Evaluating AD/DA loops by means of Audio Diffmaker

[Laurend]

Because I've heard better sounding AD/DA converters than the Motu, I wanted to understand how these numbers correlate with the audio quality. I've done the following test. Using the same protocol, I've tested a FLUX Pure Compressor plug-in set on default settings except for "auto delay" which was enabled and threshold which was at -1 dB. The following chart has ratio in first, then make up gain.

1.25 +1>>>>> Corr Depth: 38,3 dB (L), 37,5 dB (R) Diff -43.74 dBFS
1.41 +2>>>>> Corr Depth: 35,0 dB (L), 34,3 dB (R) Diff -40.60 dBFS
2.50 +4>>>>> Corr Depth: 28,9 dB (L), 28,1 dB (R) Diff -34.71 dBFS
5.00 +6>>>>> Corr Depth: 25,8 dB (L), 25,7 dB (R) Diff -32.48 dBFS
10.0 +7>>>>> Corr Depth: 24,4 dB (L), 24,3 dB (R) Diff -31.59 dBFS

The results are better for the compressor than for a lot of AD/DA converters. That's unexpected and I've no rational explanation.

[nms]

Well you have no clock drift or jitter to degrade it for one. If you posted the amount of gain reduction that would be more revealing since without that there's no indication of how much the compressor is doing.

As for converters sounding better.. Unless you're doing a side by side comparison on the same system at the same time it's a bit useless especially with expectation bias influencing what you hear.

[Laurend]

Originally Posted by nms

Well you have no clock drift or jitter to degrade it for one. If you posted the amount of gain reduction that would be more revealing since without that there's no indication of how much the compressor is doing.

I will redo this test including the gain reductions in the results. They must be roughly equal to the make up gains I've noticed. So, no just tenths of dB.

Originally Posted by nms

As for converters sounding better.. Unless you're doing a side by side comparison on the same system at the same time it's a bit useless especially with expectation bias influencing what you hear.

You're right. I've never run a regular ABX test with the Motu. My statement is just based on listening impressions souvenir.

[quakenul]

Originally Posted by nms

RMAA is handy for further exploring, but inferior for getting a true read on conversion transparency.

I got a brilliant result from a Motu 828 mk3 with RMAA. However, upon recording a loopback with my own test file and viewing the waveform I listed it for sale immediately. The Diffmaker test also corroborated the lower performance ranking.

Could you still add it to the test results?

[didier.brest]

List updated with 3 loops from an RME Fireface UFX that I recorded. Each loop is named RME Fireface/x,y/z,w, x and y being the analog output numbers, z and w being the analog input numbers. Analog outputs 1 and 2 have XLR connectors and higher level than the other analog outputs, which have TRS jack female connectors. Inputs 9 to 12 have mic preamps, the gain of which I set to 0 dB.

RME Fireface/5,6/3,4
RME Fireface/1,2/3,4
RME Fireface/1,2/9,10

DA-AD loops from this wav file evaluated by means of Audio DiffMaker.

ADDA converters

MOTU 828mk2 (laurend)
Corr Depth: 36,4 dB (L), 37,9 dB (R) Difference: -55.7 dBFS (L) -57.0 dBFS (R)

Mytek 8 x 192 (MainTime)
Corr Depth: 35,3 dB (L), 36,9 dB (R) Difference: -55.2 dBFS (L) -56.0 dBFS (R)

Aurora 8 (cylens)
Corr Depth: 34,6 dB (L), 36,3 dB (R) Difference: -54.2 dBFS (L) -55.1 dBFS (R)

TC Electronics Impact Twin (AndG)
Corr Depth: 32,0 dB (L), 33,6 dB (R) Difference: -51.7 dBFS (L) -52.7 dBFS (R)

RME HDSP 9632 (schtim)
Corr Depth: 31.4 dB (L), 33.0 dB (R) Difference: -51.2 dBFS (L) -52.1 dBFS (R)

Prism Orpheus (MainTime)
Corr Depth: 30,8 dB (L), 32,4 dB (R) Difference: -51.1 dBFS (L) -52.4 dBFS (R)

RME Fireface 400 (didier.brest)
Corr Depth: 30,2 dB (L), 31,8 dB (R) Difference: -49.8 dBFS (L) -50.8 dBFS (R)

TC Electronics Impact Twin (ben)
Corr Depth: 29,1 dB (L), 30,8 dB (R) Difference: -48,7 dBFS (L), -49,7 dBFS (R)

Echo Audiofire 12 (guze)
Corr Depth: 28,8 dB (L), 30,1 dB (R) Difference: -48.4 dBFS (L) -49.2 dBFS (R)

E-MU 1616m (left channel only, ben)
Corr Depth: 28,9 dB (L) Difference: -45,9 dBFS (L)

Echo Audiofire 4 (david1103)
Corr Depth: 25,6 dB (L), 27,4 dB (R) Difference: -45,2 dBFS (L), -46,3 dBFS (R)

Echo Audiofire 8 non adat CS4272 (guze)
Corr Depth: 26,4 dB (L), 28,2 dB (R) Difference: -40.6 dBFS (L) -40.6 dBFS (R)

RME Multiface II - Unbalanced, -10 dBV (juki, Audiofanzine)
Corr Depth: 22,7 dB (L), 24,4 dB (R) Diff -42,4 dBFS (L) -43,5 dBFS (R)

RME Multiface II - Balanced, 4 dBu (juki, Audiofanzine)
Corr Depth: 22,3 dB (L), 23,9 dB (R) Diff -41,9 dBFS (L) -43,0 dBFS (R)

Apogee Duet2 (isma)
Corr Depth: 19,8 dB (L), 21,4 dB (R) Difference: -40.2 dBFS (L) -41.6 dBFS (R)

RME Fireface UFX/1,2/3,4 (didier.brest)
Corr Depth: 18,5 dB (L), 20,1 dB (R) Difference: -38,9 dBFS (L), -40,3 dBFS (R)

RME Fireface UFX/5,6/3,4 (didier.brest)
Corr Depth: 18,4 dB (L), 20,1 dB (R) Difference: -38,8 dBFS (L), -40,3 dBFS (R)

Yamaha Steinberg MR816X (didier.brest)
Corr Depth: 19,1 dB (L), 21,0 dB (R) Difference: -38.6 dBFS (L) -40.0 dBFS (R)

RME Fireface UFX/1,2/9,10 (didier.brest)
Corr Depth: 14,7 dB (L), 16,2 dB (R) Difference -35,03 dBFS (L) -36,30 dBFS (R)

Edirol FA-66 (didier.brest)
Corr Depth: 15,6 dB (L), 17,1 dB (R) Difference: -34.4 dBFS (L) -35.4 dBFS (R)

RME Babyface (didier.brest)
Corr Depth: 9,2 dB (L), 10,8 dB (R) Difference: -28.8 dBFS (L) -29.8 dBFS (R)


Sets of different converters

Aurora8 clocked by RME HDSPe RayDAT (cylens)
Corr Depth: 34,6 dB (L), 36,3 dB (R) Difference: -55.3 dBFS (L) -56.5 dBFS (R)

Echo Audiofire 8 with ADAT clocked by RME HDSP 9632 (schtim)
Corr Depth: 25.9 dB (L), 27.5 dB (R) Difference: -45.5 dBFS (L) -46.5 dBFS (R)

M-Audio Profire2626 clocked by RME HDSPe RayDAT (cylens)
Corr Depth: 24,4 dB (L), 25,9 dB (R) Difference: -44.1 dBFS (L) -45.0 dBFS (R)

M-Audio Profire2626 clocked by Lynx Aurora8 (cylens)
Corr Depth: 24,4 dB (L), 25,9 dB (R) Difference: -44.0 dBFS (L) -44.9 dBFS (R)

RME Babyface --> RME Fireface 400 (didier.brest)
Corr Depth: 16,6 dB (L), 18,4 dB (R) Difference -29,4 dBFS (L), -28,8 dBFS (R)

Benchmark DAC1 phone output ---> Echo Audiofire 4 (david1103)
Corr Depth: 10,4 dB (L), 10,2 dB (R) Difference: -22,6 dBFS (L), -23,1 dBFS (R)

For contributing to this test :
- download the test 2 x 44 kHz x 24 bit wav file (31 Mb),
- cable link the 2 DAC outputs to 2 ADC inputs,
- play back the test file to the DAC outputs and record from the ADC inputs,
- upload to mediafire or any other file sharing site the 2 x 44 kHz x 24 bit wav file from this recording and
- provide the download link here with information about ADC and DAC identities.
Thank you!