On Sun, Feb 14, 2016 at 2:24 PM, jonetsu@xxxxxxxxxxxx <jonetsu@xxxxxxxxxxxx> 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
> 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
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