Center channel Impedance.

[Sir Terrence the Terrible]

I don't mean to to contrary, but I found the opposite to be true, dialog clarity has increased, even though I know what you are saying makes sense. I suppose that there are other variables in play here. It might be that they are planer dipole speakers and not so much point sources. I don't know.

Here are links to what others have said...

Magnepan center channel field test - wendell diller - Planar Speaker Asylum

The Audio Beat - Monday at Magnepan

The Audio Beat - Magnepan's Tri-Center: The Sound of Things to Come for Home Theater?; Magnepan speakers

The Audio Beat - Magnepan's 3.7/Tri-Center System: The Second Time Around; Magnepan 3.7 and Tri-Center speakers

Tri-Center

So let me get this straight, a guy that works for a speaker company tells you that dual or even a trio of center speakers is best. And you believe this? This guys want to sell speakers, but he must understand something called "wave interference" as demonstrated on this page.

2-Point Source Interference Patterns: Changing Separation Distance

You notice that when the speakers are separated, there is a very complex interaction between the two waves.This causes wave interference that causes cancellations and boosts to the frequency response. As the sources are moved until they almost are one source, that interference pattern decreases, and eventually would go away completely. This is what happens when dialog in split between two speakers, and why only one speaker works best for this application.

On the other issue of "Your idea that a single center speaker reproducing the dialog is flawed is in itsef flawed." . I'm not in agreement with you except for the distance factor from the speaker. The further from the center speaker we are, the better it integrates. In most home settings, that distance isn't achievable. Oh, I also agree with you on the ear/brain mechanism, except that, for me, it takes an effort to ignore where the sound is actually coming from.

This is nonsense. The fusion point is based on the size of the speakers, and the distance between the drivers. I sit 5.4" from a mini-monitor, and its drivers are long integrated with each other at that distance. It would be integrated at 2ft, and that can be easily measured using speaker measurement software like MLSSA. I can sit 10ft away from my Dunlavy SC-V, and all of the drivers sound is fully integrated at that distance. I can sit 5ft away from the system in my signature, and the drivers sound is fully fused at that distance. All of these distances are easily achievable in most hometheaters.

Sir... My intention is not to be argumentative. You have been a great contributor to this site and have exhibited that you have an in depth knowledge of audio. However, theory doesn't always apply, nor do our tastes always mesh. From your equipment list that you posted, your "TV" room is the exception and not the norn. Your screen is bigger than my entire wall, hence I have to assume that your room is much much larger than what I have. From that, it makes sense that your center would integrate better than what is available to me or to most people.

Theory does not always apply, but in this case, it does and can easily be demonstrated. Once again, look at the example above as it is a simulation of exactly what would happen when two spaced speakers are playing the same signal. You can also measure what the interference does to the overall frequency response coming from those two speakers. The effect leads to comb filtering, and comb filtering has a diffusive effect on the sound, not a cohesive effect.

This is not designed to be augmentative as well, but as a person who mixes movie soundtracks for a living, I completely understand how to get articulate dialog from a single speaker set up. You are essentially creating a phantom image between the two speakers. Phantom images have notches in the frequency response depending on how far the speakers are spread. The sound goes from a notch very close to the speakers, to full out cancellation and boosting further away. This is not good for dialog. Movie soundtracks are designed with a single discrete source for each channel across the front and sides, and matrixed or discrete channels in the back rear.



Just a thought...

It seems odd to me that many people compare their home systems to a theater. I quit going many years ago because of the sound (too loud). Theaters are great at producing loud sound with little distortion and the large room size is great for creating that spacious ambiance. Where theaters fall short is creating a depth to the image (it's wallpaper, if you know what I mean)..Home theaters are much better in that regard. Neither is better. all things considered.

Actually this is not quite correct. Movie theater sound system create depth in a DIFFERENT way than home theaters do. The sense of depth in home theater speakers comes from the complex interaction of front wall reflections at low and mid bass frequencies. Side wall reflections create a sense spaciousness. Since movie theaters are pretty reflection free at mid and high frequencies, in order to create depth, we pull images out in to the room using the surrounds. If you mirror the signals coming from the fronts to the surrounds, the image will pull into the room all the way back to the backwall with current 6.1 and 7.1 configurations.

BTW, I bet your theater systems sounds terrific.

Thanks for the compliment.

It seems from reading on the net, most folks that use this dialog left feature have their speakers far too close to the floor, or sitting on it. This is a total compromise and will induce boundary reinforcing effects to the signal. You can lift the dialog higher, but it still won't reduce the effect of the boundary reinforcement unless the center speaker is off the floor. Lift it off the floor, and closer to the television screen, and the eye/ear mechanism can do its magic.