38 lines
1.8 KiB
HTML
38 lines
1.8 KiB
HTML
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<p>
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In the days of analog tape recording, the routing of monitor signals was
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performed with relays and other analog audio switching devices. Digital
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recorders have the same feature, but may impart some
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<a
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href="@@latency-and-latency-compensation"><dfn>latency</dfn></a>
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(delay) between the time a noise is made and the time that it will
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come back from the recorder.
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</p>
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<p>
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The latency of <em>any</em> conversion from analog to digital and back to
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analog is about 1.5–2 ms. Some musicians claim that even the
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basic <abbr title="Analog to Digital to Analog">A/D/A</abbr> conversion
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time is objectionable. However even acoustic instruments such as the piano
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can have approximately 3 ms of latency, due to the time the sound
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takes to travel from the instrument to the musician's ears. Latency below
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5 ms should be suitable for a professional recording setup. Because
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2 ms are already used in the A/D/A process, extremely low
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<dfn>buffer sizes</dfn> must be used in the workstation <abbr title="Input/Output">I/O</abbr>
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setup to keep the overall latency below 5ms. Not all
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<a href="@@the-right-computer-system-for-digital-audio">computer audio systems</a>
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are able to work reliably at such low buffer sizes.
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</p>
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<p>
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For this reason it is sometimes best to route the monitor signal
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through an external mixing console while recording, an approach taken by
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most if not all professional recording studios. Many computer I/O devices
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have a hardware mixer built in which can route the monitor signal "around"
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the computer, avoiding the system latency.
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</p>
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<p>
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In either case, the monitoring hardware may be digital or analog. And in
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the digital case there will still be the A-D-A conversion latency of
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1–2 ms.
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</p>
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