[AG-TECH] Real Time Music Collaboration

Joey Mendoza jam at ncar.ucar.edu
Tue Mar 12 13:52:52 CST 2002

As a member of a drum and bugle corps that tours all summer, I've had
some experience in the way we line up our sounds on a football field so
that they reach the audience at the same time.  

First, we have a drum major (conductor, click track, etc.), providing a
zero-latency pulse to everyone.  The people farthest away from the
audience at the back of the football field (ie. those with the greatest
latency) play exactly in time with the drum majors pulse.  Those closest
to the audience (ie. minimal latency) play in time with the sounds being
produced from behind them.  If they played in time with the drum major
their sounds would reach the audience first and our score for that
competition would reflect that. =]

Now the actual logistics of getting something like this to work over the
AG may be pure madness, but having each node *try* to play in time with
the nodes with the greatest latency might work.

But I don't know, thats how we do it in the *real* world.  =]

By the way, I play the drums.

"Osland, CD (Chris)" wrote:
> 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.
> Cheers
> Chris
> ____________________________________________________________________
> Chris Osland                         Office tel: +44 (0) 1235 446565
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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
> --
>    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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