14 Feb
2016
14 Feb
'16
3:43 p.m.
On Sun, Feb 14, 2016 at 2:24 PM, jonetsu(a)teksavvy.com <jonetsu(a)teksavvy.com>
wrote:
the web page it is mentioned, and shown, that an input
and output (in
this case from the mb audio interface, and USB) are not made to be
connected together and doing so could/can damage the card.
In that case its a line output, and microphone input, which are different
levels.
Then I have
to ask before doing anything: is it possible to simply use a plain
stereo RCA cable to connect the stereo out pair to the stereo in pair
of a 1010LT card ?
So long as they're both the same level, no problem.
For the Art USB Dual Pre, just a normal guitar jack lead:
http://openavproductions.com/loopback_cable.jpg
If so, then how is jdelay connected and told to
measure these connected
ports ? The man page mentions to connect the jdelay in and out
together and that's all. I guess this connection is used as a
reference to measure the actual audio connections. The web page doe snot
mention any argument to jdelay. Will it detect which ports are
connected?
jack_iodelay is "just" a JACK client. You connect it to whatever you want,
in this case, we wish to measure the soundcard latency:
1) Patch RCA cable system-output-1 to system-input-one
2) connect jack_iodelay output to system:playback_1
3) connect jack_iodelay input to system:input_1
The *output* of jack_iodelay (it generates a sine-wave) gets played
through the output of the audio interface, the analog signal is recorded
again by the input, which is passed to jack_iodelays *input* port.
jack_iodelay compares how many samples have passed since it sent
that output, and can very accurately calculate how much time has passed.
The resulting audio path of this setup:
software playback -> ADC -> DAC -> software record.
Recording & playback with Ardour is:
ADC -> software record -> software playback -> DAC.
Note that the overall amount of work done is the same: its only
in a different order. The latency measurement taken is the exact
amount of latency you will experience when recording music.
Hope that clears up exactly whats going on :) -Harry
--
http://www.openavproductions.com