What is audio latency? – We look at what causes it, and how to fix it
Audio latency is the scourge of the recording world. Wherever there is computer-based recording, you’ll hear talk of it. If you’re new to recording and music tech, you might well wonder what it is, and why it’s such a problem.
In this post, I’ll explain in simple terms what audio latency is, why it occurs, and what you can do to fix it. So, without further ado…
What is it?
Put simply, audio latency is a delay or lag affecting digital audio playback.
The most commonly noticed occurrence of this problem is when using music software on a PC with the standard, installed soundcard.
Let’s say you’re using a set-up like this, and when recording a guitar track to your chosen software package, something is wrong. There is a very noticeable delay between your actual performance, and what you can hear back through the headphones or speakers connected to the computer.
This is latency.
It can also affect things like virtual effects and instruments. If you’ve ever used a virtual synth on a similar set-up to the system above with a controller keyboard, pressed a key and had a delay before the note plays, this is also latency.
In this case, it is easy to think that the connected keyboard causes the problem, but it isn’t…
Why is it a problem?
If you’re trying to perform it is pretty mandatory that you can hear exactly what you’re doing, at the time that you’re doing it… Hearing your performance playing back half a second behind makes concentrating on a performance nearly impossible. Plus, if you’re playing a virtual instrument, pressing notes, and not hearing them until a fraction of a second later makes accurate performance impossible.
What causes it?
Audio latency is caused by delays processing the audio data as it travels from the outside world (or from the triggered note on a keyboard), to the computer’s processor and back out again.
- Firstly, the audio is converted via A/D converters on the soundcard to digital data.
- It passes through the Bus, and then this enters an input buffer on the PC or Mac.
- After this, it hits the computer’s CPU proper. As the computer is running all manner of other programs via the OS, this can present many extra obstacles.
- The computer then has to process the audio, but the more it is doing at the time, the more data is backed up in buffers.
- Once all effects, software synths or whatever else has been processes, it is sent back via an output buffer. This then passes the data to a D/A converter, to convert the data back to audio, and it is heard via the speakers, or headphones you have connected.
Each of these stages takes time, albeit milliseconds, but they add up to a noticeable delay. As multi-media type OEM soundcards that are shipped with PCs (Mac soundcards tend to perform better) are not designed for this type of use, this process can take longer than is useful.
How do I fix it?
Each of the stages outlined above has the potential to add audio latency. So, how do you get around it?
Firstly, having a good computer is the foundation of good performance. So, get a computer with the fastest CPU, and most RAM you can afford, with large, fast hard drive, too.
The most common, and usually easiest fix, however, is to use an audio interface that is designed specifically for use with audio recording applications.
These have drivers that are capable of processing audio data far faster. As such, they can reduce latency to few milliseconds, which the vast majority of people would not even notice.
Some of these also feature direct-monitor modes. These route the signal from the input directly to the output (speakers or headphones). This means that computer, and all of the audio latency it causes, is cut from the process- you hear your performance as it travels through the input.
There are many excellent audio interfaces available, at all price points from Roland, Focusrite, Akai, Native Instruments and more. If you’d like to know more about them, and find out which will suit your needs, have a look at this article here.
So there we are- fix your latency woes, and don’t delay… (Ho! Ho! Ho! What?)