Why HiFi? pt. 9

By: Gary Alan Barker
October 29th, 2020

Multi-Channel vs. Two-Channel

Thanks to COVID I don’t have a system to review this month, so I thought instead, I would review my home theater system. After completing that review I realized it was of little use to you readers so I wrote this instead. I should point out that the reason I don’t use this system in my reviews is that most of the components are over 40 years old and the manufacturers don’t exist anymore, at least in the form they existed at that time, most of them were bought by Asian concerns and none of the people involved in their design are still with them, though there are exceptions to this rule, yet I don’t feel that these components are totally relevant to the modern consumer due to their rarity. The newest component of this system is at least 30 years old and that is my Audible Illusions Modulus preamp, which kinda lets the cat out of the bag, my current home theater system is two-channel. To understand the trials and tribulations that brought about my current home theater system requires a little history.

Back in the dark annuls of time before digital surround there was something called Dolby Pro-Logic which was a four-channel surround system which consisted of right, center, left, and surround, and before that, there was Dolby Surround which was a rehash of Quadrophonic surround from the ‘70s which came in three varieties; SQ, QS, and CD-4. CD-4 was a discrete 4 channel surround in which the primary channels were cut off at 20kHz and the rear channels were encoded into the bandwidth from 20kHz to 40kHz which required special playback equipment, IE: a cartridge with a linear bandwidth of 40kHz, and of course the CD-4 decoder along with a second stereo amp and a second pair of speakers. SQ and QS on the other hand are matrix systems where the rear channels were recorded out of phase atop of the main channels with the side benefit that SQ and QS records could be played back on conventional stereo equipment (Quadraphonic listening still required a decoder and four channels of amplification and speakers, but many European Classical labels simply recorded everything in QS as a matter of course). In fact, home theater surround owes its birth to Quadrophonic holdovers who discovered with the development of stereo VCRs that when the stereo tapes were mixed down from the six-track masters, the rear channels lent themselves to matrix decoding.

Which brings us back around to my story: My introduction to home theater began in the early ‘80s or late ‘70s, I can’t say for sure when I integrated my VCR into my audio system, but it was almost immediate and it was in mono. There were of course simulcast events before that dating back to the ‘50s, but the VCR allowed me, for the first time, the ability to fully integrate my video into my sound system.

As a musician, I was a huge Quadrophonic fan, as it was natural for me to be in the center of the band, so when Beta Hi-Fi introduced stereo to the mix, I was one of those who discovered the full immersion of home theater that surround channel information introduced. And then Robert Lee (of Acoustic Zen fame) introduced me to the magic that is Two-Channel, and I never looked back (at least for music). I still integrated video into my sound system, in fact, I found that video helped in setting up systems since it gave a visual reference for what I was listening to. And that was when I discovered that with a Pro-Logic encoded source, in a properly set up system with proper center fill and proper rear wall reflection, I could get full surround using just two speakers (this led me to later, when I was working for Angstrom the company that made the first digital surround processor as well as the first DTS and Dolby Digital home processors back in the mid-’90s, to try to talk the designer into making a processor that would re-encode DTS and Dolby Digital into Pro-Logic which turned out to be a violation of the rules at the time).

That is not to say that I had totally abandoned multi-channel sound, in the late ‘80s when I was working as one of the early custom installers, I helped design and install the first in-home THX surround system, which used a complete professional theater THX system (this was before they developed scaled-down THX systems for smaller box theaters or had begun marketing to home audio manufacture) and a GE Light Valve (this was the huge professional projector used at rock concerts and such). And of course, there was my stint at Angstrom where I did PCB layout, board mods, and final assembly.

After Angstrom, I worked for TAG Mclaren Audio, the designers of the first seven-channel processor, the first processor with a height channel, the first processor with an onboard video scaler, and the first to incorporate Room EQ into their processor, as their US Product Specialist and Service Manager.

My last brush with surround sound in home theater was about 13 years ago when I worked for Halcro, who made what is most likely the best sounding and least reliable surround processor that will ever be produced (eight-channel LPCM has all but disappeared as has Blu-Ray itself). So for three years that was my home theater system until Halcro folded and I was forced to return to my previous Two-Channel system, and funny enough, I don’t miss it.

Ok, so Multi-Channel vs. Two-Channel, for home theater, though one can achieve perfectly acceptable performance with Two-Channel, Multi-Channel is the clear winner, and I’ll explain why in a minute. On the other hand, for music reproduction, it becomes a matter of perspective and experience. It is a simple question of do you want to be in the band or in the audience. If you have never seen a live performance and are not trying to relive that experience, or if you prefer to imagine yourself as a member of the band, then Multi-Channel is your logical choice, and though rare, there are a few recordings out there that have attempted to reproduce the audience experience in a Multi-Channel recording. Multi-Channel has definite advantages over Two-Channel. For one, placement and setup are a lot less finicky. While ideally, you want a symmetrical anechoic chamber for Multi-Channel, as long as your front three speakers are basically symmetrical in relation to the listening position, the center channel is centered on the listening position, and the surround channels are equidistant from the listening position, you are set. Even room treatment is simpler since you are simply trying to kill sonic reflection, not control it to build a sound stage. On top of that, you can get away with a lot less expensive speakers, since most Multi-Channel systems include a subwoofer, full-range speakers are no longer necessary, and things like soundstage and imaging are no longer an issue, though dispersion still is (you want wide horizontal dispersion and narrow vertical dispersion, this used to be part of the requirements for THX certification).

Conversely, Two-Channel is the domain of the true audiophile who wants to create the illusion that one is attending a live performance. While it is true that a few Multi-Channel recordings try to reproduce this experience, they rarely do it well, and for the most part, Multi-Channel music recordings are gimmicky things like early stereo recordings, randomly sticking different musicians in the different channels. Not only that, they often break the synergy of the original recording mix (kinda like remixes) that made the song appealing in the first place.

Finally, though one can often playback music through a home theater system for a thoroughly adequate experience or one can use a well-designed stereo system for watching film with satisfactory results, the actual goals of home theater and music reproduction are completely different.

For music reproduction the goal is to reproduce the original environment as accurately as possible, whereas with home theater you are trying to create something larger than life. The catchwords for home theater are clarity and dynamic range, you want to understand the dialog and want the presentation to be exciting, and for this reason Multi-Channel is king with its heavy deep rumble of the LFE channel, the vocal clarity of the center channel, and the immersive ambient experience of incidental sounds coming from the surround channels. Yet, for the audiophile, for all the reasons stated above, Two-Channel is the perfect choice for music reproduction.

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