I'm posting out of desperation, as I have not been able to solve this issue. In my 2011 JCW w/HK, about half the time I turn the sustem on, it seems almost as if there is a phase issue going on. A very heavy right side bias appears on the front channels, and it really DOES sound as if something's out of phase.

At other times, it's perfect, with a far more balanced sound from both sides. It does not change back and forth while driving, not over bumps. It will only "switch" back and forth after turning the car off and restarting. It's intermittant, and very frustrating.

The only thing I've added is a sub and Amp, tapped in at the HK amp on the pre-amp inputs. I have triple and quadruple checked the pin numbers, and they are correct. All connections seem to be solid.

I don't think it's connected with the sub install anyway, as the issue is repeatable even with the sub disconnected. It SEEMS to do it for all sources, but is most noticeable through the IPOD interface, using only WAV files. It's almost as if the current on the left side front channels is being limited at times.

The question is, before I blindly start throwing even more money at it, is does it sound like an HK Amp problem, or like a head unit problem, and is there a good way to test which, short of trying to tear the back apart quickly while it's going on and actually measure the voltage at the harness?

I wonder sometimes if it's the cheap headphone jack for the IPOD, or even the IPOD itself, however it also seems to do the same thing with CD's or FM radio. I also have not been able to create the same effect in a friends car with HK, using my ipod.

It's very subtle, but not so subtle that it doesn't clog up my right ear immediately...just like a phase issue. I've already taken apart the whole car more than once, and nothing is hooked up with the polarity reversed.

Has anyone else experianced anything like this?

 

You stated you've added a sub and amp.
you stated its still there with the sub disconnected.

That being said, did it START when you installed the sub and amp.

 

Vic-

Sorry to hear this is still giving you trouble. It might be helpful if you can describe what you are hearing. Phase is a physical property of (individual components of) a sound field, rather than a perception. Phase issues can be perceived as timbre differences resulting from comb filtering, and can influence spatial impressions. Phase is also often confused with polarity (which results in a uniform 180 deg shift in phase). Can you describe in more detail what the issue sounds like?

 

1. I don't remember if it started with the sub installation. I re-installed the sub from the previous two mini's the same week I bought the car, and was having too much fun thrashing it around the twisties to bother with the radio before I did that.

2. When it "goes bad" it sounds as if there is a sudden right side bias, especially in the mid range. The only way I can describe what it does to me ear is a "clogging" effect in the right ear. Almost exactly as if the midbass was wired out of phase. When it "sounds right" there is a noticeable increase in left hand sound, especially midbass frequencies. You almost look down, and to the left, to see where all the sound is coming from. Ears pop right open, no clogging. I wish I could describe it better. Two seperate professional shops have listened, and heard the same thing, but no solutions. Again...it's either "right" or "wrong" right away when starting the car. Bumps, or driving does not change it, only turning off the car and restarting. Like I stated, it's very subtle, but definately there.

I guess the next step will be to actually re-soldier all the connections at the amp harness, just to completely rule that out (again). Then work my way up the chain with new components, First Amp, then Head, in case it's a voltage issue. I'll also change out the Ipod interface, just for ***** and giggles...as it's most pronounced then, though I believe that's due to the limited width of the sound stage through the Ipod.

 

You should start by removing the installation, and returning it to the state prior to installation of the sub and amp.
That is the point of origin.
If the issue is resolved, then start again.

 

Phase issues will be more pronounced with high frequencies, in highly (data) compressed audio, thats why your iPod sounds the worse.

 

I only use WAV files on my ipod. They aren't compressed at all, thank you. Unless you're refering to the crappy output stage of the Ipod. That is bad.

I don't think a solution is going to be easy to find. It will just take perseverence. I was just hoping someone else on this board had experienced the exact same thing, and could point me in the right direction.

I don't believe the subwoofer is the cause. The more I trouble shoot, the more I believe it's an output stage voltage issue. Unfortunately, once I've cut into the harness, I'm way beyond any warranty, so was hoping to pinpoint where the issue lies before shelling out big cash.

 

This may be a key statement: "Bumps, or driving does not change it, only turning off the car and restarting." Turning off the car is the only thing that resets multiple protection circuits in both the HU and the HK amp. If you aren't losing an entire channel, then the issue is almost certainly in the amp.

Next time it happens, leave the stereo on, get out, and carefully check to verify that each speaker is actually on and is similar in level and sound to it's counterpart on the other side. It's possible that the overvoltage or overcurrent protection circuitry is activating on one of the amp channels for some reason (intermittant fault in one of the speakers possibly), or you could have a problem with one half of the BTL output on one channel in the amp.

 

Yeah...could be. Thanks Kevin. I'll play with it more tonight.