Latency free monitoring solutions

For all their many advantages, DAWs have one serious disadvantage, latency. As we know, latency is the time delay created by the finite amount of time it takes for digital processes to execute. This is true for any audio processor including A to D and D to A convertors, effects processors and digital mixers, but in the case of these devices the latency is within the time frames of that which occurs naturally as sound travels through the air. In short, it's all but inaudible.

The story is different for a DAW. In the case of the round trip latency between a DAWs input and output,  the delay is compounded by the need to buffer samples until processor time becomes available. This i/o buffering is what causes performers the most problems when we are monitoring the DAW output. A delay of more than 30ms can be off-putting to many performers, especially guitarists.

i/o buffer settings in a Logic project

There are a number of solutions and all have advantages and disadvantages.

1) Direct out audio interface monitoring. In this case, the audio interface duplicates the input signal before conversion and passes one copy to the A to D and the other back to the stereo monitor output. This process is analogous to a tape recorder's input-copy-monitor function (see this video on tape delay).

However,  because the recording of the performance is not being monitored, any problems will not be evident until playback. This is why playback was such an essential part of multi-track tape recorder recording.

A second disadvantage is that any effects or processing applied to the signal (track) in the DAW will not be heard. Some audio interfaces offer a monitor reverb which is added to the direct out signal to help blend the performance with the backing track.

If you plan to use this approach, you must ensure your audio interface software provides suitable tools for balancing monitor mix levels, especially if you are recording many performance simultaneously (eg tracking).

2) Reduce the latency to the lowest possible sample count by optimising the DAW system and turning off any latency inducing processes during recording.

This method can be tedious, often requires a software and/or system re-boot and is not always successful in reducing latency to an acceptable level.

3) Turn-off software monitoring in your DAW,  split/duplicate the signal to be recorded and send one to the audio interface and the other to a spare channel on a separate hardware monitor mixer which is also monitoring the DAW stereo out. You can add hardware effects reverbs to the mixer's send and return or buy something like a Yamaha O1V which has effects in-built.

This solution requires more hardware (much of which is dirt-cheap on eBay), including a mic/line level splitter, but may ultimately be more scalable, flexible, easier to configure and intuitive. And of course it provides a completely latency free monitor mix for your performers.

A Yamaha O1V mixer being used for DAW and live performance monitoring

If you have an alternative solution for combating latency which works for you, please let us know.

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