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New single BR

Printed From: Speakerplans.com
Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=103425
Printed Date: 05 July 2020 at 9:12am
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com


Topic: New single BR
Posted By: smitske96
Subject: New single BR
Date Posted: 12 March 2019 at 11:09am
And there I am again with again opting for a BR build LOL
My current setup is not suited anymore , so I'm looking for something new and smaller.

What do I need?
-Not more then 300L external
-Low profile so it's easy to stack two + top cabinet with pole
-Strong till 35 Hz
-Output good enough for It's size

So obviously this can be done with some BR cabs!

At the moment I'm busy with designing a cab with triangle ports (and I know the tradeoffs), but they are pretty big (short sides 17x17cm).
Internal net volume will be laying (ideally) around 180L, but then comes the drivers choice..

Current short(long)-list:
-B&C 18SW115, absolutely a beast but maybe overbuild for BR applications.
-B&C 18SW100 little brother of the 18SW115 but more suited parameters for BR applications (sims also better then 18SW115). 
-18sound 18TLW3000, I'm reading some pretty good reviews of it on German forums, and some even say it's better then the 18SW115 in a BR cab, but also the most expensive option.
-Faital Pro 18XL1600 can't find much about this driver but it simulates good in winisd.
-Faital Pro 18XL2000 Spec wise looks allot like the 18SW115
-RCF LF18N405 new RCF driver which It hink they use in their new high-end BR cabs
Current amplification is Crown IT-8000, but I'm planning on an upgrade in the future.

Obviously the best way would be to test all drivers in practice but I just can't afford that, so I'm depending on reviews to shorten the list to two drivers, maybe three drivers to test.
I'm planning on finishing the first drawings this week, so will post them by the end of this week.



Replies:
Posted By: Jo bg
Date Posted: 12 March 2019 at 5:49pm
Hi Smitske, we seem to follow similar paths again

I am keeping the bigger system but planning from long time to build smaller BR subs for dj booth/b-rig, with aim more to quality and decent extension than spl.

I am using 18sw115 in my ths so i thought about using them, they allow for very small enclosures, but went for cheaper ceramic b&c 18tbw100 instead.
i got a good price on second hand and decided i didn't need the ultimate output (and premium price) of 18sw115, still got the tapped horns for huge spl.

So i've got the drivers sitting there, i settled on a design with shelf port like the b&c sub, and ended around 180 internal liters too as good compromise (in winsd at least, but i'm gonna keep an option open to play with port lenght once the first is built and measured), but can't fine the time to finalize this and start the build righ now.
so i am following!





Posted By: RoadRunnersDust
Date Posted: 12 March 2019 at 9:54pm
look up Scott Hinson on FaceAche... He's put together a fairly comprehensive DIY design for about what you're looking at



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Buying myself a TFL-760H... piece by piece >.<


Posted By: smitske96
Date Posted: 12 March 2019 at 10:49pm
I've read the write-up it does look good but the single version does need some extra port area for drivers with more xmax. The dual version has more , but is not ideaal with handle placement. I would like the cabinet as high as ~50cm in normal use, so having handles on the side is the goal. Also designing something on your own is always more fun Smile


Posted By: JonB67
Date Posted: 12 March 2019 at 11:28pm
Originally posted by smitske96 smitske96 wrote:

Also designing something on your own is always more fun Smile

Totally, which is why i came onto this forum to learn enough to do just this.

Its a sense of satisfaction to know that your cabs are built to do what you wanted, not what someone else needed!


Posted By: Crashpc
Date Posted: 13 March 2019 at 7:13pm
Hey smitske. Apart from PM, here once again.
All else being equal, if you have good amp giving you good voltage swing, you always go for driver with more displacement volume and motor force. These are basic predispositions for output. There is no reason why 18SW100 should win against beastier beasts.

With WinISD and many other simulators, you do not see full story. It looks at the speaker in not very good angle of view.

I put my 21DS115 in 125l box, and I still thing it has great power density and size/value ratios compared to some mentioned drivers.  The maximum SPL output should also be greater.
Do not look at sims for optimums. It usually doesn´t show you efficiency, and large signal reliability, which are major elements in the equations. These are "completely" missing in many simulators.


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: smitske96
Date Posted: 14 March 2019 at 1:41pm
I'm indeed opting for a 21", but the main problem would be it's hight. 55cm would be the max, so I'm busy with designing a 21" reflex which is only 55 high 65 wide and atm 80cm deep. It looks like the TW audio BSX cut in half but frontal area is smaller. Port is ~62cm x 10cm , and also pretty long.


Posted By: smitske96
Date Posted: 14 March 2019 at 7:13pm
So at the moment I'm also busy with the 21" version for the B&C 21DS115-8.
Main problem is the max height of ~55 cm , so I have to angle the driver.
Main disadvantage is the wasted space in front of the driver, it also needs a big port(s), so another challenge. I'll probably get some gain from the angle but higher up then the desired response, which is 30-90 Hz.

This is the first sketch (absolutely not the final one):

-The driver panel can be shifted forward some more for extra internal volume.
-Extending the port in front of the driver panel is an option, but would give me some problems with installing/uninstalling the driver. So making that part removable or mounting the driver from the inside via a removable panel above is necessary. If done this way the port can be made shorter in the back which results in more net internal volume.
-There will be bracing but not on the sketch yet.

Why 21"? First of all I'm still not sure which way to go.
The 21DS is pretty cheap for me (10 euros more then the 18SW115)
And ofcourse I'm after max results from what is possible.




Posted By: Crashpc
Date Posted: 14 March 2019 at 7:27pm
To me it looks like the volume available for the driver would be about 100l. That is finally too small for 21". You really need to get to 125l or above for fastest drivers like 21DS115. 18" makes more sense here, for cone excursion reasons. Namely 18DS115, or possibly models with more cone excursion (Faital? BMS?). The 21" would not move enough to cool itself down.


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: smitske96
Date Posted: 14 March 2019 at 7:43pm
At the moment net volume is 110L, moving the driver panel a bit to the front and extending the port to the front gives 20L extra. Also the depth of the cabinet can be made 85cm which gives another 15L. So 145 L total.


Posted By: Crashpc
Date Posted: 14 March 2019 at 7:56pm
Yes. The speaker takes about 10l, handles and braces usually another 5l. So with those enhancements, you´re at 130l netto, and that´s the way to go. You either make it hard (but I support this extreme approach), or you go easy with 18". The good thing is that with the hard approach, it is proved that it works with this driver. The outcome and output will be there. I didn´t have such luck with developing other boxes though. My 21DS115 now sits in 125l box happily, so if you have the nerve to make difficult box, I encourage you to do that with this driver...

How about your amplifiers for these beasts? You need to get some amps capable of delivering high output voltages. 120-140VRMS is preferable for harder music, 140-180V for milder program content with 8Ohm drivers.


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: smitske96
Date Posted: 14 March 2019 at 7:58pm
At the moment it is a crown IT8000, but on a later stage I want to step up.



Posted By: Crashpc
Date Posted: 14 March 2019 at 8:06pm
That looks very usable for starters. You´ll see then....


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: bob4
Date Posted: 14 March 2019 at 8:54pm
What about mounting the driver in reverse, mgnet out?


Posted By: smitske96
Date Posted: 14 March 2019 at 10:52pm
Originally posted by bob4 bob4 wrote:

What about mounting the driver in reverse, mgnet out?

That I haven't thought about that Embarrassed



Posted By: mini-mad
Date Posted: 15 March 2019 at 12:42am
Originally posted by smitske96 smitske96 wrote:

Originally posted by bob4 bob4 wrote:

What about mounting the driver in reverse, mgnet out?

That I haven't thought about that Embarrassed


THATS how I thought you was mounting it in the 1st place.. then you lot were talking about driver displacement and I was like "why would that affect it when the magnet is facing out anyway??"


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If it sounds like a gorilla is trying to escape, turn it down.


Posted By: Crashpc
Date Posted: 15 March 2019 at 5:01am
Good point. I forgot about this possibility. That is another 20l, or so...
And possibility of hearing some chuffing in larger excursions. On the other hand, 21DS115 isn't that loud. The large excursion behavior is "cultivated".


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: smitske96
Date Posted: 15 March 2019 at 11:01am
Sometimes it's so obvious that you don't see it. But that's probably the way to go.
Main challenge now is to find the best way to mount the driver in a doable way. So the front part of the BR port has to be removable. For now I'm thinking of using 4 Tnuts on the cabinet, and then screwe the panel inplace from above. Ofcourse also making everything as airtight as possible.


Posted By: smitske96
Date Posted: 23 March 2019 at 3:06pm
Update:

I'm almost certain I'm going the 21" way. Also slot port instead of triangles and normal driver mounting.
So I adjusted my demands a bit Smile. Current external dimensions: 590x740x780, also with these dimensions the cabs fit perfectly in my trailer. Port will be around 150x556 mm so 831 cm2 of port surface. 

Driver choice: Not sure yet, the RCF LF21N551 looks really interesting, but so does the 21DS115.
Probably gonna buy both and test.


Also busy with a dual 10 design for above the subs. Thinking of D&B Q style but with lower xover >900 Hz, also looked at Acoustic line K20 and TW audio T20, but the horn mounting would be a challenge. When I'm more busy with the design it probably deserves it's own topic Thumbs Up


Posted By: MarjanM
Date Posted: 23 March 2019 at 3:37pm
Have you managed to do some simulations?
High BL drivers in a reflex box will have a dip in the 50-60 region. That is exactly where kick drum fundamentals are.
A loss of 3db in that range is not a good thing to me.
Most of the drivers you are listing are mor esuited for horn loading.
They will drop low, but they know to sound a bit "slowish" because the dip in the responce that makes them lose some impact in the kick region.


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: smitske96
Date Posted: 23 March 2019 at 4:07pm
I did, It falls of a bit after 100 Hz. Main problem is that there are not much high Xmax drivers with not that high BL.
18TLW3000 would still be first choice but it's even more expensive then the 21DS115.. 

Edit: the newer RCF LF18N405 looks good but limited experience because they are pretty new.


Posted By: corell
Date Posted: 23 March 2019 at 4:27pm
You can allways decrease BL by having a resistor wired in serial but not the other way around. Ofcourse you can Do the same with EQ. There is no Problem with a high BL driver as long as you dont expect it to Play flat out of the box with no processing.


Posted By: MarjanM
Date Posted: 23 March 2019 at 5:16pm
Resistor in series with a 1800W driver? Where do i find 1800W resostor?
If you look at the impedance plot and excutrsion plot, you will se that max excursion is exactly where the dip is. So boosting is out of the question.
Cutting some at 40hz means you are deleting the main advantage of such driver and just waisting resources.
18TLW3000 is cheaper then any high power neo B&C. You are just not shopping at the right place.


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: smitske96
Date Posted: 23 March 2019 at 6:15pm
I almost looked everywhere and the 18TLW300 is still more expensive..
18TLW3000 = 385,-
18SW115 = 343,-
18SW100 = 275,-
LF18N405 = 290,-
21DS115 = 382,-


Posted By: Crashpc
Date Posted: 23 March 2019 at 8:08pm
Uh, oh!
Corell is right, but there is no reason to decrease Bl.
There is no easier way than EQing things out, as the driver will like it. At no point, it would bottom out sooner than "lower Bl driver" when all else being equal.  Quite the opposite.
21" in compact box already suffers from low cone excursion and poor cooling. Putting some  Juice in greatest cone excursion range is about good thing, to get the coil ends cooled down.
In compact box, there is not much of a dip to speak about. Rather steady sensitivity decrease. That is easy to handle.
Weaker driver already has more cone excursion to begin with, because more power goes in with usually lower impedance.  Higher BL driver gets less power, due to the higher impedance. Only where strong motor driver struggles is amplifier capabilities. One needs greater voltage swing to feed the driver with sufficient power. I would greatly recommend RCF LF21N551 if money allows, then 21SW152 for torture, then 21DS115 for digging deep with sensible program content.


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: smitske96
Date Posted: 24 March 2019 at 11:08pm
@Crashpc

Do you have any measurements of your current box?


Posted By: Group2
Date Posted: 25 March 2019 at 6:02am
interesting, following. 


Posted By: Crashpc
Date Posted: 25 March 2019 at 7:46am
Smitske: Not the one I would like to share, but it is coming soon.  Slight peak at BR tuning frequency is there,  but within 3db range, which would help to make the characteristic flatter after HPF subsonic application. 
It is more complex than that though. With efficient driver, one should even think about very different approach.  I'm now exploring possibilities to drastically downsize the bassreflex port volume without any side effects for my setup, as the port might be used less (for PA, cut HPF at, or above port tuning frequency). I have yet to compare efficiency compared to closed box, and the port might actually only remain in the box as a cooling tunel changing air in the box for fresh one. I'll keep you updated.


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: Crashpc
Date Posted: 25 March 2019 at 8:13pm
Okay. After some sims, it really looks to me like this approach with cutting at the (low) port tuning frequency might actually work well for PA. In the meantime, I jumped on the other project of my adequately small 10"+1" tops. Hopefully I don't stagnate, finish tuning these (3d printed custom horn  for driver can be pain in the arse to develop) in oncoming two days, and get back to finish squeezing that 21" box into absolutely final version at dimensions 58*58*73cm(75 with legs). Measurements will be made and published.

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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: smitske96
Date Posted: 26 March 2019 at 2:17pm
Okay current options:

21" reflex with the 21DS115 which would need some EQ at 50/60 Hz..
18" reflex with 18SW100, RCF LF18N405 or the 18TLW3000.

Current amp is the itech 8000 which can do 200 V max (k20 or so in the future).

The 21DS stays well within excursion limits when feeding it 2000 Watt.
18TLW3000 goes past xmax around 50 Hz, and both 405 and SW100 stay within their limits. I have to add I uses Xvar for the SW100, don't know how far the other drivers can be puched within some limits.

I'm now leaning to 4 18" BR with the option to add two in the future..
So many options and dilemma's Cry 


Posted By: toastyghost
Date Posted: 26 March 2019 at 2:33pm
Those drivers might not exceed excursion at that power level but you can be damn sure they’ll get hot if you give them that long term. The ‘real power’ for the 21SW152 from the Klippel data provided by B&C shows approx 900w max with 4dB+ power compression in free air.

So make sure you have peak and RMS limiting if you need to eke out maximum performance as well as some semblance of longevity from the box.

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http://www.neuronproaudio.co.uk" rel="nofollow - http://www.neuronproaudio.co.uk


Posted By: smitske96
Date Posted: 26 March 2019 at 3:53pm
I had some spare time so did some quick simulations in WinISD.

21DS115 180L 32Hz:
 

LF18N405 180L 33Hz:
 

18TLW3000 180L 32Hz:
 

18SW100 180L 35Hz:
 

18SW115 180L 32Hz:
 


Max SPL when fed 2000Watt:

Blue: 18SW100
Yellow: 18TLW3000
Red: LF18N405
Green: 21DS115
Purple: 18SW115




Posted By: Crashpc
Date Posted: 26 March 2019 at 9:35pm
Not that I would encourage anybody to torture their speakers, but in real life, it might be less demanding than klippel test. If we consider different program content, better cutoff between 30 and 95Hz, real power VS apparent power, those beasts would withstand 4kw peak and 1kW RMS from the amp without much issue. BUT,one still can burn the speaker, if it is pushed steadily as one note bass line situated on box bassreflex tuning frequency, where apparent power is also real power, and where the voice coil doesn't move s lot. Therefore poor cooling.

I cannot agree with these sims. Very inaccurate. Hornresp might do better job regarding SPLmax.


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: toastyghost
Date Posted: 26 March 2019 at 9:41pm
Originally posted by Crashpc Crashpc wrote:

Not that I would encourage anybody to torture their speakers, but in real life, it might be less demanding than klippel test. If we consider different program content, better cutoff between 30 and 95Hz, real power VS apparent power, those beasts would withstand 4kw peak and 1kW RMS from the amp without much issue. BUT,one still can burn the speaker, if it is pushed steadily as one note bass line situated on box bassreflex tuning frequency, where apparent power is also real power, and where the voice coil doesn't move s lot. Therefore poor cooling.

I cannot agree with these sims. Very inaccurate. Hornresp might do better job regarding SPLmax.


Which is why I tend to do the maths and then drive the box hard with 6dB crest factor stressful music content to see if there’s any smell, clear thermal compression or change in impedance before settling on limiter values.

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http://www.neuronproaudio.co.uk" rel="nofollow - http://www.neuronproaudio.co.uk


Posted By: MarjanM
Date Posted: 27 March 2019 at 12:59am
As i have said, the highest BL drivers are the worst.
180lit box is really too small to justify using a strong 21 inch in it. I am not shure why you are focused on such small box. Something of 230-250 pure internal volume would make significant difference.
As someone have said earlier, there is no replacement for displacement.


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Crashpc
Date Posted: 27 March 2019 at 8:06am

toastyghost: Yes, that is one way to do that. And if it burns down for some reason, and it isn´t caused by operator, then one can conclude that he didn´t want such poor driver anyway. :-)

 

MarjanM: No. You cannot fully trust the sims here. Higher BL drivers have less desirable curve in voltage sensitivity graph. That is the only issue, rather related to the amplifier voltage “feeding” capabilities. Look at it this way. The driver has most displacement (cone area * cone excursion) capabilities. It has most motor force (Newtons pushed per Watt).

It has very nice force to cone mass and cone area ratio, usually better than its peers. At no point there is a reason it should behave worse, than weaker smaller drivers.

When we establish this, we need to do corrective action for the outcome we see in the simulator…

 

If a simulator tells you this wrong piece of data, then it is otherwise – something is wrong with the simulation. For the most part, it is the voltage driving of the driver.

The simulator does not show “2000W” of power to the speaker in the least. It cannot. It picks some arbitrary point, by which it decides it is 2000W, but it is not. It cannot be - for impedance and phase reasons. It seems that nobody cares about these, yet these are vital part of the driver evaluation.

 

You might spot, that those 18”s do have significantly more cone excursion in the same sim, than 21”. Cone excursion * cone area will make SPL. The allegedly weaker driver moves more air than strong 21” in the simulation. Doesn´t this look weird to you yet?

 

The 21DS115 still works superb down to 125l (tested), and will outdo most 18”. It will not run far though, but if one is after most power output density in smallest box, this is the way...

My person is focused on this approach because I want most compact setup that I can load into normal european sized car, do gig here and there, and still have nice compact setup that I can put back in the living room or "working room".

 

Last night, I about finished development of my 10" tops:

 

 

up to 1kW into each. Same reason. Highest power output density in a smallest box.

 

 



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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: snowflake
Date Posted: 27 March 2019 at 9:48am
if you want highest power per volume then look at B6 alignment


Posted By: Crashpc
Date Posted: 27 March 2019 at 10:55am

Of course, I meant highest power density with some fixed requirements like frequency range, or total output in some way. If there were no boundaries, most power would be achieved very different way. Two 18IPALs would definitely outdo one 21DS115 in the same box volume for SPLmax, no doubt.



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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: MarjanM
Date Posted: 27 March 2019 at 2:56pm
I have done tons of actual box/driver measurements to confirm that the sims are not entirely wrong.
They are more right then wrong. At the time when we tested different high power 18 inch drivers for our reflex products this was confirmed by measurements too. So we didnt go with the high BL driver at the end.
They do have more excursion, but when they are less sensitive, you need to apply more power to get them moving and compensate what lower BL drivers can do without the need of so massive excursion.
If your goal is more infra, then subwoofer, go with high BL. If you need to have more general purpose subs cpable of covering wide type of music material, then go with the lower BL drivers.


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Crashpc
Date Posted: 27 March 2019 at 6:27pm
I would mostly agree. For sake of getting to the point, I will skip these agreed parts.
Here is the core of the issue I see:

Originally posted by MarjanM MarjanM wrote:

...you need to apply more power to get them moving and compensate what lower BL drivers can do without the need of so massive excursion.


That piece of text is not right. One needs to apply more VOLTAGE to the high BL speaker, to even get to the same power.  High BL driver fed with the same voltage will get less power.
If you fed the high BL driver more voltage to feed equal power compared to the low BL driver, then it would be fair power comparison. It is not in sims and it is not with same approach/signal on particular amplifier in real life too. Voltage does not equal power, and that´s why the speaker output assesment is very flawed.

We would continue to discuss how hard is to feed the speaker, how hard is to find the suitable amp, and I would agree. Yet it is different topic.

Again. All else being equal, at no point speaker with more Newton force per Watt will create less displacement volume by its excursion, or exhibit less sound pressure. It is not possible to break basic physics with simulation with unequal circumstances for compared speakers.

There are caveats and exceptions to this, of course, but as nobody even touched these, I will ignore these for the moment.




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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: MarjanM
Date Posted: 27 March 2019 at 7:53pm
Voltage equals power when you connect a speaker. Right? So why is my part wrong?
If a given 8ohm driver does 95db with 2.83V applied, and the other makes 96db with same 2.83V applied, how do you compensate the 1db difference if you dont apply 30% more power? (higher voltage if we want to be pedantic)



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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Crashpc
Date Posted: 27 March 2019 at 8:56pm
No, voltage is not necessarily equal power.
Power *can equal Voltage times current. For current to flow, we need a conductor - speaker coil, or rather the whole speaker. Nominal impedance rating will not cut it. Different 8Ohm speakers have different resistance and impedance too. That will cause different amount of current to flow to the speaker at the particular voltage, and it will result in different amount of power applied.

The difference can be very significant. This difference correlates with speaker Bl to a point. All else being equal, higher Bl driver will have higher impedance, less current draw, so less power will be applied to it, so it will appear less sensitive.

Those speakers rather don´t have 8Ohm across their frequency range.
In extremes to show at least something, High Bl 8Ohm driver can have impedance peak of about 100-200Ohm. If you apply 2,83V to it, only 0,04W of power (P=U*I, I=U/R) will be applied. Not 1Watt.
At 0,04W for 95db, the speaker is very efficient then...

This peak happens to weaker drivers too. The point is, the peak is always lower, and it is more in phase. That means two things. One thing is that more power will flow for the same voltage, and that the apparent power = real power = all burnt as heat.

Hope it helped a little bit.
The knowledge of this is no win though. It comes with all kinds of obstacles and trouble to make use of speaker with such excotic and strong motor. You still have your important point right.
If one has an amplifier, and needs better speaker, higher Bl speaker might not be a good way, unless he is willing to change more expensive things in his setup for this advantage to take any effect. It seems that to fully utilize such driver, one needs amp marked as "4000W" (if not more) for each driver (even though the power will not need to be that high in real), and rather D-Class with Switched mode power supply amplifier, because even before counting for the nominal amplifier efficiency, one will burn 50% of the energy as a heat on the amplifier side on conventional AB/Toroidal supply amplifier. Due to the phase shifts, and difference between real power and apparent power.







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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: smitske96
Date Posted: 27 March 2019 at 9:11pm
At the moment it's the itech 8000, still one one the bigger amps available.
After that you have powersoft k20, X8 , pkn xe10000 and I will not mention the H8 Embarrassed 

Other update from my side of the project:
I can get a really good deal on 4 pro grade grills, and suitable for a 18" BR box (still a bit smal, but I'll make it work). 


Posted By: Crashpc
Date Posted: 27 March 2019 at 9:31pm
These are nice amps, and if speaker impedance is matched to the amplifier capabilities right, you are safe. What applies for 21DS115 still applies for 18"s too.... Get most refined drivers with best excursion capabilities, low Qes and high Bl. You will enjoy even more power density, as for example with B&C, same motor and coil structure is applied on more speaker sizes. Same motor, with just smaller speaker cone. Same analogy with V8 in a Minicooper. 😀 = Mordor, murder, terror....

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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: Crashpc
Date Posted: 28 March 2019 at 10:12am

MarjanM:

Here is example between 18SW100 and 21DS115 in 180l box with bassreflex port tuned at 35HZ.

I haven´t seen simulator software capable of showing all in one graph, so I will pick WinISD and I will pick discrete frequency to compare and see.

 

We feed both speakers exactly one watt of real power at 80Hz( real power = power burnt as heat, that´s what we should count when we are after speaker output and performance and loading capabilities).

 

How do we do that? We set Power P at 1Watt.

P = U*I*cos(θ).

We do not know current “I” in the advance, we count it from the equation I = U/Z. We put that in our first equation.

P = U*(U/Z)*cos(θ).

We want to feed one watt of power. Therefore P = 1W, therefore:

1 = U*(U/Z)*cos(θ).

We know Z and Cos(θ) from the simulation. It is shown in the “Impedance” and “Impedance phase” graphs.

At 80Hz, Z is 14,54 for 21DS115 and 11,98 Ohms for 18SW100. Cosinus(θ) is function of phase angle. 64° and 54,55° means cos(θ) for these speakers is 0,438 and 0,58 respectively.

So, for two speakers

1 = U*(U/14,54)*0,438 for 21DS115 and

1 = U*(U/11,98)*0,58 for 18SW115.

 

For 1Watt of power, the voltage needed to go into the each speaker is:

5,77V for 21DS115 at 80Hz.

4,55V for 18SW100 at 80Hz.

Now let´s look at graphs with this value set (21DS115 is green). Don´t forget to look only at 80Hz, because in different frequency points, the situation is different.

At some frequencies, 21DS115 would not run away or win, in some frequencies it runs further:

 

 

Interesting thing is, what Winisd thinks is the power in watts, down in the window. It says 3,9W for 18SW100, while it says 6,5W for 21DS115….

That is not the power going to the speaker…

 
 

// EDIT:

I counted SPL for each 10-100Hz points and 200Hz point for 21DS115(red) and 18SW100(green) with 1Watt of real power input at each point. Here is the outcome. The graph basically shows efficiency curve:

 

Taking more cone displacement capabilities of 21DS115 and larger coil into account, it should outperform 18SW100 by about 3dB at SPLmax I would guess.

//I see different outcome between my first and second try. First time I didn´t put that much effort into describing general thing and counting with tiny fractions. There is still room for mistakes, things take time, which I don´t have in the required amount...



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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: MarjanM
Date Posted: 28 March 2019 at 6:44pm
Why are you calculating at 80hz. The problem is at 55-60hz, not 80 hz. At 80 hz you will probably lowpass and be at -3 db or so against the average sensitivity.

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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Crashpc
Date Posted: 28 March 2019 at 8:56pm
It´s just one randomly picked point. In my last table, it is visible that even at 60Hz, 21DS115 still has 2,25db advantage over 18SW100, both at 1W. While 21DS115 having larger coil, it is expectable there will be 3db maxSPL difference. The last graph was created the same way as 80Hz calculation, I just put each calculation at "respective 10Hz mark" in the graph to see the whole picture across frequency range. I cut my subs at 95Hz for PA.


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: MarjanM
Date Posted: 28 March 2019 at 10:25pm
This is all good, but my comment was high bl vs not so high bl drivers. Not 21 vs 18. That one is very obvious.
Try that same math and compare 18SD115 and 18TLW3000. And take 55 or 60hz or whichever frequency it the point of the dip at the 18sd115. Or 18sd115 vs 18sw100.
It would be interesting to see that comparison.


-------------
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Crashpc
Date Posted: 29 March 2019 at 7:18am
My eye caught this claim:
 
"As i have said, the highest BL drivers are the worst. 180lit box is really too small to justify using a strong 21 inch in it."
 
When we revealed otherwise, it is not fair that it is 21" now hehe....
Just joking. The trend is obvious. All else being equal, higher Bl is a good thing.
If we put a single wire near the magnet, and Bl will be closer to 0, no doubt it will not play loud.
 
//EDIT
 
It might be, that at some point, resonant nature of weaker driver with loose suspension might win for part of the frequency range. That is good argument. Yet overall efficiency is more than that. And we don´t have an idea how these speakers behave with large signals, where things get very different.
Now, I prepared few sims and graphs, lets analyze 180l box, 32Hz tuning for all...
 
Dark blue:  21DS115
Light blue / cyan: 18DS115
Green: 18TLW3000
Red: 18SW100
 
 
Seems that 21DS115 is inferior and 18DS115 is in big trouble, right?
Now lets see strict 1W comparison:
 
Same colors. 21DS115 mostly leads the pack, 18SW100 and 18TLW3000 good, 18DS115 only good in 30-40Hz and 90-100Hz region, bad in 50-80Hz range. Why is that? Bl? Nope.
I would like to point out the 50Hz point. In first sim, it looks like 18DS115 struggles at 50Hz, yet in the second graph, it is on par with 18SW100 at 50Hz.
 
18TLW3000 has loose suspension with Qms of 13, While B&C is just over 4. That means less dampening, less backwards and restoring force, more sensitivity for TLW. Nothing to do with magnet. To prove that, I added Yellow - 18DS115 with still tighter than 18TLW suspension, but looser than original one. And again, stronger motor wins then. If I set the stiffness the same way, not to mention cone weight, it would trash 18TLW badly.
Yet it is only desired speaker, not existing one. 18TLW might be better choice for bassreflex box.
If box width is not issue, 21DS equipped with the same motor structure as 18DS still makes the cut...
For some reason, B&C does stiffer cones. That´s the one thing I do not understand.
There must be some reason for that....
 
You might spot, that there are differences between original graph in previous posts and this one. Yes. Different rounding of numbers, a lot of data - some small mistake here and there can be. Yet I believe there is no consistent mistake, that would influence all points in the frequency range...
 
Hope it was valuable response...
 
 
 
 
 


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: smitske96
Date Posted: 02 April 2019 at 11:56am
Great effort for showing the graphs Clap
For my personal project I went with the 18", the grills are just to cheap for not doing it.
I'll keep you updated!


Posted By: Keen
Date Posted: 08 April 2019 at 10:55am
"Q is a measure of energy stored divided by energy dissipated, meaning that higher Q means more energy storage Wink "Dissipated energy" is loss"
Joachim Gerhard of Audio Physik
 
So high QMS is stiffer supspension.

21DS115 and 18DS115 are horn drivers, thick heavy cones, big motors, low damping (because the bass horn does the damping)

the others are more suited to reflex.

hth


Posted By: Keen
Date Posted: 08 April 2019 at 10:59am
It's a bit tricky getting your head around Q, I haven't yet, and I remeber lots of seemingly contradicting statements that only make sense once you learn more. 




Posted By: Crashpc
Date Posted: 08 April 2019 at 9:50pm
Eerr Low Q means high damping, not low....
It is also obvious from low voltage sensitivity 18DS115 has.
It is not a good idea to chase low Qs with no other reason in mind. Low Qs really can get to a point of being enemies, if rest of the setup isn't offseting it somehow. I take low Q drivers for better for very different reasons.


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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: odc04r
Date Posted: 08 April 2019 at 10:11pm
Originally posted by Keen Keen wrote:

"Q is a measure of energy stored divided by energy dissipated, meaning that higher Q means more energy storage Wink "Dissipated energy" is loss"
Joachim Gerhard of Audio Physik
 
So high QMS is stiffer supspension.

21DS115 and 18DS115 are horn drivers, thick heavy cones, big motors, low damping (because the bass horn does the damping)

the others are more suited to reflex.

hth


Slightly the other way around I think unless my mind is wandering again. Q ~ (stored energy)/(energy lost per cycle) so comparing different systems with the same stored energy the one with the highest Q is losing the least energy per cycle. In case of suspension that would be a loose driver which has the least resistance to movement. You can also think of Q as proportional to the number of oscillating cycles it takes a system to lose its stored energy.

A stiff suspension driver that offered higher resistance to movement would have a comparatively lower Q value as it would dissipate the same stored energy in less cycles, because each one is performing more work.

Think of it is your large voice coil strong motor drivers are all low Q(es) because the strong motor makes them highly electrically damped. Same works for the mechanical damping which is often also seen in lower Cms and higher cone mass for lower Q(ms) drivers. And then all of this features into with Fs also.

Q is quite a mathematical abstract thing, but it directly relates to the linear coefficient term of 2nd order differential equations which are also the same reason people talk about alignments such as Butterworth etc.  All loudspeaker equivalent circuits can be simplified to a series of 2nd order equations working in parallel with each other.




Posted By: smitske96
Date Posted: 08 April 2019 at 10:16pm
I've shortened the list to these two drivers:
18SW100
LF18N405

At the moment the 18TLW3000 is not worth the extra 400,- for four drivers.


Posted By: Crashpc
Date Posted: 09 April 2019 at 5:16am
What drives this choice? I would be thinking between LF18N405 vs 18SW115 at that point  

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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: Keen
Date Posted: 09 April 2019 at 9:31am
Originally posted by odc04r odc04r wrote:

Originally posted by Keen Keen wrote:

"Q is a measure of energy stored divided by energy dissipated, meaning that higher Q means more energy storage Wink "Dissipated energy" is loss"
Joachim Gerhard of Audio Physik
 
So high QMS is stiffer supspension.

21DS115 and 18DS115 are horn drivers, thick heavy cones, big motors, low damping (because the bass horn does the damping)

the others are more suited to reflex.

hth


Slightly the other way around I think unless my mind is wandering again. Q ~ (stored energy)/(energy lost per cycle) so comparing different systems with the same stored energy the one with the highest Q is losing the least energy per cycle. In case of suspension that would be a loose driver which has the least resistance to movement. You can also think of Q as proportional to the number of oscillating cycles it takes a system to lose its stored energy.

A stiff suspension driver that offered higher resistance to movement would have a comparatively lower Q value as it would dissipate the same stored energy in less cycles, because each one is performing more work.

Think of it is your large voice coil strong motor drivers are all low Q(es) because the strong motor makes them highly electrically damped. Same works for the mechanical damping which is often also seen in lower Cms and higher cone mass for lower Q(ms) drivers. And then all of this features into with Fs also.

Q is quite a mathematical abstract thing, but it directly relates to the linear coefficient term of 2nd order differential equations which are also the same reason people talk about alignments such as Butterworth etc.  All loudspeaker equivalent circuits can be simplified to a series of 2nd order equations working in parallel with each other.


Hi odc04r, can you have a look at page 11 here:
https://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Dynamical%20Measurement%20of%20Loudspeaker%20Suspension_Klippel.pdf" rel="nofollow - https://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Dynamical%20Measurement%20of%20Loudspeaker%20Suspension_Klippel.pdf

I'm reading it as: if losses of suspension parts are low, Qms is high. So if the suspension is losing nothing the QMS is infinite. Is it logical to then think a stiffer suspension is losing less, to its opposing force???

Many thanks


Posted By: toastyghost
Date Posted: 09 April 2019 at 9:32am
Just to throw a curveball, I may have some 21SW115 that I can do a pretty good price on...

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http://www.neuronproaudio.co.uk" rel="nofollow - http://www.neuronproaudio.co.uk


Posted By: odc04r
Date Posted: 09 April 2019 at 5:17pm
Originally posted by Keen Keen wrote:


Hi odc04r, can you have a look at page 11 here:
https://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Dynamical%20Measurement%20of%20Loudspeaker%20Suspension_Klippel.pdf" rel="nofollow - https://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Dynamical%20Measurement%20of%20Loudspeaker%20Suspension_Klippel.pdf

I'm reading it as: if losses of suspension parts are low, Qms is high. So if the suspension is losing nothing the QMS is infinite. Is it logical to then think a stiffer suspension is losing less, to its opposing force???

Many thanks
[/QUOTE]

The first part is right, if you have zero loss then QMS is infinite and if you were to excite the speaker then after you tool the signal away it would continue to move forever assuming no electrical losses. Think of a bell that rings for a long time when struck, that is a low loss high Q system.

When you model a speaker's mechanical side there is an inductor, resistor, and capacitor in parallel.  The inductor represents accelerating the speakers mass, the resistor represents the losses in the movement, and the capacitor represents the Cms of the driver which is the 'stiffness' as it defines how for the suspension wil move given an applied force. Because dispacing the suspension from its rest position stores energy (restoring force wants to go back to the centre) it behaves like a capacitor. So in the T/S modelling the stiffness of the suspension is considered seperate from the mechanical losses.

However in real common sense terms, you would consider that if a driver had high stiffness (low compliance) then your mechanical losses might also generally be higher. But not necessarily so...




Posted By: Keen
Date Posted: 10 April 2019 at 12:19am
thanks


Posted By: odc04r
Date Posted: 10 April 2019 at 7:51am
Was thinking a bit more on this, if you consider the modelled Cms as lossless (no capacitor in the real world is, but modelling...) then a stiffer suspension means for a given force a driver will displace less from its rest position than another with a higher compliance. But it doesn't tell you anything about how the motion of the driver will dampen once the force holding it in position is removed and it moves back towards its rest position. This is where Qms comes into play, in conjunction with Rms which represents the mechanical losses of the driver. Just thinking from common sense I would wager Rms has a lot to do with driver mass, Sd, and air resistance in general.

Generally it doesn't matter a lot because Qms is seen in parallel with Qes such that Qes dominates, and Qes is often much lower.


Posted By: Crashpc
Date Posted: 10 April 2019 at 8:43am

I would be very afraid of such simplistic view, and very careful with conclusions based on these.

 For example B&C drivers are known for that the suspension is the main mechanical limit of the cone excursion.

Therefore at some point, mostly Cms eats up the whole force developed by the voice coil (which is not that high, with 50% or more coil out of the magnetic field).

The Qms and Qes relations only work with small signals, and relations can get absolutely different in not that high excursion.

Also carefully about ignoring certain elements in the math, as their chronology is important for the outcome. Rms is not just static parallel element to the Cms and for all frequencies. You cannot deduce one from each other and count with it like that to reach the right outcome.

But I´m happy to see that communities are diving into this science deep stuff.. J



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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: odc04r
Date Posted: 10 April 2019 at 11:02am
Yes I should make it clear that I refer only to small signal models, anything large signal is a different model of behaviour entirely. You always have to beware of modelling limitations to use one properly.

Sure you can also have series resistances with Cms etc too, you can put a resistor pretty much anywhere in an acoustic model to represent air leaks or enclosure wadding etc if you have a good reason to.

Another problem with regression of real data to TS models is that some elements (especially resistances) will compensate for the behaviour of one another. It is easy to overfit such a model with terms that can end up describing noise in the data - which is another world of science in it's own right.


Posted By: smitske96
Date Posted: 11 April 2019 at 8:04pm
The Br cab design is almost finished but, I'm also going to build two TH-18's.
They will look like the original TH-118 with only two handles and the two wheels, that way it's easy enough to roll them around for one person. 

So two BR cabs loaded with 18SW100-4, two TH-18 with 18SW115-4.
Reason for going for 4 ohm drivers would be that I've got some more amplifier choice, atm I'm looking at two K3 or one X4. 

Also grills:

They have two sparing for cardioid arrangment, not going to use them, but install the speakons just for the looks.


Posted By: Crashpc
Date Posted: 11 April 2019 at 8:20pm
The project looks interesting. Let us now about the results!😍

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Nikon and Canon people should not be married to each other. Why did you let this happen?


Posted By: IvCu
Date Posted: 12 April 2019 at 1:44am
Originally posted by smitske96 smitske96 wrote:

The Br cab design is almost finished but, I'm also going to build two TH-18's.
They will look like the original TH-118 with only two handles and the two wheels, that way it's easy enough to roll them around for one person. 

So two BR cabs loaded with 18SW100-4, two TH-18 with 18SW115-4.
Reason for going for 4 ohm drivers would be that I've got some more amplifier choice, atm I'm looking at two K3 or one X4. 

Also grills:

They have two sparing for cardioid arrangment, not going to use them, but install the speakons just for the looks.


If you are looking at X4 that is on markplaats now - it seems as a pretty nice deal! Smile



Posted By: smitske96
Date Posted: 12 April 2019 at 8:17am
I saw that one, but those fotos are from another ebay lot (which alrrady ended for a more normal price). So I don't trust it LOL


Posted By: IvCu
Date Posted: 12 April 2019 at 11:50am
haha apparently too good deal to be true, busted!! 


Posted By: smitske96
Date Posted: 12 April 2019 at 1:49pm
The only time I had such a good deal whas on my old PL380 , 450 euros Smile


Posted By: smitske96
Date Posted: 19 May 2019 at 2:38pm
Update: I've now got two Powersoft 3004PFC4 amps available. They would be ideal with 1X TH-18 and 1X top per side, running the TH-18 on two bridged channels. Other option would be to still go for 4X BR cabs, but the amp module would only give 1500 Watt per sub, which gives me no headroom Unhappy


Posted By: smitske96
Date Posted: 27 May 2019 at 6:20pm
Instead if another TH-18, I gave it a try to build a paraflex design.

Test cab (not finished):
Probably a bit light on bracing, but I'll see how it performs. Also the diagonal pieces will be added in the mouth.

Powersoft module:

If they pass the test, I'll build two out of ply, and add wheels and some small handles.


Posted By: Maze
Date Posted: 03 June 2019 at 1:02am
Originally posted by smitske96 smitske96 wrote:

Instead if another TH-18, I gave it a try to build a paraflex design.

Test cab (not finished):
Probably a bit light on bracing, but I'll see how it performs. Also the diagonal pieces will be added in the mouth.

Powersoft module:

If they pass the test, I'll build two out of ply, and add wheels and some small handles.


How did it go with this one? (the paraflex)

I'm might look to built these over the summer. I haven't heard them though, so I'd like to hear what you think of them.


Posted By: smitske96
Date Posted: 03 June 2019 at 10:12am
I've tested the cab 2 days ago, results where encouraging but it needed more bracing in the mouth. For me they go low enough, I used 24dB BW @30Hz, HPF and 24dB LR @80Hz NOTE: those filters where just figured on the go, so probably not optimal. For amplification I used one channel of a CTS-3000.

If possible I'm going to add some bracing in the next coming weeks and test again.
Also using the 21SW152 for the cab is on my mind.




Posted By: FrederikMA
Date Posted: 04 June 2019 at 6:56am
Those components are some powerful players smitske96. Does anyone have any background info on paraflex enclosures? When searching, paraflex seem to be the name of whatever hybrid of series/parallel BP6, transmission-line, tapped horn, planar wave or reflex one can come up with.

About drivers, if a Paraflex is anything like series BP6, low Qes is critical to low-frequency performance. In simulations I gained approximately 10Hz of extension (40Hz-30Hz) going from 21SW115 (Qes of 0,39) to 21SD115 (Qes of 0,24), in a 300L series BP6. Try to sim it if you haven't.


Posted By: smitske96
Date Posted: 04 June 2019 at 9:52am
Yes but using the 21DS115 in the type-C the width of the cabinet would become 81 cm.
Using the 21SW152 the width of 61 cm can be used due to the lower Le.

Until now I still don't know which driver to use. price difference is about 100 euros here.



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