I noticed today that there may be an issue with my ML system. You too may have the same issue. I have never been thrilled with the sound of the stereo in my car and started to investigate today. Supposedly, it's supposed to be "sooo good" etc, etc, but I always found it to be merely adequate. I had a loaner IS250 this past week without premium sound it it sounded better than my LS.

What are my complaints? Well, no matter what position the DSP is set to, I don't get a solid center image. A telltale sign of a polarity issue.

Couple of things I noticed. It appears the front woofers are wired out of phase. I verified this with a simple test from http://www.audiocheck.net/audiotests_polaritycheck.php and can be played straight from your iphone via the tape deck. Its very easy to hear the differences of in and out of phase.

Listen to the guitar, if the system is wired correctly, you will hear the guitar more focused etc. Mine sounded more focused when i played the out of phase file. FML. I also checked the rear speakers,(which were wired correctly via the test) and while I was in the back seat, i noticed that the treble response was MUCH better, almost making the front stage seem dead and lifeless. It made me think that both my front tweets were shot and only the midranges in the dash were playing. Hmmmm.

Now, your mission should you choose to accept.......

Run the same test I did.

Listen to the files- when you hit the in phase file it should sound more precise and come from the center, if it sounds more focused with the out of phase file, then your fronts are wired out of phase, like mine. Also remember to use the fader to only have the fronts or rears on when working with the respective speakers.

Don't forget to let me know if your front treble response is poor compared to the rear. It is very noticable in my car.

Let me know what you think!

 

do you guys think it's possible that the speakers being out of phase vs. the rear speakers is done on purpose to give a more broad image? I'm reading in other forums that some cars do this on purpose....
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anybody want to take a stab at it?

 

Interesting.

Try this simple test. Fade everything to the front then use balance to go left to right and back. Use a song selection that has some lower frequencies in it. If the bass response is better when balanced full left and full right but poor when centered than they are definitely out of phase. Usually the lower frequencies are lost when drivers are out of phase due to destructive interference.

 

Yeah, the speakers are def. wired out of phase, but i realize now that they are supposed to be that way from the factory. Over the weekend I realized that a few weeks ago I put in the rubber weathertech mats in my car because i was going to be in some muddy conditions. I forgot to switch over to my carpet mats. That was the culprit in the poor sound. the rubber mats degrade the sound a LOT!

 

I'll admit I'm not an expert on the ML system but I have never heard of ANY system purposely wired out of phase!