bass reflex woofer in acoustic suspension

[mosfetmaster]

Hello,

I'd like to know if it would be possible to get a bass reflex woofer (qts=0.28) working properly in a sealed box (acoustic suspension or infinite baffle), and in case how to get such a result.

Thanks

 

[richie00boy]

Not without adding series resistance to raise Q, or Linkwitz Transform.

 

[mosfetmaster]

simply adding a series resistance would be sufficient?
...and what's the linkwitz transform?

thanks

 

[sreten]

Hi,

Any driver suited for bass reflex will work sealed in a box ~ half
the volume of a suitable vented box. for Q=0.28 vented box
volume is ~ 1/3 Vas, for sealed ~ 1/5 Vas.


rgds, sreten.

Infinite baffle (large sealed box) is not a good idea.

 

[Flaesh]

..would be possible to get a bass reflex woofer (qts=0.28) working properly in .. infinite baffle..

it's possible. with some peculiarity and limitations .
<--- in my system now for example. Qts ~.3. it's working definetly better than previous Qts .4x.

 

[454Casull]

simply adding a series resistance would be sufficient?
...and what's the linkwitz transform?

thanks

linkwitz transform - Google Search

 

[richie00boy]

Low Qts woofers "work" in a sealed box I'm not disputing that, but what you will end up with is a much poorer bass extension.

 

[doug20]

Low Qts woofers "work" in a sealed box I'm not disputing that, but what you will end up with is a much poorer bass extension.

Isn't that why we have the LT circuit and tons of power (if the driver can handle it)?


I know the LMS5400 with 18" (Qts = .325) is a beast in a 3 cuft box with 4000Watts and boost down low.

 

[Charles Darwin]

I've tried simulating the response of my 12" Tannoy drivers (Qts 0.4) in a sealed cab.
Regardless of box size it will start to roll off from ca. 150Hz while in a 200L ported cab it will reach 29Hz (-3dB).

 

[DualTriode]

Hello,

I'd like to know if it would be possible to get a bass reflex woofer (qts=0.28) working properly in a sealed box (acoustic suspension or infinite baffle), and in case how to get such a result.

Thanks

Hello,
What makes a driver with a Qts of 0.28 a bass reflex driver?
Most sources that you read tell you to adjust the size of the sealed enclosure to combine with the driver for a total Q of 0.71. The lower the Qts of the driver the smaller the box can be.
DT
All just for fun!

 

[Cal Weldon]

The more you lower the box volume in order to raise the q, the higher the F3 and F10 becomes.

 

[DualTriode]

The more you lower the box volume in order to raise the q, the higher the F3 and F10 becomes.

Hello,
If the driver starts out with a high Qts it is also likely F3 is also higher to start with.
BTW Size does matter.
DT