Do I need a subsonic filter ? *car audio*

crawford

Golden Member
Jan 23, 2002
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Im gonna have two Resonant Engineering SE 12s, in 2 cubes per sub after displacement ported tuned to 33hz.
The amp is a jbl 1200.1 so it has no subsonic filter. Someone told me when tuned at 33 hz I may not even need a subsonic filter. Ive heard if you go ported you always need a subsonic filter. If i need one, im gonna go with Harrison Labs 20 or 30 hz.
So do I need one ? All i know is that I cant afford to replace these subs if they blow. Thanks a lot.
 

jfall

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Oct 31, 2000
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I would recommend that you use one. They are geared towards ported enclosures. If you were using a sealed enclosure then one would not be needed. You don't absoultely need one though. Many people run ported off of JBL 1200.1's without subsonic filters.

Basically what the subsonic filter does is block certian frequencies going to your subs.. sort of like a crossover. If you do get a subsonic filter, set it at about 3-5hz below your tuning frequency
 

TomC25

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Oct 12, 1999
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Subsonic filters are good for keeping the wattage of the amp powering the frequencies you want powered, and not wasting power trying to reproduce very low frequencies.

I cannot say that you NEED a filter, but it does somewhat depend on your music tastes.

If you want to feel the 15Hz notes when they arise then you could be shorting yourself.
 

crawford

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Jan 23, 2002
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yea its gonna be ported. Obviously if i can avoid it I wont get it, but i still dont know.
 

crawford

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Jan 23, 2002
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Originally posted by: TomC25
Subsonic filters are good for keeping the wattage of the amp powering the frequencies you want powered, and not wasting power trying to reproduce very low frequencies.

I cannot say that you NEED a filter, but it does somewhat depend on your music tastes.

If you want to feel the 15Hz notes when they arise then you could be shorting yourself.


Well I want to feel the low hz but if its gonna blow my subs i wont
 

TomC25

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Oct 12, 1999
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Yes, you will have to think about the fact that ported enclosures create less control of the woofer at frequencies lower than the tuning frequency.

Generally, a lot of rock and rap music does not extend below 30Hz. Unless you have a track that is made for low bass or a track that has explosions you will not encounter very low frequencies in music.

Classical music can extend very low.

It really depends on your music tastes and how loud you will listen to your system.

Very short notes at low frequencies would not hurt your woofers. Long exposure of low notes lower than the tuning frequency will hurt woofers in a ported enclosure if driven hard.
 

crawford

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Jan 23, 2002
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Originally posted by: TomC25
Yes, you will have to think about the fact that ported enclosures create less control of the woofer at frequencies lower than the tuning frequency.

Generally, a lot of rock and rap music does not extend below 30Hz. Unless you have a track that is made for low bass or a track that has explosions you will not encounter very low frequencies in music.

Classical music can extend very low.

It really depends on your music tastes and how loud you will listen to your system.

Very short notes at low frequencies would not hurt your woofers. Long exposure of low notes lower than the tuning frequency will hurt woofers in a ported enclosure if driven hard.

Thanks for your help man. Im thinking its worth the 30 bucks it costs just so i wont have to worry about it. :)