Subsonic Filtors

[nismos14 5,000+ posts]

Question, so I love all these ported boxes, and all the nice installs but my question is, do you all run subsonic filters in conjunction with ported setups?

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[matt_martin87 10+ year member]

It is very necessary to keep the sub from unloading at frequencies below tuning. So yes, I do.

 

[joetama 5,000+ posts]

Yes I do.... You don't want to put your driver in over excursion and if it plays too far below tuning it can do this.

I'm sure a lot of people don't but I would rather have it on and not be able to play 10Hz tones than to damage my speaker...

 

[nismos14 5,000+ posts]

I mean I run mine too, but I'm thinking not everyone does. I am not ready to destroy my expensive sub lol.

I had to go the in-line route because of the fact that my amp doesn't not incorporate one.

Next question: I have a box tuned to about 31 - 32 hz, and my ssf is at 30 hz, is there a typical convention used in deciding what frequency to set your ssf at?

 

[joetama 5,000+ posts]

I mean I run mine too, but I'm thinking not everyone does. I am not ready to destroy my expensive sub lol.
I had to go the in-line route because of the fact that my amp doesn't not incorporate one.

Next question: I have a box tuned to about 31 - 32 hz, and my ssf is at 30 hz, is there a typical convention used in deciding what frequency to set your ssf at?

Well in my box building program you can view the sub's excursion at a particular frequency. So, you set a little above the point of the speaker bottoming out. You could set it lower than 30 Hz and still be fine.

 

[j3bus2k3 5,000+ posts]

I usually figure 5-8hz below tuning...

 

[nismos14 5,000+ posts]

Hmmm since I have to go the route of in-line xovers, does it seem too low to go to 20hz with an fmod in line subsonic xover?

 

[joetama 5,000+ posts]

Hmmm since I have to go the route of in-line xovers, does it seem too low to go to 20hz with an fmod in line subsonic xover?

The big issues is to listen and make sure the sub is not unloading on it's self. If it isn't then 20Hz would be fine.

 

[nismos14 5,000+ posts]

That makes sense. I guess I may just hold off for now and decide if I want to go with a box tuned lower.

 

[joetama 5,000+ posts]

What speaker are you running?

 

[nismos14 5,000+ posts]

Dls Sp12

 

[PESteele 10+ year member]

where did you get the inline ssf and how much did it cost

 

[JohnBlayz142 10+ year member]

where did you get the inline ssf and how much did it cost

You should be able to find them at partsexpress.com

 

[nismos14 5,000+ posts]

Yep partsexpress.com F MOD in-line crossover if you search for harrison labs at partsexpress you should find them.

The lowest is 20hz, next is 30hz. The were about 34 or 35 bucks shipped.

 

[helotaxi 5,000+ posts]

Depending on the sub, enclosure and power sent to it you may or may not need a SSF. The same parameters will also dictate where you want the SSF set. Too low it does you no good, too high and it costs you output. The filter has an effect above the freq it's set to, so really you want it low as possible.