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well my sub's frequency response is 26-400 Hz
this means i shouldnt play it under 26 and over 400 right? since i have a JBL amp that doesnt have a subsonic filter, i'm guessing it plays everything under what i set the low pass to? so would this mean i should get a 26hz high-pass filter? i'm thinking about getting the harrison FMOD there's either a 20hz sub (aka sonic filter) or a 30hz one... should i go with 30 since if i get a 20hz my subs still vulnerable for the 20-26hz?

 
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personally, i dont think it would be a big deal to run the 20hz filter...

just cause you arent really going to hurt the sub by attempting to get it to play lower than the specs... it just means that you'll get a fair SQ/SPL drop off lower than that point

(although, i have heard that people say subs will be damaged if played at sub-sonic frequencies.. thats <20)


also.. you'll prolly want to low pass filter somewhere below 400... maybe 80 or 120.. but thats really up to the sound you like

 
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thats just a company rating, you wouldnt want to play your subwoofer at 400 Hz!

your low end is defined by the box, not the woofer. if you are runnign a sealed box, there no way that jbl amp will push that woofer at 2 Hz, can you imagine the control and power youd need to be able to push that constantly agasint the air pressure in teh box? think if you were benchpressing, you go slower, its harder to do more reps, right?

ported boxes, its different. the port cant limit airpressure much below the tunning frequency. here its SUPER easy to exceed mechanical limitations of the subwoofer with even small amoutns of power below tuning frequency. thats where you want your subsonic filter. sealed the box does that job for you.

especially with JBL (you got the 1200.1, right?) its important to ensure only certain frequencies are getting to your woofers, that amp is a powerhouse, but no control. its why its so inexpensive [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

but frequency response sis a function of boxdesign, for sure. thats why box is so important!

 
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ya i know i should be fine without a subsonic filter for a sealed box but i'm thinking maybe even with the sealed i was running a lower frequency then 26... i dunno i'm still trying to figure out how i blew a 1000wrms sub with just 500 clean wrms or so.

but ya even tho i have a sealed now i hope to get a ported soon so ya just wondering which i should get.. the regular 20hz subsonic filter or the 30hz cause my subs limit is 26hz

 
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Don't worry about the sub sonic filter with the sealed enclosure, you don't need it. If you go ported, then the filter's frequency will be determined by the frequency you tune the port to.

 
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if you have a sealed box, a subsonic filter is useless

 
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well in all truth there is VERY VERY little music with passages below 33hz..and even then, if it's in a sealed enclosure it will limit the low end extension of the woofer and pretty much preven the possibility of any harm.

Just lay off the Max Killa Hz Bass CD's and hardcore organ music and you'll be fine [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

 
Rep Power: 345

With the JBL you definantly won't need an infrasonic filter with a sealed box, However the crossover on the amp is pretty $hitty. It is really hard to get the voice out of the subs...anywayz, it is prolly more important to get an F-mod that is a LPF then an infrasonic filter one if you really want to have one. For me, I have finally been able to get most of the voice out, and get the bass response that I want out of my subs, by using both my HU crossover, and the crossover on the amp.