Electronic music - notes on audio latency

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The physical and human spects dealing with audio, video, and images

Vision and color perception: objectively describing color · the eyes and the brain · physics, numbers, and (non)linearity · color spaces · references, links, and unsorted stuff

Audio physics and physiology: Basic sound physics · Human hearing, psychoacoustics · Descriptions used for sound and music

Digital sound and processing: capture, storage, reproduction · programming and codescs · some glossary · Audio and signal processing - unsorted stuff

Image: file formats · image processing

Video: format notes · encoding notes

Noise stuff: Stray signals and noise · sound-related noise names · electronic non-coupled noise names · electronic coupled noise · ground loop · strategies to avoid coupled noise · Sampling, reproduction, and transmission distortions

Electronic music: Studio and stage notes · Notes on audio latency · Effects · Gaming synth · Some history, ways of making noises

Unsorted: Signal analysis, modeling, processing (some audio, some more generic)

For more, see Category:Audio, video, images


Why latency exists (the long version)

Hardware, and the nature of digital audio

Why larger buffers are generally useful

On drivers and APIs

Windows APIs

Some history

On ASIO wrappers

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)


ASIO usually refers to native ASIO, a driver talking directly to the sound hardware and exposing the ASIO API, much of the point being ignoring windows's sound architecture completely.


ASIO wrappers are different. They open a sound card via a regular Windows sound API (in practice typically WDM/KS or WASAPI), force settings that are lower latency, and present it via ASIO API.

Yes, this is counter to ASIO's shortest-path-to-the-hardware principle.

And yes, you will only get latencies that were always possibly to get from that underlying driver API anyway.

So why add a layer?


Convenience, mostly. Having one central place to configure a small-buffer, possibly-exclusive way to these existing APIs means figuring out those settings just once, in the wrapper's settings, rather than for every DAW-soundcard combination you have, which is usually more work, and the config details may vary somewhat between DAWs which can be more fiddly and/or confusing.Sso using that wrapper can also be easier to explain to people.

There's also some DAWs/software that ignore everything not ASIO, sometimes just because they have a divide and conquer approach: Figure out low latency in something external, and talk to that. (Some supply such a wrapper themselves)


There's a few more useful reasons hiding in the details, like

you can often force WASAPI card to be fairly low-latency without exclusive mode, which means you don't have to dedicate a sound card, to a DAW that only talks ASIO. Which is pretty convenient e.g. when playing piano on a laptop on the go.
some ASIO wrappers can talk to on sound cards for input and another for output (at the cost of slightly higher latency), which DAWs talking native ASIO will typically refuse to do (for latency reasons).


As far as I can tell

  • FL Studio ASIO (a.k.a. FLASIO) is a WASAPI wrapper.
Comes with FL studio, also useful in other DAWs
can talk to different sound cards for input and output
  • ASIO4ALLv2 is a WDM/KS wrapper.
needs to force exclusive mode
can talk to different sound cards for input and output
  • "Generic Low Latency ASIO Driver" is similar to ASIO4ALL but with different options
from Steinberg, comes with Cubase


And there appear to also be ASIO multiclient wrappers, basically ASIO in ASIO.

ftp://ftp.steinberg.net/Download/Hardware/ASIO_multiclient_driver/


"So which API is best?"

Linux APIs

OSX APIs

Lowering latency

In general

Everyday latency

Decide how low is necessary

The basic steps

API stuff

Windows API tweaking

Use a sound API designed for lower latency

Use sound API settings that lower the latency: exclusive mode

Use sound API settings that lower the latency: smaller buffer sizes

Linux API tweaking

OSX API tweaking

DAW considerations

Considering effects

Higher sample rates?

"Delay compensation?"

End-to-end latency

Further considerations

Hardware bus?

On network latency

Unsorted