Please help, obsessive audiophile question

it might be the door in back of your listening position. do you usually listen with the door open or closed? i have the same issues as you and it was the room.

Newbie: I thought about that, but my wife hears it too, it could be that the problem is contagious? *grin*

Sean: Oh no! I was going to do the out of phase check this evening, you are saying it might not work? Maybe I will check with ML. Although, If I just switched the speakers, and the problem stayed the same, I guess we would know its the room, as we already eliminated the amplification chain.

As fas as sitting in the middle, yes, asn I hate to admit this, but I checked it with the laser, which ended up right on my nose. I know my fellow audiophiles will only partially think I am nuts...c'mon, fess up, someone out there has done this.

Dlwask: I am leaning towards your solution after verifying it is not a speaker problem. If it is a speaker problem, I will try to get it fixed. Thanks for the encouragement, your right, a little part of me will suffer if it is not perfect, but I can deal with that if it sounds good.

Fefer77: Yep, the door is ALWAYS closed. I actually replaced the original door with the solid wood door (and spent forever staining the darn thing) in order to get better sound.

I will report back after moving the speakers.

Rlips, I didn't realize that you have a picture of your setup until I read Sean's comment. I always try to look for most abvious - your plants behind speakers are not the same size, did you try to swap them around?

I see my last post did not make it?

OK, here is the report:

Sean was pretty much correct, it was a combination of 2 things:

1) One speaker is slightly louder than the other

2) The room is re-enforceing the left side.

As soon as I switched the speakers, the image moved to the right side. However, it was much closer to the center, and only required half the correction to bring it back left to center.

I moved the right side back 1, then 1.5", and the system is now centered.

So, one speaker is slightly louder than the other, and the room has an asymetrical response. I will call the speaker manufacturer to discuss this, but I am not to worried at this point, as I have the system SOUNDING good. If there is an adjustment, fine, but if not, I think I can live with this.

Thank you all for your thoughtful responses, it never would have occured to me that one speaker would have a slightly different response.

Best Regards,
Ron

Glad that you were able to work things out and come to some type of a conclusion.

Personally, i would not let Martin Logan off the hook without having the problem corrected no matter what. Not only are the speakers not performing correctly in terms of balanced output between them, it is quite possible that one or both is skewing what you are hearing in terms of frequency and transient response. If both speakers respond to the same signal in varying manners, they will excite the nodes in the room differently. This is true due to the non-symmetrical loading characteristics that are present in most rooms.

Given that swapping sides with the speakers helped to balance things out tells me that the speakers are not loading up the same due to variables in the room. Changing the loading conditions changes the nodal points in the room, which will in turn highlight or minimize output in specific regions. The fact that moving the speakers allowed you to achieve proper balance confirms that there is both a problem with the speakers and that the room isn't quite as linear as you think. Believe me, you are NOT alone in this, even with room treatments.

A good test for something like this is to play a slow frequency sweep as can be found in the Ayre Acoustics "Irrational But Efficacious" CD or on the Cardas LP. Sit dead center in the sweet-spot, turn off the lights and listen to the frequency sweep with your eyes closed. In a perfect world, the sound will remain perfectly centered between your speakers if room acoustics / speaker loading are optimal. In the real world, you will hear the image shift from from side to side as frequency varies. The more consistent that the image stays centered, the better your room / speaker interface. My guess is that ANYBODY that puts their system through this test WILL hear the image walking around. At some points, you can literally hear ( it almost seems like you can see & pinpoint ) the image as it moves around the room. In some systems that i've done this in, the sound is literally flying around the room like a helicopter bouncing off the walls. Cool for special effects but horrid as far as audio goes.

Not only will the image walk around, listen to how consistent the volume of the tone remains. My guess is that you'll hear some spots that are "hot" and others that drop out quite noticeably. The nodes and reflections in the room effect every aspect of the sonics that you hear, both in amplitude and in phase. Doing this test will tell you just how non-linear your room / system is in terms of both amplitude linearity and frequency response. Bare in mind that the results are only valid AT YOUR SEATED LISTENING POSITION. If you want to see what i'm talking about in terms of listening position, run the test several times and then scoot over a few feet in either direction. You'll get completely different responses with each move.

Once you've done this in stereo and you're very disappointed, try doing the same test in mono. You'll be amazed at how much smoother the response is, both in terms of amplitude and frequency response. The image will remain centered most of the time and the peaks and dips in amplitude will have evened out quite a bit. This is the type of response ( or even better ) that you're shooting for in stereo mode. All i can say is "good luck" when trying to achieve this : ) Sean
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