here goes, I got my alpine V12 2ch. amp back from circuit citys repair service today.I originally brought it in for "low output & distorted bass fidelity",it had a sign on it that said "please check your speakers",according to the service slip "labor charges of $54.00 were covered by your circuit city extended service policy"
repairs performed on APN MRVT502 :
"electrical alignment of a circuit was made to audio circuit" I don't know about you,but being in the field of electronics repair myself,that sounds like a bunch of Bull sh*t! now heres the wierd malfunction that baffles me(car stereo is a grey area for me) when the balance is thrown all the way to the left or right,the bass hits harder than both speakers together. when it is balanced,it seems to "cancel out" the bass,upper frequencies aren't as noticable. it's not the head unit,I checked that already,it can't possibly have anything to do with the speakers.feel free to get as technical as you need to,to explain.if your not a tech,I still would like to know if youv'e conquered this problem.where does circuit city find these people??

 

You might want to check speaker polarity to make sure the speakers are in phase with each other.I've been in the car audio profession for almost 10 years,and that's what the problem sounds like to me.It may be at the speaker or the amp terminals.If those look okay,it may be internally in the amp.That might be what they mean by "electrical alignment for audio circuit",because output polarity might have been crossed internally. Do you still have the same problem,or was it before the amp was repaired?

 

That sounds like phase cancellation. It's always more pronounced in the lower frequency range.

 

definitly phase cancellation,I double checked the polarity to the speakers.It's still messed up after being serviced by circuit citys non-techs.I didn't notice the balance thing before I brought it in(I don't normally use the BAL adjust)I discovered that after I re-installed it,all I knew was it didn't sound like it should when I first brought it in.what can they alighn inside? they didn't touch any of the user accessable adjustments.

 

Reverse the polarity of one speaker. It wouldn't be the first time I found a driver incorrectly marked, so even if everything is visually correct, you could still be out of phase.

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