USB Audio interface for measurement

[jfetter]

Ok. Just saying there are practical limitations.
I travel a lot , have two locations for my hobby.
Have not owned a desktop for many years.
PCI just wont work for me.
The cheap mass market interfaces make sense.

 

[H713]

I agree that USB interfaces are my preference, but in my case this will probably end up stationary at a test bench.

One other PCIe option that looks interesting is the EVGA Nu Audio card. It uses the AK5572 ADC, which looks pretty enticing from a THD standpoint. Anyone played with this at all? Assuming they did their analog design well and didn't limit the bandwidth to 20kHz (and that's a big assumption), the AK5572 looks like it should be about the best ADC available for measurement usage.

 

[phofman]

EVGA Nu Audio is a USB card with onboard PCI-e USB controller.

 

[H713]

EVGA Nu Audio is a USB card with onboard PCI-e USB controller.

Interesting, so I would expect the latency to be slightly worse. That's probably not a dealbreaker for me, but definitely could be for some people.

The marketing wank they're using is annoying, I really don't see why they need a 300 MHz bandwidth op-amp, but the specs I've seen look promising.

 

[jcx]

Motu M4

I bought this a week ago, listened to headphone out while binging

ran RMAA just now, TRS balanced line in/out 3' cables, win 10 Laptop

RightMark Audio Analyzer test report
Testing device [ASIO] MOTU M Series
Sampling mode 24-bit, 96 kHz
Interface ASIO
Testing chain External loopback (line-out - line-in)
RMAA Version 6.4.5


20 Hz - 20 kHz filter ON
Normalize amplitude ON
Level change -2.5 dB / -2.5 dB
Mono mode OFF
Calibration singal, Hz 1000
Polarity correct/correct



Summary
Frequency response (from 40 Hz to 15 kHz), dB
+0.04, -0.03
Excellent

Noise level, dB (A)
-115.6
Excellent

Dynamic range, dB (A)
115.5
Excellent

THD, %
0.00034
Excellent

THD + Noise, dB (A)
-101.0
Excellent

IMD + Noise, %
0.00139
Excellent

Stereo crosstalk, dB
-110.9
Excellent

IMD at 10 kHz, %
0.00128
Excellent

General performance

Very good

 

[jfetter]

Looks like motu claims are real.

 

[H713]

THD comes close to the Lynx. Very impressive, and it's nice to see some spec sheets that aren't regurgitated numbers from the Analog Devices or AKM datasheets. Anyone tested the measurement bandwidth yet?

 

[DNi]

I bought this a week ago, listened to headphone out while binging
ran RMAA just now, TRS balanced line in/out 3' cables, win 10 Laptop

Thank you very much for sharing the results.
The M4 seems to be the successor to the Audio Express model which I've been using for the past five years or so. Two years ago I exchanged all op-amps in it for a presumably better stock, and THD improved by 6-7dB.
Comparing now the M4 results with the Audio Express ones I obtained with the same S/W and under almost the same conditions (my signal cables are twice as long, and my interface to the laptop is FW400), I see that the principal difference is the much improved noise floor of the M4. This of course pulls all (xxx + N) results in the right direction (s. attachment).

Regards,
Braca

 

[electronic]

Which is the ADC inside the Motu M line?

 

[mecedo]

One thing to note. The input impedance of the scarlett is about 13,437 ohms

Which generation of 2i4 do you have? Beacuse for 2nd generation in specification input impedance is 52kOhms

 

[stuartmp]

Which generation of 2i4 do you have? Beacuse for 2nd generation in specification input impedance is 52kOhms

Yes, I have a gen 2. I spent a fair bit of time to actually measure the input impedance and it was about 13.4k when measuring a 1k sign wave.

 

[stuartmp]

I bought this a week ago, listened to headphone out while binging



ran RMAA just now, TRS balanced line in/out 3' cables, win 10 Laptop

Hi Jcx,

I just downloaded a 21 trial of RMAA and wanted to test my scarlett 2i4 as you have done in your previous post.

Would you mind giving me a run down on how to set RMAA up to preform this test the same as you. I will then post my results.

Thanks

 

[jfetter]

Data M2

 

[jfetter]

Have not calibrated absolute levels yet but just running a quick resp to 60khz looks good. Still getting a handle it all.

 

[electronic]

Data M2

Thanks!

Maybe with some elbow grease it can be upgraded to AK5572?

 

[jfetter]

I done playing with the m2 analyzer. It works great, its a major upgrade now back to the projects.
Here is screen pics my old software using the M2 on Osx/wine and w10.
Made a couple of RCA to 1/4" mono plugs.

 

[H713]

Has anyone tested the bandwidth of the MOTU M4 with it running at 192kHz sample rates? the -3dB @45kHz (while running at 96k) is good to see (they don't have a brick wall at 20k), but if it has response up to 90kHz then I'm especially excited.

 

[DBMandrake]

Has anyone tested the bandwidth of the MOTU M4 with it running at 192kHz sample rates? the -3dB @45kHz (while running at 96k) is good to see (they don't have a brick wall at 20k), but if it has response up to 90kHz then I'm especially excited.

Why would a sound card sampling at 96Khz have a brick wall filter at 20Khz ??

 

[jfetter]

Traded up from M2 to the M4, its very sweet (BH Photo).
Nice line out/in and the motu driver is perfect. I looking at new software as my old RTA is now defunct and no longer supported.
On w10 testing now the Visual Analyzer from Italy.
So far looking good. M4 basic thd 0.0004 and thd+n 0.0009
Visual Analyser details

 

[trobbins]

Spectrum plot may benefit from averaging. Not sure if you lock the generator signal to the FFT sampling rate.