Mac Mini not recording at 96khz

[dbel]

Hi all

 

This is my first post here. Great website!

 

I am trying to do 24/96 vinyl transfers using a Behringer SRC2496 as an ADC going into the mini toslink input of a mac mini (latest version purchased three weeks ago). I go into Audio Midi and set the input to receive 96 khz, but mac automatically reverts the setting to 48 khz. If I connect the output of the Behringer to my Monarchy NM24 DAC via toslink, the Monarchy recognizes the 96 khz with no problem! Any help is appreciated.

 

Thanks

David Belsheim

 

[dbel]

I took my Behringer to the local apple store and connected it to there Mac mini with the same result. This is my understanding of what apple says the problem is. The digital stream includes the 96 khz digital audio as well as "control status bits". The control status describe the digital stream including the sampling rates. Apparently the ADC chip in the Behringer does not set the control status bits correctly. Core Audio receives the 96 khz digital, but then Quicktime examines the invalid control status bits, it rejects the 96khz and reverts to 48 khz. Apparently earlier versions of Quicktime would have not cared that the control status bits didn't match. My conclusion is that if you want to use an external digital source at 96khz into the Macs own digital input, it needs to be tested as there are no guarantees.

 

[John]

Are you sure that it is your Behringer setting the status bits incorrectly and not the mac reading them incorrectly? I would be surprised if it were the former. My experience with a Macbook is that the spdif metadata is generally wrong. For output I use spdif because my dac safely ignores the metadata (so Cambridge tell me). For ripping vinyly though, I use a USB adc so the issue goes away.

 

- John.

 

[dbel]

You could be right. I am just going on what Apple tells me and they may not admit that its a Mac problem. My new plan is to get a Firewire interface, probably a TC electronic Konnect 8, to use with the Pure Vinyl recording software. If necessary I could use the digital out of the Konnect 8 for 96 khz playback.

 

David