The importance of a sub sonic filter
11-18-2009, 08:02 AM
#1
The importance of a sub sonic filter
is it necessary to have one (on the amp or in line with the RCAs) or is it ok to not have one? for daily use of course, as I can't see how it would affect burps.
11-18-2009, 08:10 AM
#2
If it were necessary i would think all amps would have one. My amp does have one thats set to 30hz, on or off i dont notice any difference in "sound". I just leave it on, no point in wasting power on frequencies i cant hear anyways.
11-18-2009, 08:22 AM
#3
i have never got into tuning boxes to specific frequencies etc, but aside from increased efficiency, will a sub not be highly susceptable to loose control under its tuned frequency? resulting in a damagaed sub? i thought SSF's will help prevent this primarily.
i may be off on that....but i thought thats what i remember being told.
i may be off on that....but i thought thats what i remember being told.
11-18-2009, 08:53 AM
#4
You can tune to 35 and set the filter at 30 safely if it has a beefy surround but I didn't even notice a difference with the SSF set at 30-40. With a 35hz tuned box I was playing a 20hz test tone with the car off and normally it would just be very quiet, the SSF was at 20hz, and for some reason it started over excurting and was a lot louder, I thought I damaged something but it was fine although I did fry a tinsel months later, I'd like to know how it got the extra dB's, gain & eq at 3/4, it happened once. I didn't really notice a difference but it should sound tighter nearer the box tune.
11-18-2009, 09:43 AM
#5
They do what they're designed to do. Cut-out the lower frequencies. This in turn allows the power to be more focused on the frequencies you want the sub to play.
In ported applications, subs tend to "unload" when played below the tuning frequency. Some subs handle this "unloading" better than others. My JL's had to had the SSF set about 4hz below the tuning frequency. Otherwise they "flapped in the wind" like there was no box at all. I've also found that how much port area you use has a large effect on how easily the sub "unloads".
My two cents... I use them. Usually about 5hz under tuning. It will still play the notes below tuning just without the sub "unloading". This is much more noticeable with higher tuning than with lower, because with higher tuning the SSF will actually cut out some of the lower frequencies all together. Just depends on the cut rate (slope).
In ported applications, subs tend to "unload" when played below the tuning frequency. Some subs handle this "unloading" better than others. My JL's had to had the SSF set about 4hz below the tuning frequency. Otherwise they "flapped in the wind" like there was no box at all. I've also found that how much port area you use has a large effect on how easily the sub "unloads".
My two cents... I use them. Usually about 5hz under tuning. It will still play the notes below tuning just without the sub "unloading". This is much more noticeable with higher tuning than with lower, because with higher tuning the SSF will actually cut out some of the lower frequencies all together. Just depends on the cut rate (slope).
Last edited by DeadlySones; 11-19-2009 at 03:27 AM.
11-18-2009, 07:09 PM
#6
I have one but its off (infrasonic filter has a min of 15Hz and I like my sw8200 to drop down to 7hz lol)... my previous driver will sound like a nasty queef below 15hz so it depends on the driver like it was already said... and you can still "hear" below 20hz- however is more sensing then actual sound... you can feel the compression in your ears- great for movies
11-18-2009, 08:31 PM
#7
Yeah I know I can feel 20 hz better than I can hear it, but the new amp I'm planning to buy I don't think somes with a sub sonic filter, at least not an adjustable one. It may have a set one built into but I haven't found anything to prove that, so its really a guess based on what I heard about another amp that didn't have an adjustable one. The only reason I'm asking is because I want to know if I should invest in some FMODS or am I worrying too much. This is all related to a daily setup by the way, just in case anyone was wondering.
11-22-2009, 08:52 PM
#10
well somebody told me (two people actually, and they're two guys who really know they're stuff) that if an amp has a frequency response of say 20hz-xxxhz, then the amp has a built in SSF of 20hz, which makes sense, but then makes me wonder why some amps have a frequency response have low rating of 20hz, but an SSF that goes down to 15hz. doesn't that mean you're filtering out frequencies that the amp doesn't play anyways?
