</p>
<p>
- A <dfn>clock</dfn> determines the speet at which one or more systems
+ A <dfn>clock</dfn> determines the speed at which one or more systems
operate. In the audio world this is generally referred to as
<a href="https://en.wikipedia.org/wiki/Word_clock" title="https://en.wikipedia.org/wiki/Word_clock">Word Clock</a>.
It does not carry any absolute reference to a point in time: A clock is
used to keep a system's sample rate regular and accurate.
- Word clock is usually at the frequency of the sample rate—at 48 kHz, its period is about 20 μs. Word Clock is the most
+ Word clock is usually at the frequency of the sample rate—at 48 kHz,
+ its period is about 20 μs. Word Clock is the most
common sample rate based clock but other clocks do exist such as Black and
Burst, Tri-Level and DARS. Sample rates can be derived from these clocks as well.
</p>
</p>
<p>
- JACK provides clock synchronization and is not concerned with time code
+ JACK (Ardour does this internally if using the ALSA backend) provides
+ clock synchronization and is not concerned with time code
(this is not entirely true, more on jack-transport later).
On the software side, jackd provides sample-accurate synchronization
between all JACK applications.
- On the hardware side, JACK uses the clock of the audio-interface.
+ On the hardware side, JACK and Ardour use the clock of the audio-interface.
Synchronization of multiple interfaces requires hardware support to sync
the clocks.
If two interfaces run at different clocks the only way to align the
signals is via re-sampling (SRC—Sample Rate Conversion), which is
- expensive in terms of CPU usage and may decreases fidelity if done
+ expensive in terms of CPU usage and may decrease fidelity if done
incorrectly.
</p>