Beyma driver looks promising for T39

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Think
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Re: Beyma driver looks promising for T39

#16 Post by Think » Thu May 25, 2017 6:00 pm

iliasroub wrote:I was in a hurry for a party and went ahead and ordered the Beyma SM212 drivers to build 3 18" T48's.
They were build to spec as I had the panels cut at a friend's CNC.
The result was amazing!!!
I compared them with my LAB 12 T48 and my ears could not tell any difference either in quality nor volume.
They went through a 50V limit 5 hour heavy bass music hammering and everything seemed ok.
.....
Still going strong?

The SM-212 is 5.5 dB more sensitive @40hz and 4.3 dB @60hz compared to the 12SW1300Nd. How much does that matter?
http://www.beyma.com/products/lowmidfrequency/112SM2128
http://www.beyma.com/products/lowmidfre ... 112SW13ND8

xmax is 8.25 vs 10mm, 350W vs 1200W, €100 vs €350, 10lbs vs 16lbs

Which will be the loudest at full power?

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Bill Fitzmaurice
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Re: Beyma driver looks promising for T39

#17 Post by Bill Fitzmaurice » Thu May 25, 2017 6:14 pm

Think wrote:
Which will be the loudest at full power?
The one with more xmax. You can't use the SPL measured in a wall to compare how they work in a horn.

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Re: Beyma driver looks promising for T39

#18 Post by Think » Thu May 25, 2017 6:38 pm

But why then is the 3012lf (9.1mm Xmax) equil or better in performance compared to the Lab12 (13mm) in Titans?

Is there a topic where I can find info on the the different speaker parameters in relation to performance?

Rich4349
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Re: Beyma driver looks promising for T39

#19 Post by Rich4349 » Thu May 25, 2017 7:48 pm

Bill Fitzmaurice wrote:
Think wrote:
Which will be the loudest at full power?
The one with more xmax. You can't use the SPL measured in a wall to compare how they work in a horn.
Isn't it the combination of Xmax times Sd?
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

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Bill Fitzmaurice
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Re: Beyma driver looks promising for T39

#20 Post by Bill Fitzmaurice » Thu May 25, 2017 9:02 pm

Think wrote: Is there a topic where I can find info on the the different speaker parameters in relation to performance?
Where horns are concerned there is not, outside of highly technical documents. The short answer is that all of the parameters matter, and you have to know how to use horn modeling software to make comparisons. Having 50 years of experience working with horns doesn't hurt either. :wink:

Grant Bunter
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Re: Beyma driver looks promising for T39

#21 Post by Grant Bunter » Thu May 25, 2017 9:43 pm

Think wrote:But why then is the 3012lf (9.1mm Xmax) equil or better in performance compared to the Lab12 (13mm) in Titans?
Horn subs drivers don't "complain" when nearing their limits, in other words, you don't hear them starting to distort like you would in a direct radiator sub.
If you drive horn sub drivers to hard, they simply fail.

This is why you voltage displacement limit the drivers in Bill's designs (and why the discussion is under the heading "protecting your drivers").

As Bill said above, all the parameters matter, but in decreasing significance.
The top 2 parameters are Xmax and impedance.
The 3012lf has lower Xmax than the Lab12, but higher impedance.
So the voltage displacement limit ends up being the same for those 2 drivers.

Also, the design dictates response, not the driver, in horn subs, so they will sound the same, and have the same output...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Re: Beyma driver looks promising for T39

#22 Post by Think » Tue May 30, 2017 4:59 pm

So I first need to have horn design skills to select an other then the recommended Eminence driver? :confused:

This problem for all outside the USA could imho only be tackeled by you, with a list of posible suitable alternative drivers per design based on specs. And when people report back their experiences like performance, durability etc. this data becomes more and more valuable.
People can look up the prices for those drivers localy and make a choice instead of a total guess, at least that is what this experience of selecting a driver seems to me.

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Re: Beyma driver looks promising for T39

#23 Post by Grant Bunter » Tue May 30, 2017 6:21 pm

Think wrote:
Bill Fitzmaurice wrote:
Think wrote: Is there a topic where I can find info on the the different speaker parameters in relation to performance?
Where horns are concerned there is not, outside of highly technical documents. The short answer is that all of the parameters matter, and you have to know how to use horn modeling software to make comparisons. Having 50 years of experience working with horns doesn't hurt either. :wink:
So I first need to have horn design skills to select an other then the recommended Eminence driver? :confused:

This problem for all outside the USA could imho only be tackeled by you, with a list of posible suitable alternative drivers per design based on specs. And when people report back their experiences like performance, durability etc. this data becomes more and more valuable.
People can look up the prices for those drivers localy and make a choice instead of a total guess, at least that is what this experience of selecting a driver seems to me.
No, you don't need horn design skills to select a driver other than Eminence.
Alternatives are listed in most plans, and if you want to look for other drivers, the most important criteria are there for you to see, and based on that, start searching. So it's not a total guess at all.
Bill mentioned some other manufacturers to explore in your "the box speaker" thread.

To suggest Bill should search for drivers right round the world re suitability would be outside the ethos of what he is doing with his designs plans. If he did, we wouldn't be able to buy them at $15 each. He selects the ideal driver, designs the cab, tests it, revises it if and when necessary, and releases it for us to build. Then he throws in some other driver options, as well as the most significant TS parameters, and we get to build and still save heaps compared to commercial cabs.

Would you try to say to JBL they need to offer you driver options in "x" cab. I don't think you would.
They build the cabs on the same basis. Use design parameters/TS specs for drivers, design the cab, build it, sell it for "X' dollars.

It seems your sticking point is driver purchase cost. It's a simple fact of life that quality drivers, as used in pro sound cabs, can be expensive. Yes, in some countries, they are more expensive than others.
They are like that because the company has to stand by it's product in that it will continue to perform day in day out, without a high rate of failure. Any company that sells cheap drivers that continue to fail will quickly disappear.

By your own admission, Eminence is available to you, but not at a cost you wish to justify buying.
Heck, cabs built on Bill's designs are already cheap compared to commercial equivalents and, at the very minimum, perform at least as well as, if not better than them.

There's a very old saying here in Australia that might be appropriate;
If something promises amazing performance, yet is so cheap, it seems to good to be true, then it probably is...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Bill Fitzmaurice
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Re: Beyma driver looks promising for T39

#24 Post by Bill Fitzmaurice » Tue May 30, 2017 9:16 pm

Think wrote: So I first need to have horn design skills to select an other then the recommended Eminence driver?
You asked which of two drivers would be the better. I told you.

byacey
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Re: Beyma driver looks promising for T39

#25 Post by byacey » Thu Jun 01, 2017 9:46 pm

Think wrote:So I first need to have horn design skills to select an other then the recommended Eminence driver? :confused:

This problem for all outside the USA could imho only be tackeled by you, with a list of posible suitable alternative drivers per design based on specs. And when people report back their experiences like performance, durability etc. this data becomes more and more valuable.
People can look up the prices for those drivers localy and make a choice instead of a total guess, at least that is what this experience of selecting a driver seems to me.
If you think Eminence is expensive, price out what TAD 4001 are going for these days...
Built
T48s
WH8s
SX212

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DJPhatman
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Re: Beyma driver looks promising for T39

#26 Post by DJPhatman » Sat Jun 03, 2017 10:53 am

byacey wrote:If you think Eminence is expensive, price out what TAD 4001 are going for these days...
Think is in South Africa, byacey.
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice

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Re: Beyma driver looks promising for T39

#27 Post by Bruce Weldy » Sat Jun 03, 2017 11:18 am

byacey wrote: price out what TAD 4001 are going for these days...
YOW :shock:

$3000 and it only can handle 30 watts.....granted, it's very efficient......but $3000? For a driver? And it weighs 25 pounds....

But, it does go down to 600hz....and I do like a lower crossover point.....maybe I'll pick up a few.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Re: Beyma driver looks promising for T39

#28 Post by Think » Tue Jun 13, 2017 1:01 pm

Bill Fitzmaurice wrote:
Think wrote: So I first need to have horn design skills to select an other then the recommended Eminence driver?
You asked which of two drivers would be the better. I told you.
:lol: Yes, and I thank you for that, but I also like to learn a little from this.
I'm the kind of guy who likes to figure things out and learn instead of asking 50 times. :ugeek:

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Re: Beyma driver looks promising for T39

#29 Post by Think » Tue Jun 13, 2017 1:05 pm

Bruce Weldy wrote:
byacey wrote: price out what TAD 4001 are going for these days...
YOW :shock:

$3000 and it only can handle 30 watts.....granted, it's very efficient......but $3000? For a driver? And it weighs 25 pounds....

But, it does go down to 600hz....and I do like a lower crossover point.....maybe I'll pick up a few.
If I had that money to spend on drivers I would ask Bill for a private consultation on location and spend it a lot better! :cowboy:

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Re: Beyma driver looks promising for T39

#30 Post by Think » Tue Jun 13, 2017 1:06 pm

I just got a private reply from the Beyma SM-212 user that they do well and he doesn't hear a difference in sound or loudness compared to his lab12's.

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