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From: Murray McDowall <murraymc@...> 
Date: Sun Jun 2, 2002 9:01pm 
Subject: Re: [OT] How do Dsp cards and pro tools differ?  



Eli Krantzberg <elik@c...> wrote:

>> Can pro tools TDM give real time guitar effects etc whereas UAD-1 has
>> prohibitive latency?
>Yes.
>> How does pro tools offer these advantages?
>Through it's unique "time division multiplexing" technology. TDM for
>short. It uses phone related technology in it's dsp architecture in
>order to route data around with next to no latency. This propietary
>architecture is one of the reasons why TDM is so expensive.

TDM methods are just one of the ways to share a serial data pathway or a
radio frequency band.  Any Audio breakout box which has multiple ins and
outs and a firewire connector cable is using some sort of TDM to shunt all
those audio streams simultaneously down a few connectors. I seem to recall
that Creamware use something similar in their proprietory bus to connect up
their Pulsar and Scope cards.

TDM technology is everywhere (GSM phones) and not inherently expensive. I
think the answer is simply that Digi has been around a long time and has
its hardware and software systems well sorted. It is thus able to use very
small buffers for its audio steams and then it just charges what the market
will bear.
$4000 dollars US for a PCI card? Nice work if you can get it.

Regards,
Murray