This is called latency. All computers will experience some latency during recording. In terms of computer recording, 'audio latency' is defined as the minimum time required for a computer to store a sample from an audio interface into application memory and copy that same sample from application memory to the audio output. Tests have shown that the minimum latency the ear can detect is 11ms, so providing the 'audio latency' of a system is under this figure, there will be no problems when recording. After the signal enters the interface, it must be converted from analog to digital. This operation takes an amount of time that varies from one device to another but is typically around 0.5ms. Latency is also introduced when the signal is returned from the computer and is converted back to the analog again.

There are a couple of things that can be done to reduce latency. Latency will be affected by processing time, so it is best to have a few as programs running as possible while recording, ideally just the recording program. Latency may increase over time as you are recording