Today I installed an aftermarket sub/amplifier in my Fiero. I used the stock sub box.

The amp is a Sony unit and it has a 50 Hz or 80 Hz low pass filter option.

I've never really looked into car audio too much, but if someone can explain to me the effect of each setting, that would be great. I'm not familiar with how to optimally set up a stereo system.

Thanks!

http://www.crutchfield.com/.../car/crossovers.html

The lower the frequency, the more the sound is felt rather than heard. Even 80 Hz is pretty low. Most car subs are in the 100-200 Hz range.

Also, the size of the speaker will matter quite a bit. Generally the lower the frequency, the larger the sub you want because small subs just don't do the low frequencies very well. For those frequencies I would want at least a 10" sub unless you have a sub + enclosure combo specifically made for such low frequencies.

Okay, a low pass crossover built into an amp is probably 12 db per octave, Meaning, if you set it to 50 hz, 100 hz will be cut 12 db, 200 24 db, 400 36 db, 800 48 db and so on. 80 hz will be down 12 db at 160, 320 24 db, 640 36 db amd 1280 48 db. Basically what it boils down to is how much you want those upper frequencies cut. The 50 hz will cut out more midbass then the 80 hz. Best thing to do is try it both ways and see which one sounds better. If you cut it off to low you will have a gap in the midbass section. Cutt it off to high and the midbass section will be to loud. They have the 2 settings because they don't know what the end user is going to have in the car along with the sub and amp plus the physical acoustics of the car will make different settings more desireable. Most car naturally boost the bass a little bit, soit just depends what your car is boosting and what your other speakers are covering.

I have to agree with Doug85GT though. Those seem awful low points for a 6.5" sub. It's already going to have it's lower extension limited because of cone size. I don't think I've seen a 6.5 that get's down past 30 hz, where as 10"+ I've seen down to the 20hz range. Set at 50 hz, you may be really limiting what the speaker puts out. I usually set mine with 10's around the 100 hz area (but then my amp has a variable crossover so I can dial it in better).

Sorry for any spelling errors. I just got home from a BBQ and had several drinks.

[This message has been edited by Khw (edited 04-01-2012).]

Depends on how your box/sub responds and resonates.

I flop back and forth between 80 and 120, on a dial i would probably put it around 100 and leave it.

Thanks for the info guys.

I've noticed now that my other speakers are not trying to play the deep bass. Reduces the crappy crackling noises at high volumes.

[This message has been edited by doublec4 (edited 04-01-2012).]

Yeah, when you can cut back on the bass your full range drivers are trying to produce it usually does sound better .

[This message has been edited by Khw (edited 04-01-2012).]