Car Stereos: frequency response, crossover frequency, subwoofer crossover

Question
QUESTION: Hi Brian,me again! I've finally put all of my stuff in the pontiac and u were right,I was surprised to say the least!! I had the ap-2002 pushing the lanzar heritage 69.3 and the vibrant 256 pushing the L5.It was weird though, i eventually took the ap-2002 out cuz I had both bass remotes hooked up by one another and both amps were being controlled by the others remote! But anyway, the L5's freq. response is 18-100 hz, would it ruin the sub if I set the crossover higher than 100, say maybe 200 or 250 hz? Reason being is I mainly listen to rap for the bass but in alot of the songs, it sounds "challenged" due to the low end freqs. being cut off at 100 hz! e.g. in the middle of a bass line that goes higher than 100hz the bass just cuts out and doesn' t play until the freq. goes back under 100. It sounds ridiculous! THANK YOU VERY MUCH, YOU'RE THE MAN!!!!

ANSWER: Hi Jesse,

It certainly won't damage anything to increase the crossover frequency. Usually, if you're trying for a balanced overall output, it's useful to keep the subwoofer crossover frequency low because that makes it more difficult to locate the subwoofer by ear.  In other words, if the sub isn't playing higher bass tones, and it's well balanced with the front speakers, you can get the illusion that all the bass is coming from the front speakers instead of from behind you.  However, if you're just looking for a powerful bass output instead of a balanced overall sound, then you're going to hear a dropoff at the point where the subwoofer leaves off and the front/rear speakers take over.  In this case, you can try increasing the crossover frequency and see if you get the results you're looking for.  I don't know how much it will affect your output problem, but as long as you're not getting audible distortion from the sub, then you're not likely to damage the sub or the amp by doing this.

Hope this helps!

Brian

---------- FOLLOW-UP ----------

QUESTION: Hi Brian, another quick question. Do you remember me mentioning the hi-low output converter in the grand am? Well, when I had both the amps in there I had them both (rca) running off of y-cable splitters because for some reason only the rear output  works(its a 4 channel converter- cheapie from ebay!). When they were both in there I found out the left and right were putting out a signal, but once I removed the ap-2002, now it's back to only one output working!! ( Oh, I found out the front works  the same way, only the red output works) Any idea what can cause that? Thanks again, and again, and again!!!!!!

Answer
Hi Jesse,

I don't really have an answer for that one.  If I were troubleshooting, I'd use a multimeter set for AC volts to verify that there's an audio signal on the input wires connected to the factory speaker wires.  If you verify an input signal, but there's not output signal, then it has to be a defective converter.  On the other hand, the lack of an input signal might mean that you don't have it connected to the right wires.  Without directly testing, though, it's hard to be sure.  

Brian