JL w6 in Aperiodic enclosure?

invecs2 · 12-21-2001, 05:20 PM

Hello! Is this possible to do? Is the w6 a good sub for AP enclosures? Pls help. Thanks!

12-26-2001, 08:11 PM

yes you can do them just make sure they have a low QTS and you should be just fine. The Jl do indeed have a good Qts so proceed with the enclosure.

Keith Turner · 12-28-2001, 12:48 AM

<blockquote>quote:</font><hr>Originally posted by rlbrown:
yes you can do them just make sure they have a low QTS and you should be just fine. The Jl do indeed have a good Qts so proceed with the enclosure.<hr></blockquote>For AP setup you need a QTS of 0.45. The JL should work ok.

invecs2 · 12-30-2001, 01:45 AM

Is it really worth the SQ if I go AP? or should a sealed box work as fine?

Keith Turner · 12-31-2001, 02:29 AM

Man if you don't care about SPL do the AP setup. The AP setup if done right is very sweet, easy going, nice bass. The seal box is good also better SPL. But and the end the AP is like a 36-24-36 lady very nice.

ALL4SQ · 01-04-2002, 08:55 PM

<blockquote>quote:</font><hr>Originally posted by invecs2:
Hello! Is this possible to do? Is the w6 a good sub for AP enclosures? Pls help. Thanks!<hr></blockquote>
================================================== =================
I used 3 JL 12W6 subs with Wave Mod AP mats back in 1997. They worked fine.

Its always great not to have a huge wood box in your trunk. Great performance in very little space. AP mats work for me.

Thanks

biomed_eng_2000 · 01-06-2002, 08:47 PM

Mark or anyone else that has build many AP systems,

Who started this 0.45 QTS rule of thumb thing anyway?

Why won't a woofer with a QTS of .451 work?

or for that matter

Why wouldn't a woofer with a Qts of 0.8 work?

Would the woofer with a Qts of 0.8 in an AP system just require so much damping that the system would be VERY inefficient?

Mark Eldridge · 01-16-2002, 02:30 PM

A Qts of 0.45 as a standard? That's the first I've heard of that. [img]smile.gif[/img]

The whole idea of over damping the sub system is to create a system that has as accurate a mechanical transient behavior as possible. The membrane systems simply allow the sub to operate in an over damped state.

Any woofer can be used in an aperiodic system. The lower the Qts, the less damping will be needed on the part of the membrane. A woofer with a Qts of 0.3 will require a very light membrane material, while a woofer with a Qts of 0.8 will need a very dense material to achieve the same overall performance. The denser the material, the more the efficiency of the speaker is reduced. It's quite common to see the output at resonance reduced by 3 to 15 dB, depending on the membrane material density, and the particular speaker involved.

The overall Qtc of any speaker system, when placed in a baffle or a box, will be higher than the free-air Qts of the driver alone. The membrane simply acts as a "shock absorber" to damp the drivers natural resonant characteristics, bringing the Qtc down to the desired level.

So, you are exactly right. Any speaker can be used with a membrane. It's all a matter of how much damping is needed to achieve the desired results.

C-ya!

01-20-2002, 04:34 PM

<blockquote>quote:</font><hr>A woofer with a Qts of 0.3 will require a very light membrane material, while a woofer with a Qts of 0.8 will need a very dense material to achieve the same overall performance. The denser the material, the more the efficiency of the speaker is reduced. It's quite common to see the output at resonance reduced by 3 to 15 dB, depending on the membrane material density, and the particular speaker involved<hr></blockquote>
Mark, just to make sure I understand this....if I select a sub with a Qts of 0.20, and an SPL rating of 98db @ 1w/1m does this mean that the efficiency is barely compromised?

Mark Eldridge · 01-21-2002, 11:01 AM

The woofer efficiency is reduced the most at the resonant frequency. With a woofer Qts of 0.3, you'll want to use a mid density membrane, which can reduce the output at resonance several dB (probably between 5 and 10 dB). It's not an insignificant reduction, but it can have a big effect on the overall SQ.

When I was building membranes for Autosound 2000, we built membranes for woofers with all Qts values for a while. We learned that woofers that have Qts values much below 0.2 didn't benefit that much, and the membrane was so "flexible" because of the very light density material, that we stopped making membranes for those woofers.

A Qts of between 0.25 and 0.5 work really wellin a membrane system. Qts values above that work well also, but the efficiency is really crushed.

C-ya!