What buffer size setting should you use in your DAW?
Unlike analog audio equipment, your computer can't process audio instantaneously. It takes a little time to process a recording, playback, or plugin. This time is short, measured in milliseconds, but it is significant and it will affect your recording process.
Your DAW's buffer is an area of memory where digital audio samples are temporarily stored.
Your digital audio workstation (DAW) will have a preference setting for buffer size. Different DAWs do this differently, and you can find the exact method in your DAW's online manual.
Buffer size is measured in the number of samples that can be accommodated in the DAW's buffer at any one time. Digital audio is recorded at a certain number of samples per second. 44,100 and 48,000 samples per second are common sampling rates.
Holding a number of samples in the buffer gives your computer time to do its work. Fewer samples - a smaller buffer or lower buffer setting - allows less time; more samples - a bigger buffer - allows more time.
The important thing is that the computer has a certain amount of work to do and it needs enough time to do it. If the buffer setting is too low, then playback or recording will stop, or the audio will glitch, possibly unpleasantly or severely.
So the buffer setting needs to be high enough so that your computer has plenty of time to process. A buffer setting of 1024 samples is normally enough for anything. The number 1024, by the way, comes from 2 x 2 x2 x2 x2 x2 x2 x2 x2 x2, or 2 to the power 10, which is a binary math thing.
On playback, it doesn't matter how high the buffer setting is. Set it as high as you can and it will take just a fraction of a second to fill up and playback will start.
On recording however, the size of the buffer affects latency, which is the delay between sound going into the microphone and sound coming out of the performer's headphones, which is the most critical point.
If the latency is too much, there will be a noticeable delay between sound going in and sound coming out, so the performer hears an echo of their voice or instrument, which can be intensely distracting, to the point of not being able to perform.
If the latency is a little too much then it is distracting and the performer will not be as comfortable as they could be, or should be.
With low enough latency, the delay is hardly noticeable and for all intents and purposes is as near zero as it needs to be.
So for mixing, you can set the buffer to 1024 samples and your computer will perform perfectly. This applies to simple playback too.
For recording, you should set the buffer to as low a value as your computer can handle. 64 samples is a good place to aim for; 127 samples can be adequate; 32 samples - if you can manage it - is an excellent place to be.
How to manage the buffer
Suppose that you have built up the instruments of your recording with lots of tracks and lots of plugins, and now you want to record a vocal. So you set the buffer to as low a setting as you think you can get away with. But your computer glitches, stops, or complains. And a higher buffer setting results in distracting latency. What can you do?
Well, it's the complexity of your session that is the problem, so you need to make it temporarily less complex. One way to do this is to freeze your tracks. This will convert software instrument tracks, or audio tracks with lots of plug-ins, to plain audio tracks with no active plug-ins, and you will hear them just as they were before freezing.
Now your computer has much less work to do and you can record with a low buffer setting. You can unfreeze later.
Alternatively, you can mix your instruments to a stereo file and open that up in a new session. Record your vocal, then when that's done import it back into your original session. This might sound like an unnecessary complication but it can actually be easier because there are fewer things going on on your computer when you are trying your best to produce your vocalist.
The buffer is a nuisance but it's necessary. Use a high buffer setting when you're mixing; use a low buffer setting when you're recording. Manage your session effectively so that when recording you can set as low a buffer as you can.