1 Topic by bevikon (edited by bevikon 2019-04-20 17:24:24)

  • Registered: 2019-04-20
  • Posts: 3

Topic: about ADI-2 DAC possible problem with Mac os USB defult-driver

Hi,
My new ADI-2 DAC USB Connect to Mac os on defult-driver , I found that high frequency is less than before audio system.

play pink_noise to check the full frequency.

1.ADI-2 DAC USB Connect to Mac os with defult-drive

2.Play Pink noise , and found Level attenuation from 16Khz on the ADI-2 DAC screen 

3.ADI-2 DAC Line out to PC ,and run Smaart（Audio frequency software） to double check，and it also exist : Level attenuation start
from 17.4KHz

4.ADI-2 DAC USB Connect to Windows (with MADIface driver ), Play Pink noise ,found No Level attenuation, is very OK

5.ADI-2 DAC select another Audio player （ VOX iTunes ）on Mac os  is also  Level attenuation at high frequency

6.another DAC SONY PHA3 Connect to Mac os with defult-driver （ Audio player （ VOX iTunes ）） check is OK


https://ws3.sinaimg.cn/large/005BYqpggy1g29k7f2pu1j31400u079j.jpg


I think there will be some compatibility issues with the default-driver on Mac os ？
and Is there any other driver to choose except default-driver on Mac os?

My ADI-2 DAC hardware 25 (update new verson)  SN:57750XXX ; Mac os 10.14.4

  • Registered: 2019-04-20
  • Posts: 3

Re: about ADI-2 DAC possible problem with Mac os USB defult-driver

Connect to Windows (with MADIface driver ), Play Pink noise ,found No Level attenuation, is very OK

https://ws3.sinaimg.cn/large/005BYqpggy1g29kajib33j31400u0afb.jpg

  • jiw
  • AES/EBU artist
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  • Registered: 2018-07-13
  • Posts: 161

Re: about ADI-2 DAC possible problem with Mac os USB defult-driver

What is the sample rate of the DAC and what is the sample rate of the pink noise?

Using 44.1 kHz -20 dBFS RMS pink noise, if I set the DAC's sample rate in the Audio MIDI Setup to 48kHz or higher and let macOS upsample the data, it introduces a high frequency roll-off much like the one you mentioned.

Using 96 kHz -20 dBFS RMS pink noise, if I set the DAC's sample rate in the Audio MIDI Setup to 48kHz or lower and let macOS downsample the data, it introduces a high frequency roll-off much like the one you mentioned.

Using 2 kHz and a 20 kHz -20 dBFS RMS sine waves, displays similar behaviour. With 44.1 kHz sample rate, there is ~7 dB drop at 20 kHz relative to 2 kHz for the DAC having a sample rate of 48 kHz or higher. With 96 kHz sample rate, there is a 3.1 dB drop off at 48 kHz sample rate and a 6.4 dB drop off at 44.1 kHz sample rate whereas there is no drop off at 20 kHz for sample rates of 88.2 kHz or higher.

The exact same happens using SPDIF optical up to sample rates of 192 kHz.

I am using the signal generator part of the Room EQ Wizard (V5.19) on macOS 10.13.6 and the DAC's spectrum analyser and level meters for the USB input and additionally DIGICheck for the SPDIF input.

Using the same sample rate for the DAC as the output from the generator, according to the DAC's display, the spectrum and level for USB and SPDIF seem to be identical. Further, DIGICheck shows that in this case there is no high frequency roll off. Also, for pink noise, using different playback software (iTunes and QuickTime Player) makes no difference.

The DAC's firmware is a test version of the upcoming firmware 26.

4 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
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Re: about ADI-2 DAC possible problem with Mac os USB defult-driver

Dedicated players like VOX, HQ Player, JRiver etc, and of course also all DAWs include the ability to always change the system's sample rate matching the source file - > 'problem' gone.

Else you need to complain to Apple headquarters if you don't like their SRC. I can 100% predict the outcome of that...and in this case I would agree...it's good enough for what it is supposed to do.

Regards
Matthias Carstens
RME

MC's Website

5 Reply by bevikon (edited by bevikon 2019-04-21 06:57:19)

  • Registered: 2019-04-20
  • Posts: 3

Re: about ADI-2 DAC possible problem with Mac os USB defult-driver

Hi,jiw

Thank you for your reply.

All test use same pink noise.wav :44.1Khz  16bit
The sample rate of the DAC is same macOS and Windows ( The above test ):48.0Khz   



I am very glad that you also found The roll-off ，and I did more testing just.




Windows :
Play pink noise.wav( media player ) , difference sample rate  of the DAC to test ( MADIface driver Setup )

44.1KHz  48.0KHz  96KHz  192KHz  384KHz  found No Roll-off



macOS :
Play pink noise.wav( iTunes vox ), difference sample rate  of the DAC to test ( defult-driver on macOS with  Audio MIDI Setup)

44.1KHz   found No Roll-off
48.0KHz  96KHz  192KHz  384KHz 768KHz  found  Roll-off



Play pink noise.wav( HQPlayer 3.22.0 ), difference sample rate  of the DAC to test ( defult-driver on macOS with HQPlayer 3 Setup)

44.1KHz  48.0KHz  96KHz  192KHz  384KHz 768KHz found No Roll-off




So I think it interesting Roll-off with ADI-2 DAC USB defult-driver on macOS is exist .

Looking forward to new DAC's firmware , and what ablout MADIface driver for macOS ?  smile

Have a nice day .

  • jiw
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Re: about ADI-2 DAC possible problem with Mac os USB defult-driver

bevikon wrote:

So I think it interesting Roll-off with ADI-2 DAC USB defult-driver on macOS is exist .

As my testing shows and as MC said, the high frequency roll-off is the result of the resampling algorithm (sample rate converter) part of macOS.

To clarify my first post, I should add that the SPDIF optical signal comes from the mini-TOSLINK (3.5 mm) output of my MacBook Pro. Thus, the roll-off is introduced by resampling the data in macOS before the outputs go to their respective interfaces (e.g. USB or SPDIF).