Tweet
How far down (in db) should I strive to tame the break-up mode in a metal woofer? I'm working with a aluminum woofer with a peak at 7k and a second larger peak at 9k. How far down is the MINIMUM I should aim for so these peaks will not be a significant sonic problem?
-
-
Here's a quick and simple answer ....:wink:
The recommendation from Jonmarsh is when possible use a XO frequency no less than one full octave below the cone breakup mode. He uses 48dB/octave filters for this purpose.
IB subwoofer FAQ page
"Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson -
I think I remember him also saying that -40 to -50dB down is pretty good... though most probably would not notice it at -30dB. ;-)Comment
-
Thanks Thomas & JonOriginally posted by JonP
When saying -40 to -50 db down are you saying it should be this far down starting from the top of the peak of the raw driver OR this far down from the amplitude at the intended x-over point?Comment
-
Scroll down to where it says "Crossover Concept"
IB subwoofer FAQ page
"Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-BressonComment
-
Thanks Thomas! I'll read it.Originally posted by ThomasW
Jon, I'm still interested if you have a answer to my question. Thanks again.
MSComment
-
Remember, I'm not an expert! :B
I would think generally you are talking below the overall driver level. When you compensate for the Baffle Step gain (the BSC) you lose some, not more than 6dB, and usually a few less than that. Not a huge difference.
It's relative, as well... Say you have a speaker that you crank up to 90dB, if your cone breakup is -40dB down, then it's at a 50dB volume level. Fairly quiet, but it has to compete with that loud 90dB of everything else. Go to 100dB and now your cone breakup output is 60dB, not all that quiet, but the system is that much louder in proportion.
As you can see, the greater attenuation the better, -50dB starts to not look that extreme if you really want a clean system..Comment
-
There's no peak to attenuate if the XO point is an octave below the breakup frequency.Originally posted by Mark S.
IB subwoofer FAQ page
"Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-BressonComment
Comment