally drilled into one of them and killed one of the 3 internal batteries, thus I know how they are constructed. Each internal battery has a BMS circuit for over/under charge and short circuit protection, as advertised. If you know of a good (simple) circuit/method to test true mAH capacity, please share.

TIP220 - did you wetsand and then buff out the final coat of lacquer? You have a great shine and I'm wondering if I have to set up a paint booth (dust free) to get that great finish. Wetsand and buff of final coat removes any surface imperfections, i.e. dust particles drying into the final layer) and makes the final finish smooth as glass.



Posted By: Larzman
Date Posted: 28 February 2013 at 1:56pm
maybe this battery pack will work, 12V 8000mAH looks pretty good, with 1 year warranty & free shipping, $28.

http://www.ebay.com/itm/Portable-12V-Li-po-Super-Rechargeable-Battery-Pack-DC-for-CCTV-Camera-8000mAh-/170937990572?pt=US_Rechargeable_Batteries&hash=item27ccb2bdac



Posted By: Saturnus
Date Posted: 28 February 2013 at 2:10pm

Originally posted by Larzman Larzman wrote:

maybe this battery pack will work, 12V 8000mAH looks pretty good, with 1 year warranty & free shipping, $28.

You can try and order it. I think it's pretty certain that you after a week or two will get a notice saying they cannot ship it to you, and you get your money back.



Posted By: Saturnus
Date Posted: 28 February 2013 at 2:31pm
Originally posted by davey t davey t wrote:

Sorry I'm playing catchup a little here... 

I can't open the sketchup file cos my sketchup is out of date.. haven't used it in year. But from the online view and the photos, it looks like a sealed enclosure? Is that right? 

With 4 Aura 6" drivers to give you 360degree sound. and you are running a passive xover between the 6" and the hf. 

It's a cool design.. should be nice an compact to carry with 1 person. 

So the reason why you're not running at 24V is to make the battery last longer? Guess this makes sense.. The aura driver is 8ohms correct? so you're only putting in 10W.. This will give you around 100db with 1 driver, or around 110 with all 4 at 40W.... I guess that's pretty loud :)

Should sound really nice with those dayton tweeters. Is there any eq or custom bass filtering going on or are you just running things flat down to 30hz or whatever the natural response of the amp is? 

As I said, apologies if it's already been mentioned, I couldn't find this info easily. I love to see these 12V projects

Doesn't take more than a minute to download and install the new version :D But yeah, it's sealed to keep volume needed minimal and to make it useful indoors as well (no overtuned BR).

It's not just battery life. It's also a question of not exceeding Xmax of the drivers too much as there is only the bass filtering in the amp and the sealed tuning roll-off to limit excursion. Large cone excursions have a very bad effect on midrange performance. Xlim is actually about 18mm p-p but it shouldn't get anywhere near that. And if it did, the surround would probably hit the grills first. 

It's also plenty loud already for a box this small as you pointed out.


Posted By: slaz
Date Posted: 28 February 2013 at 4:03pm
Originally posted by Larzman Larzman wrote:

Davey T - the 6800mAH LiPo's I bought last summer are working very well except for the one I fried. Don't know if they are up to stated capacity, but the advertised voltage is spot on, 12.6V. The 12V packs use 3 LiPo batteries, each producing 4.2V when fully charged. As far as 6800mAH, I don't have a reliable test method to qualify that, but they do seem to last long and charge in about 2 hours (from 11.1 to 12.6). I accidentally drilled into one of them and killed one of the 3 internal batteries, thus I know how they are constructed. Each internal battery has a BMS circuit for over/under charge and short circuit protection, as advertised. If you know of a good (simple) circuit/method to test true mAH capacity, please share.



Sounds like the same ones I've had good results with. Encased in black plastic - yes ?
I never (attempted to) measure the real-world capacity either - but have been pleasantly surprised how long they a 2020 amp for (although I've never really sought run times more than about 6-7-8 hours anyway).

BTW - anyone here genned up on whether (or how) these new regulations affect travelling with them ? - I mean as personal property - not commercial export. I've taken em (2 or 3 at a time) on a long-haul flight before now (at least twice) without any probs - but last time was just under 2 years ago. Can't remember if they were in carry-on or checked baggage .... but obviously both get X-rayed. (Would Lithium batteries show up or be identifiable as such on X-rays as such anyway ?)

I can't see anything new in the regulations for passenger luggage restrictions I've just looked at (dated 2012, and I'm assuming current) ..... there's mention of Lithium batteries, but there has been for quite a while. 100Wh is mentioned as a maximum capacity - so 6800mAh/12V scrapes insides that anyway.

Just looked at my laptop's batteries (one original Asus branded, one 3rd party cheapie), and neither have any UN-xxxx certifications printed on em ...... so will THOSE be banned ?



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REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON


Posted By: enal
Date Posted: 28 February 2013 at 4:43pm
Originally posted by Saturnus Saturnus wrote:


It's not just battery life. It's also a question of not exceeding Xmax of the drivers too much as there is only the bass filtering in the amp and the sealed tuning roll-off to limit excursion. Large cone excursions have a very bad effect on midrange performance. Xlim is actually about 18mm p-p but it shouldn't get anywhere near that. And if it did, the surround would probably hit the grills first. 

It's also plenty loud already for a box this small as you pointed out.
 
Point taken!  I think I will maybe save the two ClassDAudio Mini Amps that I have for full size Boominators instead since they have qualities that will benefit something large.
 
Any recommended Mini Boominator amps that are also available in the USA or is everyone just getting them from China?  I see a lot of people in forums talking about the little Dayton Audio DTA-2 Amp that's built on the TA2024 and just wondered what the past experiences were from anyone here?


Posted By: Saturnus
Date Posted: 28 February 2013 at 4:54pm
Originally posted by slaz slaz wrote:

100Wh is mentioned as a maximum capacity - so 6800mAh/12V scrapes insides that anyway.

Just looked at my laptop's batteries (one original Asus branded, one 3rd party cheapie), and neither have any UN-xxxx certifications printed on em ...... so will THOSE be banned ?

Yup. 100Wh max for a separate battery.

Don't need to. The restrictions regards separate batteries. Not ones that are in an electronic device (as long as it's not over 100Wh max).

Above 100Wh max. You need the UN certification.



Posted By: Saturnus
Date Posted: 28 February 2013 at 5:13pm
Originally posted by enal enal wrote:

Point taken!  I think I will maybe save the two ClassDAudio Mini Amps that I have for full size Boominators instead since they have qualities that will benefit something large.
 
Any recommended Mini Boominator amps that are also available in the USA or is everyone just getting them from China?  I see a lot of people in forums talking about the little Dayton Audio DTA-2 Amp that's built on the TA2024 and just wondered what the past experiences were from anyone here?

Actually the ClassDaudio Mini would be excellent here. On a battery it'd have the same output as any other class D amp on the same battery (unless it's single ended and not BLT but I doubt that). Not sure if it can handle stereo 4 ohm load at 12V though. You need to ask classDaudio about that. 



Posted By: Big SturL
Date Posted: 03 March 2013 at 11:20am
Good day my fellow DIY'ers.

I have recently cut out all the walls/plates that make up the Boominator Mini, and am awaiting some parcels for further advancemet.

However, I am incertain of how I should assemble the walls. Seeing as they are only 9mm thick, using screws seems a troublesome task... Is it sufficient if I only use glue? And what glue is recommended?



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