Optical digital input (S/PDIF) problem (sampling rates)

I have a huge problem with my 2009 iMac's digital input that I didn't run into on my older MacBook running the same OS (10.6.x), and it's driving me nuts!
Basically, I'm trying to record a digital feed from an ADC hooked up between my hand-built tube amps/turntable and my iMac, with the goal being the transfer of some of my LP records to 48/24 LPCM for archiving and editing. The ADC's output rate is fixed at 48000Hz and cannot be changed. My iMac, however, refuses to lock on to the device rate, instead forcing 44.1kHz in the audio/midi setup. In fact, I can't get it to do anything but 44.1kHz on anything I plug in (even my DAC's passthrough) despite the fact that I need to use 48kHz. The audio is correct for a few seconds, then forces back to the wrong rate again. No matter how many times I try, the computer insists on using the wrong sampling rate, which has rendered impossible any hope of using my iMac as an audio recorder.
I've tried setting up an aggregate device, but to no avail. Nothing I do seems to work, and since the problem is with Core Audio, any program used to catch the audio records gibberish. Is there a way to force Core Audio to use 48kHz in the terminal? It's not like the computer can't do it, as I get about 2 or 3 seconds of correct audio when changing the sampling rate manually. I just can't get it to stick!

Seeing the exact same thing here. External digital source is 48kHz, and this Mac Pro Desktop will only stay on that setting very temporarily (for about .10 or .15 seconds) then it reverts back to 44.1kHz. Even if I don't have a signal or even a Toslink cable plugged in to the input.
(I'm surprised you are getting 2 or 3 seconds of correct audio, when I'm getting about 1/10th that before it reverts back to the wrong sample rate. Maybe related to a buffer size option somewhere?)
I have tried every known option to reset or re-configure this, and even to the point of creating a new user, resetting PRAM, resetting SMC, etc. I was going to try upgrading to 10.6, thinking maybe it was a 10.5.x problem, but now I'm not sure that will help.
Had I the choice to set the setting to be 48kHz and lock it in, it should stay on that setting - (even if the chance exists that what I'm getting is not correct.)
More often than not, I know what I'm doing more than Mac OS does, and I want to force it to do what it needs to.
There really needs to be a "do it because I told you so" option for most of the Mac audio configuration system. This automatic "the hardware decided to do something for you" stuff is absolutely horrid for a system that is marketed as "Pro". A real "Pro" system would let me edit the configuration once, with the tool (text editor hopefully) of my choice, rather than attempting (and failing) to automate things.
+1 for another instance of this being "a huge problem" and "it's driving me nuts!"

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Huge Core Audio issue with Optical digital input (S/PDIF) on MacPro

Hello to all,
I just realized that it's just impossible to switch the digital optical input (S/PDIF) on a MacPro to 48kHz, it immediately reswitches to 44.1 !!!
To reproduce (not sure of the english names, french OS here):
- launch "Audio MIDI configuration"
- select "Digital audio input" in Properties
- try to switch Format to 48kHz / 24bit
In a few seconds, the format reswitches to 44.1 !!!
Even if feeding the optical input with a correct S/PDIF signal at 48kHz/24bit, no way to change the sample frequency to something other than 44.1, resulting in wrong tonality or distorted sound.
Please Apple, fix this ASAP, this is just not usable in a pro or even semi-pro environment !
Test on Leopard 10.5.8 and Snow Leo 10.6.2. I'm pretty sure it worked with Tiger.
Bye.

Thanks Keith, but i don't think Logic users could have a clue on this issue (no pun intended).
I'm a Pro Tools and Nuendo user, so i'm a bit reluctant to ask in a Logic forum... Too many fanboys there IMHO...
Thanks anymway.
Bye.

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I have hooked up my XBOX 360 to my computer monitor using the XBOX HDMI output to the monitor's DVI input via a HDMI/DVI adaptor.
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Hi,
I fell bad about answering a question with a question- but I noticed your comment about "...when I go into GarageBand and turn the monitor on (this is the only way I could find to allow the audio input to play straight through to the audio output)"
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Thanx
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I see the SB Li've 24-Bit has a miniplug coaxial digital I/O. I was wondering, if i were to connect a coaxial output carrying stereo audio to this jack, what sampling rate will it record at (if it is even possible)? Is it 24-bit/96kHz like the audigy series?
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I am fairly confident it CAN record digital stereo audio through its minplug SPDIF jack. Since it supports the Creative Digital I/O Module (which supplies coax and toslink input/output) it seems like it must be capable of acting as an input. Now, anyone know the sampling rate?Message Edited by cmp223 on 04-04-2005 03:0 AM

Audio problem ( sample rate/ mismatch samplerate )

Hi everyone,
I'm using a Macbook white Mid 2010, everything is fine but recenly i bought a USB interface to record music from my instruments ( Mic and guitar ) through garageband..
I have watched steps on how to connect guitar to garageband, and i did those steps by selecting USB channel as input..
The problem is every time i test my guitar or microphone, it sounds terrible just like little chipmunk or something. Some ppl told me my sample rate is mismatch. I also was checking around on Audio Midi Setup, i can't change my sample rate for my USB audio interface. The input for it, is 28000KHz, and i was told garageband only accepts 44000KHz.. So i thought my USB interface was having a problem..
However today i have tested my microphone on my old iMac white, i did plug in my USB interface and microphone, it worked so fine. The sound was not like on my macbook. it just fine and very clear. So my USB interface is not the problem..
BTW audacity also works fine on my macbook, only garageband..
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Make sure you have "abort capture on dropped frames" and "create new clip on timecode break" enabled in fcp: user preferences: general and do not capture over a control track break (where you see just "noise" in the video

DIgital audio in sample rates, 441 48 96 but no 882... is there a way to ad

When feeding my macbookpro a digital audio signal via optical cable while viewing the audio midi setup utility, it shows that the mbp's internal clock automatically switches to the incoming sample rate. I got it to work with 441,48 and 96k. When I fead it the 882 sample rate it automatically switches back to the mbp's internal clock and reverts to line input instead of digital. So the audio midi setup utility shows when it is in digital input mode the three sample rates 441,48 and 96k in the format pop up window and not 882 so it must be just a software issue and I am wondering if there is a way to add the sample rate to the list. If it can take in 96k it should also be ale to take in 882. So does anyone know how you could ad a sample rate of 882 to the list in the audio midi utility format list?

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Optical digital audio input does not work

Hi all,
I am trying to record some of my old DCC cassettes onto my imac, however, for some reason the optical digital input does not work.
I have searched everywhere, tried all settings in audio/midi setup.
I did notice that when I connect the digital cable to the output, the build in audio automatically recognizes it, and switches to 'digital output'.
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Wouter

I share your frustration. I record audio tracks into logic using digital optical recording desks.
I have a phone call appointment with apple tomorrow and will be happy to share any fixes if they find any.
Steve

Optical Digital Audio in

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"Компьютер Apple iMac A1208 (MA590RS/A)" looks like a late C2D 17"
Audio In / Optical Audio in port
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Headphone out / Optical audio out port
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Hello all,
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Knowlege Base
As for
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"External sample clock" and "Rate" for digital input acquisition

Dear all,
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Cedric,
dddsdsds wrote:
[...]In my case, i want to get the data at the rising edge of the external clock signal, so at a frequency of 50 kHz. How can I do that ?[...]
You answered your question already. If you want to use an external clock, you have to configure the timing source of your task to be external. In order of proper buffer configuration, you should enter 50kHz as rate in addition to the external configuration, but this will not influence the speed of the acquisition (since it is "clocked" externally!)
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CEO: What exactly is stopping us from doing this?
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Digital Audio Optical Input S/PDIF on Mac Mini 10.9.2

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I have replaced or swapped out the cables first off, to no improvement -- I called Apogee and we were able to prove the input to Apogee with an Eventide Esclipse's S/PDIF output.
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I just setup the repaired unit and now the S/PDIF out (from the Mini to the Rosetta) works -- the Sound pane shows that shows the functioning digital input however, and conspicuosly, the Audio/Midi does not (and used to).
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The optical digital audio input is a good way to get basic digital audio data into the Mac - assuming you have the audio in that format. Most vinyl digitizing folks do not.
The most common hardware configuration is to use your old vinyl turntable, connected to the proper phono input of a stereo (most modern stereos do not have this and you have to buy an outboard phono preamp). Then the recording (tape) output of the stereo goes to an audio interface that connects to the Mac with Firewire or USB, and not using the Mac optical input at all. There are dozens of famous makers of interfaces from a hundred dollars to thousands. For the casual user, I'd say $250 is a nice spot. You can get a stereo interface that takes analog input from your stereo, digitizes it, and send it to the Mac. It will also accept microphones, should you want. You'll need software to record and edit the audio (Audacity is free and works) and you can use iTunes to make CDs (although cumbersome).
There are interfaces that do have optical outputs that you could connect to the Mac. But since optical interfaces are rare on computers, and have many limitations, this isn't so common.
There are many tutorials on the net about digitizing LPs on computers.

Digital Audio Optical Input S/PDIF cable recommendation

I have a 2010 iMac. I am beginning to research a project for my mom that involves converting old recordings a group my dad was in years ago to digital from vinyl. I have a couple of input options available but I'm seeing reference to optical input on the iMacs. It appears that this would give me the best audio quality. So, my question is this: To go from a pre-amp output, what cables, converters, et cetera would I need to in order to make use of the optical input for audio? I have looked through the forums and see some mention of the subject, but nothing that seems directly to address the specifics of this.
Thank you.

The optical digital audio input is a good way to get basic digital audio data into the Mac - assuming you have the audio in that format. Most vinyl digitizing folks do not.
The most common hardware configuration is to use your old vinyl turntable, connected to the proper phono input of a stereo (most modern stereos do not have this and you have to buy an outboard phono preamp). Then the recording (tape) output of the stereo goes to an audio interface that connects to the Mac with Firewire or USB, and not using the Mac optical input at all. There are dozens of famous makers of interfaces from a hundred dollars to thousands. For the casual user, I'd say $250 is a nice spot. You can get a stereo interface that takes analog input from your stereo, digitizes it, and send it to the Mac. It will also accept microphones, should you want. You'll need software to record and edit the audio (Audacity is free and works) and you can use iTunes to make CDs (although cumbersome).
There are interfaces that do have optical outputs that you could connect to the Mac. But since optical interfaces are rare on computers, and have many limitations, this isn't so common.
There are many tutorials on the net about digitizing LPs on computers.

Optical digital input (S/PDIF) problem (sampling rates)

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