[AG-TECH] Real Time Music Collaboration

Osland, CD (Chris) C.D.Osland at rl.ac.uk
Tue Mar 12 07:07:19 CST 2002

I see, by looking back at an e-mail I sent last week, that I
rather buried two possible solutions to the latency problem.
May I restate them, as I think they have some mileage...

Method 1 - "Audio Conductor"

One site produces in effect an augmented click track, with enough
of the melody for people not to get lost.  This goes to all
players, who just listen to this and play in time with it.
Hence the term "audio conductor".  All feeds from the players
go to one site, which retimes them individually, having worked
out which node is last to arrive.  This site then rebroadcasts
the resulting mix to everyone but only the listeners, not the
players, listen to it.  This is rather like an orchestra doing
the score for a film, each listening to parts of what is
happening on headphones.

Method 2 - "Round Robin"

One site lays down a bed for the piece - maybe a drum track.
A second node listens to this and plays (=adds) their player(s)'s
contributions.  This feed goes to the third playing node, which
does likewise.  The feed from the n'th node (if n nodes are playing)
is the one that all the listening nodes listen to.  Typically the
n'th node will be the vocals (if the piece is pop/folk/rock/vocal).
This is rather similar to the multi-layer approach taken by
groups that do the drums in LA, the guitars in London and
the vocals in the Seychelles, by lugging a 24-track tape or
ProTools system around.

It has been pointed out to me over lunch that many classical
pieces (e.g. string quartets) cannot be done this way, as at
different times each of the instruments may lead the timing;
possibly a non-recorded harpsichord continuo would be appropriate
in this case!

The person who noted this is a classically trained cello player,
so I guess I can lob that in as a possible contribution from
here as well.



Chris Osland                         Office tel: +44 (0) 1235 446565
Digital Media and Access Grid      Medialab tel: +44 (0) 1235 446459
BIT Department             Access Grid room tel: +44 (0) 1235 445666
e-mail:   C.D.Osland at rl.ac.uk               Fax: +44 (0) 1235 445597

CLRC Rutherford Appleton Laboratory (Bldg. R18)
Chilton, DIDCOT, Oxon OX11 0QX, UK

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-----Original Message-----
From: Don Morton [mailto:morton at cs.umt.edu]
Sent: 12 March 2002 01:53
To: Michael Grobe
Cc: Osland, CD (Chris); 'Jonathan C. Humfrey'; ag-tech at mcs.anl.gov
Subject: Re: [AG-TECH] Real Time Music Collaboration

Michael Grobe wrote:

> too quickly for more than a 3 step pipe.  however, it would also be
> possible for dancers to listen and perform in the audience venue....
> though distributed dancers would not be synchronized...something that
> might be as much an "opportunity" for creativity as it is a problem.
> (oh, simulating these things in my head gets confusing...)
> but wait...maybe this is another application for mark herald's personal
> proxies operating as a means of overcoming transmission latencies to mars?
> hmmmm.

honestly, i think this is one direction we want to proceed in
(just my opinion :)).  clearly, one needs to work out issues
of latency to play the kinds of music we're all used to
hearing but, what happens when we have an AGN on the moon
that wants to participate in one of these concerts?  absolutely
no way around the latency, and one HAS to think differently...
clearly, mark's mars example stretches the implications :)
in my opinion, it's time to be thinking about new ways of
expressing ourselves in a latency filled environment......
of course, i'll leave it to the composers to figure out how
the hell to do that!!  but, isn't it possible to imagine
some sort of music that's expressive through various patterns
that happen at "roughly" the right times, but not necessarily
synchronously????  i don't know.....  i'm only a lead guitar
player from a famous rock band in the 70's :) :) :) :) :) :)


   Don Morton                   http://MRoCCS.cs.umt.edu/~morton/
   Department of Computer Science       The University of Montana
   Missoula, MT 59812 | Voice (406) 243-4975 | Fax (406) 243-5139

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