Oh yeah, latency. Let’s go there.
Let’s assume a sample rate of 48 kHz and let’s be generous and go for a latency of 128 samples. This will give a delay of 128 ÷ 48000 = 0,0027 seconds or 2.7 ms.
For the speed of sound we use 343 m/s (that’s in dry air at 20°C).
Now let’s calculate the distance sound can travel through air in 2.7 ms: 343 × 0,0027 = 0,9 m.
Yup, that’s right. Less than a meter. That’s about the distance between your hands and your ears when you clap your hands…
The lesson from this is that latency is always present in any kind of analog as well as in digital audio. I highly recommend http://whirlwindusa.com/support/tech-articles/opening-pandoras-box/ if you find this subject interesting.