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Evaluating AD/DA loops by means of Audio Diffmaker Audio Interfaces
Old 27th August 2014
  #571
Here for the gear
 

don't think the original file is well recorded. I'm afraid this will affect the result...
Old 28th August 2014
  #572
Gear Head
 

MOTU 16a:

https://www.dropbox.com/s/35ip0rwgbc...0Test.wav?dl=0

Can't wait to see how this thing compares. Do I need to upload anything else?
Old 28th August 2014
  #573
Lives for gear
 
didier.brest's Avatar
 

Quote:
Originally Posted by davidbayles View Post
Do I need to upload anything else?
No. You have swapped L and R channels. After correction the result is:

Audio DiffMaker
723,7usec, 1,519dB (L), 1,515dB (R)..Corr Depth: 43,4 dB (L), 45,6 dB (R) Difference: -45.9 dBFS (L) -45.6 dBFS (R)
Matlab
Matlab 728.5 µs, 1.518 dB (L) 1.513 dB (R) Difference: -51.1 dBFS (L) -50.1 dBFS (R)

I have updated the previous list of results.
Old 29th August 2014
  #574
Gear Head
 

I've read elsewhere on the site that the 16a uses the same chips as the Symphony I/O. According to this test, their scores are nearly identical. Thoughts?
Old 30th August 2014
  #575
Lives for gear
 
didier.brest's Avatar
 

I have found that the Forssell MDAC-4 ----> Focusrite Blue 245 loopback file has a strong DC offset, -71.5 dBFS (L) / -71.4 dBFS (R), that dominates the difference file.When removing this offset, which does not produce any sonic component, from the loopbback file, the difference level is lowered from -70.2 dBFS (L) / -70.2 dBFS (R) to -77.1 dBFS (L) / -78.1 dBFS (R).
For all the other loopbacks files tested here the DC offset is below -90 dBFS, and for most ones, well below the own DC offset of the original file, the level of which equals -97.5 dBFS (L) / -106.7 dBFS (R), except for the Motu 828 MK3, the DC offset level of which equals -69.7 dBFS (L) / -71.4 dBFS (R), which is low enough for not impacting significantly the difference level that is about 20 dB higher.

funkakunchi has provided on Pragmatic Audio another loopback file where the input sensitivity of the Focusrite has been changed from 0 dBFS = 16 dBu to 0 dBFS = 20 dBu. The difference level is -76.6 dBFS (L) / -62.4 dBFS before DC offset removal and -80.7 dBFS (L) / -79.7 dBFS (R) after DC offset removal, which is the best result achieved up to now.

Updated list of results:

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

'Difference' indicates RMS level figures measured in Wavelab from the difference file delivered by Audio DiffMaker.
'Difference*' indicates RMS level figures got from a difference file generated in Matlab after refining the time offset and gain figures provided by Audio DiffMaker in order to get the lowest difference level. Hence the 'Difference*' figures are lower than the 'Difference' figures.

AD-DA converters performing from their internal clock

Apogee Rosetta 800 (davidbayle)
0.2 dB (L), 0.2 dB (R) Corr Depth: 39,7 dB (L), 41,7 dB (R) Difference*: -64.0 dBFS (L), -63.2 dBFS (R)

Lynx Hilo (CoolColJ)
- 6 last second part disregarded
-0,1 dB (L), -0,1 dB (R) Corr Depth: 41,8 dB (L), 43,7 dB (R), Difference*: -59.1 dBFS (L), -59.2 dBFS (R)

MOTU 2408mk3 (ram75)
0,1 dB (L), 0,1 dB (R) Corr Depth: 36,3 dB (L), 37,9 dB (R) Difference*: -56,7 dBFS (L), -58,1 dBFS (R)

MOTU 828mk2
laurend: 6.1 dB (L), 6.2 dB (R) Corr Depth: 36,4 dB (L), 37,9 dB (R) Difference*: -56.7 dBFS (L) -58.0 dBFS (R)
MusicManic: -0.1 dB (L), -0,0 dB (R) Corr Depth: 36,3 dB (L), 37,9 dB (R) Difference*: -56.7 dBFS (L) -58.0 dBFS (R)

MOTU 24I/O (Zam on Pragmatic Audio)
0,1dB (L), 0,1dB (R)..Corr Depth: 36,3 dB (L), 37,9 dB (R) Difference: -56,0 dB (L), -56,7 dB (R)
MOTU 24I/O (ram75)
0,1 dB (L), 0,1 dB (R) Corr Depth: 36,3 dB (L), 37,9 dB (R) Difference: -55,80 dBFS (L), -56,8 dBFS (R)

Mytek 8 x 192 (MainTime)
0,4 dB (L), 0,5 dB (R) Corr Depth: 35,3 dB (L), 36,9 dB (R) Difference*: -55.8 dBFS (L) -57.1 dBFS (R)

Lynx Aurora 8 (cylens)
-0,1 dB (L), -0,1 dB (R) Corr Depth: 34,6 dB (L), 36,3 dB (R) Difference*: -54.5 dBFS (L) -55.6 dBFS (R)

Lynx Aurora 16 (Touf on Pragmatic Audio)
-0,1dB (L), -0,1dB (R)..Corr Depth: 34,6 dB (L), 36,3 dB (R) Difference -54,2 dBFS (L) , -55,1 dBFS (R)

TC Electronic Konnekt 48 (DownSideUp)
13,1dB (L), 13,2dB (R)..Corr Depth: 33,2 dB (L), 34,8 dB (R) Difference: -52.9 dBFS (L) -53.8 dBFS (R)

Merging Technologies Hapi with premium DA and AD cards (Touf on Pragmatic Audio)
0.08 dB (L), 0.07 dB (R) Corr Depth: 35,9 dB (L), 37,2 dB (R) Difference*: -53.0 dBFS (L), -52.8 dBFS (R)

ESI [email protected] (Agustin Mongelli)
5,6dB (L), 5,7dB (R) Corr Depth: 33,0 dB (L), 34,6 dB (R) Difference: -52,5 dBFS (L), -53,7 dBFS (R)

ESI [email protected] XTe (DUJS)
-0,4 dB (L), 0,0 dB (R) Corr Depth: 32,7 dB (L), 34,3 dB (R) Difference: -52,3 dBFS (L), -53,5 dBFS (R)

TC Electronics Impact Twin (AndG)

-0,4dB (L), 0,0dB (R) Corr Depth: 32,0 dB (L), 33,6 dB (R) Difference: -51.7 dBFS (L) -52.7 dBFS (R)

RME HDSP 9632 (schtim)
0,5 dB (L), 0,5 dB (R) Corr Depth: 31.4 dB (L), 33.0 dB (R) Difference: -51.2 dBFS (L) -52.1 dBFS (R)

Prism Orpheus (MainTime)
0,1 dB (L), 0,1 dB (R) Corr Depth: 30,8 dB (L), 32,4 dB (R) Difference: -51.1 dBFS (L) -52.4 dBFS (R)

RME Fireface 400 (didier.brest)
0.3 dB (L), 0.3 dB (R) Corr Depth: 30,2 dB (L), 31,8 dB (R) Difference*: -50.7 dBFS (L) -52.0 dBFS (R)

MOTU Track16 (EvgenyStudio)
7,0 dB (L), 6,9 dB Corr Depth: 30,0 dB (L), 31,5 dB (R) Difference: -50,4 dBFS (L), -51,6 dBFS (R)

Apogee Symphony I/O (Ajantis)
0,0 dB (L), 0,0 dB (R) Corr Depth: 43,4 dB (L), 45,6 dB (R) Difference*: -51,2 dBFS (L), -50,1 dBFS dB (R)

MOTU 16A (davidbayles)
728.5 µs, 1.518 dB (L) 1.513 dB (R) Corr Depth: 43,4 dB (L), 45,6 dB (R) Difference*: -51.1 dBFS (L), -50.1 dBFS (R)

Prism ADA-8XR (shelterr)
-0,03 dB (L), -0,03 dB (R) Corr Depth: 37,5 dB (L), 39,5 dB (R) Difference*: -50,7 dBFS(L) -50,0 dBFS(R)

Crane Song HEDD-92 (Spartacus)
0.5 dB (L), 0.5 dB (R) Corr Depth: 36,6 dB (L), 38,4 dB (R) Difference*: -50.7 dBFS (L) , -50.0 dBFS (R)

TC Electronic Impact Twin (Coucou)
-0.1 dB (L), -0.0 dB (R) Corr Depth: 29,1 dB (L), 30,4 dB (R) Difference: -48,9 dBFS (L), -49,2 dBFS (R)

TC Electronic 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)
0,7 dB (L), 0,7 dB (R) Corr Depth: 28,8 dB (L), 30,1 dB (R) Difference: -48.4 dBFS (L) -49.2 dBFS (R)

Motu 828 MK3 hybrid (South Paul)
4.5 dB (L), 4.4 dB (R) Corr Depth: 30,0 dB (L), 31,6 dB (R) Difference*: -48.3 dB (L), 48.4 dB (R)

DAD AX24 ([email protected])
-0,1 dB (L), -0,1 dB (R) Corr Depth: 27,4 dB (L), 28,9 dB (R) Difference*: -46.8 dBFS (L), -47.3 dBFS (R)

Behringer ADA8200 (didier.brest)
gain @ 10 o'clock : 4,3dB (L), 4,6dB (R)..Corr Depth: 27,6 dB (L), 29,2 dB (R) Diff. -46,6 dBFS (L) , -47,7 dBFS (R)
gain mini : 14,7 dB (L), 14,3 dB (R)..Corr Depth: 27,9 dB (L), 29,5 dB (R) Diff. -46,8 dBFS (L) , -47,9 dBFS (R)

E-MU 1616m, left channel only (ben)
-0,4 dB (L), Corr Depth: 28,9 dB (L) Difference: -45,9 dBFS (L)

Universal Audio Apollo Quad (davidbayles)
0.3dB (L), 0.3dB (R). Corr Depth: 26,5 dB (L), 28,0 dB (R). Difference*: -45.7 dBFS (L), -46.4 dBFS (R)

Echo Audiofire 4 (david1103)
0,5 dB (L), 0,4 dB Corr Depth: 25,6 dB (L), 27,4 dB (R) Difference: -45,2 dBFS (L), -46,3 dBFS (R)

Steinberg UR824 (kegn51)
-0,3 (L), 0,2 dB (R) Corr Depth: 20,5 dB (L), 22,2 dB (R) Difference: -45,0 dBFS (L), -46,1 dBFS (R)

Mackie Onyx Blackjack (kegn51)
2,9 dB (L), 2,9 dB (R) Corr Depth: 30,5 dB (L), 32,3 dB (R) Difference*: -45,1 dB (L), -44,5 dB (R)

Metric Halo ULN-2 (DownSideUp)
Corr Depth: 25,3 dB (L), 26,9 dB (R) Difference: -44,9 dB (L), 46,0 dB (R)

ESI ESP1010 (Agustin Mongelli)
-0,2 dB (L), -0,2 dB (R) Corr Depth: 24,0 dB (L), 25,7 dB (R) Difference*: -44.4 dBFS (L) , -45.9 dBFS (R)

M-Audio FireWire 410 (JonasNorberg)
0,2dB (L) 0,2dB (R)..Corr Depth: 24,5 dB (L), 26,2 dB (R) Difference: -44.1 dBFS (L) -45.3 dBFS (R)

Echo Audiofire 8 non adat CS4272 (guze)
0,8 dB (L), 0,9 dB (R) Corr Depth: 26,4 dB (L), 28,2 dB (R) Difference*: -44.0 dBFS (L) -43.9 dBFS (R)

ECHO INDIGO io (bezen4uk)
0,6 dB (L), 0,6 dB (R) Corr Depth: 26,1 dB (L), 27,8 dB (R) Difference*: -43,8 dB (L), -43,7 dB (R)

RME HDSPe AIO(Touf on Pragmatic Audio)
0,7 dB (L), 0,7 dB (R) Corr Depth: 23,0 dB (L), 24,5 dB (R) Diff. -42,7 dBFS (L) , -43,6 dBFS (R)

RME Multiface II (juki, Audiofanzine)
Unbalanced, -10 dBV: Corr Depth: 22,7 dB (L), 24,4 dB (R) Difference: -42,4 dBFS (L) -43,5 dBFS (R)
Balanced, 4 dBu: Corr Depth: 22,3 dB (L), 23,9 dB (R) Difference: -41,9 dBFS (L) -43,0 dBFS (R)

RME Fireface 800 (genelec79)
Corr Depth: 22,3 dB (L), 23,9 dB (R) Difference: -41,9 dB (L), -43,0 dB (R)

MOTU Traveler MK1 (sinebox)
Corr Depth: 22,2 dB (L), 23,9 dB (R) Difference: -41,8 dBFS (L), -42,9 dBFS (R)

Avid Mbox 3 (Coucou)
5,1 dB (L), 5,1 dB (R) Corr Depth: 21,8 dB (L), 23,6 dB (R) Difference*: -41.3 dBFS (L), -42.0 dBFS (R)

Apogee Duet2 (isma)
1,0 dB (L), 0,9 dB (R) Corr Depth: 19,8 dB (L), 21,4 dB (R) Difference: -40.2 dBFS (L) -41.6 dBFS (R)

Yamaha Steinberg MR816X (didier.brest)
1.1 dB (L), 0.5 dB (R) Corr Depth: 19,1 dB (L), 21,0 dB (R) Difference*: -39.9 dB (L), -41.2 dB (R)

Focusrite Saffire Pro 24 DSP (CoolColJ), first 45s part disregarded
5,2 dB (L), 5,2 dB (R) Corr Depth: 20,2 dB (L), 22,0 dB (R) Difference: -38,9 dBFS (L), -39,9 dBFS (R)

RME Fireface UFX, XLR outputs 1-2 to TRS inputs 3-4 (didier.brest)
0,8 dB (L), 0,7 dB (R) Corr Depth: 18,5 dB (L), 20,1 dB (R) Difference: -38,9 dBFS (L), -40,3 dBFS (R)

Sony Vaio [email protected] (kegn51)
Corr Depth: 20,4 dB (L), 22,0 dB (R) Diff. -38,9 dBFS (L) , -40,0 dBFS (R)

Antelope Orion (davidbayle)
Corr Depth: 19,2 dB (L), 20,7 dB (R) Difference: -38,9 dBFS (L), -39,9 dBFS (R)

RME Fireface UFX, TRS outputs 5-6 to TRS inputs 3-4 (didier.brest)
0,7 dB (L), 0,7 dB (R) Corr Depth: 18,4 dB (L), 20,1 dB (R) Difference: -38,8 dBFS (L), -40,3 dBFS (R)

Focusrite Forte (Coucou)
9,9 dB (L), 9,9 dB (R) Corr Depth: 18,3 dB (L), 19,8 dB (R) Difference: -38,3 dBFS (L), -39,4 dBFS (R)

Focusrite Liquid Saffire 56, Line output to microphone input + pad (Melodeath)
0,2 dB (L), 0,2 dB (R) Corr Depth: 17,9 dB (L), 19,3 dB (R) Difference: -37,9 dBFS (L) -38,9 dBFS (R)

Lavry Blue (Touf on Pragmatic Audio)
Modes Crystal and Narrow : 0,2 dB (L), 0,2 dB (R)..Corr Depth: 16,8 dB (L), 18,3 dB (R) Difference -36,5 dBFS (L) , -37,5 dBFS (R)
Mode Wide: Corr Depth: 16,8 dB (L), 18,3 dB (R) Difference: -36,4 dBFS (L) , -37,6 dBFS (R)

TASCAM UH-7000 (sm5)
6,8 dB (L), 6,5 dB (R) Corr Depth: 15,5 dB (L), 17,1 dB (R) Difference: -35.2 dBFS (L) -36.2 dBFS (R)

Asus 11.6" laptop (kegn51)
1,3 dB (L), 1,7 dB (R) Corr Depth: 15,5 dB (L), 17,0 dB (R) Difference: -35,2 dBFS (L) , -36,2 dBFS (R)

RME Fireface UFX, XLR outputs 1-2 to XLR preamp inputs 9-10 (didier.brest)
0,5 dB (L), 0,4 dB (R) Corr Depth: 14,7 dB (L), 16,2 dB (R) Difference: -35,0 dBFS (L) -36,3 dBFS (R)

Edirol FA-66 (didier.brest)
1,0 dB (L), 0,6 dB (R) Corr Depth: 15,6 dB (L), 17,1 dB (R) Difference: -34.4 dBFS (L) -35.4 dBFS (R)

Focusrite Scarlett 2i2 (EvgenyStudio)
15,5 dB (L), 15,5 dB (R)Corr Depth: 19,3 dB (L), 23,6 dB (R) Difference*: -32,4 dBFS (L), -31,7 dBFS (R)

Line 6 POD Studio UX2 (Piux)
-0,5 dB (L), -0,4 dB (R) Corr Depth: 11,0 dB (L), 12,5 dB (R) Difference: -30.6 dBFS (L) -31.6 dBFS (R)

RME Babyface (didier.brest)
0,6 dB (L), 0,7 dB (R) Corr Depth: 9,2 dB (L), 10,8 dB (R) Difference: -28.8 dBFS (L) -29.8 dBFS (R)



External clocking


MOTU 828mkII clocked by Lucid GENx192 (MusicManic)
-0.1 dB (L), -0,0 dB (R) Corr Depth: 36,3 dB (L), 37,9 dB (R) Difference*: -56.7 dBFS (L) -58.0 dBFS (R)

Lynx Aurora 8 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)

Ferrofish A16 MK-II (ST.) clocked by
0,3 dB (L), 0,3 dB (R) Corr Depth: 26,6 dB (L), 28,2 dB (R) Difference: -46.3 dBFS (L) -47.3 dBFS (R)

Apogee Rosetta 800 clocked by Universal Audio Apollo (davidbayle)
Corr Depth: 39,7 dB (L), 41,7 dB (R) Difference: -45,9 dBFS (L), -45,8 dBFS (R)

Apogee Rosetta 800 clocked by Antelope Orion (davidbayle)
Corr Depth: 39,6 dB (L), 41,6 dB (R) Difference: -45,9 dBFS (L), -45,8 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)

Behringer ADA800 clocked by RME Fireface UFX (Krisprolls on Pragmatic Audio)
minimum gain : 13,4 dB (L), 13,4 dB (R)..Corr Depth: 24,4 dB (L), 25,9 dB (R) Diff. -44,0 dBFS (L) , -45,3 dBFS (R)
gain @ 4 : 1,2 dB (L), 1,4 dB (R)..Corr Depth: 23,9 dB (L), 25,5 dB (R) Diff. -42,3 dBFS (L) , -44,5 dBFS (R)

Universal Audio Apollo clocked by Apogee Rosetta (davidbayle)
Corr Depth: 26,5 dB (L), 28,0 dB (R) Difference: -42,7 dBFS (L), -43,0 dBFS (R)

Universal Audio Apollo clocked by Antelope Orion (davidbayle)
Corr Depth: 26,5 dB (L), 28,0 dB (R) Difference: -42,7 dBFS (L), -43,0 dBFS (R)

RME Fireface 800 clocked by Yamaha 02R (genelec79)
Corr Depth: 22,3 dB (L), 23,9 dB (R) Difference: -41,9 dBFS (L), -43,0 dBFS (R)



Sets of different converters


Synchronised mode ('master' indicates which converter delivers the master clock)

Forssell MDAC-4 ----> Focusrite Blue 245 master, (funkakuchi on Pragmatic Audio)
Focusrite sensitivity 0 dBFS = 16 dBu
0.1 dB (L), 0.0 dB (R) Corr. Depth: 64.7 dB (L), 65.6 dB (R) Difference*: -70.2 dBFS (L), -70.2 dBFS (R)
Focusrite sensitivity 0 dBFS = 16 dBu, DC offset removed
0,1 dB (L), 0,0 dB (R) Corr Depth: 64.7 dB (L), 65.7 dB (R) Difference: -77.1 dBFS (L) -78.1 dBFS (R)
Focusrite sensitivity 0 dBFS = 20 dBu
4.0 dB (L), 4.0 dB (R) Corr Depth: 66.9 dB (L), 69.8 dB (R) Difference: -76.6 dBFS (L) -62.4 dBFS (R), Difference after DC offset removal: -80.7 dBFS (L) -79.7 dBFS (R)

MSB Platinum IV Plus DAC ---> MSB Studio ADC master (DUJS)
4,9 dB (L), 4,9 dB (R) Corr Depth: 62,8 dB (L), 63,4 dB (R) Difference: -77,7 dBFS (L), -77,4 dBFS (R)

ReQuest Audio, The Beast DAC master ---> MSB Platinum Studio ADC (DUJS)
Corr Depth: 62,0 dB (L), 63,4 dB (R) Difference: -76,9 dBFS (L), -76,3 dBFS (R)

[email protected] XTe DAC ---> MSB Studio ADC master (DUJS)
Corr Depth: 46,0 dB (L), 48,0 dB (R) Difference: -65,3 dBFS (L), -66,7 dBFS (R)

Forsell MDAC-4 ---> Studer D19 master (funkakuchi on Pragmatic Audio)
0,1 dB (L), 0,1 dB (R) Corr Depth: 34,3 dB (L), 36,2 dB (R) Difference: -53.9 dBFS (L), -55.3 dBFS (R)

Lynx Aurora 16 ---> Focusrite Blue 245 master (funkakuchi on Pragamatic Audio)
0,04 dB (L), 0,02 dB (R) Corr Depth: 63,4 dB (L), 62,2 dB (R) Difference*: -53.4 dBFS(L) -52.5 dBFS(R)

Forsell MDAC-4 ---> Forsell MADC-2 (first version) master (funkakuchi on Pragmatic Audio)
0,5dB (L), 0,5 dB (R) Corr Depth: 29,6 dB (L), 31,1 dB (R) Difference: -49,2 dB (L), -50,3 dB (R)

Atoll DAC200 --> RME Babyface master (didier.brest)
Corr Depth: 10,1 dB (L), 11,9 dB (R) Difference: -30,0 dBFS (L) -31.3 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)

Unsynchronized mode. The DA and AD converters run each on its own clock. Measurement performed with sample rate drift correction activated in Audio DiffMaker and limited to the first half of the sample. Because the RMS level of this first half is 1 dB lower than the RMS level of the full-size sample, one must increase the difference RMS level figures by 1 dB for comparison with the synchronized mode.

ATOLL DAC 200 --> RME Fireface UFX (didier.brest)
2,3 dB (L), 2,4 dB (R). rate adj=8,8289 ppm.Corr Depth: 23,2 dB (L), 25,3 dB (R) Difference: -44,0 dBFS (L), -45,4 dBFS (R)

ATOLL DAC 200 --> RME Babyface (didier.brest)
Rate adj=-4,3193 ppm.Corr Depth: 10,8 dB (L), 13,0 dB (R) Difference: -31,5 dBFS (L), -33,1 dBFS

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.
Your contribution is welcome even if your converter is already in the above list.
Thank you !
Old 3rd September 2014
  #576
Gear Head
 

Quote:
Originally Posted by davidbayles View Post
I've read elsewhere on the site that the 16a uses the same chips as the Symphony I/O. According to this test, their scores are nearly identical. Thoughts?
Anyone have any thoughts on this?

Does this mean that the 16a should sound nearly identical to the Symphony I/O?
Old 4th September 2014
  #577
Lives for gear
 
didier.brest's Avatar
 

Quote:
Originally Posted by davidbayles View Post
Does this mean that the 16a should sound nearly identical to the Symphony I/O?
The test performed on the MOTU loopback file in place of the original and the Symphony loopback file as the copy achieves an excellent result:

parameters: -1,001sec, -1,477dB (L), -1,504dB (R)..Corr Depth: 76,0 dB (L), 78,5 dB (R) Difference: -73.2 dBFS (L) -74.5 dBFS (R)

Which shows that both loopback files are much closer each other than to the the original. Hence both converters have very similar distortions when tested on the same audio file.
Old 7th September 2014
  #578
Here for the gear
 
hollowaxis's Avatar
Hey Didier

Here is my file, hope this came out correctly.
The ADC is a Ross Martin Audio PCM4222 and the DAC is a Ross Martin Audio PCM1794A

https://www.dropbox.com/sh/fu94p5j37...ZufwReQ4a?dl=0

Let me know if there is anything else I need to do.

I'm getting a Lynx Hilo next week, so I'll be interested to see the results of this test on the Ross Martin units.
Old 7th September 2014
  #579
Here for the gear
 
hollowaxis's Avatar
Don't know why my first post duplicated. Edited it out.
Old 7th September 2014
  #580
Lives for gear
 
didier.brest's Avatar
 

Quote:
Originally Posted by hollowaxis View Post
Hey Didier

Here is my file, hope this came out correctly.
Hi,

it seeems that both converters are not synchronised. May be because the
PCM1794A has no word clock input, neither output ?



Anyway the result without sample rate correction is very bad: Corr. depth 8.5 dB (L), 6.5 dB (R).
Old 8th September 2014
  #581
Here for the gear
 
hollowaxis's Avatar
Quote:
Originally Posted by didier.brest View Post
Hi,

it seeems that both converters are not synchronised. May be because the
PCM1794A has no word clock input, neither output ?



Anyway the result without sample rate correction is very bad : Corr. depth 8.5 dB (L), 6.5 dB (R).
There is a Focusrite Scarlett 6i6 inbetween them.
SPDIF in from the AD and then SPDIF out to the DAC.
AD is being the master and everything is synced to it, so they should be synced.
Old 8th September 2014
  #582
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didier.brest's Avatar
 

Another issue is that your file is mono: L and R channels are identical.
Old 8th September 2014
  #583
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hollowaxis's Avatar
hmmm. Clearly I have screwed something up along the way here.
Sorry I wasted your time on that.
I'll try it again tonight and check everything more carefully.
Old 8th September 2014
  #584
I wonder why is the "exception" of Motu16a/ Symphony having the difference file "not as low" as other units with similar correlated results. It could be up top with a difference file proportional to the other units.

also Can you remind us why you choose the order of diff files instead of core depth ?
Old 8th September 2014
  #585
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didier.brest's Avatar
 

Quote:
Originally Posted by hollowaxis View Post
hmmm. Clearly I have screwed something up along the way here.
Sorry I wasted your time on that.
Don't worry ! I'm much appreciating your effort.
Old 9th September 2014
  #586
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didier.brest's Avatar
 

Quote:
Originally Posted by DownSideUp View Post
I wonder why is the "exception" of Motu16a/ Symphony having the difference file "not as low" as other units with similar correlated results. It could be up top with a difference file proportional to the other units.

also Can you remind us why you choose the order of diff files instead of core depth ?
Corr. depth stands for Correlated null depth. The ranking according to the correlated null depth is close but not identical to the ranking according to the difference RMS level. The reason is that the correlated null depth is measured in a frequency band limited to 100 Hz - 12 kHz and even in this band it is different from the standard null depth equal to the ratio of the original RMS level to the difference RMS level.

The difference level is an unambiguous feature taking into account any effect (noise, linear and non-linear distortion) that makes the gain and delay compensated copy different from the original.
Old 11th September 2014
  #587
Gear Addict
 

Here are a couple more files if you don't mind testing them. I appreciate what you're doing here. Both are from one Motu 828mkii. One is internally clocked, and the other is clocked using a Lucid GENx192. I connected the Main Outs of the Motu828mkii to the Analog 1 and Analog 2 Inputs. I connected directly using two 3 foot EWI Starline TRS patch cables. Looking forward to the results.
Thanks!

Internal Clock:
https://www.dropbox.com/s/e74izxmbg1...Clock.wav?dl=0

Lucid Clock:
https://www.dropbox.com/s/j4tfq9pcc8...Clock.wav?dl=0
Old 12th September 2014
  #588
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didier.brest's Avatar
 

Quote:
Originally Posted by MusicManic View Post
Here are a couple more files if you don't mind testing them.
Thank you much for your contribution !

Audio DiffMaker result files from both loopback files have the same contents:

parameters: -1,17msec, -0,063dB (L), -0,042dB (R)..Corr Depth: 36,3 dB (L), 37,9 dB (R)


Both difference files from Audio DiffMaker have the same RMS levels measued in Wavelab :

Difference: -55.8 dBFS (L) -56.8 dBFS (R)

Actually the internal clock and the external clock loopback files are very close as shown by the following result from Audio DiffMaker when comparing them each other:

parameters: 0sec, 0,000dB (L), 0,000dB (R)..Corr Depth: 109,2 dB (L), 108,9 dB (R) Difference: -99.6 dBFS (L) -99.6 dBFS (R)

Note also that the results from this test of the Motu 828 MKII are very close to the one from another test by laurend (see above list of results):
Audio DiffMaker: Corr Depth: 36,4 dB (L), 37,9 dB (R) Difference: -55,7 dBFS (L) -57,0 dBFS (R)
Matlab: Difference*: -56,7 dBFS (L) -58,0 dBFS (R)

Comparing the loopback files from this previous test and this new one by means of Audio DiffMaker and Wavelab gives:
Corr Depth: 65,3 dB (L), 63,8 dB (R) Difference: -82.9 dBFS (L) -82.4 dBFS (R)

Which shows very close performances from two units of the same model.

I will update the previous list of results later on.
Old 12th September 2014
  #589
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Cool! I'm surprised that the internal and external clocks matched up so closely.
Old 12th September 2014
  #590
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Deckdaddy's Avatar
Does clocking do much difference in a loopback anyways? And isnt most internal clocks working better than externals in most cases?
Old 12th September 2014
  #591
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didier.brest's Avatar
 

Refinement of the results from the Motu 828mkII loopback test by Music Manic :
Audio DiffMaker:: -1,17msec, -0,063dB (L), -0,042dB (R) Corr Depth: 36,3 dB (L), 37,9 dB (R) Difference: -55.8 dBFS (L) -56.8 dBFS (R)
Matlab: -1.1713 ms, -0.062 dB (L), -0.044 dB (R) Difference: -56.7 dBFS (L) -58.0 dBFS (R)
Added to the above list of results.
Old 15th September 2014
  #592
Gear Addict
 

Here's something that might be of interest. I decided to do my own tests using Audio DiffMaker to test how my Motu 828mkii performs with loopback at higher sampling rates. I decided to use a portion of a high resolution 96k file from 2L - the Nordic Sound for testing. I tested 96k, 88.2k, 48k, and 44.1.

For each sampling rate, I first created my own .wav "reference track" from their original 96k 24bit flac file by looping once in my DAW(Reaper). I then discarded their flac file, and I looped the new reference track once to create a "compared track." I did this from scratch from the same 96k flac file for each sampling rate (including 96k). Tell me any thoughts you have as to whether my testing method was sound and what the results below might mean. Thanks.

96k
-536.1 usec, 0.063dB(L) 0.029dB(R), Corr. Depth: 37.2dB(L) 37.0dB(R)

88.2k
-581.4 usec, 0.008dB(L) 0.010dB(R), Corr. Depth: 38.0dB(L) 37.7dB(R)

48k
-1.064 msec, -0.037dB(L) -0.048dB(R), Corr. Depth: 42.7dB(L) 42.0dB(R)

44.1
-1.158 msec, -0.039dB(L) -0.035dB(R), Corr. Depth: 43.4dB(L) 43.3dB(R)
Old 15th September 2014
  #593
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didier.brest's Avatar
 

Your method seems right in order to determine which sample rate of your converter achieves the most exact copy. But it is difficult to interpret your results because I don't know the exact definition of the 'correlated null depth' considered by Audio Diffmaker. Did you measure the level of the difference files delivered by Audio DiffMaker ?
Old 15th September 2014
  #594
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Quote:
Originally Posted by didier.brest View Post
Did you measure the level of the difference files delivered by Audio DiffMaker ?
I didn't. What's the best way to do that?
Old 15th September 2014
  #595
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didier.brest's Avatar
 

I use to do it in Wavelab. I do not know how to do it in Reaper. There is likely some plugin that does it also.
I can do it for you if you upload your files.
Old 16th September 2014
  #596
Gear Addict
 

Quote:
Originally Posted by didier.brest View Post
I use to do it in Wavelab. I do not know how to do it in Reaper. There is likely some plugin that does it also.
I can do it for you if you upload your files.
Do you just need RMS total loudness after playing through the file? Using one plugin called Schwa audio statistics I got the following:

96k
-56.23(L), -55.96(R)

88.2k
-56.9(L), -56.48(R)

48k
-59.55(L), -59.68(R)

44.1k
-59.89(L), -60.18(R)
Old 16th September 2014
  #597
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didier.brest's Avatar
 

Well, these results show that the faster is the sampling rate, the less accurate is the conversion.
Old 16th September 2014
  #598
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Quote:
Originally Posted by didier.brest View Post
Well, these results show that the faster is the sampling rate, the less accurate is the conversion.
Interesting. So the correlation depths by themselves show that as well as the RMS values by themselves, or is there a calculation that you did?
Old 17th September 2014
  #599
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didier.brest's Avatar
 

Yes. But one could argue that the increasing distortion of the copy with respect to the original is rather due to the original having higher frequency contents at higher sampling rate. So my conclusion would be more valid with the same result from an original at 44 converted to 48, 88 and 96 since the spectral contents of these four files would be the same.
Old 17th September 2014
  #600
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stinkyfingers's Avatar
 

Quote:
Originally Posted by didier.brest View Post
Well, these results show that the faster is the sampling rate, the less accurate is the conversion.
i checked the frequency response of my 828mkII and noticed that at 96 kHz there is a more 'relaxed' LPF than at 44.1 kHz. that could be why there is more of a difference. (see pic)
what i thought was strange though was a gentler slope of the HPF at 96 kHz. i figured that would stay the same as 44.1 kHz...maybe not.
i would mess around with my unit a little more but it's due for some repairs (ie...noisey). maybe i'll send it to black lion and see what that's all about.
anyway, interested to see the results for the test you proposed with a 44.1 kHz (up-sampled) file in a 96 kHz loop.
Attached Thumbnails
Evaluating AD/DA loops by means of Audio Diffmaker-96kwhite_44kblue.jpg  
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