Quote:
Originally Posted by michael c
Is there any advantage to using Avid I/O or Omni versus ones by Apogee, UA, MOTU etc. as far as latency goes?
Thanks.
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Latency is a general term. In Audio recording we usually are concerned with what many call Round Trip Latency (RTL) which is defined as the time it takes audio to do a roundtrip from analog input --> Recording System --> analog output. To do this loop entails many individual "latencies":
A/D time,
transfer time from data bus to DAW, (TB, PCIe, FW, USB, Ethernet etc...)
DAW buffer in,
Any plug in delay
DAW buffer out,
transfer time back to data bus (TB, PCIe, FW, USB, Ethernet etc...)
D/A
This is the general case and there are many interfaces that intercept the incoming signal before it gets to the DAW buffer and feed that back to the performer for low latency recording.
So the whole concept of reducing latency is many faceted. The AVID converters are middle of the road (~0.47ms (A/D + D/A) at 96k). I wish all manufacturers would publish all the specs (they almost always tell you the 96k one cause its the fastest). From these (AFAIK) the MOTU, Apollo and Apogee converters are all fairly similar at 96kHz. Certainly within 0.25ms at 96kHz.
The Data bus transfer times are usually very significant. PCIe, TB and the DigiLink ones (AVID) are all near enough to zero to be ignored. FW and USB are huge in comparison (1 - 2 ms and at times much more).
The DAW buffer itself for in and out is a pretty big player: 64 samples X 2 /96kHz = 1.33ms.
So - the AvID I/O's may reduce your latency (assuming you have the right hardware to plug them into). In the Pro Tools 12 case there are only three options for using these these. HD Native or HDX for PT12HD. DiGiGrid DLS or (DLI + SoundGrid server) for PT12 Vanilla.