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Resonant Frequency ?
Posted: Tue Jan 23, 2007 10:04 am
by bdubs767
May be a silly question but least in my mind kinda makes sense....
If I were to slap a deadner on to the basket of a woofer, would that in theory drop the Resonant Freequency?
Posted: Tue Jan 23, 2007 10:06 am
by Bfowler
or even what about putting it on the cone itself?
Posted: Tue Jan 23, 2007 10:12 am
by stipud
Brian's on the right track.
With a passive radiator, you install weights on the cone to lower the Fs.
I don't think doing this on a speaker would be a great idea though...
Posted: Tue Jan 23, 2007 10:13 am
by bdubs767
On a cone would do it but I think it would cause more problems then it would solve...but on a basket that is not O so strong, wouldn't it help?
Posted: Tue Jan 23, 2007 10:31 am
by VW337
Basket no cone yes.
If you add weight to the moving structure of the sub you will lower the Fs since the weight in motion allows the cone to move to its peaks easier. The drawback is you need to add motor strength to compensate to control the moving mass in turn raising the Fs back up. Vicious circle?
Posted: Tue Jan 23, 2007 10:33 am
by stipud
It wouldn't do much to change the Fs of the speaker, but it would keep the basket from resonating. I haven't heard of any designs that were this weak however. Umm... I really don't know what you are trying to achieve

Posted: Tue Jan 23, 2007 10:34 am
by bdubs767
hmmm...so would deading the basket have any benefit? Like with cheaper woofers who's baskets may be flimsier then wanted.
Posted: Tue Jan 23, 2007 10:40 am
by VW337
All a basket does is hold the assembly together. In some applications it can be utilized for additional thermal management instead of using a proper cooling design (moving air) to begin with. In the case of a really thin stamped steel frame you may get some ringing through the basket which can color the sound or cost the driver some moving energy.
Posted: Tue Jan 23, 2007 3:08 pm
by Francious70
You wanna drop the Fs?? Add mass to the moving assembly, the lower your efficiency, the lower the Fs.
Posted: Tue Jan 23, 2007 3:22 pm
by bdubs767
no dont was JW