Subsonic filter needed?

[veggie-man]

The box that i think i will be getting requires a 30hz subsonic filter. first off if i get that (box/filter) is my SQ going to plummet making my sub sounnd like crap and just hear the boom? or is that filter just making sure the sub doesnt play certain signals and the end result making it sound better?
i do want a decent SQ on my sub but if this box/filter is going to make it sound bad should i just get a diffrent box?
box:http://www.topedgeonline.com/detail.aspx?ID=13565
i really like the box cause it is designed for my sub.
Note:
sub:http://www.sonicelectronix.com/item_5527.html
amp:http://www.onlinecarstereo.com/CarAudio ... ctID=15324

[JeremyC]

All a subsonic filter does, is keep the sub from going to far below the boxes porting freq and over doing itself. It shouldn't affect your SQ.

[veggie-man]

humm so my understanding is that it would be good to get one but not necesaary.... the only thing is i cant find any subsonic filters....
but doesnt a highpass crossover work the same way? could i just get a crossover and set it to highpass or am i missing something?

[Justin from Detroit1]

Most HP xovers don't go below 50hz

[veggie-man]

ok i have searched for 3 hours now(no exaggeration) trying to find an external subsonic filter and have found nothing... am i just going to have to get an amp that has a filter already on it or does anyone know a place where i can buy an external subsonic filter? your help is very much appreciated!

[Ryan from Ohio]

problem with that box: 1.78 cubes total.

That doesnt include for the loss of volume from your sub.

Your sub requires a 2.0 cubic foot box.

That box is to small.

[GlassWolf]

a subsonic filter should be set at the tuned port frequency of the sub.
below that frequency, the sub won't play anyway, since it rolls off like a cliff at anything below the tunded frequency.
The amplifier also has to use tremendous power to produce anything below the tuned freq of the box, and at that point the output is very difficult to control.
When playing below the tuned freq of the box, the sub can lose it's damping, or suspension, which will cause the sub to over-extend, blowing the sub and destroying it.
The purpose of the SSF is to protect the subwoofer, and to prevent the amplifier from wasting power trying to produce notes it can't handle due to box design anyway.

You shouldn't hear any degradation in output or frequency response by using the filter properly.

[joeyc]

everything kiki just said, i already knew all of that......no, really, i did

[veggie-man]

thanks alot for your help guys i really appreciate it! i have decided to go with a sealed box so i dont have to go through all of the hassle of finding a subsonic filter. plus i get better SQ! or so they say :happy055:

[GlassWolf]

for the record, most mono sub amps today come with the SSF built-in.
Also, you can get FMOD filters (in-line RCA style) for about $20 on http://www.partsexpress.com if you need them.