Axiom Home Page Forums General Discussion Home Theater center channel sound imaging issue ...

Axiomicians,
made up that word a second back...

When I watch Kill Bill, or Terminator 2, *some* dialogs don't appear to be anchored to the TV, but appear to originate from the center channel speaker. Currently, the center channel speaker is placed *over* the TV, aiming downwards.

This is slightly puzzling because this issue doesn't surface with all movie dialogs. For example, in Kill Bill 1, during Uma's introduction prior to the fight sequence with Vivica, her voice appears to come from above the TV. However, other dialogs appear to come from the center of the TV. Again, David Carradine's voice sometimes appears to come from above the TV, but some of the other actor's voices come normally (from the center of the TV).

I observed the same issue when watching Terminator 2.

I know Alan L recommends against the use of the equalizer feature in the 3805 receiver. However, when I turned it on (normal), the spatial issues disappear, and any and all dialogs are firmly anchored to the center of the TV. The side effect is that some voices get to be deeper (unnatural).

How do I fix this issue without needing to color the sound by enabling the room equalizer feature ... any tips/advice would be appreciated. Hopefully, this will not include the need to add a second center

Thanks very much guys.
Ananth

You probably have an issue with only certain frequencies, sounds like higher voice frequencies, resonating in your room somehow. The parametric equalization detected that and minimized those frequencies. Such problems can have a very narrow frequency range, which is why you don't notice it on all voices, or even the same voice all the time.

Clearly Alan would be better to answer this, but my understanding is that you have two options; placement or equalization. (there's the third option of acoustic treatment for the room, but for most of us that isn't an option.) Have you tried under the TV, angling up?

Bruce

Ananth,

I would suggest lowering the output of the center by a dB or 2 as it sounds like your center may be overpowering your main speakers. Did you check the speaker balance with a meter with the EQ off?

Stuart

I'm not sure that I have a specific answer to your question, but I thought it could be helpful to keep something things in mind: When you say that you have a problem with certain movies (and assumingly not with others), it might be the material.

Not all movies, nor music, nor TV Productions are created equal, and sometimes a reproduction system designed for accurate and/or pleasant playback needs some tweaking by the owner. When an engineer sits down to mix or remix a soundtrack to 5.1 for home viewing on a DVD, he or she faces many choices in terms of channel levels, equalization and dynamic range. No different than music remixes for SACD, each engineer has some creative decisions to make in terms of subtle use of channels or raucous, wild use. The point is, there is no standard in which to compare the end mix.

Just like many engineers mixing a music track will choose to "normalize" or heavily compress a track to sound louder, an engineer could choose to EQ a center channel of a DVD to offer what he considers to be a little more "intelligibility" in the dialog. Or change the panning (or soundstage).

Picture this: your visual is a medium shot of a room. When the actor is towards the back of the room, and you're watching him full-length, his voice is best represented with some energy from the center and some from your L and R speaker. (Illustration "A")

Now, the actor continues talking but walks right up to the camera position (getting right "in your face", so to speak). You would naturally assume that the sound from the L and R speakers will lessen, and the center speaker will now carry 100% of that actor's dialog. (Illustration "B").



So in the first scene, with all three speakers firing, the dialogue will seem to come from a point midway between all three speakers (assuming they are each getting the same "percentage" of that vocal in the soundtrack). And would essentially place the dialogue aurally as coming from the TV.

In scene B, however, with 100% of the sound coming from the center channel only, it can't help but sound as though the dialogue is coming from the center speaker itself 9because it is!) and will tend to make you feel like the dialogue is not coming from the TV. In other words, you are now easily "locating" the center channel and it is, in effect, calling attention to itself. It's not the fault of the speaker, nor receiver, but to a large degree the position of the speaker in that it's not dead-on with the TV screen. As a matter of fact, I think a better speaker that provides good imaging (for example a "point-source" design) would be much more prone to this than a "diffused" design.

I think the preference is to usually put the center above the TV rather than below with all things being equal. But two strong factors in placement will always be whether the most identifiable drivers (tweeters) are mostly in line with each other and how close you can get the center to the screen.

If the three front speakers are reasonably matched in tonality and volume the two variables left are positioning and the source material. Try a good selection of source material and if you're still not satisfied, try a different position for the speaker keeping the above in mind.

You could "soften" the response of the speaker a little in the treble with some EQ, but the crispness and clarity of dialogue might suffer a bit. And I don't know about you guys, but I seem to be finding more and more actors "mumbling" a bit to stay within "character". I guess it wouldn't be realistic for a doc in "E.R." to stop all the surrounding chaos to clearly enunciate "He's losing blood fast! Get me the Rapid Infuser!!".

Nicely done Mark! Thanks.

-dale

Bruce, Stuart, Mark,
Great replies. I've been a bit lazy, and haven't used my RS soundmeter yet I merely used the Denon microphone to calibrate the receiver. I really need to purchase either the Avia or Digital Sound Essentials DVDs and calibrate the receiver through the DVD player (and adjust the center channel maybe).

Mark, you are the man! I have an understanding of the underlying concept behind this issue now.

Thanks again guys.
Ananth

Ananth, you haven't been lazy at all. You paid good money for the 3805 and its microphone and you're justified in relying on the results that it gave you. There's no sound reason(intended)to assume that a manual calibration will be more accurate(or even as accurate)than what the 3805 has done. Since you indicate that you already have an RS meter, it'll be interesting to use it to doublecheck the center channel level compared to the mains.

In reply to:

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There's no sound reason(intended)to assume that a manual calibration will be more accurate(or even as accurate)than what the 3805 has done.

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Actually, I've found that my 3805 and mic do a very good job for channel levels and speaker distances, but doesn't seem to be succesful at all in EQing the room. I've heard many others say the same, though I certainly don't trust the RS meter to be terribly accurate either!

Sometimes, 'ya just gotta trust your ears and do what sounds best to YOU!

edvacdude,

Have you watched Kill Bill in DTS and DD? Do you have the same problem with both? It may just be my imagination, but it seems that on some movies, one or the other (DTS or DD) sounds much better than the other to me. On most movies I can't tell much of a difference, but with Kill Bill I think I remember that I did prefer one to the other. (Although I can't remember which I preferred because I have not watched it in a while.)

i prefer ALL movies in DTS. its just very impressive.

bigjohn