1 Topic by GoldenOne (edited by GoldenOne 2020-09-05 09:48:15)

  • Registered: 2020-09-05
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Topic: Can I plug the ADI-2 Pro into itself?

This might seem an odd question, but I'm wanting to use the ADI-2 Pro to record the impulse responses of various DACs and filter methods for a video I'm working on, and would like to include the ADI-2 itself in that test. (The device would be in USB mode)

I wanted to check, can I connect the Analog output of the ADI-2 Pro directly to the Analog input via an XLR cable, so that I can record the analog output from the DAC portion?
Just wanted to make sure this wouldn't cause any issues and that recording would work fine.

Thanks!

  • ning
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Re: Can I plug the ADI-2 Pro into itself?

No problem at all.

The only thing you need to be aware of is the self loopback may make the result different.
for instance, jitter tests may give better results, as the IOs in loopback have exactly the same clock.
also for your impulse response of various filters test, depends on your testing method, you might not get the test result you want --- again for the same reason that IOs have exactly the same clock.

3 Reply by KaiS (edited by KaiS 2020-09-05 16:26:23)

  • KaiS
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Re: Can I plug the ADI-2 Pro into itself?

To display the real impulse response you need a device with at least 4, better 10 times the sampling rate used in the DAC under test.
Best use a digital or analog oszilloscope.

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4 Reply by MC

  • MC
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Re: Can I plug the ADI-2 Pro into itself?

You can easily record the impulse responses of DACs with the ADI-2. It should be used at 768 kHz then. For simpler stuff (normal ringing) 384 kHz is enough too. Examples are here:

https://forum.rme-audio.de/viewtopic.php?id=26952

I did these in the DSO software part of Virtin's Multi-Instrument, and it looks absolutely identical to a DSO measurement.

For this reason measuring the ADI's own output won't work. You can not play back a single sample impulse at 44.1 kHz while recording it at 768 kHz within one unit.

Regards
Matthias Carstens
RME

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