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Multi-Way Conventional loudspeakers with crossovers

The birth of a 15 inch woofer
The birth of a 15 inch woofer
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Old 23rd August 2019, 12:39 PM   #11
Sabbelbacke is offline Sabbelbacke  Germany
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Ah, now I get it - you want to build a speaker yourself (or let someone do it)...
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Old 23rd August 2019, 12:42 PM   #12
oks81 is offline oks81  Norway
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Hello!

I have simulated quite som drivers in winisd, and find there is not so many drivers available today with this kind of specs and t/s.
The Beyma mentioned I did not know about, but seems also no longer available.

In the simulation here you can see that the TAD TL1601B follows the same curve as the Snickers 15"
I have never heard the TAD but seems like a nice and good driver, a little expensive....It has a good reputation.
I have heard from BMS the 15N630 in 180 litre box tuned to about 25hz.
Think that BMS makes fine drivers with neo magnets and shorting rings.
In the simulation it follows about the same curve down to 30hz.
This curve I think is nice rolloff in bass for home use when adding room responce.

About the motor of this driver I think the best is that Snickers explains himself.
But it should be a dual VC with no DC components, big shorting rings, and the iron around the VC gaps driven to saturation.
Attached Images
File Type: jpg Snicker Bass TAD 1601b BMS 15N630.JPG (213.4 KB, 577 views)
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Old 23rd August 2019, 12:44 PM   #13
Snickers-is is offline Snickers-is  Norway
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Quote:
Originally Posted by chris661 View Post
Sounds interesting. Will it really stand 1KW long-term?
I've been thinking about aiming for more low-frequency extension for my PA system, and this looks promising.

Chris
Hard to say, but I could not care less. I use that number to avoid the software from taking any compression into account.

The motor will consist of a 3 inch coil former with two coils on it. That will give it the same surface area as a long 6 inch coil. In addition to that, there are about 28mm of open ends exposed outside the motor at all times. Since this driver produces 105dB SPL @ 10W, and most people will use at least two of theese, I do not think heat will be an issue. 105dB SPL might not sound like much, but a 1/8-factor is commonly used for calculating heating needs in audio applications. This means that an average power of 10W equals 80W, which means the traisnents are at 120dB for a pair of drivers (half space, 1m etc). And, last time i checked, that is quite loud.

But for PA, this driver might have a few disadvantages (that I think are advantages for high end audio). First of all, it will have soft suspension, and it will also have a large diameter spider and high (for a driver of this type) surround to give it a less progressive suspension.

Further, I have avoided forced air cooling since it is not needed, and I do not want to add losses that are not needed.

Last, but not least, as the aim was to get saturation (around 2.2T) in the poles, they are pretty thin. That means any case of over excursion will lead to a brutal decline in force factor once the coils start leaving their gaps.

But I am considering to add a shorted braking turn between the coils to handle cases of abuse. Maybe it could fit the application anyway, if you are more concerned with sound quality at (for pro use) moderate levels.

EDIT: I am not sure you want that kind of roll off for pro applications. Since pro applications are typically outdoors, or in significantly larger rooms, they might just lack the low end energy that you are after. But you could tune it higher in frequency and get a more flat result with the addition of more capacity as well.
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Last edited by Snickers-is; 23rd August 2019 at 12:47 PM.
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Old 23rd August 2019, 12:48 PM   #14
phase_accurate is offline phase_accurate
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It is not that thard to find 15" drivers that can achieve a response like that at the lower end. But it is difficult to find 15" drivers that can go that low AND than can be used up to around 800 Hz easily.

Regards

Charles
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Old 23rd August 2019, 12:50 PM   #15
oks81 is offline oks81  Norway
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That is correct phase-accurate.
Forgot to mention that
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Old 23rd August 2019, 12:51 PM   #16
Snickers-is is offline Snickers-is  Norway
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Quote:
Originally Posted by phase_accurate View Post
That would indeed be a nice woofer. Especially if it wouldn't cost as much as a TAD. There are not many 15" like the TADs available anymore, compared to the eighties when there were lots of woofers like that available from Fostex and Coral etc. But do you really want to bulid a monster sub-driver with that much of x-max and Pmax when you want to design a TAD equivalent ?

Regards

Charles
You are right, there are not many that fits that kind of tuning, and indeed are they mostly focused on pro applications rather than studio or home.

This is not a "monster sub-driver". The x-max will give some 3-4dB more capacity than the TAD, but the lowered distortion is more interesting than the added SPL.

I believe it will end up around 5-600 USD/pc, and it is hard to get a classic TAD, Coral, Altec, Fostex etc. for that kind of money these days.
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Old 23rd August 2019, 12:52 PM   #17
Snickers-is is offline Snickers-is  Norway
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Quote:
Originally Posted by Zvu View Post
Beyma 15K200 had almost exactly parameters from first post, disregarding Re and Bl of course. Low Fs, low Qts, High Vas, High Qms and Mms around 105gr, very similar Cms. Even a little better than proposed here me thinks. I listened TAD1601 and 15K200 and there is nothing between them actually, in terms of perceived sound quality.
I am not familiar with that Beyma driver, but in what way would you regard it to have more desirable parameters?
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Old 23rd August 2019, 12:56 PM   #18
Snickers-is is offline Snickers-is  Norway
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Quote:
Originally Posted by Lojzek View Post
Only the voice coil wires can easily weigh 70g. Will 40g be enough for the other moving parts?
Well, it is actually the other way around, the coil windings end up at 40g, and I have 70g for the rest.

This is, as you point out, important figures. Especially for midrange performance. A heavy coil easily kills an otherwise great driver.

The coils are single layer aluminium ribbon, and the VC is 76mm. If I were to use copper, and 4 inches, it would be significantly more heavy, probably more than the total Mms.

This is also some of the explanation to the high Re, but it is possible to reduce it by selecting a wider wire.
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Old 23rd August 2019, 01:09 PM   #19
Snickers-is is offline Snickers-is  Norway
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Quote:
Originally Posted by Sabbelbacke View Post
10-12mm real xmax is not easy to find on big subwoofers - but those have far more heavy cones than your model above...
As I wrote in a recent post, I will have around 70g for the excess moving parts, including the voice coil former. The former (titanium) is 6,5g, so the rest is for cone and suspension. This means there are around 50g for the cone alone. It that number was 30g lower, I would have 20g for the cone, and the coil would be almost twice as heavy. That would indeed have been a struggle.

For every gram you can shave off the coil, you get a stiffer cone that has to carry less mass.

Quote:
Originally Posted by Sabbelbacke View Post
24 Hz Tuning =! Roll off -6dB 30 to 35 Hz
In 150l, you will still need a very long port to get this low tuning - it will take a lot of volumen, so you have to give it little Port area, which is counter productive. Port area of 300 gives around 25 liters...

Put your driver in hornresp, you will see what is happening.
Also, max spl is not that great, even with this much xmax (which should be hard to achieve with this light cone...).
One can always use a passive radiator. But the bass reflex port with less than 15m/s for full excursion would be some 70cm long. If one sets the bar lower (plans to use it up to 8mm excursion, equaling around 123dB for a pair of woofers), they need only to be around 55cm long. If the ports are equipped with large flares, they can handle more than 15m/s without creating wind noise, and they would also have less defined ends, leading to a reduction in port resonances.


Quote:
Originally Posted by Sabbelbacke View Post
You could check for the Monacor SPH-390TC, which has a lot of xmax, low tuning... (I even have two of these here), but also more mms (which is unavoidable, in my oppinion).

BMS manages to get the cones pretty light compared to other high-excursion woofers from b&C, 18S, etc.... So take a look at the 15n850 (which I happen to have, too...) - I suppose the 150l will be a little to much for it...

Otherwise - these type os speakers were more common many years ago - but with much less xmax than you want...

I am very much familiar with the 15n850. It is on the heavier side, which is typical for high x-max pro woofer with some low end extension. So, as you say, there are not many left of this type of drivers in the market.
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Old 23rd August 2019, 01:10 PM   #20
Snickers-is is offline Snickers-is  Norway
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Quote:
Originally Posted by Sabbelbacke View Post
Ah, now I get it - you want to build a speaker yourself (or let someone do it)...
I will indeed build a bunch of them if there are some others interested also.
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