Magnepan 3.6 Set Up

Steve A -- Mon, 06/28/2010 - 04:52

I recently moved and am trying to set up a new listening room. I have a pair of Magnepan 3.6 speakers. Because of the way the room is laid out, I have to position the speakers along the long wall of the room. The right speaker is almost 8’ from the right side wall and the left speaker is about 15’ from the left side wall. Both speakers are 4’ from the back wall. The speakers are 9’ apart and the listening position is about 12’ away. I can’t seem to get the stereo image to lock in the middle of the speakers. Everything is pulling to the right. I’ve tried toeing in the speakers and moving them closer/farther apart with minimal results. Magnepan recommends setting the speakers up so that the listening position and the speakers form an equilateral triangle so I have also moved the listening position closer to the speakers but this doesn’t seem to work either. This wasn’t an issue in my last listening room so I don’t think this is an equipment issue. Any suggestions on how to get a better stereo image with the center image in between the speakers where it should be? Or is there some set up tips that I’m not using?

Thanks

Steve

majesticgiraffe -- Mon, 07/05/2010 - 09:55

check out cardas.com for tips
usually best to set up an equilateral triangle...so with speakers 9 ft apart aim for listening position to be 9 feet away

RanaKabir -- Mon, 07/05/2010 - 16:50

I doubt the side walls have anything to do with this since even the closer wall at 8' is plenty far. (My current setup is similar to yours.)
Since you did not mention, I am assuming the following:
The wall behind the speakers is identical/symmetrical for both speakers.
There is no object between the speakers to create acoustic interference.
There are no objects such as a coffee table in front of listening position between listener and speakers.
Also anything behind your head??

With the above conditions met I have encountered two reasons for the phenomena you speak of:
Comb filtering effects and imperfect signal match between the speakers.

Comb filtering effects can cause the image to shift. I have over the years come up with two specific ways to mitigate Comb filtering effects with the Maggies. The first one requires a cheap LASER leveler with a + crosshair. Using the Laser on the floor under the tweeter (aligned to the closest feet/stand) get the beams to cross in front of you (where your nose is). It is easiest to aim the beam from the LEFT tweeter straight to the listener’s RIGHT ear and the beam from the right tweeter to the left ear. [Disclaimer: If attempting this with someone sitting in the chair don't burn their eyes out! :-) ] Also a good mono recording with plenty of high frequency energy is particularly helpful since the filtering and/or other sources of interference are clearly audible by moving your head around during listening.
The other is, contrary to the strict equilateral triangle rule you will get a superior image if the distance between the speakers is slightly shorter than the other two legs of the triangle; in the neighborhood of 80% of the distance to the ear. So 9' apart with 12' away, you had it close to ideal (as long as you are sitting smack in the middle).

The second reason for this image shift could be that there is a mismatch (either phase/time or energy) of audio signal going into the speakers. One time I found that the speaker terminal of the right amp had loosened after my re-configuration of the room, causing the image to shift. We both know that these are extraordinarily resolving speakers, responding to minute signal changes upstream with great clarity. So double check all your connections. Perhaps it is time to treat all ICs and wires with CAIG contact cleaners & enhancers. If any of your wires are directional make sure you have them right. Double check the equipment with headphones to make sure it’s not the speakers. (There is always the possibility that the problem was always there but circumstances in your earlier setup either masked and/or favored conditions to compensate for it and you are now hearing this due to a more ideal/accurate setup.) Hope this helps.

Rana N. Kabir
CEO, ENDS Technologies

Steve A -- Wed, 07/07/2010 - 20:14

Thanks Gents. I think I have it dialed in.

etienne_leflore... -- Tue, 07/20/2010 - 17:30

Hi,
One of the things that most audiophiles over look is that the balance between the left and right channels must be equal. Use a mono signal and verify that your output from the amplifier to the left and right speaks is the same. Adjust the balance control as necessary.