I can't seem to get the phase right in my 2010 Camry with an aftermarket stereo system. I have 2-way component speakers in the front, and they sound better with one side wired with reverse polarity. For a given polarity for the subwoofer, such that it sounds best from the driver side, it needs to be reversed for the passenger seat. The problem is present even with a LPF set far below the crossover frequency.
Is it common for car audio to have this problem?
How do the poor acoustics inside a car account for the need to switch one side to reverse polarity?
I wonder if I need to design a system with phase shifters. My goal is to find a setup that sounds good to both driver and passenger.
Are you sure that each of the 2-way speakers in the front are actually wired the same, or is there a possibility that one of the woofers or tweeters is itself wired with reverse phase compared to the same speaker in the other channel?
What is your criteria for "sounds better"?
Quote from: Arnold B. Krueger on 21 August, 2012, 02:35:48 AMAre you sure that each of the 2-way speakers in the front are actually wired the same, or is there a possibility that one of the woofers or tweeters is itself wired with reverse phase compared to the same speaker in the other channel?I did some more testing, this time with the tweeters disconnected, so that just the 2 front door woofers are connected.Quote from: Arnold B. Krueger on 21 August, 2012, 02:35:48 AMWhat is your criteria for "sounds better"?When the speakers are wired correctly, they sound fine from either of the back seats of the car, or from a position in the center of the car. However, when sitting in either of the two front seats, the speakers sound as if one of them is wired with reverse polarity. It sounds like it does on a home system with one channel inverted. When I actually do invert a channel, I get some relief from the out of phase sound, and it sounds closer to normal. This is what I meant by "sounds better." The wiring that sounds less like the speakers are wired out of phase is "better," though it is incorrect. When I move to the center of the car, the speakers are now obviously out of phase.It would be interesting to find which frequencies are causing this problem, and what relative phase is required to correct it. Is there software that would allow me to play stereo test tones and change the phase of one channel in real time?
What stereo do you have?
This sounds like a strong reflection from the inside of the vehicle might be the problem.You should be able to use a CD with test tones recorded on it to determine which frequencies are causing problems. Make or buy!
...but I would have a lot more control with software that did arbitrary phase shifting or delay on the fly. I'd like to plug my laptop into my radio, play a tone, then dial in the phase that sounds correct. Does anything (free) come to mind that would have this feature?
Very strange problem... If the left & right channels are in phase, I don't see how it's possible to get different results on the left & right sides of the car... Everything should be symetrical. (That's assuming no "time alignment" adjustments.) With only 2 speakers (no sub and no rear speakers), it should be symetrical, even when out-of-phase.
You said you disconnected the tweeters... Are the door speakers 2-way or 3-way? I'm thinking that one of the drivers in the 2-way or 3-way speaker might be mis-wired (by the manufacturer) so that either the woofer, tweeter, or midrange is is out-of-phase, and switching the connections causes the other driver(s) to go out-of-phase.Maybe something's screwed-up or defective in the "location" time-alignment firmware in the head-unit. Do you have a portable stereo or something you can plug-into the car speakers in place of the head unit?