Why is 2 Channel better than multi-channel?

The type of reasoning put forth by Stehno is flawed and ultimately wrong. He incorrectly focuses upon the playback side of the equation. The real question is whether 2 channels of audio is sufficient to record the sound of an instrument playing in a real space? As a practical matter it's done all the time and with good results, but it's not perfectly done. There are at least 10 different microphone techniques for two channel stereo recording (spaced omni, X/Y, Blumlein, Jecklin, binaural, etc.) and that's a tip off to the problem. There are too many techniques. If one of the techniques really worked as opposed to just doing an okay job, then there wouldn't be a need for such a variety. Everyone would just use the one recording technique that worked perfectly. Now if you can't capture the sound of an instrument playing in a real space with only two channels, then it stands to reason that a two channel playback of the same is faulty.

If you're willing to settle for a rough approximation, let's use Stehno's 15-20%, of the sound of an instrument playing in a hall, then 2 channel playback is a proven technology that works well. Personally, I'm more than satisfied with just 2 channels. However, if you really want to fully capture and reproduce all the sound being produce in a hall, you'll need more than 2 channels.

Actually, Onhwy61, whether my response is incorrect or flawed depends entirely on the perspective or premise of the question being asked and you bring up some good points.

First there's the all important question,

In general, is the vast majority of music information recorded at the live event (regardless of the 5 or 10 most common methodologies employed) sufficiently transferred to the final recording medium?

My answer is yes. Perhaps not for every last recording but certainly for the majority of recordings including oldies, Redbook, on up. Therefore, from where I sit, this is not an issue. So yes, my post above had to do with playback only in this thread.

So I think there are two questions remaining,

1) If 2-channel playback systems in general are accurately capturing and audibly reproducing the vast majority of music info embedded in the recording and thereby produce a relatively natural and believable music presentation, then can a similar quality multi-channel system improve on that presentation?

My answer is probably. But since I presume nobody was at this level, this most likely was not the question asked, unless it were at the time pure hypothetical.

2) If 2-channel playback systems in general are NOT accurately capturing and audibly reproducing the vast majority of music info embedded in the recording and thereby produce a music presentation that is anything but natural and believable, can a multi-channel system of similar quality improve on that presentation so that it's at least a bit more natural and believable than the 2-ch version?

My answer here is generally no.

The multi-channel system may create a more intriguing or more exciting presentation (because it's different) but it has to be just as unnatural and unbelievable as the 2-channel version because the system is still only able to retrieve and process the exact same poor percentage of music info as the 2-ch..

So if a recording engineer sticks a couple of recording mics out in the concert hall lobby for the rear channels, sure you might hear a car horn honk, a toilet flush, or people talking there, but you're still going to only hear 50% of the horn honk, 50% of the the toilet flush, and 50% of the talking. Simply because multi-channel is only dealing with the effects of the deficiencies rather than the cause, therefore multi-channel cannot offer a better recovery system of unprocessed music information embedded in the recording.

In other words, the toxicity of all reproduced sound remains the same, whether it's 2-channel or 563 channels. And this is where my toxic water and multi-shower head analogy came in.

-IMO

2-channel is for purists only!

Stupid comment - 2 channel is for anyone who uses it. Many people see no reason to introduce the gimmickry and complexity of multi-channel. It is very possible to ignore 5.1 or 7.1 or 11.1 or whatever else the marketeers are able to dream up for you to buy. That doesn't mean they are purists but simply tat they do not respond to every opportunity to buy something new. Maybe they are content or poor or busy elsewhere. Audiophools need to come to grips with the fact that too many of us treat this like a bleeping religion. It's just stuff.
2 channel is for music. Multi-channel is for sound effects.

Multichannel is for better music but I understand that others reject it for reasons of bulk, cost and prejudice.