2 Replies
      Latest reply on Dec 4, 2019 8:30 PM by umetzu
      koscsof1 Level 1 Level 1 (0 points)

        I have an external USB 3 audio interface called Holo Audio Spring 2 for testing.

        It supports up to 1,536 kHz / 24 bit audio sample rates natively.

        I see that there is a chance now to choose this very high sampleing rate in 16 and 24 bit in Audio Midi to get the incoming audio stream upconverted in Core Audio up to this rate. I can get it work in 16 bit but it does not work in 24 bit using my 18 core iMac Pro. To upconvert the same audio stream which works with 1,536 kHz / 16 bit to 1,536 kHz / 24 bit results a distorted sound, using any rates like 44,1 kHz, 48 kHz, 88,2 kHz, 96 kHz, 176,4 kHz, 192 kHz, 352,8 kHz and 384 kHz ( i have audio files recorded professionally with these sample rates) 


        I wonder if it is a bug in Core Audio or it is a bug of the firmware of the USB audio device?

        Any body has a similar experience?


        By the way is there any chance to learn what kind of algorthm and noise shaping is used for such high upcinversion in Core Audio? Is it the same as it was earlier for lower rates or different?


        Thanks a lot for any suggestion.

        • Re: Sampling rates in Core Audio / Audio Midi
          Razormaid Level 1 Level 1 (0 points)

          I have the same exact problem with sample rates except mine is only affected when using LOGIC PRO. It takes my pro recordings at 44.1 and 48k and states "Sample rate not compatible" and thinks it's 6k sample rate.


          If I use "preview" (QuickLook) it plays my files fine, but if we run the audio out of LOGIC PRO via Thunderbolt -> to our ZOOM Tac-8 digital converter, the music is scrambled badly.  We've tried everything but the only thing that returns the sound to normal is to go back to 10.14.4. This started with beta 1 and now even with the current beta (May 7th) it persists.  If it were just Core Audio I don't think Quick Look and playing from the laptop would work, so my guess is it's something else.


          If we open any other music software (Wave Editor, iTunes, etc) everything sounds fine playing via the TAC 8.  For us it's just when using Logic Pro 10.4.4 and the new OS X Betas (todays is beta 5 18F131a)  in combination.