Stereo vs 3 Channel? DAC's the question?

[Deleted]

Hi all, 

Interested in your thoughts about stereo vs 3 channel listening. Personally, I run a 3 channel setup. I love the extra channel separation where the DAC works its magic. My question to you for various listening types music, movies, etc are which do you prefer and why? And what would it take or what did it take for you to transition from stereo to 3 channel listening? 

Enjoy,
William

[pedrocols]

I may try it as Magnepan recommends it.

[KeithL]

I'm personally not a big fan of adding a center channel... except in a few specific situations...

Assuming you're starting with a pure stereo signal then there is no center channel to start with.

But, if you have two stereo speakers, and they're set up properly, and you sit in the middle, you should have a rock solid "phantom center".

(And, if so, you should literally hear no difference if you add a physical center channel speaker.)

You can create a center channel by summing L+R to a center speaker ... but, while that may fill in the center if your speakers are far apart, it isn't going to widen the sound stage.

Alternately, you can use PLIIx, or something similar, to synthesize a center channel, which is somewhat more than just a sum of L+R.

In that case you may end up with a wider sound stage, which may sound pleasant (I know plenty of folks who do that and enjoy it), but I personally always feel that it sounds somewhat artificial.

A DAC itself shouldn't be doing anything odd like that (since a "pure DAC" doesn't do any processing and shouldn't alter the sound).

The situations where I find having a center channel to be a benefit is if you either have a very wide room, or you have a large seating area, or you tend to move around while listening to music.

If you have a wide room, or otherwise hear a "gap in the center of the sound stage", then a center speaker may help.

Likewise, if you move around while listening, or have a very wide or off-center listening area, the center channel tends to "pin the center to the center", which "holds the sound stage in place".

With only two speakers, if you move to the left or right, as you get closer to the left or right speaker, the center of the sound stage tends to pull towards the speaker you're approaching (because it is now closer and louder).

By having a real physical center channel speaker, you reduce or eliminate that affect (as you move right, instead of the image pulling to the right, the center is now to your left, where it should be).

So, as you move around the room, or if you sit off center, the sound stage remains more as it should be, or shifts less.

So, for listening to stereo music, while seated in the prime listening position, I prefer two speakers.

(The third speaker adds the potential for unwanted interactions and comb filter effects.)

But, for watching TV, especially if moving around the room, or potentially sitting off-center, I see a definite benefit to three.

Since I have an RMC-1 at home I can choose which to use by simply using two different speaker profiles.

With a two-channel DAC you can create a center channel by summing the left and right channels using a passive mixer (which is very simple).

DO NOT try to mix the left and right channels to create a center channel using a "simple reversed Y-cable".

This may actually work with some DACs that have dual outputs with separate protection resistors on each...

However, doing it this way is NOT recommended, and may reduce your main outputs to monaural, or even permanently damage your DAC.

Feb 26, 2020 10:19:34 GMT -5 @shimei said:

Hi all, 

Interested in your thoughts about stereo vs 3 channel listening. Personally, I run a 3 channel setup. I love the extra channel separation where the DAC works its magic. My question to you for various listening types music, movies, etc are which do you prefer and why? And what would it take or what did it take for you to transition from stereo to 3 channel listening? 

Enjoy,
William

[Deleted]

Feb 26, 2020 11:28:30 GMT -5 KeithL said:

I'm personally not a big fan of adding a center channel... except in a few specific situations...

Assuming you're starting with a pure stereo signal then there is no center channel to start with.

But, if you have two stereo speakers, and they're set up properly, and you sit in the middle, you should have a rock solid "phantom center".

(And, if so, you should literally hear no difference if you add a physical center channel speaker.)

You can create a center channel by summing L+R to a center speaker ... but, while that may fill in the center if your speakers are far apart, it isn't going to widen the sound stage.

Alternately, you can use PLIIx, or something similar, to synthesize a center channel, which is somewhat more than just a sum of L+R.

In that case you may end up with a wider sound stage, which may sound pleasant (I know plenty of folks who do that and enjoy it), but I personally always feel that it sounds somewhat artificial.

A DAC itself shouldn't be doing anything odd like that (since a "pure DAC" doesn't do any processing and shouldn't alter the sound).

The situations where I find having a center channel to be a benefit is if you either have a very wide room, or you have a large seating area, or you tend to move around while listening to music.

If you have a wide room, or otherwise hear a "gap in the center of the sound stage", then a center speaker may help.

Likewise, if you move around while listening, or have a very wide or off-center listening area, the center channel tends to "pin the center to the center", which "holds the sound stage in place".

With only two speakers, if you move to the left or right, as you get closer to the left or right speaker, the center of the sound stage tends to pull towards the speaker you're approaching (because it is now closer and louder).

By having a real physical center channel speaker, you reduce or eliminate that affect (as you move right, instead of the image pulling to the right, the center is now to your left, where it should be).

So, as you move around the room, or if you sit off center, the sound stage remains more as it should be, or shifts less.

So, for listening to stereo music, while seated in the prime listening position, I prefer two speakers.

(The third speaker adds the potential for unwanted interactions and comb filter effects.)

But, for watching TV, especially if moving around the room, or potentially sitting off-center, I see a definite benefit to three.

Since I have an RMC-1 at home I can choose which to use by simply using two different speaker profiles.

With a two-channel DAC you can create a center channel by summing the left and right channels using a passive mixer (which is very simple).

DO NOT try to mix the left and right channels to create a center channel using a "simple reversed Y-cable".

This may actually work with some DACs that have dual outputs with separate protection resistors on each...

However, doing it this way is NOT recommended, and may reduce your main outputs to monaural, or even permanently damage your DAC.

Feb 26, 2020 10:19:34 GMT -5 @shimei said:

Hi all, 

Interested in your thoughts about stereo vs 3 channel listening. Personally, I run a 3 channel setup. I love the extra channel separation where the DAC works its magic. My question to you for various listening types music, movies, etc are which do you prefer and why? And what would it take or what did it take for you to transition from stereo to 3 channel listening? 

Enjoy,
William

Seemingly the phantom center occurs under ideal speaker placement in front of a single listener in the ideal listening location. Is that correct, Keith? Would you say that 3 channel front sound stage attempts to bring the ideal stereo sound stage to every listener throughout the room in less than ideal positions?

You also bring to mind a question I had pertaining to speaker width separation. Ideally, I've noted reviewers of my particular towers which placed the speakers together nearly half the distance I utilize now. Is there a benefit in increasing speaker separation of L and R IF utilizing a center channel? Wouldn't there be more pronounced stereo separation and effect with increased separation? 

On my Onkyo unit I have a button that says "pure audio". A simple click turns off the center and subwoofer and only stereo is played. I can still hear that phantom center at times when both L and R "harmonize". Point is that you've largely answered for music playback but what about movies? Are most movies which are encoded with multiple channels better utilizing a separate channel? I mean in a lot of movies seems the center channel is receiving the greatest dose of signal where just about all the dialogue is coming through. 

Enjoy,
William

[mgbpuff]

Way back, long before digital, there was a lot of thought over how multi-track recordings could be made to give a more realistic result than the then current mono channel approach. Experts played with 2 channel (stereo) and 3 channel (L, R, and C) tracks and came to the conclusion that 3 channel track recording gave the best results. Many high quality recordings, especially classical recordings were made with 3 tracks. The Living Stereo recordings of classical music were done in 3 tracks on tape. The only way these could ever be heard was via a 3 track tape recorder, an expensive rarity. However, today the multichannel SACD sets of these recordings have the original three channels as they were recorded.

[KeithL]

That is basically correct.

The term "phantom center" is really a sort of overstatement.

What it really means is that, if you have a pair of stereo speakers, set up properly, they should be able to reproduce the entire sound stage properly.

So, if there is a vocalist or instrument in the center, that's where you will hear them, and it would sound no different if you were to add a properly configured center speaker.

(You don't "hear a center speaker that isn't there"; you simply hear a sound stage that is spread across the front, as it should be, with no noticeable gaps or weak spots.)

In order to achieve a perfect stereo sound stage you want to have two identical speakers, the same distance from the listener, with the listener sitting along the center axis.

In general, for a given speaker model, and a given room, and a given place along that center line, there is also a specific amount of toe-in on the speakers that works best as well.

You will hear varying opinions on the proper amount - but the reality is simply that it varies.

Some speakers work best facing straight out; others should be angled to "cross" in front of the listener.

For most speakers there is also an optimum vertical angle... which has to do with the relative location of the tweeter or midrange relative to the height of the listener's ears.

With most towers, the optimum angle is more or less vertical, and can be "fine tuned" by adjusting the height of the front and rear feet or spikes.

With many older large box speakers, it was optimum to tilt the speaker back about 10 or 11 degrees, which most speaker stands do.

The idea was to "time align" the various drivers by arranging things so the centers of all the driver cones was aligned vertically.

However, in any given situation, you should be able to find a combination that yields a "perfectly filled sound stage spread across the front of the room" at the listening position.

In general, you can often produce a wider sound stage by toeing the speakers outward.

Remember, though, that the ideal situation is to produce a PROPER sound stage... and not specifically to produce the widest sound stage possible.

And, often, if you arrange the speakers to produce the widest sound stage, the result may be an apparent gap in the middle.)

You are quite correct...

Most movies are mixed with the expectation that a separate center channel speaker will be used.

So, while they should work fine without one, it's easier and more reliable to play them the way they were intended.

Also, since the main dialog often occurs in the front center, doing so allows you to easily adjust the dialog channel separately.

And, finally, separating channels helps ensure that loud music or noises in the front left and right won't distort dialog in the center, and vice versa... especially if you play things a bit too loud.

Feb 26, 2020 11:44:41 GMT -5 @shimei said:

Feb 26, 2020 11:28:30 GMT -5 KeithL said:

.....................

Seemingly the phantom center occurs under ideal speaker placement in front of a single listener in the ideal listening location. Is that correct, Keith? Would you say that 3 channel front sound stage attempts to bring the ideal stereo sound stage to every listener throughout the room in less than ideal positions?

You also bring to mind a question I had pertaining to speaker width separation. Ideally, I've noted reviewers of my particular towers which placed the speakers together nearly half the distance I utilize now. Is there a benefit in increasing speaker separation of L and R IF utilizing a center channel? Wouldn't there be more pronounced stereo separation and effect with increased separation? 

On my Onkyo unit I have a button that says "pure audio". A simple click turns off the center and subwoofer and only stereo is played. I can still hear that phantom center at times when both L and R "harmonize". Point is that you've largely answered for music playback but what about movies? Are most movies which are encoded with multiple channels better utilizing a separate channel? I mean in a lot of movies seems the center channel is receiving the greatest dose of signal where just about all the dialogue is coming through. 

Enjoy,
William

[KeithL]

Good observation...

Even then there were some people who were trying to make accurate recordings... and to reproduce them accurately.

Of course vinyl, which is limited to two channels, and then cassettes and FM stereo, and then CDs, locked stereo in as the most popular distribution format for quite some time.

SACDs were then the first attempt to resurrect surround sound and multi-channel recordings... and were met with very limited commercial success.

(The competing four-channel formats of SQ4 and CD4, mostly available on vinyl, were also not commercially very successful.)

I should also point out that, back in the early days, speaker science was rather less advanced than it is today.

Therefore, it was more difficult to design a speaker whose horizontal and vertical dispersion could be accurately controlled, and which could deliver an accurate sound stage.

When stereo was first offered, many early stereo recordings featured extreme and unnatural separation, with instruments or vocalists appearing in only one speaker, or moving around rather oddly.

And, even though multi-track recording became available, the science of mixing sound between and across channels, rather than simply placing instruments in various locations, was in its infancy.

At the time, many recording engineers deliberately exaggerated stereo separation, or used it as a special effect, and many people complained that often popular stereo recordings sounded extremely unnatural.

Believe it or not, some early audiophiles deliberately used mismatched stereo speakers, "so that the two channels would sound different and one or the other would reproduce certain instruments better".

(It also achieved a sort of mock-stereo effect when playing monaural recordings.)

Feb 26, 2020 12:21:19 GMT -5 mgbpuff said:

Way back, long before digital, there was a lot of thought over how multi-track recordings could be made to give a more realistic result than the then current mono channel approach. Experts played with 2 channel (stereo) and 3 channel (L, R, and C) tracks and came to the conclusion that 3 channel track recording gave the best results. Many high quality recordings, especially classical recordings were made with 3 tracks. The Living Stereo recordings of classical music were done in 3 tracks on tape. The only way these could ever be heard was via a 3 track tape recorder, an expensive rarity. However, today the multichannel SACD sets of these recordings have the original three channels as they were recorded.

[Deleted]

Feb 26, 2020 12:39:55 GMT -5 KeithL said:

I should also point out that, back in the early days, speaker science was rather less advanced than it is today.

Therefore, it was more difficult to design a speaker whose horizontal and vertical dispersion could be accurately controlled, and which could deliver an accurate sound stage.

When stereo was first offered, many early stereo recordings featured extreme and unnatural separation, with instruments or vocalists appearing in only one speaker, or moving around rather oddly.

And, even though multi-track recording became available, the science of mixing sound between and across channels, rather than simply placing instruments in various locations, was in its infancy.

At the time, many recording engineers deliberately exaggerated stereo separation, or used it as a special effect, and many people complained that often popular stereo recordings sounded extremely unnatural.

Believe it or not, some early audiophiles deliberately used mismatched stereo speakers, "so that the two channels would sound different and one or the other would reproduce certain instruments better".

(It also achieved a sort of mock-stereo effect when playing monaural recordings.)

Feb 26, 2020 12:21:19 GMT -5 mgbpuff said:

Way back, long before digital, there was a lot of thought over how multi-track recordings could be made to give a more realistic result than the then current mono channel approach. Experts played with 2 channel (stereo) and 3 channel (L, R, and C) tracks and came to the conclusion that 3 channel track recording gave the best results. Many high quality recordings, especially classical recordings were made with 3 tracks. The Living Stereo recordings of classical music were done in 3 tracks on tape. The only way these could ever be heard was via a 3 track tape recorder, an expensive rarity. However, today the multichannel SACD sets of these recordings have the original three channels as they were recorded.

Keith, I'm sure you've sat on the balcony of an indoor concert above numerous violins? Speaking of a place where no electronics or speakers are actually in play. Just wondering if you've actually heard a system that has indeed reproduced the lifelikeness of such an example?

Enjoy,
William

[garbulky]

I've not had a weakness of center channel with my setup. However, that doesn't mean that there aren't setups that center channels don't providea noticeable benefit.

[SteveH]

That is a very interesting subject.  From 1992 - 2019, I had a Carver CT-17 prepro with Sonic Holography and the Sonic Holography actually sounded really good, you just had to make sure you were seated in the proper location.  As for movies, I definitely will stick with my 7.2.4

[405x5]

Feb 26, 2020 10:19:34 GMT -5 @shimei said:

Hi all, 

Interested in your thoughts about stereo vs 3 channel listening. Personally, I run a 3 channel setup. I love the extra channel separation where the DAC works its magic. My question to you for various listening types music, movies, etc are which do you prefer and why? And what would it take or what did it take for you to transition from stereo to 3 channel listening? 

Enjoy,
William

I’ve been using the center for music nearly 20 years going.
My system is on the wide wall which is probably the opposite of a typical HT setup. The results vary depending on the recordings. I’ve been using DTS music more lately, sometimes pro logic but mostly all stereo with both the surrounds and the center kicked back -5db.

Bill

[405x5]

Feb 26, 2020 18:14:18 GMT -5 SteveH said:

That is a very interesting subject.  From 1992 - 2019, I had a Carver CT-17 prepro with Sonic Holography and the Sonic Holography actually sounded really good, you just had to make sure you were seated in the proper location.  As for movies, I definitely will stick with my 7.2.4

I miss the holography on my older Sunfire processor, and the room effects that were just plain fun! Cathedral was my favorite!

Bill

[405x5]

Feb 26, 2020 18:14:18 GMT -5 SteveH said:

That is a very interesting subject.  From 1992 - 2019, I had a Carver CT-17 prepro with Sonic Holography and the Sonic Holography actually sounded really good, you just had to make sure you were seated in the proper location.  As for movies, I definitely will stick with my 7.2.4

stereotimes.com/acc112000.shtml

When I updated to the XMC1, all I kept hoping was that it would sound AS GOOD as this puppy did.
Despite the fact that this thing had No HDMI...
Playing Blu-ray Discs via Digital coaxial for the audio and using “re encoded dts” setting on the player, it sounded every bit as good to me as master audio via HDMI.

Bill