Re: surround sound tech info?

[Hermann Stemberger <hermann@xxxxxxxxxxxxx>]

Hi Jim!

Well, you asked for really much information... But let's start:

> Where can I get detailed descriptions of how to generate
> surround sound
> using csound and other computer music languages?

I'm not programming c-sound yet but i have seen a header from a tutorial
where you can define how many output channels you would like to have.
Programs where surround-material usually is mixed like Emagic Logic
Audio, Steinberg Nuendo, Cubase SX, Sequotia, Digidesign Protools,
Samplitude, ... are already prepared for surround-production and have
therefore presets from 4.0 up to 10.2 Surround-Systems.

At first, it is not possible to "compare" a surround system with a
stereo system in a fair way.
When you type Surround do you mean a 5.1 Setup?
There are many types of Surround: Dolby Stereo (Analog, mono-surround
channel), Dolby Surround (Analog - also called "Pro Logic"), Dolby
Digital (Digital - Discrete 2.0 (stereo) up to 5.1 stream), Dolby
Digital EX (matrizied 6.1 (possibly also 7.1) stream in 5.1 channels),
dts (Digital, from Stereo in 192khz/24bit up to 5.1 stream in
48khz/24bit), dts-es Matrix (not sure, i think matrizised 7.1 in 5.1
stream), dts-es Discrete (digital 7.1 stream), MLP (Meridian Lossless
packaging, up to 6 streams PCM in 96khz/24bit - also called DVD-Audio -
no video data).

This was the "first point" of Surround.

Running with 5 Speakers always causes (more than 2 speakers)
interferences at your listening point. This is the reason why comparing
stereo with Multichannel Formats is very critical. In my opinion you
can't compare those objective.

For all formats that i meantioned special encoders are necessary. If you
want to produce Multichannel audio just for your own work you will not
need those encoders - you can save either as multichannel-PCM file or
save 5 or 6 WAV files that you playback over a soundcard with at least 5
outputs.



If you really want to produce Multichannel in a commerical way you will
need either a Dolby Encoder (the hardware unit is about US$ 3000 when i
remember correctly - software version about US$ 1000) or a dts-Encoder
(that is priced about the same).

> Which are the best sound cards, laptops, and external processors?

The "best" soundcards are those that have the biggest
Signal-Noise-Ratio, minimum Total Harmonic Distortion, best linearity,
shortest latency, highest bit- and Samplerate and enough outputs for
your demands (in your case at least 6). It is a question of money where
you go: High-End Systems are Digidesign HD, RME Audio, and many others.
Budget systems are quite cheap, e.g. Audiotrak Maya 5.1 EX (there are
many more systems that i didn't mention - just visit a online music
store to browse the big palette

> Which are the most accessible surround sound processors to the blind?
> That means ability to control them by key strokes,
> without reference to the on screen menues.

I don't know that - but switching between stereo on surround will always
be noticed because you're "switching on" (at least) one Surround-channel
(from the back!).

If you want to compare different encoder formats in multichannel - i
have not seen any kind of software that switches e.g. from a dolby
digital stream to a dts stream without latency. But possibly there is
one...

> I am especially interested in surround sound music, both in
> new formats,
> and simulation of surround sound using older stereo recordings.

There are different socalled "upmix" (=make e.g. 5.1 channels out of 2)
algorhythms available. The most known is the (already mentioned) Dolby
Pro Logic Encoder. The main principle of all Up- and Downmixes (=make 2
out of 5.1 channels) is phase coherence. Surround upmix means - very
simplified - putting phase incoherent signal parts in the Surround
speaker(s).
When you do a google-search on "dolby pro Logic encoding" you will
probably get information about the upmix process that Dolby Laboratories
uses.

> I want to learn about both arrays of speakers and simulations
> with headphones.

As far as i know there is just one professional headphone surround
system from STUDER that is in development stage.

> I need manuals for Dennon, Yamaha, Panasonic, and other
> external surround
> processors and receivers,
> and comparisons of their different models.
> I need these manuals in plain text, not PDF.

You can download manuals of the mentioned manufacturers from their
homepage - and most are in PDF format :-(.
Every manufacturer has plenty of surround receivers (at least 10 per
manuf.).
You will have to convert or print those files on a computer that can
read PDF files.

Two external surround processors are the aforesaid Dolby Laboratories
Original 19" Hardware En- and Decoder (professional studio use) and the
DTS Hardware units.

The Decoding process is the same on all units because it comes from
dolby and dts.
This is the reason why all the units have stickers with "dolby digital"
and "dts" on them.
The difference between them are different output connections (digital,
analog) and the quality and maximum Bit- and Samplerate of the
DA-Converters.

One mailinglist in English that deals with Surround-Sound is the
"Sursound Mailinglist" (
http://mail.music.vt.edu/mailman/listinfo/sursound ).
If your native language is german there's a Surround-Sound Forum (
http://www.tonmeister.de/ ).

As far as i know both lists are quite audio engineer oriented but
they're friendly people and will help you if they can.


Multichannel sound is a really BIG field...

Hope that helps a bit,
Best regards,
Hermann