Sub 18hz driver control

[mayhem13]

I'm using an HPA500 power amp in my dual 10" sub build and i'm concerned with cone excursion below tune of 21hz. Can i wire in some type of passive electronics directly between the driver and the amp. Sort of like a high pass filter set to 20hz. If so, what components would i need to make this or can i buy them already assembled? Thanx in advance.

[ccdoggy]

Sure you could, but the component would be expencive to support that amount of power.

when you say uts the HPA500 you really mean the HPSA500 right? I cannot confirm it but i remember seeing somewhere that it has a built in subsonic filter that is not adjustable. I am sure someone else can confirm or deny this.

Also I vote you give it a try and see what happens, if you need the filtering then go forward on that front, if you find that its fine then dont worry about it.

[eyekode]

mayhem13 wrote:

I'm using an HPA500 power amp in my dual 10" sub build and i'm concerned with cone excursion below tune of 21hz. Can i wire in some type of passive electronics directly between the driver and the amp. Sort of like a high pass filter set to 20hz. If so, what components would i need to make this or can i buy them already assembled? Thanx in advance.

You probably want to filter the low level signal not the high level. Note that a passive filter at 20Hz would be stoopid big and stoopid expensive.
Zl = 2*PI*f*L

If you want a single pole filter with the 3db point to be at 20Hz the inductor would be ~70mH!

Edit: I looked it up and a 20mH inductor is ~35$

I have been considering this product: http://www.edesignaudio.com/product_...roducts_id=657
I have not read any reviews of it yet though...

[deromax]

eyekode wrote:

If you want a single pole filter with the 3db point to be at 20Hz the inductor would be ~70mH!

Except the OP want a subsonic filter, in other word a high pass filter. That would be a capacitor, not an inductor!

[DRB]

SVS used to market the SVS Subsonic Filter SVS01, made by Marchand Electronics. This device was, IIRC, placed between the sub amp and the sub driver in the signal chain. It allowed multiple subsonic filter settings as well as tweaking phase and such.

How's my memory doing today?

[eyekode]

deromax wrote:

Except the OP want a subsonic filter, in other word a high pass filter. That would be a capacitor, not an inductor!

Ha! you are right, I was being a moron. But the result is the same. You would need stoopid big passives. Here are some 3rd order filters:
http://www.wa4dsy.net/cgi-bin/lc_fil...&funits=HZ&Z=4