Head unit x-over

**ajoliver2010** · 06-19-2012

I just have a noob question. Whats the purpose of the x-over on the hu when there's a x-over on the amp? Its confusing me to death! I have an alpine amp that has x-over points of 60/80/100/200hz. I dont have bass now since my cheap amp finally gave up on me lol, but my 4 channel amp is set around 200hz for the front and 100hz for the back. When the hu is set to 80hz the music has no type of mid bass what so ever, but when set to 100hz its has a nice boom and sounds perfect. Someone plz explain the science of x-overs

**PurpleGuy** · 06-19-2012

Not really a science. Crossovers just filter out frequencies. For example the tweeter side of your crossover filters out all the low noises/frequencies so that the tweeter only sees high noises/frequencies. Better sound and better life of the tweeter. The midbass side of your crossover filters out the high and low frequencies and you're left with the mid frequencies. Again, sounds better and extends the life of the speaker.

**I800C0LLECT** · 06-20-2012

There is somewhat of a science when you consider length of sound waves and their inherent relationship to the frequencies nearby. They can easily cancel each other out. Overlap or underlap of these frequencies can change your overall response as well.

**crysalis** · 06-22-2012

Headunit crossovers usually filter the cut frequencies to a sub/rear output. So, if you crossover at 100hz, everything over will go to your doors/deck. Everything under 100hz will be sent to the sub or rear output, depending on the head unit. If you aren't using the sub or rear output correctly (sounds like you aren't), you'll hear the lower frequencies drop off.

I usually let the headunit do the crossover work and set the amp's hi pass as high as it will go (usually 200hz) so it is completely allowing the HU to cross over the frequencies. They build them into amps for when your headunit doesn't support it, or you are feeding line level inputs (from an amp) to the sub without being filtered first.

**ajoliver2010** · 06-23-2012

Originally Posted by crysalis

Headunit crossovers usually filter the cut frequencies to a sub/rear output. So, if you crossover at 100hz, everything over will go to your doors/deck. Everything under 100hz will be sent to the sub or rear output, depending on the head unit. If you aren't using the sub or rear output correctly (sounds like you aren't), you'll hear the lower frequencies drop off.

I usually let the headunit do the crossover work and set the amp's hi pass as high as it will go (usually 200hz) so it is completely allowing the HU to cross over the frequencies. They build them into amps for when your headunit doesn't support it, or you are feeding line level inputs (from an amp) to the sub without being filtered first.

I have an Eclipse XA4200 amp. The crossover goes all the way to 500hz. Should i turn it up that high??