Just wondered if it did, because on my a/v system if I put it through 6.1 it sounds really nice! I made my speaker setup so its a custom made, it really kicks out! But is that just a "simulation" or does HD really support 6.1?

Well, the 6.1 your doing could either be a simulation (reverb) or matrix decoding (which renders out of phase content to the rear and side speakers). Try using Pro-Logic IIx for a good martix decoding.

It should also be noted that most "6.1" is thus far just 5.1 audio with a martixed rear channel, and "7.1" is a stereo matrix. As of the least few years, and with the introduction of Blu-Ray and HD-DVD, discrete 7.1 is becoming more of a reality.


As for discrete surround sound, I believe that the infrastructure can be upgraded to include such. I think I read something on the iBiquity website a while back about the surround sound using an additional 26k for a surround difference channel (meaning it isn't discrete 5.1).

HD Radio (as it is now) doesn't really have the bandwidth to do discrete 5.1 (or better), and frankly NO ONE (except you, me and two other people) CARES!!!!!! ....And the people who really care want that discrete 5.1 in 96/24 or 192/24, which would suck up a frickload of bandwidth!

As for discrete surround sound, I believe that the infrastructure can be upgraded to include such. I think I read something on the iBiquity website a while back about the surround sound using an additional 26k for a surround difference channel (meaning it isn't discrete 5.1).
Ibiquity suggests using the two extra audio channels (24K and 96K) in the MS2 full-digital mode (not hybrid) for surround sound and other "enhancements" to the main audio. The document just suggests this as a possible use for the channels and doesn't explain how it would be done.

Exactly, this is like the possibility that OTA DTV could do other formats other than MPEG 2 (and the set resolutions), but you'd have to get totally new equipment to do it.

The good news is that in the full-digital mode, there are definitely enough channels to send eight or nine discrete high quality channels and maybe enough for another low-quality channel.

The bad news is we may not see full-digital stations in our lifetimes, and probably not many stations besides classical stations are interested in true surround sound.

Yes there are ongoing experiments with surround for HD. But it's not discrete. It DOES however work much better than the matrix "quadraphonic" systems of the past. It's from Neural, and I've read it works quite well.

The problem, of course, is that there really isn't enough surround content for a 24 hour format, without including weird mixes that were simply thrown together. The vast catalog of recorded music is HUGELY weighted toward stereo and mono.

Mike and Scowl,
Sorry to get a little off topic here, but do you guys remember the discrete "Quadraphonic" from the 70's (quad FM, 4 tracks and CD-4 records)?

The problem, of course, is that there really isn't enough surround content for a 24 hour format, without including weird mixes that were simply thrown together. The vast catalog of recorded music is HUGELY weighted toward stereo and mono.
You would probably have stations doing some sort of cheesy reverb effect in the rears for mono and stereo recordings.

I know because I do that with mono recordings at home, but that's because I often need some idea what an ancient recording will sound like when played in a large room before I play it in a large room (will people be able to hear the rhythm?).

Indeed I do remember quad, discrete and matrix, mattdp. I was a teenager at the time, but was VERY "into" quad. I built the "Dynaco" decoder for my first matrix box....simple to do...front left and right are connected to the amp's left and right front channels. For the rear, the positive terminals are connected to the positive terminals of the left and right rear speakers, and the negative terminals of the rear speakers are connected to each other. Voila! Only out of phase (usually reverb/ambience) information goes to the rear. Add dual "pots" (volume controls) to attenuate front and rear speakers, and you can balance the sound between front and rear. IT ACTUALLY WORKS...not just with matrix surround recordings, but also with stereo...especially "real" stereo...picked up with spaced microphones (as opposed to the "fake" stereo on most pop and rock recordings, where each insrument occupies ONE tape track, and is "panned" into position...using amplitude cues ONLY (rather than a combination of amplitude and phase, as occurs in the "real world" and in recordings made with spaced mics).

The CD-4 records had one side benefit to phono playback, which some find important today. Prior to the early 70s, most phono cartridges had trouble reaching 20khz or a little beyond. Since the FM subcarriers for CD-4 were above the audio range, "quad" phono cartridges needed response to 45khz or higher. The finer stylus shapes required to do this are still in use today, and today's phono cartridges routinely meet this spec for EXTREME hf response. Whether that's important, well....

Did you actually have any experience with CD-4 records and quad 8-tracks. Did the rear channel content on CD-4s really wear off fast?

Also, what is your "professional opinion" on the adoption of surround sound in the music world? Will it ever happen?

I have 30+ year old CD-4 records that OBVIOUSLY still have the surround subcarriers on them, because you can hear it if you slow the record down. Place the stylus in the groove, and slowly rotate the platter manually between songs, or in the lead-in groove. Hear the high pitched sound? THAT'S THE QUAD SUBCARRIERS!

I don't think there's much interest among the GP (general public) for surround. Think about how much music listening is done through headphones/earphones, and how many people still listen to a mono table radio at work all day. We're in a mono/stereo world as regards music. I don't see that changing, except in audiophile circles. And I'm not as gung-ho on it as I used to be. CLEAN AUDIO is more important (to me) than the number of channels. Hell, there were some stunningly good sounding mono recordings in the 50s!

Ok, I'll have to play a CD-4 really slowly if and when one pops up a Savers.

Do/did you ever actually own a CD-4 playback system? at least according to This Site (http://hometown.aol.com/matrixquad/cd-4.htm), the rear channels started sounding bad after the first dozen plays and the whole playback system had to be calibrated near perfectly (and you needed to clean record often) for it to actually work right.

[Sorry, I've got a real interest in old recording technologies.]

Yes there are ongoing experiments with surround for HD. But it's not discreet. It DOES however work much better than the matrix "quadraphonic" systems of the past. It's from Neural, and I've read it works quite well.
HD Radio can only do stereo at best. (Sat Radio, too!) That makes it a candidate only for matrix surround systems. Neural, Pro Logic, and SRS are the only options, and they are not as good as discrete surround (like what you find on a DVD.) Stick with stereo and use a Pro Logic decoder to decode something in surround as an "improvement" but not true surround. By the way, matrix decoders available today are remarkably similar to their quad ancestors -- and simpler, too!

For highest quality sound, you need discrete channels. The overwhelming amount of music is in two channels. This being the case, all you need is a high end stereo system for the best in music.
Richard

HD Radio can only do stereo at best.
True only in hybrid mode. If full-digital mode stations ever appear, they'll be able to do as many as seven discrete channels.