How to control your audio latency?

We frequently hear/read about people complaining about an excessive latency due to a too accurate audio interface of the X brand or to shoddy drivers of the Y brand, or because we use a particular kind of computer and not another one and we have to change everything and… STOP!

Several points require to be clarified. We’ll present you the factors that influence your projects latency.

What is audio latency?

Technically, it’s the period of time between the moment a sound is produced by an instrument and the moment it comes out of the speakers after being processed by the recording system.

Here is the path: instrument -> audio interface -> computer -> audio interface -> speakers.

Example: I play an A with my guitar which is directly connected to my audio interface. How much time does it take before I hear this A note coming out of my speakers?

For a successful recording, the sound played by the musician(s) must be retransmitted in “real time”. If there is a too significant latency, we hear the played note delayed, like an echo. This is VERY difficult to play with and doesn’t make for a good performance. This situation can also sometimes be observed while sending a MIDI signal (from a keyboard for example) that triggers a function of a virtual instrument. Thus, it’s very important, at least for recording or composition, to be able to work with a low latency, not to hear this echo.

The sound produced by an instrument goes through a number of stages before coming back to our ears: even if it seems instantaneous there is always a slight latency.

Blog Pure Perception audio scheme audio latency
Article Pure Perception audio “what is audio latency?”

Extract from the article “The truth about Digital Audio Latency” published by Presonus (full article, click here).

HOW TO ACT ON AUDIO LATENCY?

The elements influencing latency are:

  • The interface and (especially) its drivers
  • Your audio interface configuration
  • The technology of the connection
  • The operating system optimization
  • The quality of your workstation
  • The plugins you use
  • Your DAW

Audio interface and drivers

It’s obviously a crucial point. Some audio interfaces manufacturers are better than others. RME, for example, has a well-deserved reputation because of the stability and the excellent performances of its drivers. On the contrary, Presonus has produced less efficient interfaces (see for example this test of AudioFanzine) although they use a very recent technology (USB 3.0).

A driver is a computer program which enables the operating system to interact with a peripheral, in this case with your sound card. Thus, the driver’s quality has a significant impact on the sound treatment performances and especially on the latency and the workstation stability.

Configuration of your audio interface

Two parameters are absolutely crucial: the sample rate and the buffer size.

Buffer size: it’s a temporary storage space where the data that will be treated by your processor is saved. The processor doesn’t process the information continuously: it treats successive blocks. It also sends at regular intervals a small amount of data for them to be processed by your audio interface. Since it’s a real-time process, the processor can’t “stack” the blocks. It sends them regularly, otherwise it would interrupt the flow of data your sound card receives and would produce artifacts (glitch, cracking).

Result n°1: the smaller these blocks are, the quicker the processor and the better optimized your computer should be, so that the flow is not interrupted (cracks and pops). It’s not mandatory to reach the lowest latency possible : as long as it’s imperceptible to your ears, to record should be happening in good conditions.

Result n°2: if these blocks are large, the processor needs more time to process them which implies a higher latency, since more calculations are necessary to process this data.

Sample rate: It’s the number of “digital pictures” of the sound signal that your computer will take every second to restore the sound in the digital realm. For example, the CD standard is of 44.1kHz (that is 44 100 “sound pictures” per second). This is how we write the equivalent of analog audio flow down into the digital world.

Result n°1: the higher this parameter is, the better will be the quality and the size of the files (see the article about sample rate).

Result n°2: if you increase the number of “sound pictures” per second, your buffer memory will be filled faster, resulting in a latency reduction. However, the files to be processed are larger which could produce artifacts if your computer doesn’t have the necessary resources to process them.

A balance has to be found to allow your system to have a sufficiently low audio latency to record without cracks and other artifacts, while maintaining the desired audio quality.

This balance might be different depending on the projects and the production phases (writing, recording, editing, mixing or mastering).

For a more detailed explanation, I recommend you to watch this excellent video of Richard Ames.

Connection technology

There are many connection interfaces, and they all have their specific advantages and drawbacks. Here comes a list:

  • USB 2.0/3.0
  • FireWire
  • Thunderbolt
  • PCI-Express
  • Ethernet

Of course, we are dealing with audio interfaces, not with audio interfacing. That’s why other standards such as AES, ADAT or MADI are not included in this list. We will treat them in another article.

Every existent technology has different specifications in terms of latency, and you would be better knowing before choosing one. I will address this point in an article entitled “Which connection standard choosing for your audio interface?” (online soon).

Quality of your digital audio workstation

Let us not be afraid of pushing open doors: the more powerful your computer is, the higher its processing capabilities and speed are. The matter here isn’t only your processor: a computer should have a balanced and harmonized configuration to function at its best. Thus, the best processor will be restrained in its performances when coupled only to a mechanical hard disk, for example.

All the components of the machine have to be taken into account:

  • Processor
  • Motherboard
  • RAM
  • Storage mediums (SSDs and hard disks)
  • Power supply
  • Operating system

For example, it’s not appropriate to use hard disks for this kind of workstation, preference should be given to SSDs. It’s not necessarily essential to look for the largest quantity of RAM possible (editor note: my personal computer “only” have 8Gb and I don’t have any problem with that).

These various characteristics need to be adapted according to the use you make of your workstation: number of virtual instruments, average number of tracks, etc.

The computers of major manufacturers (Dell, HP, Acer, etc) are rarely sufficient for a good record quality, apart maybe for people who want to start out with Computer Music.

For passionate or professional producers, it’s better to choose audio and computing specialists (Pure Perception for example 😀 )

Operating system optimization

It’s a crucial point: the operating system (or OS) is at the very heart of the functioning of every digital production architecture. Doesn’t matter which one you use, its optimization depends on the proper functioning of all the other elements (drivers, DAW, plugins, etc).

You will find more information about that in a future article. However, here are some initial indications:

  • Use a correctly set up antivirus
  • Remove all the useless programs loaded on startup.
  • Set up the advanced systems
  • Remove the bloatwares

Plugins

Some plugins can induce a supplementary latency if your computer isn’t performing/optimized enough. It’s a phenomenon sometimes observed with guitar or bass amplifier simulators (BIAS Amp, Waves GTR, etc) or with plugins that use heavy sample libraries (some Kontakt instruments, for example).

Note that it’s possible that even with a well-optimized computer and the proper resource to execute it, some plugins can remain unstable or create artifacts. Generally, it’s necessary to stop using this plugin. This case is very rare and I have, personally, never had to resort to such measures. It’s a situation in which we can end up with old plugins that are not no longer updated.

DAWS

We are all using different DAWs for different reasons. Depending on your needs and on the performances of your workstation, it may be interesting to use a specific DAW.

For example, on a laptop, I often recommend Reaper because it is so light which liberates a lot of processing power.

On a desktop computer, there are many options, depending on your working habits. Lately, I have been going back and forth between Cubase Pro 8.5 and Reaper depending on the project and on what I wanted.

IN CONCLUSION

All the listed elements affect the audio latency, and obviously, a properly balanced configuration helps a lot. The most important is: a good computer, since everything else depends on it, then the drivers/audio cards and the DAWs.

Getting an adequate latency requires to pay attention to your whole installation, and to calibrate it in function of the projects you have to lead and the desired quality you want to reach.

Don’t hesitate to contact us if you need assistance with the configuration of your equipment or advices to optimize it.

#latenceaudio #interfaceaudio #stationdetravailaudionumérique #silentcomputer

SOURCES

Video of Richard Ames

Article of Presonus

 

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