Print Page | Close Window

Double 10" Sealed Enclosure Advice please

Printed From: Speakerplans.com
Category: General
Forum Name: Newbie Discussion
Forum Description: Newbie Discussion/Questions. Look less stupid here...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=105108
Printed Date: 11 August 2020 at 7:39am
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com


Topic: Double 10" Sealed Enclosure Advice please
Posted By: Jack1991
Subject: Double 10" Sealed Enclosure Advice please
Date Posted: 13 April 2020 at 4:40pm
I want to build a double 10" mid range sealed speaker enclosure. I have been thinking of using these speakers 
https://m.thomann.de/gb/the_box_speaker_102508a.htm" rel="nofollow - https://m.thomann.de/gb/the_box_speaker_102508a.htm
If you have other suggestions of driver or what to look out for when choosing a midrange driver let me know. I have been going by frequency range.
They will be used with 2x Tham12 subs. And 2x tops.

Ive been reading and reading mixed information and also downloaded winisd but i cant get my head around it. I want to build sealed mids as its easier for my first time. I wrote driver details in on this site and this is the results:


So i assume i now just double that VB figure and then add the speakers displacement on top of that to get my final internal volume size? If so my final volume would be 1.16ft³. This figure just seems far too small to me though, so i feel like there must be more to it??

Any help would be great cheers 🙂👍🏼



Replies:
Posted By: Jack1991
Date Posted: 13 April 2020 at 5:28pm
Heres info from another forum someone posted for finding PORTED ENCLOSURE size. He does then say to reduce that size by 20% for a Sealed Enclosure (not pictured in the screenshot i know). 



So if i used this information my final size would be 1.87ft³ which is very different to my previous volume. This is why its confusing me. 


Posted By: APW
Date Posted: 13 April 2020 at 6:19pm

You won't need a double 10 above a tham 12 it will be overkill, a decent single 10 happily keeps up with TWO tham 12s a side.

We often use a single tham 12 per side with either a small 8 or 10 + 1 reflex cab for smaller gigs and two thams per side and a single 10” + 1” reflex for larger gigs, the 10 + 1 seems to keep up very well.

You may find that a sealed mid will NOT be able to play low enough to reach the tham without the a large box as the thams are only any good up to about 120Hz.

My mid/tops are only about 22 ltrs (0.777 Cubic feet) and are tuned to about 73 Hz with 98db/w output. They use a cheapish fane sovereign 10-300 driver.



Posted By: Jack1991
Date Posted: 13 April 2020 at 6:28pm
Originally posted by APW APW wrote:

You won't need a double 10 above a tham 12 it will be overkill, a decent single 10 happily keeps up with TWO tham 12s a side.

We often use a single tham 12 per side with either a small 8 or 10 + 1 reflex cab for smaller gigs and two thams per side and a single 10” + 1” reflex for larger gigs, the 10 + 1 seems to keep up very well.

You may find that a sealed mid will NOT be able to play low enough to reach the tham without the a large box as the thams are only any good up to about 120Hz.

My mid/tops are only about 22 ltrs (0.777 Cubic feet) and are tuned to about 73 Hz with 98db/w output. They use a cheapish fane sovereign 10-300 driver.


Thanks APW appreciate the feedback man. All taken on board 🙂

My question is still unanswered with the way to work out enclosure size though so if i did go with just 1 mid i still dont know how to calculate it? Any pointers with that? As you can see the 2 different outcomes from 2 seemingly good sources


Posted By: Jack1991
Date Posted: 13 April 2020 at 6:33pm
I am happy to go ported too by the way. But equally i want to know the CORRECT way to work out enclosure size. As keep reading conflicting formulas.

Sealed seems more easier for first timer though and i prefer the pros of a sealed enclosure.

But after you saying 10" reflex id be happy to give that a go. Need info on the port size/length and ecnlosure calculating though man 🙂👍🏼


Posted By: Peter Jan
Date Posted: 13 April 2020 at 7:51pm
Don't know about conflicting formulas, but without T/S parameters of that speaker, there's no way to simulate or calculate anything usefull in any software like WinISD or another. That particular speaker is probably more of an allround bass speaker (most likely suited for BR use ) than it can be a midspeaker.
It might work decent for what you need it to do, but it could be just as well very much out of wack for either closed or BR too.
You need the T/S parameters first ( or choose a speaker with known T/S parameters ).


Posted By: APW
Date Posted: 13 April 2020 at 8:04pm
Some are on the datasheet on Thomann's website

https://images.static-thomann.de/pics/atg/atgdata/document/manual/193262_datasheet_v2_en_online.pdf" rel="nofollow - https://images.static-thomann.de/pics/atg/atgdata/document/manual/193262_datasheet_v2_en_online.pdf


Posted By: Jack1991
Date Posted: 13 April 2020 at 8:05pm
No problem. Here are the TS parameters. I have entered these into various websites to get the enclosure volume but as stated i get various results. So dont know what to trust. Also i dont really know what to look for in the TS parameters for a mid range speaker? 




Posted By: Jack1991
Date Posted: 13 April 2020 at 8:08pm
Im happy to use any other speaker driver. My main concern here is knowing what to look for for a mid range speaker and also how to calculate the volume of a ported or sealed enclosure correctly. 

As when i calculate ported it shows ridiculous port sizes which are obviously not correct. And then various enclosure sizes vastly different from one another when entering ts paraneters of the same speaker into different sites 


Posted By: Peter Jan
Date Posted: 13 April 2020 at 9:23pm

Put it in WinISD...
Let it calculate and played around with volume, tuning frequency and lowcut filter at 100 Hz.
Doesn't look weird to me ...

Edit : where has the screenshot gone I put here ?


Posted By: Peter Jan
Date Posted: 13 April 2020 at 9:25pm


Posted By: APW
Date Posted: 13 April 2020 at 9:37pm

As Peter has said above… Use WinISD (or similar) and not random online calculators. With WinISD you can quickly play around with various box sizes and tuning to get the best response for the driver. I tend to model using TWO different simulators, and they both tend to give fairly similar results with the actual measured response being somewhere in-between the two.

NO calculations or simulator is 100% correct but a decent simulator will get you in the ball park and will take away some of the hard work. Also they only predict the lo-response for the driver/box combo.



Posted By: Jack1991
Date Posted: 14 April 2020 at 8:24am
Cheers guys i have tried winisd. I can enter a new speaker and write in all n the TS parameters all fine. And obviously i can read the volume of the box etc. 

But i dont actually know what im looking for with the outcome. Like the graph with the line on, i dont get what shape or where it should be at all.  And also 'tuning frequency hz' i have no idea what i should be setting that too?


Posted By: JonB67
Date Posted: 14 April 2020 at 9:06am
You need to balance the parameters to suit your needs

I'd suggest you just start changing the box volume and tuning frequency to see what happens to the graph. Move tuning 5 or 10hz and 10 litres at a time to start with. You'll soon see what's happening then you can dial it in to the hz! In my option its more important that you understand how the parameters  interact than you just get the result straight away.  You want a balance of a sensible box size with the port stopping the low frequencies rolling earlier than you need.

Obviously you want a flattish line, and you don't want it to drop off before it reaches your crossover point (Apw says tham reaches 120 so you need to be flat to there at least)




Posted By: APW
Date Posted: 14 April 2020 at 10:06am

At Jon said, you need to get the response as flat as possible in the band you are trying to reproduce, this is achieved by adjusting/balancing the box size and tuning, this in turn will dictate the port size. You can get into a situation where you get a very good response however it’s not physically possible to fit the port inside the box… Everything is a compromise!!

Peters screen grab looks good as he has the response flat down to 100HZ with the f3 at about 85Hz; this is achieved in a small box (21Ltr) with a sensibly sized port. The box size is very similar to my tops, however mine are tuned slightly lower (75Hz f3) and as I’m using a more efficient driver (98dB/w vs. 94dB/w) for every watt of power I put into the box I will get about twice the SPL out, a 3dB increase is double the sound energy.

BTW: 120Hz is the absolute highest you want to run the Thams, I x-over at about 100 - 110Hz. They will work higher than 120Hz but they don’t sound so nice!!



Posted By: Jack1991
Date Posted: 14 April 2020 at 10:29am
Lovely cheers guys makes alot more sense now. I have been watching youtube videos on how to use winisd too (before posting this thread) but sometimes they go into too much detail. Where as you guys have explained just what im looking for so thanks for that 🙂👍🏼

So now using the info youve all explained to me. As i was looking originally at making a sealed box can i use the same info but for sealed and see if i can get a good outcome? Down to 100hz.  Obviously i know i wont have a port to tune.  


Posted By: Peter Jan
Date Posted: 14 April 2020 at 11:00am
That's what I did, I played around with volume and tuning and with a lowpass filter of 12dB/oct slope, because I guesstimated that "could" be the slope in the Pioneer amp and mainly to see what a crossover does to the respons and how you could go down to meet a Tham without compromise. Without this filter, you will see a bump in respons in the lower part, which may be not what you want, but all things have to be taken into account, not just cab size and port dimensions. You have to play around with all variables and see what it does to the respons and how you can shift it to where you want it to be. More or less flat respons is what you preferably aim for and whether the combo can properly "reach" your other components in frequency. In a closed box for example, this speaker does not go down low enough to reach a Tham. It rolls off too fast for any given cab size. Try simulating it and higher/lower cab size, you'll see the respons never ever gets in neighbourhood of let's say 100Hz ( and with crossover it only gets worse ) and also not with a somewhat flat respons.
I checked to have an as big port as possible to be able to get it in a relatively small box and ~8 cm diameter is good compromise size wise. The bigger diameter you start with, the longer the port needs to be for a given cab size and diameter or the port. Also, the smaller you make the cab, the longer a port gets for a certain tuning frequency and vice versa. Given this speaker/cab combo doesn't need to go down really low in frequency and the relatively low power that's gonna be put into it, the port does not need to be all that large in size to avoid "breathing" of "shuffing" of large amounts of air being pushed fast in en out of that port. You could go smaller in port size, but than the length is going to be short(isch) and that would lower the working of that port. I like to keep a port at least more or less as long as the diameter ( or longer ) to have it work properly as a resonator, because that's what a port is. A too short port is more a glorified airleak/hole than a resonator ;-)


Posted By: Jack1991
Date Posted: 14 April 2020 at 11:15am
Perfect thanks again Peter Jan. This makes perfect sense now thankyou. I will have a play around today and see how i get on. I will try different drivers and sealed and ported to try and understand it more.

I will post results when i think i have got it correct and get your feedback if thats ok. To make sure i have it correct before building.🙂👍🏼


Posted By: Jack1991
Date Posted: 14 April 2020 at 4:25pm
Vent diameter and length is what im now struggling with. 

Example:
Vent length is always minus numbers unless i make the diameter a ridiculous size like 15cm even then the vent length will be something like 1.9cm. Setting the vent length to 10cm makes its length -1.56cm which is obviously wrong. 

I feel like im missing something here again?


Posted By: APW
Date Posted: 14 April 2020 at 5:03pm
What size is your box and what tuning are you using?

The only way I can get the port length to go negative is by making the box about 4x to large i.e. 75-80 litres for a single driver that requires a 20ltr box, this seriously de-rates the power handling of the driver.


Posted By: Peter Jan
Date Posted: 14 April 2020 at 5:08pm
It's not wrong per sé, the program does things on a pure mathematical level. A minus value makes just as much sense on a mathematical level as a positive on. Now for cabinets and a port length of course not so much...
It just means that you have chosen a too small diameter port to begin with, once you manually change to a bigger size ( as you did ), the values will make sense again.
Everything considerred, some values of cab size - port diameter - tuning frequency does not work out as desired with that speaker. You need to change a few things...


Posted By: Peter Jan
Date Posted: 14 April 2020 at 5:11pm
Originally posted by APW APW wrote:

What size is your box and what tuning are you using?

The only way I can get the port length to go negative is by making the box about 4x to large i.e. 75-80 litres for a single driver that requires a 20ltr box, this seriously de-rates the power handling of the driver.


Like he said, probably a way too large box.


Posted By: Jack1991
Date Posted: 14 April 2020 at 5:59pm
I have been trying to design it for 2x speakers. For 2x speakers i am getting a result for around 50L at 78hz with the port length being in the minus until i reach a diameter of around 15cm.

Am i better off designing it for 1 speaker, rather than trying to design it in winisd as 2x speakers.   But then when making the enclosure make 1 big box with 2x seperate chambers.


Posted By: Peter Jan
Date Posted: 14 April 2020 at 6:23pm
That makes sense... 2 speakers also means double cab volume and two of the same ports as the port for one speaker.


Posted By: Jack1991
Date Posted: 14 April 2020 at 8:21pm
Right i think i got it. I have gone for a square slotted port heres a photo of the style i would potentially like to make the mid range box, but with the slot on the bottom instead. The sizes i have put in WINISD is just for 1 speaker enclosure. As i want to make sure i understand and got it correct.

Not shown in the photo but i have also put the high pass filter on too @ 100hz


 
Doesnt have to be square slotted. Happy to have round ports and different shape enclosure. Just for example to check i understand it correctly now?


Posted By: Peter Jan
Date Posted: 15 April 2020 at 5:19pm
Looking good  Thumbs Up


Posted By: Jack1991
Date Posted: 15 April 2020 at 5:26pm
Originally posted by Peter Jan Peter Jan wrote:

Looking good  Thumbs Up

I assume by that i have done it correctly Peter! 😀




Posted By: Jack1991
Date Posted: 15 April 2020 at 7:00pm
I have read how you need to be ALOT more precise when building ported enclosures, compared to sealed.

I like to be as precise as i can woth things in general but i would like to know exactly how close you do need to be realistically when building a ported enclosure? Is it say within 1 to 2cm³  or is it a bit more leanient than that?

I imagine its hard to out an exact number on it but if i can get a rough idea


Posted By: Jo bg
Date Posted: 15 April 2020 at 7:21pm
Hi there is some leeway more than 1 cm... But more prominently there will be some differences from sim to reality.
Enclosure Shape, effective shape of port and placement in the box, actual driver T/s parameters will have an effect and change the tuning a bit.

Good practice would be test the enclosure before sealing it so you can check and adapt the port once measured , often this means shortening the duct as usually the port acts as it was longer than in the sim thanks to nearby walls.


Posted By: Jack1991
Date Posted: 16 April 2020 at 8:16am
Cool okay thanks. Because i was thinking things like speaker cable and speakon socket does that need to be measured and taken into consideration aswell? I would assume so.

Actually i just thought, i will have a look on winisd adding & subtracting a few cm³ and see what the overall result is. 🙂👍🏼


Posted By: Peter Jan
Date Posted: 16 April 2020 at 10:13am
Volume is indeed always net volume, so you have to take into account all these things that take up space inside the cab. Barhandles, the speaker(s), bracing and the BR port(s). Do a rough calculation of all these things when determining the final cab size. It does certainly not listen to a few cm³ even a liter doesn't do all that much.


Posted By: Jack1991
Date Posted: 16 April 2020 at 9:31pm
Right fairly sure i got this correct now. Would be grateful if someone could check it to make sure i am correct though. I have completely changed the driver & box design from yesterday and also gone with a round port instead.

The photo with the design on is exactly to size. Just without the top on obviously so you can see inside. It has a 10cm port, 11.5cm long.

I have made each chamber 26.695 Litres as this includes displacement total of driver/port/cable etc.

I dont know what 'Alignments' is on WinIsd. So i selected the top one which is called QB3. I also tried Chebychev too and it made no difference. So went with QB3 in the end.

I am going to use a Passive Crossover to go from the Mids to the Tops. I havent accounted for that yet on winisd as i wanted to ask, is that just add in a low pass filter at 2.5khz the crossovers point, or is there more to it than that?

Also is it better to have a steep or shallow roll off? My instinct is shallow would be better but im not sure?








Posted By: Peter Jan
Date Posted: 17 April 2020 at 9:06pm
Originally posted by Jack1991 Jack1991 wrote:

Right fairly sure i got this correct now. Would be grateful if someone could check it to make sure i am correct though. I have completely changed the driver & box design from yesterday and also gone with a round port instead.
The photo with the design on is exactly to size. Just without the top on obviously so you can see inside. It has a 10cm port, 11.5cm long.
I have made each chamber 26.695 Litres as this includes displacement total of driver/port/cable etc.

Seems correct all the way.
BR ports can be anywhere, just make sure the cab can be placed with the port(s) fairly free at all times ( not against a wall or something ).
The center panel can be left out, doesn't make make any difference or cut out some wood to save some weight, so it still acts as bracing. makes it also easier for cabling inside.
Probably cover all sides with a layer of damping material, as it is a mid cab and very likely needs some damping to avoid cab resonances/standing waves inside the cab.


Originally posted by Jack1991 Jack1991 wrote:

I dont know what 'Alignments' is on WinIsd. So i selected the top one which is called QB3. I also tried Chebychev too and it made no difference. So went with QB3 in the end.

There's not much difference between QB3 or Chebychev allignment, but there is more with the other allignments. It all depends what the purpose of the cab is going to be, to choose one or the other as a starting point, but it doesn't matter what you start with as you can tweak volume and tuning around at will.


Originally posted by Jack1991 Jack1991 wrote:

I am going to use a Passive Crossover to go from the Mids to the Tops. I havent accounted for that yet on winisd as i wanted to ask, is that just add in a low pass filter at 2.5khz the crossovers point, or is there more to it than that?

You can put a lowpass filter in WinISD to get the general idea visually, but WINISD isnt meant for that. You need to have a lowpass on the midspeakers and an highpass on the tweeter/horn-driver.
Depending on the used components ( their sensitivity ) you need to attenuate one or the other to match them loudness-wise, usually the highs are the loudest as they tend to be more sensitive than larger cone speakers.


Originally posted by Jack1991 Jack1991 wrote:

Also is it better to have a steep or shallow roll off? My instinct is shallow would be better but im not sure ?

Passive filters are to be calculated on the specific speaker components, especially their impedance at/around crossover point. No speaker(s) are exact 8 Ohm (or 4 Ohm or ... ) over their entire range. The speakers connected to passive crossovers are an integral part of that crossover circuit, so speaker impedance ( impedance curve comes in handy here ) has to be accounted for.
Active filters, like the ones in your Pioneer amp, don't have that impedance "problem" to consider.
Shallow or steep is not a matter of one being better than the other by definition. What is used when or where or why, depends on many considerations. The simplest form ( 6dB/octave slope ) meaning the least amount of components, sometimes does it just fine, when speaker components can take it. A woofer or mid speaker doesn't mind "too much" highs from a technical standpoint, sound can be another thing though. High speakers ( tweeter or horn/driver ) on the other hand are not made to support lower frequencies, so their crossover frequency and/or slope steepness comes into play. Other than that, what sounds best at what crossover frequency can also be a factor, but power capability at what frequency always has to come first.
In this case I don't think there's all that much power involved, so a simple crossover could just be the ticket, since highs ( nor mids ) are not going to be used at an inch of their life at any time.
Crossover at 2,5kHz is pretty high too, so highly unlikely you will need a steep highpass for the highs and can get away with the simplest form of crossover. Basically a coil in series with the mids and a capacitor in series with the highs if you don't count the attenuation for the highs. That attenuation is going to take one or two resistors.




Posted By: Jack1991
Date Posted: 18 April 2020 at 9:27am
Perfect all makes sense thanks again Peter! 😀👍🏼 

Oh okay cool i thought each speaker needed its own chamber. Seeing as it doesnt i will leave the centre panel out and just reduce the depth slightly to make up the difference. It will make it easier to line the insides then too.

And yes i was thinking of lining the internal walls with this 30mm 'egg box style' foam which i have seen others use. I do not need to account for this displacement when calculating internal box volume though do I? 




Posted By: APW
Date Posted: 18 April 2020 at 9:46am
Personally I'd leave the centre panel intact, as it being there provides two benefits…
1.    It adds structural stiffness to the enclosure; this helps shift panel flex/resonance up where it’s less disruptive.
2.    If the centre panel is not fitted or has holes within it and you have a driver fail open circuit the tuning of the system shifts dramatically, this can result in the driver becoming unloaded  allowing the driver to reach or exceed ”x-damage” resulting in two dead drivers. However if the panel is fitted you effectively have two separate cabinets and so the failure of a driver doesn’t result in the remaining driver becoming unloaded and subsequently failing.



Posted By: Jack1991
Date Posted: 18 April 2020 at 10:41am
Cool okay yeh that makes sense too. Thanks 

How about the egg box lining displacement? Or do I not need to account for that as its like a open cell, rather than solid mass?


Posted By: APW
Date Posted: 18 April 2020 at 10:58am

there is already several threads on cabinet stuffing, Basically you don't need to worry about the stuffing volume…. Again this is a personal thing but I prefer to use polyester wadding (the Duvet stuffing stuff!!)  rather than the foam

https://forum.speakerplans.com/acoustic-wadding_topic45924.html" rel="nofollow - https://forum.speakerplans.com/acoustic-wadding_topic45924.html

PS… I have just found a thread regarding stuffing the box vs effective volume and you are the OP.

https://forum.speakerplans.com/speaker-enclosure-size-affecting-damping-foam_topic104999.html



Posted By: Jack1991
Date Posted: 18 April 2020 at 11:05am
Cool cheers man. 

Yes i know i made a thread asking about damping volume. I am just was seeking others opinions. As you literally just said the opposite to Peter Jan earlier about the centre panel. So i like to ask others just to get there opinions on things too.

Thanks again man appreciate the help 😀👍🏼


Posted By: APW
Date Posted: 18 April 2020 at 11:19am

Peter isn't wrong about the panel, both arguments are correct and will work just fine,  I just pointed out that are some possible benefits in keeping the panel in place and it’s down to personal preference.

 When building speakers there are many trade-offs that have to be made, you have to build to your requirements and taste ….. One size most certainly does not fit all in the audio world!!



Posted By: Jack1991
Date Posted: 18 April 2020 at 12:06pm
Of course yes, i understand, pros & cons and also personal preference to it all, thats why i like to get various peoples views as im very new to it all.

A lot more to it than i first realised but its really interesting learning about it all. So i appreciate your help 


Posted By: Peter Jan
Date Posted: 18 April 2020 at 3:55pm
Originally posted by APW APW wrote:

Peter isn't wrong about the panel, both arguments are correct and will work just fine,  I just pointed out that are some possible benefits in keeping the panel in place and it’s down to personal preference.

 When building speakers there are many trade-offs that have to be made, you have to build to your requirements and taste ….. One size most certainly does not fit all in the audio world!!


Yes, I just meant you can leave it out from a strict technical standpoint, determining cab volume, tuning,...
But the bigger a cab is, the more some kind of bracing is needed to avoid large surface panels from unwanted resonating, so put some ribs in or a whole panel and cut some “meat”, because that works just as well as a whole panel.. and saves a bit of weight.
By the way, you’re not going to find many commercial available cabs pro/hifi/car/... with seperate chambers for each speaker doing the same frequency band and/or connected to the same amplifier channel. While it is possible a speaker going bust, because it’s brother cuts out for some reason, but it’s very, very unlikely, even when flogged hard. Besides open circuit is just one way of going wrong, but what about burned/shorted and/or coil mechanically blocked in the gap ? The connected amp is much more lickely to protest. 
I agree many decisions are more personal preference, than true technical need.


Posted By: APW
Date Posted: 18 April 2020 at 5:23pm

I agree with you that not many commercial designs have separate chambers for each driver, technically it makes very little difference to the performance of a well braced design and removing the centre reduces the size and weight slightly….

…. however I have had this exact mode of failure in the past: For many years I ran 8 dual 18, shared chamber cabinets (classic G-sub style enclosure but a little larger) that were loaded with Fane 18XB Colossus 600 drivers, on one of the drivers the tinsel wire failed mid gig (probably due to the age of the drivers), shortly afterwards the 2nd driver failed in the same cabinet, this time with mechanical damage to the VC (Voice coil detached from bobbin and damage to the end of the bobbin from contact with the back of the pole plate), the 14 other drivers in the other 7 cabinets were  all OK as was the driver with the broken tinsel once the tinsel had been replaced, the other driver had to be re-coned!   



Posted By: Chris Grimshaw
Date Posted: 19 April 2020 at 6:10pm
Originally posted by Jack1991 Jack1991 wrote:

Cool okay yeh that makes sense too. Thanks 

How about the egg box lining displacement? Or do I not need to account for that as its like a open cell, rather than solid mass?


I did some measurements recently - I'll see if I can dig them out.

Anyway, I use wool carpet underlay. One layer over most of the internal walls, and added a couple of extra layers at the top and bottom, since there was a fairly strong standing wave in that direction.

The impedance curve went from bumpy (lots of small peaks) to smooth in the 700-1kHz range, indicating those resonances had been damped out.
In terms of frequency response, there had been a narrow dip/peak combo in that region, which also disappeared. Cleaner midrange immediately.

Chris


-------------
Quality sound from Sheffield
www.grimshawaudio.com


Posted By: Jack1991
Date Posted: 19 April 2020 at 8:28pm
Oh cool thats good to know thanks Chris 🙂👍🏼

Im surprised at the different materials people use and seem to work well. Pillows, Duvets, Carpet underlay. All a fair bit cheaper than "branded" damping materials too. Dead handy


Posted By: Chris Grimshaw
Date Posted: 19 April 2020 at 9:16pm
Yeah, I just picked up a big roll of the stuff and use it as/when needed. It does shed a little, but shaking it out gets most of the loose fibres out before installation.

Chris


-------------
Quality sound from Sheffield
www.grimshawaudio.com


Posted By: Jack1991
Date Posted: 28 April 2020 at 4:45pm
To save making a new thread for 1 question. For my tops im building a seperate box. This will house 2x 1" compression drivers mounted on horns and also the 2x passive crossovers. Id like to know if they can be fitted quite close together as there wont be much room inside. The comp driver is like a big magnet so i was worried that it might do something to the crossover??

Or would i be best to fit a ply panel between the 2 like the second photo.




Posted By: DMorison
Date Posted: 29 April 2020 at 1:21pm
A ply panel will do nothing to stop a magnetic field, FWIW.


Posted By: Jack1991
Date Posted: 29 April 2020 at 1:32pm
Originally posted by DMorison DMorison wrote:

A ply panel will do nothing to stop a magnetic field, FWIW.

Oh okay it would be 15mm the same as the rest of the enclosure. I did put a piece of 15mm ply between the driver and a piece of magnetic metal and it doesnt get pulled to it. So im not saying your wrong but i dont understand why that wouldnt work?

What would you suggest instead then please? Or does it not matter anyway?

There will be a 50mm gap between the crossover and the comp driver magnet.


Posted By: studio45
Date Posted: 29 April 2020 at 3:37pm
I don't think a static magnetic field does very much to the behaviour of an inductor anyway - of course there will be a small force generated as the current flows, but if your inductor is properly mounted that shouldn't cause any actual movement or vibration and no effect on the filtering action. 
If it is an iron-cored inductor, the magnetic field could have a small effect on the saturation behaviour of the core - but you shouldn't be operating an inductor anywhere near its saturation point in any crossover, especially not a tweeter highpass filter!


-------------
Studio45 - Box Builder Commotion Soundsystem -Mobile PA


Posted By: Jack1991
Date Posted: 30 April 2020 at 8:14pm
Cool cheers studio45, just wanted to check before fitting it all. 


Posted By: Jack1991
Date Posted: 04 May 2020 at 11:50am
So ive made the mids and tops, they are not glued or anything yet. But just done a dry run to see how it looks and i like it but i think i should have gone with 2x 8" mids instead as it would look better. 10" look too big


I have since done a mock up on sketchup to see and the 8" (one on the left) looks alot better cause it is smaller. The ratios look better. Any smaller than 8" though i think would look too small.


I might try and sell the 2x 10" speakers and get the 8" versions.
Before i do though, does anyone have any other suggestions as ive not actually heard what it sounds like with 10s or 8s but a few people said 2x 10" or 2x 8" will be too much for the 2x Tham12s anyway. So what would you guys suggest? Im at a bit of a dead end for now im not sure what to do. I have nothing to compare it to as ive not done anything like this before.

Amp power wise it will be:
Mid tops will have 70w each (per mid top)
Thams will have 150w each



Posted By: cravings
Date Posted: 04 May 2020 at 12:15pm
what horns have you got for your compression drivers? they'll work better if you angle them so one points a bit left and one right.. you won't get a dead spot in the middle that way. (sorry if this seems a bit late now.. should have picked up on it from your diagram on the last page)


Posted By: Jack1991
Date Posted: 04 May 2020 at 12:19pm
Ah ok cool i will try that later on when home. I havent glued the mids or tops yet so it can be amended. 

These are the horns i have 



Posted By: Peter Jan
Date Posted: 04 May 2020 at 5:47pm
The only difference ( very generally speaking ) would be the 10" could get you a tiny tad lower respons than 8", though that depends largely on the T/S parameters of the speakers involved. An 8" speaker cab might be a bit smaller than a 10" cab, but it could be the other way around too. Again, depends on the speaker and the wanted flat(isch) respons you need to have, combined with the low/bass cabs.
As a rule of the thumb, I would say : try to keep function (proper working) before form (looks) Smile.



Posted By: Jack1991
Date Posted: 04 May 2020 at 6:08pm
Cool ok thanks peter. I see what you mean.

How about in terms of being too loud for the subs. Do you think the 10 or 8 would both be too large, or 1 'better' than the other?

This is the 10" mid speakers i went with in the end.
https://www.bluearan.co.uk/index.php?id=BMASM110N&browsemode=category" rel="nofollow - https://www.bluearan.co.uk/index.php?id=BMASM110N&browsemode=category

If i was to change it to 8" i would probably use these which are the same but a 8" version  https://www.bluearan.co.uk/index.php?id=BMASM108&browsemode=category" rel="nofollow - https://www.bluearan.co.uk/index.php?id=BMASM108&browsemode=category



Posted By: Peter Jan
Date Posted: 04 May 2020 at 7:01pm
One or the other would not be louder in general, sensitivity is very close between the two, but the 10" simulates much better in the lower region.
If the crossover point would be 200-250 Hz or more, it wouldn'd matter or maybe an advantage for the 8", because the cab could be made a tiny bit smaller and cheaper for about the same desired respons.
By the way ... this SM110N is a great sounding speaker, so based on that alone, I would probably choose it over the SM108N, especially when used from ~90-100 Hz and up.

As for two 10" or 8" being too much per two Tham12's, I doubt that. I don't know what the Tham12 sensitivity will be ( depends also on the used 12" speakers ), but the Tham12's get about double the power, so that already accounts for 3 dB louder on itself and I can't imagine they will have a sensitivity in the high 80 dB or low 90 dB range with any speaker, unless the 12's are HiFi units.


Posted By: Jack1991
Date Posted: 04 May 2020 at 7:08pm
Ah right ok perfect! 

Ill stick with the 10s for now then see how they sound. And yes i would cross over to the mids at around 100hz as APW said in one of the first posts the thams work well up to 120hz. So sounds good to me. 

I do still prefer the look of the 8" as they look more in proportion with the subs then. But i can always change to them in future i suppose.


Posted By: Peter Jan
Date Posted: 04 May 2020 at 7:16pm
Originally posted by Jack1991 Jack1991 wrote:

Ah right ok perfect! 

Ill stick with the 10s for now then see how they sound. And yes i would cross over to the mids at around 100hz as APW said in one of the first posts the thams work well up to 120hz. So sounds good to me. 

I do still prefer the look of the 8" as they look more in proportion with the subs then. But i can always change to them in future i suppose.


It's a lot less likely you will find a suitable 8" speakers that can do that lower region.
You could make the double 10" cab with a bit smaller front, if that looks more pleasing to the eye ( your eyes, that is Smile ).

Again ... look into my eyes ..... function over form .... function over form ... Big smileBig smileBig smile


Posted By: Jack1991
Date Posted: 04 May 2020 at 8:08pm
Hahaa 😂 function over form. I need to remember that.

Right i think ill make it as it is then. And once the edges are rounded over, its all painted and ive got the Tham grilles on it will hopefully look a bit more matching.

Also the Tham drivers i went with are these. They are highly recommend for Tham 12s (if you dont want to spend lots) on another 12v forum im on. They have a 95db sensitivity.
https://m.thomann.de/gb/the_box_speaker_12_280_8_w.htm" rel="nofollow - https://m.thomann.de/gb/the_box_speaker_12_280_8_w.htm



Posted By: Peter Jan
Date Posted: 05 May 2020 at 9:01am
The 95dB is an average figure over a wider range than (sub)bass only, but that's the thing with every speaker.
Even so, with maybe a few dB less than 95 dB/1W sensitivity where it will be used ( up to ~100 Hz ), the Tham design makes up for that.
Considering the fact that our ears are somewhat less sensitive for lower frequencies and you have about double power available, it looks like a good match all together.


Posted By: Jack1991
Date Posted: 05 May 2020 at 9:07am
Ah perfect thats good then im happy with that 😀

Thanks alot Peter!


Posted By: Jo bg
Date Posted: 05 May 2020 at 11:42am
Talking about form follow function, using the  10 inches horizontal will beam a lot over 500hz, getting more directional as it goes higher in frequency , and create interference pattern (look for comb filtering) somewhere over 1kHz.
Same  comb filter will be produced by the horns, as they are too far apart and involve frequency too small to couple. Result will be uneven response on and off axis.

If it was mine to set up I would stack the mids vertical to gain more even and broad vertical coverage to get a better match with the horn, and use only one compression driver (you can buy a better quality one), leaving the other horn  just for looks.
Anyway congrats on your nice build!


Posted By: Jack1991
Date Posted: 05 May 2020 at 12:17pm
Ah right ok thanks Jo. Comb filtering is soemthing ive not heard of before. Ill have a google in a bit.

Would this happen with any size mid driver?

I do appreciate the form over function saying, but at the same time i do need to draw a line somewhere as to what i want it to look like overall too. A happy medium sort of thing.

Or if theres any suggestions as to what i could use instead to keep that pyramid rig style, but using different drivers or something. Im happy to remake any of the enclosure for the mids or tops. 


Posted By: Jo bg
Date Posted: 05 May 2020 at 1:31pm
You absolutely have to draw a line before obsessionSmile.
You have the stack, you should try and see if it makes a difference to you.
Basically to control dispersion (not counting horns, more things to consider) dimensions of speaker or baffle should be bigger than wavelength involved.
At 100Hz , 340 cm large, your box is small so bass is almost omnidirectional.1000 Hz is 34 cm, smaller than the box width, so it will concentrate sound forward. At 2000Hz wave is smaller than a single cone, each will beam and together they will comb filter.
Ideally you want drivers to be max half wavelength apart at crossover frequency, not always possible.

One way to improve things with such a horiZontal design is to angle drivers outwards.



Posted By: Peter Jan
Date Posted: 05 May 2020 at 1:33pm
There will be beaming going on with two 10" speakers next to one another, but how "bad" that would be in the intended use of that system ( mono stack 12V rig ) isn't all that clear cut. And while I preach "form over function" in the pro audio world without exeption, this is a different animal. Same physics apply in any sort of sound reproduction, I fully agree, but in this case I tend to adapt (within reason) to the intended use and "habits" of doing things there.
Mounting vertical "could" be a better way, when trying to keep horizontal respons in check, but vertical beaming (and especially the comb filtering that comes with it) could become a worse problem with a crossoverpoint smack bang in the middle of that oh so important mid region ranging from about 1kHz to 4kHz. Having a crossover between mid and high where comb filtering heaven is going on, usually works out to be a worse (audible) problem. It's debatable of course, that's the thing with compromises and designing a sound system is all about compromising at no end ... unfortunately LOL.
A part of the beaming can be negated with a simple coil in series with one of the 10" speakers. It is something used in a lot of commercial products that have 2 (or 3) bass/mid speakers mounted vertical, especially with a somewhat higher crossover point to the highs in the range of 2kHz or higher. If just vertical mounting of mid speakers was the ticket, no one would incorporate this coil (or use active correction on the bass/mid speaker farthest from the highs).
About the highs ... again, absolutely right about the beaming, comb filtering and all that, though on- axis respons won't be a problem, but off-axis ... very nasty Dead.
I was under the impression Jack already had bought everything, so I was thinking : work with what you have, eventually splay mount the horns horizontal or mount them vertical (and also splay them ~10° vertical if you want to make the best of it).
If horns and drivers are not yet bought ... for sure use one high horn, preferably a longer one with more mouth surface and a driver that can cross waaaay lower, like 1kHz-1,2 kHz.
One bigger horn/capable driver tackles more than one problem in one go. Beaming of mids would become an almost non-issue and the highs would be cleaned up immensly in terms of uniform dispersion over their frequency range.
Suggestion for a driver : B&C DE-25 or DE-250 in 16 Ohm version. Reasons : almost ruler flat respons out of the box and 16 Ohm so you don't have to attenuate so much with big resistors to levelmatch with the mids. Maybe even no attenuation needed anymore.


Posted By: Peter Jan
Date Posted: 05 May 2020 at 1:37pm
Originally posted by Jo bg Jo bg wrote:

You absolutely have to draw a line before obsession Smile


LOLBig smileLOL ... spot on !


Posted By: Jo bg
Date Posted: 05 May 2020 at 2:15pm
All true!
Op seems wlling to learn, my idea was more to play lego with what he has and maybe learn some physics along the way!


Posted By: Jack1991
Date Posted: 05 May 2020 at 2:42pm
Thanks for all the responses again guys.

I have just got home now and was just about to go out and glue the enclosures as they are in photo. But now im wondering if i should splay the mid and tops ~10° as you said instead of forward facing. Would this make much of a improvement over how they are at the moment?

Also yes i have purchased all the drivers/horns etc now so would rather work with what i got. But im im happy to adjust the enclsoures before i glue them all. Even if it ment completely remaking them as i have plenty of birch ply.
Heres what i got anyway:

Mid Drivers: Beyma SM110/N - 10" 200W 8 Ohm

Compression Driver:  P-Audio BM-D26 Mk2 30W 1" Throat Compression Driver

Horn: B&C ME10 1" Throat Horn 90 x 60 Dispersion


Also yes very willing to learn and make changes along the way. Im not expecting to make the worlds best sound system as its my first ever one i have made. But if theres adjustments i can make to make a significant improvement then id like to do that.


Posted By: Jack1991
Date Posted: 05 May 2020 at 3:04pm
Also im im very eager to hear it all now 😆 but at the same time i will be annoyed if I rush it and then find out after a simple adjustment like a 10° splay of the mids and tops would have made an improvement. 


Posted By: Peter Jan
Date Posted: 05 May 2020 at 3:11pm
In light of keeping the looks as they are now, I would first of all splay the highs and mount the horns as close together as possible. B&C ME-10's are roughly 90° horizantal, so rather go to 15-20° splay horizontal (see how far you can go without the driver magnets touching.
Mids splay will do also a bit of good in their higher region, but not so dramatically. Mount them also as close together as possible. The beaming/combing can be negated fairly easy with one single component (coil), though the need for this depends on how high the crossover point is going to be. On that crossoverpoint, I would aim for 1400-1500 Hz, because that will be about the lowest that little horn can work properly as a horn.


Posted By: Jack1991
Date Posted: 05 May 2020 at 3:19pm
Cool ok i will splay the highs 15-20° and i will leave the mids as they are then. They are pretty much as close as i can get them now really. I tried making them close as i wanted the mids enclosure to fit smaller than the width of the 2 thams.

I already have the passive crossovers too i went with 2.5khz crossovers. As the p audio tops reccommends 2khz or higher. And i couldnt find 2khz crossovers. 


Posted By: Peter Jan
Date Posted: 05 May 2020 at 3:37pm
With crossover at 2k5, either splay the mids too or put in that coil or even do both.
What brand/type is that crossover ?
Maybe you could change a few components to get that X-over point somewhat down.
You don't have to worry about that 2 kHz recommendation, because you won't be feeding them lots of power. The graph indicates those drivers can be used down to somewhat above 1,1 -1,2 kHz. The ME-10 is the limiting factor here.


Posted By: Jack1991
Date Posted: 05 May 2020 at 3:50pm
Oh okay yes the crossovers was the bit i mainly struggled understanding. They are convair. Off blue arans website. This is the exact one.

With regards to the coil i dont know what you mean by that sorry your have to explain exactly what it is??


Posted By: Peter Jan
Date Posted: 05 May 2020 at 4:01pm
I'll have a look at the crossover...

Will you be using one of these crossovers for each 10" and horn/driver combo ?



Posted By: Jack1991
Date Posted: 05 May 2020 at 4:03pm
Yes 👍🏼

So i have 2x crossovers


Posted By: Peter Jan
Date Posted: 05 May 2020 at 4:53pm
The least intrusive would be to swap L1 for a 1,5-1,6 mH unit and take out C2 for the crossover connected to the midspeaker that has to be "tamed" a bit in the higher regions.
That L1 coil swap changes the lowpass from a 12dB/octave 2k5 to a 6dB/octave X-over @ about 800 Hz.
You could leave the original 0,72 mH in place (also take out C2) and add another 0,72 mH (or a bit higher) coil outside the PCB (placed in series between LF + out on the PCB and the + terminal on the 10"). It's technically the same, just not so tidy Wink.
This swap (or addition) makes the respons slope down more gently, but a good deal earlier frequency wise to negate the horizontal beaming/combing effect.

If you like to go further ( I suppose you won't exacltly "like" that, but you get the point... Smile), you'd have to swap out L1, L2 for higher value ones, and add some capacitors in the C4 and C1 positions.
It's more involved, but than you have a lower X-over point and probably can leave everything more straight forwarth (no need to have one 10" drop off earlier).




Posted By: Jack1991
Date Posted: 05 May 2020 at 5:00pm
Ah man thabks for the detailed response but all that is way beyond my knowledge! 

Id rather just bin these 2.5khz crossovers and buy the 1.6khz version instead. And just count the loss as a learning error.

Would that suffice to do that instead? Or would these 1.6khz version not be any good either? 

https://www.bluearan.co.uk/index.php?id=CNVX29&browsemode=category" rel="nofollow - https://www.bluearan.co.uk/index.php?id=CNVX29&browsemode=category


Posted By: Peter Jan
Date Posted: 05 May 2020 at 5:10pm
Another set of filter PCB's would do the trick of course. I just saw there is no attenuation/correction provided on these 1,6 kHz filters, so you would either have to buy a few extra components ( the R1, R2 and C3 positions ) or pull them from you 2k5 boards. If you have to go that far, why not just order a few components and swap on the 2k5 ones ? If you're going to be using a soldering iron, might as well do it cheaper and throw less parts in the bin.


Posted By: Earplug
Date Posted: 05 May 2020 at 5:15pm
If it´s not too late, some stuff about angled cabs:-

https://forum.speakerplans.com/2x12-angled-mids_topic34779.html" rel="nofollow - https://forum.speakerplans.com/2x12-angled-mids_topic34779.html






And the Fane:




Albeit for 12´s, they can be scaled down for 10" or 8" drivers.






-------------
Earplugs Are For Wimps!


Posted By: Jack1991
Date Posted: 05 May 2020 at 7:12pm
Right sorry, so just to be clear. 

If i angle outwards 15° the tops,  and also angle the mids outwards 10°  and then also get a 1.6khz crossover (instead of my 2.5khz)  that will be all i need to do to eliminate the issues that may occur?

Again im not expecting perfect speakers. But just compared to how i was going to do it before. Or would there then be other things to take into consideration after doing these things?

Also what is the "coil in series" you mentioned earlier Peter Jan?


Posted By: Jo bg
Date Posted: 05 May 2020 at 8:01pm
Really, it s always a compromise  no speaker is perfect.
I would angle the mid and highs the same degree, and as suggested get 10s as close as possibile, same thing for horns


Posted By: Jo bg
Date Posted: 05 May 2020 at 8:04pm
Originally posted by Jack1991 Jack1991 wrote:

Right sorry, so just to be clear. 


Also what is the "coil in series" you mentioned earlier Peter Jan?
just search  parallel vs series connection, a simple picture will be easier to understand than words


Posted By: Jack1991
Date Posted: 05 May 2020 at 8:17pm
Ah yeh sorry i understand series and parrallel. But i dont actually know what the coil is or what it does?


Posted By: Peter Jan
Date Posted: 05 May 2020 at 8:53pm
Coils or inductors are those round white things on the PCB. L1 is the biggest of the two on your PCB. Normally L1 would have a value of 0,72 mH (milli-Henry), so by placing an extra inductor in serieswith L1, you add up inductance to drop the crossover point lower. Inductors can do a lot of things, but here it is used to "resist" or better : roll-off higher frequencies. The higher the value of an inductor in series with a loudspeaker of a certain impedance/resistance, the lower that tipping point will be. This is a huge simplification of things, but that's basically what it does. A capacitor works in a similar fashion, it rolls-off lower frequencies from a certain point, depending the value of the capacitor, combined with the impedance of the attached speaker. Capacitors, just like inductors, can have several functions in electronics, but here it is used for its "resistance" towarths lower frequencies. Inductors and capacitors are each others counterparts in passive crossovers, simply put.


Posted By: Jack1991
Date Posted: 05 May 2020 at 8:58pm
Ah right ok cool perfect cheers. So when you said i could fit a coil in series with one of the 10" drivers to reduce beaming you mean onto the actual crossover. I thought you ment in series on the speaker cables leading to the mid driver.

Makes sense now, although still very confusing haha.

I think im decided on what im going to do now. Id Id like a bit of trial and  error as i have not heard any of the system yet. So im going to finish building the mids and tops but angle both of them and then see what it sounds like wIth the 2.5khz crossover seeing as i got them. To my ears i might not even notice any combing or beaming as i dont even know what it is or sounds like. So ill see how it goes.

Or am i massively going to notice these issues? I dont know how in depth or audiophile you guys are?



Posted By: Peter Jan
Date Posted: 05 May 2020 at 9:04pm
I actually meant on the speaker cable leading to the mid speaker, for no other reason than the lack of space on the PCB itself. Changing that inductor L1 with a higher value does the exact same thing, but there wouldn'd be a "loose" part outside the PCB, that all. That's why I said more tidy.

Adding value to the capacitors is easier, because there is space provided on the PCB to add extra parts.

Not a bad idea to build it for now just as is and go from there.
Beaming/combing issues won't be noticeable to the novice speaker builder ( even many experiences builders won't hear it either ), especially when you sit in front of it and dont move around while listening. The issues become clear once you start to walk around, you will notice no two positions in the room are the same soundwise and while moving/walking around, you will hear a constant changing of sound.


Posted By: Bams
Date Posted: 05 May 2020 at 9:13pm
This is one of the better topics in a long time.. learning along the way as i’m still in doubt of going for passive crossovers and a big amp vs a really old dsp and more amps on my rig. Thanks all involved!


Posted By: Jack1991
Date Posted: 05 May 2020 at 9:26pm
Ah right i understand now thanks again! So if i do decide i want to add the coil in series i can always do that easy enough at a later date. What size coil would you go with if adding one on the speaker cable leading to the mid? And did you say to do it on just 1 of the mids?

And oh okay thats good about it being unoticable to novice builders. I am mainly making this for a fun project and to learn a bit about the ins and outs of speakers. But also want to do it right too and not waste my time or money too i guess.

Thanks too Bams! Everyone has been really helpful on here im very grateful!


Posted By: Peter Jan
Date Posted: 05 May 2020 at 9:37pm
Originally posted by Jack1991 Jack1991 wrote:

Ah right i understand now thanks again! So if i do decide i want to add the coil in series i can always do that easy enough at a later date. What size coil would you go with if adding one on the speaker cable leading to the mid? And did you say to do it on just 1 of the mids?


Value in the whereabouts of 0,8 mH, so total value will be about 1,5 mH. On one of the mids only, that's it. Doesn't matter which one. If the 10" where to be mounted vertical, it would matter. Than it would need to be the one farthest away from the highs ( that's usually the bottom one Smile )



Posted By: Jack1991
Date Posted: 06 May 2020 at 10:00am
Originally posted by Peter Jan Peter Jan wrote:


Value in the whereabouts of 0,8 mH, so total value will be about 1,5 mH. On one of the mids only, that's it. Doesn't matter which one. If the 10" where to be mounted vertical, it would matter. Than it would need to be the one farthest away from the highs ( that's usually the bottom one Smile )


Lovely cheers peter! And last question... Does it need to be mounted to anything or can it just be "free living" inside the enclosure??


Posted By: Peter Jan
Date Posted: 06 May 2020 at 11:52am
It has to be fixed somewhere anyhow. An inductor is an hefty piece, that would rip connections fast if not properly supported. There's usually a hole in the coil carrier, where you can fix it with by means of a screw and washer or so. It's never a bad idea to put on some glue before screwing it down.


Posted By: Earplug
Date Posted: 06 May 2020 at 12:39pm
Originally posted by Peter Jan Peter Jan wrote:

It has to be fixed somewhere anyhow. An inductor is an hefty piece, that would rip connections fast if not properly supported. There's usually a hole in the coil carrier, where you can fix it with by means of a screw and washer or so. It's never a bad idea to put on some glue before screwing it down.


+1

Just don´t put any metal fixing down the center! That will change the impedance.



EDIT:-  Glue & zip ties are a good way of fixing for these.



-------------
Earplugs Are For Wimps!


Posted By: DMorison
Date Posted: 06 May 2020 at 1:57pm
Originally posted by Earplug Earplug wrote:

+1

Just don´t put any metal fixing down the center! That will change the impedance.



EDIT:-  Glue & zip ties are a good way of fixing for these.


To be fussy, a non magnetic screw like brass should be fine, but iron/steel are exactly as you say, not suitable.


Posted By: Jack1991
Date Posted: 06 May 2020 at 2:03pm
Perfect thanks again guys for all your helpful replies! 

Is beaming and comb filtering the same thing? Also would adding just this coil in series do the same job as angling outwards the mids? Just incase i end up keeping the mids facing forwards. As part of me is wanting to just get this project finished now to hear what it sounds like 


Posted By: Peter Jan
Date Posted: 06 May 2020 at 2:39pm
One simple screw does not alter impedance or whatever, maybe the inductance value will shift up by a tenth of a percent, but that's about it.

Beaming and comb filtering are not the same thing, but they are two phenomena that go hand in hand. Takes a bit more than a few sentences to explain.

Splaying will alter both phenomena to some extend, that it becomes less obvious and therefor somewhat "acceptable", but not make it go away.
Making sure one or more speakers in a group of speakers (producing the same frequencies) get less of those frequencies where the problem really kicks in, is just another way to kinda push the problems outside the frequency band they operate in.
It's all a function of frequency (wavelength) versus the dimensions of radiating surfaces (the speakers).






Posted By: Jack1991
Date Posted: 06 May 2020 at 5:28pm
Right i see thanks again Peter! Fantastic help and information much appreciated.

I have just finished altering the tops and mids and done a trial run and i MUCH prefer the look of it now. So not only has the function got better the form has also haha so double happy 😃 (my girlfriend prefers it now too so even better haha)

Here it is so far. Still all needs glueing etc so this is just a test to see how it looks.


Posted By: Jo bg
Date Posted: 06 May 2020 at 5:35pm
Clap


Posted By: concept-10
Date Posted: 06 May 2020 at 5:36pm
So nice to see a build on here, well done Smile


Posted By: Peter Jan
Date Posted: 06 May 2020 at 5:44pm
Looking good ! Thumbs Up


Posted By: Jack1991
Date Posted: 06 May 2020 at 6:17pm
Cheers guys! Happy with it all so far 🙂👍🏼

Hopefully get it all glued tommorow if im home early enough from work. Then over the weekend should get edges routered, then filled and sanded. Then i can finally test it all before painting (well wood dye and danish oiling)



Print Page | Close Window

Forum Software by Web Wiz Forums® version 12.03 - http://www.webwizforums.com
Copyright ©2001-2019 Web Wiz Ltd. - https://www.webwiz.net