Latency (again)

Posted by: MacMacMac

Latency (again) - 07/10/13 08:45 PM

I found a couple of articles about latency:
One from Presonus
One from Sound on Sound
Posted by: sandalholme

Re: Latency (again) - 07/11/13 05:09 AM

Many thanks for this. A current preoccupation of mine!
Posted by: toddy

Re: Latency (again) - 07/11/13 07:27 AM

Great article from PreSonus! The Sound Ôn Sound one is as old as the hills (2002) so the poor fellow is still grappling with Windows 98 and USB1. (Shudder)

Still, it's interesting.
Posted by: de cajon

Re: Latency (again) - 07/11/13 09:42 AM

Originally Posted By: sandalholme
... A current preoccupation of mine!


And mine. I'd been using Cakewalk's Sonar X1 DAW for a couple of years - quite happily. Then I upgraded to X2. (Always a dilemma - was quite happy but the longer you put off upgrades the worse it seems to be when you're finally forced to bite the bullet and do it.)

The latency instantly became horrendous. And I'd forgotten what had to be done to sort it. I finally found my way to the ASIO settings, fiddled with buffering (I think) and eventually got it acceptable (although I'd swear it's still worse than before).

A little while later I was playing a Yamaha C3 grand with the SG silent system as part of figuring out whether or not we were going to get a C3X with the SH silent system to replace our upright acoustic piano. The SHs hadn't come out at that time. I was surprised and disturbed to find noticeable latency. (The man at the store said it was because it was playing through external speakers shocked , but we'll draw a kindly veil over that.)

Anyway, the good news is that I can't detect any latency in the Yamaha SH silent system.
Posted by: PtJaa

Re: Latency (again) - 07/12/13 03:09 AM

Interesting links, thanks!

I liked the blueprint for a home-made MIDI->audio cable that allows testing latency compared to incoming MIDI signal in the first article.

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For excessive latency of various sound interfaces, i find this link very useful - it shows roundtrip latencies measured for many popular sound interfaces.

Even though the roundtrip latency (delay between sending a signal from a program to a soundcard and receiving it back, using a loopback cable plugged between inputs and outputs on the soundcard) is not exactly the latency relevant for virtual pianos - because of the complete ("out"+"in") roundtrip latency only the "out" part is part of the overall latency when we use VSTs, it still IMHO shows very well how well a particular sound interface is designed and what potential delay it can cause.

Also, It's easy to measure the roundtrip latency of one's sound interface at home using this utility.

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What I'm personally concerned with more, is the inherent slowness of MIDI - 1 event takes 1ms to transfer. Does it mean that if I press e.g. 8 keys at the same time, it will take 8 ms to get the last note-on event to the other side? That sounds quite disconcerting to me, more than the more often discussed quantization of MIDI velocities to values 0-127...

I mean, how great is it to get the latency in the computer to extemely low levels, if even the midi cable sees the last note played in a chord only after e.g. 8ms?

I always wonder if instruments connected through USB have the same limitation, because if not, that would IMHO make USB a better interface than MIDI.
Posted by: de cajon

Re: Latency (again) - 07/12/13 04:33 AM

But, doesn't the Presonus article make it clear that hardware delays are not usually detectable? Isn't it the quality of the programming of the drivers and their use of buffering that creates perceptible latency?