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Old 25th February 2011, 03:04 AM   #461
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Yes we are talking about PA here. It has been pointed out many times that the 3015LF likes a relatively big enclosure for proper LF response, so this is certainly not the right driver for domestic use. As jbell says, there are other more appropriate choices.

However, after reading about jbells 'clean bass' from his SS15s, I think this is the best bang for buck PA box out there; he also says he gets the feel of low bass from lifting 45Hz by a few db. My only worry is being stuck in a situation where the DJ plays music that requires sub-40Hz and my cabs can't provide them. But that again is only the rare occasion. Just trying to be prepared for all seasons.

jbell, in my previous post I included a fold of your SS15, edited by you to get more LF. Do you have a HR frequency response chart and other details. Thanks for sharing your wisdom and experience in such a marvellous, practical way.
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Old 25th February 2011, 04:26 AM   #462
jbell is offline jbell  United States
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Quote:
Originally Posted by Samuel Jayaraj View Post
Yes we are talking about PA here. It has been pointed out many times that the 3015LF likes a relatively big enclosure for proper LF response, so this is certainly not the right driver for domestic use. As jbell says, there are other more appropriate choices.

However, after reading about jbells 'clean bass' from his SS15s, I think this is the best bang for buck PA box out there; he also says he gets the feel of low bass from lifting 45Hz by a few db. My only worry is being stuck in a situation where the DJ plays music that requires sub-40Hz and my cabs can't provide them. But that again is only the rare occasion. Just trying to be prepared for all seasons.

jbell, in my previous post I included a fold of your SS15, edited by you to get more LF. Do you have a HR frequency response chart and other details. Thanks for sharing your wisdom and experience in such a marvellous, practical way.
samuel:
Unfortunately the answer to your questions can probably only be answered by building, especially since my 40-60hz measurements don't exactly line up with hornresp. Go find some cheap plywood and toss together a couple test cabinets you are willing to make into a bonfire when the testing is complete. (even with cheap ply, still use PL polyurethane glue -- it's worth it.)

(you already know) that 30hz pa, and 40hz pa are two completely different animals. A ss15 will cough up a cone before it'll do 30hz pa. I also am very sure, if you put ss15's in the hands of a dj who's first concern is to eliminate your high pass filter, just so he can have 15hz warbles off his vinyl... well the destruction of your 3015lf's will be fast and complete.

The ss15 may not be the exact right cabinet for you -- I don't know. What I am sure of, is that as a test cabinet, so that you can determine exactly how a TH behaves vs a ported 3015lf cabinet -- the ss15 is a good choice. Once you build a couple test cabinets, and put through some different material that you know you'll have to support, you can make an educated decision if they go low enough for you.
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Old 25th February 2011, 04:31 AM   #463
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jbell, thanks a ton. I will start building next week.
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Old 25th February 2011, 04:40 AM   #464
jbell is offline jbell  United States
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samuel:

I dug this picture out from the 'way back machine' it's my original cdx test cabinet, to prove to myself that this tapped horn thing really worked. Once I heard for myself, then I had faith to move forward.

I don't know what grades of ply you have to work with, but I can assure you cdx is bottom of the barrel here... And yes, I roasted hot dogs over it when done, that ply wasn't even good enough to salvage for shelving.
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Old 25th February 2011, 06:35 AM   #465
Djim is offline Djim  Netherlands
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Jbell, I have a question for you. Your measurements showed lower extension then expected. When you feed the SS15 all the way up to 50 Volts did you see or hear that the low extension became less, as if everything else rises except the freq below 50Hz?
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Old 25th February 2011, 07:02 AM   #466
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I am not sure if the response will be affected by using 18mm ply for the internals. So the safe bet would be to use 12mm ply for the internals and 18mm for the externals. I want to use 13 layer Marine grade ply. The 12 mm will also be Marine grade but with fewer layers.
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Old 25th February 2011, 01:19 PM   #467
jbell is offline jbell  United States
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Originally Posted by Djim View Post
Jbell, I have a question for you. Your measurements showed lower extension then expected. When you feed the SS15 all the way up to 50 Volts did you see or hear that the low extension became less, as if everything else rises except the freq below 50Hz?
Now that's an interesting test, that I've never done... I've only measured 28v, but run music up to 63... When the snow melts, I'll have to do that.

samuel, marine ply is expensive stuff -- great cabinet building ply. If you're going to build a test cabinet or two, find some cheap-o stuff. My test cdx cabinet had the mouth panel vibrating over 1/2" when I did my 28v tests.... and it was still 7db louder at 40hz vs the big bad boy 36" T36....
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Old 25th February 2011, 05:58 PM   #468
Djim is offline Djim  Netherlands
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Originally Posted by jbell View Post
Now that's an interesting test, that I've never done... I've only measured 28v, but run music up to 63... When the snow melts, I'll have to do that.
If you are going to run this test you should do it in two ways. One sine wave test (non-complex signal) and run one test with pink noise (complex signal).

Also did ever see or maybe done yourself some Thiel-Small parameters tests of the 3015LF?
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Old 25th February 2011, 09:56 PM   #469
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What brand ply do you suggest? Any 1/2" birch?
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Old 25th February 2011, 10:05 PM   #470
jbell is offline jbell  United States
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Originally Posted by m R g S r View Post
What brand ply do you suggest? Any 1/2" birch?
auroco from lowes is good. Not all lowes carry it. It's the best deal @ $24 a sheet.

china ply, blonde wood, etc.. from home depot is crap. (don't buy any 1/2" from home depot for speakers -- period)

Most ac or bc 3 or 4 ply is very questionable... you probably only want to use 5/8" if you go that route, not 1/2"

Most 'cabinet ply' from a hardwoods store is good stuff, 5 even plys or better.

Baltic birch (the real stuff) is always best, but most expensive.
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