Single sheet TH challenge

[jaysinet]

Hey Klampykixx....just out of curiosity for your examples of garage great and sports hall nice kick but not thumpy outside a short distance. How were you set up? All 4 SS15's together stacked? Two on each side? Corner or Wall? etc. I ask because I am finally planning on my horn sub build and DJ a lot of high schools with 2 or 3 basketball gyms for the dance. Just trying to get a reference for output and options since I am yet to hear an SS15 in person.

Thanks

Jay

[klampykixx]

post 1704 shows both setups

in the garage i had them stood up as two towers, which gave a really solid big rumble sweet spot about 2-4m back from the mouths, and stayed fairly constant right back beyond 20m away (in a straight line.) however, i didnt bother testing them in a single stack as i ran out of setup time.

in the hall however, i tried them as towers first, and then as a center stack. and as far as orientation, if you picture two basketball courts next to each other, the grandstand is on one side, and halfway across the second BBcourt at one end was where my kit was setup, aimed diagonally across the first court towards the grandstand

the towers sounded great in the sweet spot, but lacked that big single sub/bass-everywhere vibe

i then piled them together and the difference was massive. i doubt ill ever stack them separately again.

so, much better as a single stack. IMO.

ill up load pics later, pc is being annoying, but the layout is the same as post 1704, second pic.

[maxo]

Originally Posted by jbell

workable, yes. A couple db down vs the eminence in the 50-70hz range, and more expensive... It is out of xmax at 500 watts, However it does work.

The 4015lf is $100 cheaper from the same retailer....

I have a question,
can you have the same SPL's with 2 ss15's with 4015lf's
than with 4 ss15's with a less expensive driver ( less rms power rating )
?
just wondering as i have read that is best to drive them not so hard and
stack more instead of build a few and drive them hard
thing is the more compact my setup the better, however in want a stack of 4 in the future but certainly will start with 1 ( car setup to carry ) then 2 maybe i will need a small truck to carry 2 as i got a sentra , dont think that i can fit 2 in the back seat.

[weltersys]

Originally Posted by maxo

I have a question,
can you have the same SPL's with 2 ss15's with 4015lf's
than with 4 ss15's with a less expensive driver ( less rms power rating )
?

Maxo,

Doubling Xmax will give 6 dB more output (and requires about 6 dB more input power), the 4015 does not have double the Xmax of any of the suggested cones.
Doubling speakers , each at the same power, gives a 6 dB level increase.
Assuming a high Xmax driver capable of output equaling two lesser drivers, it would require 3 dB (or) more electrical power to do the same “work”, effectively four times the power in one driver, which most likely would result in thermal compression.

All the suggested light cone drivers are designed primarily for BR use, the 6 dB or so more efficiency afforded by the TH design puts a lot more stress on the cone, at X max the cone will have more output than in a BR, but also a lot more distortion.
The distortion is compounded by cabinet losses at high power using only 1/2” material, which flexes significantly even with the 3015LF when driven around 450 watts.

Bottom line: Far more clean output per watt available using multiple cabinets, slightly more output per cargo space using higher powered, higher Xmax drivers.

Art Welter

[NoDestiny]

Something I have heard over the years, but never tested...
Double displacement (cone area): +3dB
Double power: +3dB
Both: +6dB

But I believe there is a flaw there. Wouldn't it be that if you double your cone area AND power, you get +3dB? If you double your drivers and split the power to both (adjusting so they get 50/50 of the same amount of power prior and not letting the drop in resistance at the amplifier push more power than it was), wouldn't that cut the cone travel in roughly 1/2, giving no gain in displacement? Therefor, by doubling your woofers and doubling your power, you gain 3 dB? I have done research trying to find the correct answer and seems pretty debated. Seems simple enough to test scientifically.

I could be wrong on this. I have seen it calculated both ways. Obviously, the frequency response is definitely going to be extended with more drivers.

[maxo]

Originally Posted by weltersys

Maxo,

Doubling Xmax will give 6 dB more output (and requires about 6 dB more input power), the 4015 does not have double the Xmax of any of the suggested cones.
Doubling speakers , each at the same power, gives a 6 dB level increase.
Assuming a high Xmax driver capable of output equaling two lesser drivers, it would require 3 dB (or) more electrical power to do the same “work”, effectively four times the power in one driver, which most likely would result in thermal compression.

All the suggested light cone drivers are designed primarily for BR use, the 6 dB or so more efficiency afforded by the TH design puts a lot more stress on the cone, at X max the cone will have more output than in a BR, but also a lot more distortion.
The distortion is compounded by cabinet losses at high power using only 1/2” material, which flexes significantly even with the 3015LF when driven around 450 watts.

Bottom line: Far more clean output per watt available using multiple cabinets, slightly more output per cargo space using higher powered, higher Xmax drivers.

Art Welter

Ic, so even if you use good bracing inside the cabinet with 1/2" material you get significant flexes in the plywood ? i was looking at use 1/2" plywood instead of 3/4" but if 3/4" is the correct way to go... i will take the extra step
,altough does anybody have weighted finished cabinet with no driver of 1/2" material vs. 3/4" material ? to see how much weight you save and if it is worth to add more weight in favor of less distortion or you just plain go with the lightest material to save your back and can live with the negligible added looses

just wondering
Max

[jbell]

Originally Posted by maxo

Ic, so even if you use good bracing inside the cabinet with 1/2" material you get significant flexes in the plywood ? i was looking at use 1/2" plywood instead of 3/4" but if 3/4" is the correct way to go... i will take the extra step
,altough does anybody have weighted finished cabinet with no driver of 1/2" material vs. 3/4" material ? to see how much weight you save and if it is worth to add more weight in favor of less distortion or you just plain go with the lightest material to save your back and can live with the negligible added looses

just wondering
Max

A sheet of good 1/2" is about 40lbs. A sheet of good 3/4 is about 75lbs. Drivers are 10-25lbs. I choose 1/2" for obvious reasons. The only part of a SS15 as designed that has more flex than I care for is the front panel. A brace there would help. Also the mouth flexes if you don't have a metal grill or other bracing. Extra bracing only gains you a fraction of a db in my experience.

As art is pointing out, when you start getting to the limit of things, you just flat out don't get the extra spl you think you will. All kinds of losses start piling up, and the chance of smoking a driver goes up exponentially too. A pair of ss15 can fit (barely) in the back seat of many small cars, and then put your tops/amps in the trunk. For someone just starting out, that's where I'd go. Depending on your budget/weight you are willing to carry shows which of the 3 eminence drivers you should choose. The budget winner here is the kappa, at the expense of about 2-3db less max output vs the 4015lf. If a pair is all you can carry, and you have the amp, and need the spl -- the 4015lf is the way to go. If you have a truck and can carry 4, well then 4 of the kappa's is pretty interesting for budget reasons. If you have a bad back, don't consider anything but the 3015lf.

Making cardboard mock up's and then trying to load them in your car is the easy way to find out what fits, and what doesn't.

BTW, loading a car is a pain... if you can fit a hitch to your car, and then tow a small foldable trailer like this.... life becomes very easy.... it makes trips to the lumberyard to bring home more sheets of plywood for more cabinets easier too...

[Rademakers]

[/quote]so they get 50/50 of the same amount of power prior[/quote]If they're getting 50/50 instead of 100/100 the power isn't doubled at all?

Halving excursion equates to a 6 dB output loss, so -3 dB (50 instead of 100)equates to less then halving the excursion.

Wouldn't it be that if you double your cone area AND power, you get +3dB?

That would mean that either one of those two factors isn't effective. If you agree that doubling the power increases SPL by 3 dB, you're saying doubling the cone area isn't effective and vice versa.

Note that coupling is only effective if the cones are within each others range relative to the wavelength of the frequency.

.

[Djim]

@ maxo,

To bring it back to only the Panel thickness is not correct in my view. For instance, I prefer a very well braced ½” panel enclosures above any non-brace ¾” panel enclosure. Working with panels means they will flex no matter their thickness (or they become impractical heavy). Therefore in my view braces are not an option and panel thickness is a personal choice and a matter of your skills.

Braces don’t need to be thick either as long their contact surface with the panel is large enough. To get that large enough contact surface you can enforce the corners of the braces. If you use relative cheap hardwood joints, like they use for windows, it will damp the panel even better.

@ Rademakers,

Tiny correction :
“Note that coupling is only effective if the cones are within each others range relative to the quarter wavelength of the frequency.”

[maxo]

Originally Posted by Djim

@ maxo,

To bring it back to only the Panel thickness is not correct in my view. For instance, I prefer a very well braced ½” panel enclosures above any non-brace ¾” panel enclosure. Working with panels means they will flex no matter their thickness (or they become impractical heavy). Therefore in my view braces are not an option and panel thickness is a personal choice and a matter of your skills.

Braces don’t need to be thick either as long their contact surface with the panel is large enough. To get that large enough contact surface you can enforce the corners of the braces. If you use relative cheap hardwood joints, like they use for windows, it will damp the panel even better.

very interesting Djim , can you show some pics or examples of how good braces need to be done, i mean to be in the ballpark, i know that many people have their own way to do it and somepeople dont do it at all when using 3/4" material, but the less heavy the better , specially when you are not a teen anymore and your back cant take any more punishment or you cant hire a couple of roadies to setup up your linear arrays