3 title: Latency Considerations
8 In the days of analog tape recording, the routing of monitor signals was
9 performed with relays and other analog audio switching devices. Digital
10 recorders have the same feature, but may impart some
12 href="/synchronization/latency-and-latency-compensation/"><dfn>latency</dfn></a>
13 (delay) between the time you make a noise and the time that you hear it
14 come back from the recorder.
17 The latency of <em>any</em> conversion from analog to digital and back to
18 analog is about 1.5–2 ms. Some musicians claim that even the
19 basic <abbr title="Analog to Digital to Analog">A/D/A</abbr> conversion
20 time is objectionable. However even acoustic instruments such as the piano
21 can have approximately 3 ms of latency, due to the time the sound
22 takes to travel from the instrument to the musician's ears. Latency below
23 5 ms should be suitable for a professional recording setup. Because
24 2 ms are already used in the A/D/A process, you must use extremely low
25 <dfn>buffer sizes</dfn> in your workstation <abbr title="Input/Output">I/O</abbr>
26 setup to keep the overall latency below 5ms. Not all
27 <a href="/setting-up-your-system/the-right-computer-system-for-digital-audio/">computer audio systems</a>
28 are able to work reliably at such low buffer sizes.
31 For this reason it is sometimes best to route the monitor signal
32 through an external mixing console while recording, an approach taken by
33 most if not all professional recording studios. Many computer I/O devices
34 have a hardware mixer built in which can route the monitor signal "around"
35 the computer, avoiding the systemlatency.<br />
36 In either case, the monitoring hardware may be digital or analog. And in
37 the digital case you will still have the A-D-A conversion latency of