[aggieactuary]

My question mostly relates to 2 channel music. I understand that 5.1 or 7.1 channel media have a center channel, and the center speaker would simply play the center channel (and it's mostly voices/dialogue, right?).


But what happens on 2 channel music when you have your receiver set to 3.1? Does the receiver mix the left and right channel equally into the center speaker? How does that affect sound quality on music? If it just mixes into the center speaker I'm wondering if that just muddies up the sound.


And/or should the center speaker not be used on 2 channel media but only for 5.1 or 7.1 media?

 

[sdurani]



Quote:
Originally Posted by aggieactuary /forum/post/18209339


...what happens on 2 channel music when you have your receiver set to 3.1?

Sounds that would have phantom imaged at the centre of the soundstage will now come from the centre speaker. But you have to use some sort of surround processing mode (Dolby Pro Logic II or DTS Neo:6). Merely configuring the receiver for 3.1 speakers won't automatically cause the centre speaker to play.


The processing takes sounds that are correlated (in-phase) mono in the L/R channels and steers them to the centre speaker. This is the location where those sounds would have imaged anyway (assuming you were sitting in the sweet spot). The processing then inverts the extracted centre content and sends it back as a cancellation signal to the L/R speakers. This way, centre information is not reproduced as triple-mono (all three front speakers), since it is erased from the L/R speakers and only coming from the centre speaker.

Quote:
And/or should the center speaker not be used on 2 channel media but only for 5.1 or 7.1 media?

Personal preference. If you like the results, then continue to use 3 speakers for 2-channel material. If not, then stick with 2-speaker playback. I prefer a hard centre to a phantom centre, so I always listen to 2-channel music in surround.

 

[Selden Ball]

Of course, as whenever you use a center channel, it should be timbre-matched as closely as possible to the other two front speakers. An identical speaker would be best.

 

[sivadselim]



Quote:
Originally Posted by aggieactuary /forum/post/18209339


But what happens on 2 channel music when you have your receiver set to 3.1?

Nothing. Unless you specifically want it to.

Quote:
Originally Posted by aggieactuary /forum/post/18209339


And/or should the center speaker not be used on 2 channel media but only for 5.1 or 7.1 media?

This is a personal choice. As sanjay pointed out, you will have to use some sort of processing in order to create center channel info from 2-channel sources.

 

[Dave1027]



Quote:
Originally Posted by sdurani /forum/post/18209488


I prefer a hard centre to a phantom centre, so I always listen to 2-channel music in surround.

Not me. Two ears, two speakers. I have found that if you have a good enough system it will sound like a complete sound stage with some sounds coming from the middle.

 

[ATWindsor]



Quote:
Originally Posted by Dave1027 /forum/post/18212017


Not me. Two ears, two speakers. I have found that if you have a good enough system it will sound like a complete sound stage with some sounds coming from the middle.

Thats a weird logic as long as the speakers are supposed to reproduce sounds comming from a much bigger area than two points, I can understnd it for headphones, but for speakers?


AtW

 

[Selden Ball]

AT,


It's traditional. Two channels of audio can be sent to two speakers with no alterations to the signals. Processing the audio to utilize a center speaker and subwoofer is a relatively recent development, and some people still haven't come to grips with it.

The even newer possibility of compensating for speaker and room infelicities with active equalization (Audyssey and its rivals) is even more disturbing!

 

[sdurani]



Quote:
Originally Posted by Dave1027 /forum/post/18212017


Two ears, two speakers.

Huh? What does one have to do with the other? That's like saying your eyes are 4 inches apart, so video screens don't have to be any bigger.

Quote:
I have found that if you have a good enough system it will sound like a complete sound stage with some sounds coming from the middle.

Sure. But the question is whether using a centre speaker can improve playback. The reason I mentioned personal preference is because of the various factors involved: surround processing, timbre matching the speakers, centre speaker position, etc.


There was an interesting post a few years back at Audio Asylum by the recording engineer for Polyhymnia International. The first paragraph of point "3)" in his post is worth a read, since it deals with phantom imaging.

 

[Dave1027]



Quote:
Originally Posted by ATWindsor /forum/post/18212045


Thats a weird logic as long as the speakers are supposed to reproduce sounds comming from a much bigger area than two points, I can understnd it for headphones, but for speakers?

Why is it understandable from headphones but not speakers? Headphones are speakers only closer to your head.

 

[sdurani]



Quote:
Originally Posted by Dave1027 /forum/post/18216172


Why is it understandable from headphones but not speakers?

Because headphones can only work against your ears while speakers can be placed anywhere. Want a stable centre image? Add a 3rd speaker between your L/R speakers. How do you do that with headphones? Adding a 3rd earcup between the L/R earpads won't work. Where would you put it? Pressed against your forehead?


When Bell Labs was inventing stereo in the early 1930s, they came up with 2 schemes they felt sounded realistic: 2-channel, which required binaural recordings played back over headphones; and multi-channel (minimum 3), when using loudspeakers. There are fundamental differences between how headphones work vs how loudspeakers work.

 

[William]



Quote:
Originally Posted by Dave1027 /forum/post/18216172


Why is it understandable from headphones but not speakers? Headphones are speakers only closer to your head.

Also just to add on sdurani... headphones are near field without reflections. In a HT about 50% of all the sound your hear is reflected which is fundamentally different. Despite the fact that you have 2 ears (and even true with people who are deaf in 1 ear) you have the ability to hear an almost unlimited amount of sound and identify the all the directions they come from. While you only have 2 ears they are connected to a fantastic processor that makes the two similar to an infinite number.


Originally *stereo was going to be 3 speakers but was not practical from a software (records only have 2 sides on the groove) and hardware so 2 channel was selected as a compromise. All 2 channel recording use a phantom center and this can't be as good as a detected center (all things (speakers and software) equal) would be.


*Stereo doesn't (didn't) mean 2 but instead having 3 dimensions.