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RME ADI-2/4 Pro SE Filter Response Measurements

johny_2000

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Here are my own measurements of the RME ADI-2/4 Pro SE filter response. I believe they closely match the RME manual and MatLAB simulation results. Sample rate 192kHz

SD Sharp:
SD Sharp.jpg


SD Slow:
SD Slow.jpg


Sharp:
Sharp.jpg


Slow:
Slow.jpg


SD LD:
SD LD.jpg


Brickwall:
Brickwall.jpg


NOS:
NOS.jpg
 
Interesting enough only SD slow has a good proper impuls response and even it pre rings a little bit so I have to ask how you tested? SD sharp doesn't pre ring at all but it doesn't settle down even in 2x time, rest pre rings (except NOS) and negative side is bad.
 
mesureaments very very easy to do in multitones (free) from pkane too ;-)
but to associate the answer in FR...
 
Hi @staticV3
What do you mean by this?
See Archimago's excellent articles on NOS DACs:
 
The ringings are just a response to the special test signal who could not “ legally“ occur in properly bandwidth limited signals trough sampling .

IE it won’t happen with music ( normally but let’s makes this simple ) , it’s a case of wrongly interpret test signals by lay people :)

Each of these filters has a theoretical response and the measurements tells you the actual filters are close to theoretical nothing more .
One should not at all interpret these curves as if they represent some kind of transient response with music.
 
Interesting enough only SD slow has a good proper impuls response and even it pre rings a little bit so I have to ask how you tested? SD sharp doesn't pre ring at all but it doesn't settle down even in 2x time, rest pre rings (except NOS) and negative side is bad.
Thank you. Everything was done in REW with a loopback connection of the device. I also had similar concerns about SD filters.
 
Best method is to play random white noise on the DAC at 44.1 or 48kHz, then sample that noise at 96kHz ADC sample rate or higher, and use extremely long averages (1k+).
This method appears to require the use of two devices for playback and recording since different sample rates are used.
 
Best method is to play random white noise on the DAC at 44.1 or 48kHz, then sample that noise at 96kHz ADC sample rate or higher, and use extremely long averages (1k+).
I use a slightly different method.

Of course, 2 devices are needed, and the ADC has to run at higher sampling rate.
But I keep both DAC and ADC in sync, using SPDIF link between them.

Then I'm able to use a higher sampling frequency on the ADC as long as it's a multiple of the DAC frequency.
And I can then use method like periodic noise from REW or FFR (Hpw) to measure response instantly.

It's not always working, but when it works it's fast and neat.
 
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I use a slightly different method.

Of course, 2 devices are needed, and the ADC has to run at higher sampling rate.
But I keep both DAC and ADC in sync, using SPDIF link between them.

Then I'm able to use a higher sampling frequency on the ADC as long as it's a multiple of the DAC frequency.
And I can then use method like periodic noise from REW or FFR (Hpw) to measure response instantly.

It's not always working, but when it works it's fast and neat.
Whenever you get to use windowless/rectangular window FFT, it just scratches an itch. So satisfying! :D
 
This method appears to require the use of two devices for playback and recording since different sample rates are used.
The first post requires the same. This is the reason your measurements don't look like those in the data sheet or my measurements in the manual. The ADC must run on highest sample rate to fully capture the DA signal without affecting it itself.
 
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The first post requires the same. This is the reason your measurements don't look like those in the data sheet or my measurements in the manual. The ADC must run on highest sample rate to fully capture the DA signal without affecting it itself.
Good point.
Which ADC should I use for these measurements?
E1DA Cosmos / APX555B / APx516B or another RMA ADC?
 
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