Distortion At All Volume Levels

Hi All,

I put a new Alpine cdm-9821 hu in to replace my stock hu and it has a slight distortion at all volume levels. It doesn't make a whine and is quiet. Its just that the sound is a little distorted.

A month before, I had replaced my frt speakers with kenwood 6889ie's due to my frt stock ones going bad. It sounded ok and had no distortion.

It's a 93 ford ranger and got the HU from Crutchfield and got the wiring adapters to plug the alpine into my trucks harness.

I did the wiring by a diagrams that say what each wire goes to and the color coding happened to match up still anyways. I also connected the alpines HU ground wire to go thru my vehicles harness. ( Maybe a mistake?)

Everything seems to work OK with balance, fade, memory, and so on.

I am using it with bass and treble set to flat.

Thanks for any tips.............Joe

There has been some Ford trucks that i have done with the two front speaker negatives are reversed (backwards to what the wiring adaptor says)  If you have a multimeter you might want to check that out.........

i'm new at all this so I really don't know what I'm talking about, but if both negatives were reversed, wouldn't it be back in phase?

Or would having four speakers cancel that theory out?

I'll try to test the Alpine in a friends truck too.

Thanks for the suggestions.............joe

Well it could mean that both speakers would be out of phase (positive and negative swapped).  This usually wouldn't cause distortion at all volumes though.  Or he could mean that the negative wire for the left speaker needed to be connected to right speaker instead, and vice versa. 

Does the distortion come through all of the speakers, or just the front ones?

also, try wiring it straight to the battery, and getting a solid ground.  When I first installed my alpine (CDA-9807), I use the harness for power and ground, and was not impressed at all.  Someone told me that even though the manual dosen't say you need to wire it straight to the battery, that it helps alot.  Anyway, used 14 or 16 gauge wire to the battery and a solid ground, works alot better now...

Wireing it to the battery is a PITA though, so you may not want to go throught that much trouble, it's up to you.

-Drew

Its through all the speakers. its slight but enough to be not right.

Also I noticed that it seems to hurt my ears a bit. Could that be because of phase.

Anyways, thanks to all of you for the suggestions and I will try these ideas out Saturday AM and see what gets it right. I'll check phase, ground, correct wires for appropriate speakers etc.

I let you know what I find.................Joe

I think I found the problem and Its embarrassing I didn't try this earlier.

On my HU, you can pick different frequencies to control on your bass or treble as like a priority frequency to use when adjusting either your  treble or bass.

Today I tried setting it on the highest one 17.5 kHz and it seemed to clean up the sound. also my ears didn't hurt as much either.

I didn't think that the Hu would cause a distortion type sound when set to a flat setting or 0. The default setting is at 10kHz.

Thanks for all the help........Joe