Stereo Imaging

I think I've written about this before, but I wonder how many of us who use the same system for HT and music get fooled into suspecting the center channel must be generating the center image. I was playing the Abkco disc of "Let It Bleed" and found myself compelled once again to put my ear to the center channel to assure it was not generating the strong centered image I was hearing. Intellectually I knew it wasn't because I've tested it before, but the image is so strong it creates a cognitive dissonance. In a world of 7.1, I'm afraid I forget just how effective stereo can be in generating a soundstage.

This is exactly why I don't use a center channel for home theater. I really don't believe that it's necessary for a listening position between the main speakers.

The other reason is that the matching center speaker was far to big to fit into any piece of furniture that I was considering.
That reminds me of when I was sampling different cables for my system. When ever I would try a certain cable I would hear a wider soundfield and deeper into the room. So I would immediately jump up to set my pre/pro to 2 channel as I thought I had somehow switched on the rears. Then the lightbulb went on! So I bought the cables. But your story made me remember that I had been there/done that.
This is exactly why I don't use a center channel for home theater. I really don't believe that it's necessary for a listening position between the main speakers.

Agreed - a center is not necessary. It is only a benefit when you have listeners outside the sweetspot.
But all the dialog comes through the center. Do you only run two channel or do you still have surrounds? Can you tell your processor you don't have a center, so It would be like running 4.1?
I run a 4.1 setup and let my reciver mix the center channel into the mains.

The other option might be to use subtitles?
LOL, Good one.
At this point it would be easier!
I use a center channel for HT but have tried 4.1 as well. Frankly, I'd be hard pressed to tell the difference now that the HF driver in my center speaker matches those in the mains. The speech seems to track the images projected on the screen. But when the center channel HF driver was different, I really noticed the disconnect when playing opera Blue-ray discs. That's when I set the center channel to none. I went back to 5.1 based on Kal Rubinson's recommendation, but we do sit in the "sweat-spot" so I doubt the center channel is necessary.
A strange phenomenon I noticed is that the soundstage seems to extend deeper behind the mains with multichannel recordings. I don't have an explanation for the effect.

I'm running 3.1. I'm using my mains as my two channel so they only work with music with my two channel amp. I have to change the speaker cables for movies only. I listen to regular TV with the 3.1.
You wrote:

"and found myself compelled once again to put my ear to the center channel to assure it was not generating the strong centered image I was hearing."

What an incredibly great are so correct on this...well done stereo has the illusion so strong that one thinks the CV MUST be playing and no manner of intellectualizing can convince us otherwise.

Here's one that still turns my crank.
I have a disc that has a group of wild people playing drums, shouting, playing tambourines in the front. The start moving from center front to the right speaker then past the right speaker, then to one's adjascent right, then to an almost 45 degree angle to the side rear right, then BEHIND!!!!!!!!! Then of course to the left side rear, and so on, then back to the front.
It's bad enough to do it stone cold sober--but then try it after two cabernets--OMG...I'm so freaked by that recording...our ears/brains are so good at spatial clues and analysis, but this illusion is remarkable...I can't remember the album, sorry, I'll research and post it.
I've stunned disinterested friends, with the illusion so many times...people simply FREAK OUT when I play it.
God this hobby is fun!

Good listening,

I have the same experience. I have a big center speaker (Kef 204c) and two Verities parsifals for stereo and any unsuspecting listener would swear the vocals come from the center channel when I am playing 2 channel.

However, discrete multi channel is a different story. Because the dialog in movies is mixed to a discrete center channel, if you play native 5.1 on a 4.1 system a DSP needs to send the center channel info to L/R. These L/R channels then need to re-create the center channel image. I never tried 4.1, but I suspect there is come compromise involved.

On the other hand, a big advantage of 4.1 is there is no issue with timbre matching if you have different mains and center speakers/amps (as most people do).

Final consideration against 4.1 is if you prefer playing 5.1 SACD material in DSD source direct mode (like I do), bypassing conversion to PCM and the DSP. If you do this, you cannot play source direct with a 4.1 system because you would loose the center channel information.
It depends on your speaker setup. In my room the mains must be far apart, and I have used a center since before multichannel was invented.

The extra speaker provides extra volume, taking the load off the mains.

The Cd you are talking about is from a group called Deep Forest. The song is #6. I forget the name of it. Quite bizzare how those drums sound as if they are directly behind you!

My rig is a 2-channel/HT combo, but the 2-channel sources run a detour around the multi-channel gear. When I had a large SD RPTV with my center atop it, that illusion happened constantly when listening to stereo sources. Now, with a plasma, and center mounted beneath the TV on a stand, the illusion is rarer. I think this is due to the height of the center image provided by my Ohm Walsh 2000s. Most vocalists appear to be about 5'6" tall, about where my center used to be, but about 3 to 4 feet higher than where it is now. A visual disconnect.

FWIW, I did try my system with a phantom center setting, but on film soundtracks, the center just lacked some oomph that it has when I installed the center channel speaker.
Thanks, isn't that a freak out?


Good listening.

Yeah. Freaky for sure.

I actually use that drum intro to that song as a test when I try different tweaks and cables. There should be a seamless 360 degree circle from those drums. If part of the circle is missing or it's uneven then something is wrong. I'm experiencing that right now with a tweak I'm trying.

Is this their self titled CD or one of the others? This sounds like something that I'd enjoy hearing.

Right now I have a bassinet "tweak" in front of my right channel speaker. It should only last a few weeks until my wife can handle stairs after her c-section. I can't say that I've been able to turn the volume up enough to notice any difference. It's all about diapers and trying to get some sleep right now.
Enjoy every minute...before you realize it...little he or she will be out on their own, living their own life, AS THEY SHOULD...but the time passes from this moment to that, all too quickly.

Good listening,
If your center channel isn't improving the quality of your soundstage, you're system isn't set up correctly. (Your other channels play a privital role as well, but one step at a time)
Mceljo, Don't play that for your son til his teens. Congratulations!!
I agree with Cdwallace3...."If your center channel isn't improving the quality of your soundstage, you're system isn't set up correctly."

I'll just add that I have been fooled many times into thinking I was watching a movie in Dolby Movie IIx mode (center fully engaged), and enjoying it, only to notice that audio was set to 'Stereo'. But, every time this happens, it sounds better when I switch to the Movie mode, and engage the center. There is no way two horizontally arrayed speakers can compete in terms of precise localization of the image, no matter how good they are, if the center is of equivalent quality and properly set up.
+1 Cdwallace3. Actually your missing a geat deal but if your OK with it then that's all that matters.
The center is somewhat like the audio fulcrum for multi channel dialogue location. Inserting a display on plane between my two channel speakers interferes with two channel staging way too much. Putting the display well behind the two channel speakers sounds horrible to me.
"...if the center is of equivalent quality..." - Pmcneil

I can't disagree with you on this, but is the home theater advantage big enough to warrant spending a little less on the mains assuming the same overall budget? It's all about choices for people working on limited budgets.

I probably would have the matching center in my system, but I simply couldn't find any furniture that it would fit in.

Hearing a significant difference with the addition of a center channel is a little different than not missing the center when you don't have one.
My position is if you have good mains set up right and they are imaging well the center hurts the system in most cases since the center is usually a lesser speaker.

Now this is only true if you are sitting in the sweet spot. Anywhere else in the room the center is critical. The center is for everyone else.
In the digital domain, I can cleanly adjust multiple points of stereo imaging of my active L/R mains through a Behringer DEQ 2496. It's processing the unadjusted digital signal from my Pro from all sources. The DEQs' 1.0 stereo image setting is normal stereo, 0.0 is full mono, and 3.0 wide. This set-up keeps timbre matching correct in 2-channel while keeping the bass more centered for certain recordings.

My SVS Ultra13 sub is connected to the 2496's fixed balanced analog outs. For multiple channel sources, I turn on my Proceed AMP5. It takes a moment to independently adjust volume controls in multi-channel. Then, I use the Pro's INPUT SIGNAL adjustment of -8 to +8 dB's to control the entire systems volume.

The Pro's front panel has multi-channel volume attenuators for very fine adjustments of the front and surrounds, too. It's perfect to finey adjust the different timbres of my main's and surrounds.

This set-up allows a range of stereo imaging by blending my main's into the center stage, or, go full multi-channel.

As a side note, Subs can be challenging to set-up. The Ultra took a very focused listening session to set the high/low passes, and especially the phase and slope roll offs. It helped me to turn main's volume up to a "moderate low" and turn up the sub more to better hear the adjustments most accurately.
I use the center channel to fool friends all the time because since I tweaked the cables and upgraded my midrange ribbons it just sounds like (on a number of but not all) recordings that its in use. I fooled audiophiles by telling them how great the center blend was and non audio guys aswell. Its a fun thing to experience that really shows your room, system and position are really clicking! Having said that, the center is a absolute must for the best projector based widescreen movie presentation.
Getting a strong center image should be child's play for two speakers - and is on my system.

I want my soundstage to be much more than that though. Yes, a sharply defined centre vocal of a believable real size... but with its own space free of the next instrument on the soundstage. Then the other instruments on the stage extending well past the left and right speakers with their own individual space. Every instrument in 3D space detached from the speakers. I use my 5.1 HT's center and surrounds when listening to 2ch music. Love it. Love the localisation of each individual instrument and singer.
Although most of my recent SACDs are 5.0, and I play them as such, my own experience is that the forward facing soundstage Kiwi2 writes about can be generated by a pair of speakers with a stereo source. The ability to generate a strong centered image is but an aspect of generating a well imaged soundstage.

I'm not much for typical surround sound. I honestly don't believe most us truly have a room large enough to make it work. I have enjoyed demo's of dedicated 3 channel audio reproduction when all 3 channels were identical. I have found that in the better surround sound systems (in truly huge rooms) I've heard, the front mains were positioned further apart than would be typical in 2 channel stereo. In these cases the matching center channel seemed appropriate if not indeed necessary, especially for those out of the sweet spot.
I get fooled a lot. Sometimes I don't know if I want to watch TV after I am done listening to music so I put mu 2ch and 3ch amp on at the same time. When I listen to music I always put my HT preamp in bypass mode. That means that ONLY the left and right speakers are playing. More then a few times I find myself getting up from my chair and putting my ear up to the center just to make sure. It is always off but I still do it. Pretty cool.