How can i measure soundcard latency?

1. What is acceptable latency for audio recording?
2. Can you hear 30ms delay?

What is acceptable latency for audio recording?

While some keyboardists claim to hear a 5ms discrepancy in their performances, the vast majority of musicians are unlikely to worry about 10ms, and many should find a latency of 23ms or more perfectly acceptable with most sounds, especially pads with longer attacks.

Can you hear 30ms delay?

Research shows it takes between 20 to 30ms of delay before our brains perceive a sound as separate from another. So up to 10ms latency is usually ok, we won't notice it. But more than that and a musician will start losing the feel of the music and this will affect his performance.