View Full Version : Crossover Point for Front Door Comps....?

Nicky Pass
06-02-2009, 11:53 AM
I' have been tweaking my mids and highs for about a week now and I have a question. On my head unit, I can cross the mids and highs at 80hz, 100hz or 120hz. I first had it at 80hz, and I thought it sounded great, but then I put it at 100hz and I thought it cleaned up the sound a bit. I have the sub crossed at 80hz and it sound great with everything. So my question is, if the sub is crossed at 80hz, to I cross the mids and highs where the sub leaves off? Or, is that 20z not gonna make a difference?

06-02-2009, 11:59 AM
It would help to know what components you are using...

Nicky Pass
06-02-2009, 12:08 PM
Hertz HSK 165s

06-02-2009, 12:16 PM
It would help to know what components you are using...

I'm not sure that's even important to his question. Yes, it could help if the conversation gets more indepth. As it stands, it's a quite straight forward question.

Been kind of curious about this myself. The slope used should be driver dependent though. If I'm not mistaken, you would get cancellation of you speakers were crossed over at the same point.

Nicky Pass
06-02-2009, 12:22 PM
I think I worded it wrong....please correct me if I did!

The sub is crossed at 80hz, so that means all frequencies 80hz and below go to the sub, so I think I set cross over point on the mids and highs technically 81hz and above if I set the frequency to 80hz for the front door Hertz comps. I set it to 100hz, and I think it sounded a bit cleaner, so I guess I'm asking that there is technically a 20hz gap....is that a bad thing? I have the passive cross overs both set at 0db for the tweeters if that helps....and the eq on the head unit is pretty much flat.

06-02-2009, 01:54 PM
Read the section "Acoustical Power and Output" here http://www.the12volt.com/caraudio/cross.asp#bp. Basically says 2 uncrossed speakers playing the same freq will net a +3db gain at that freq. But speakers will play at -3db at a particular crossover point. So net gain is 0db at that freq point.

06-02-2009, 02:15 PM
It only cancels at places where the two speakers are reproducing the same frequencies and are out out phase with each other. Best thing to do is determine how high the subs will play and still sound good then how low the mids will play and still sound good - but you have to do them seperately, I mean sub(s) only then mids only. Then see how well they blend together. I know there is large gap between my subs and mids and I just use a shallow slope on the subs to fill in the "blank" spot.

06-02-2009, 02:16 PM
I usually start with a 24dB slopes at 63Hz on the highpass and on the lowpass 4KHz-5.5kHz.
I play around with the tweeter crossover section but a good starting point would be matching it to your lowpass point and seeing if that works or maybe have some overlapping or even a gap between your woofers and tweeters.

BTW my midbass's are playing to 31.5Hz and my subs are at 40Hz(36dB per octave)

06-02-2009, 07:30 PM
Having a x/over point of 80hz doesn't mean the music hits a wall @ 80hz. It gradually rolls off (or sharply depending on the slope) & gets quieter per octave.
A gap, underlap or overlap are all perfectly exceptable, as long as the end result is a sub stage & front stage that blend well, every install will differ.

06-02-2009, 11:28 PM
if your running a steep 24db crossover you might notice it mover but 6-12 roll off woujldnt be that bad to run mids at 140 and subs at 80-90hz reallly