Alpine 9855 - Sound clipping

**ilyawizard** · 04-24-2009, 01:21 PM

It's not exactly CAR PC related but I thought I would ask anyway. This site helped me a lot with installing my first CAR PC, so thanks a lot for that.

Now to the point. I've had my Alpine 9855 and all Infinity sound system (2 amplifiers, speakers, and subwoofers) for about 5 years now. It happened very rarely but I noticed sometimes sound clipping. Now with CAR PC it became more often. It doesn't depend on the volume, even if you put it on low volume you still hear clipping on the same spots of the songs. First I thought the tracks weren't mastered correctly, but now I'm not so sure about it. My Alpine is not using internal amplifier (may be it should?) and I set preamp to lowest in RoadRunner. Does anyone know how to remove the clipping sound? May be setup crossover to lower level? Thanks for all the help.

**nalav** · 04-25-2009, 04:28 AM

Can you tell specifically which part of the system is clipping? The PC, amps, speakers or what? Also, what specific components do you have, and how are they wired (specifically, how are the subs wired)? Keep in mind that how the subs are wired defines how much power the amp actually puts out. Also, double check all the power cables to make sure they are all on good connections and using the right size cable.

**ilyawizard** · 04-27-2009, 02:35 PM

Here's what I have:

* Alpine 9855 HU
* Infinity Reference 7541a 4-channel Amp (111 Watt/channel) powering 4x100Watt (6"x8") Infinity speakers (2 Ohm)
* Infinity Reference 611 powering 2x350Watt 10" subs (not sure how connected, did it a long time ago with a friend, but subs are not the problem here I think)
* CARPC connected through line out to Alpine HU
* There's 4-gauge wire going to both amps, and separate 8-gauge wire going to CARPC

Sound quality is really good, and the speakers (not subs) are the ones that clipping (giving really quick high pitch sound) once in a while. The gain on the speakers AMP is set on lowest. I think if I make it higher it would clip more. One more thing I've noticed if I lower sound lever on computer it clips less and less.

Thanks again!

**nalav** · 04-28-2009, 12:41 PM

Does your computer have a line out? Perhaps try using that instead of the speaker out.

**ilyawizard** · 04-28-2009, 02:39 PM

It is connected through line out. Also tried speaker out, and has the same effect. I know it's not computer cause the same thing happens with regular CDs and MP3s without using computer (although less often).

**thewizard** · 04-29-2009, 05:42 PM

Are you using the high pass filter in either the head unit or the amp? If not give it a try. I prefer to use the head unit filters whenever possible simply because adjustment is at my fingertips rather than trying to access the amplifiers buried behind the rear seats. Your amplifier is sending 139 watts RMS to your 100 watt speakers based on your 2ohm load, so yeah they will defiantly want to clip if unfiltered. I would try about 100hz hi pass to start off and creep a little lower if the speakers can handle it, say maybe 80hz.

**ilyawizard** · 04-30-2009, 09:30 AM

I played with my HU crossover a little and looks like this is it. I found the best solution is to lower PC sound level a little (80%), and cut off high pass at 160Hz.