• U2GT
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Topic: Sample Rate Problem / Question re Fireface UC and Logic Pro X

Ok, so I'm confused on how the USB Settings app works.  I have Logic Pro X connected via USB to the Fireface UC.  Everything works just fine.  But I have a guitar processor (GP) that is connected to the Fireface via SPIDIF connection and the GP only has 48k sampling (no option to change it).  The GP is also connected to my computer (and therefore LPX) directly via USB because I control it with a midi track (send midi messages) to the GP as the audio tracks are playing.  So when I turn on my my GP with a Logic File with audio tracks all in 44.1k, I get the ever so frustration color wheel of death and a system overload error. 

So I start over in Logic, import all the files again and convert them to 48k and create a 48k project.  When I do this, everything works perfectly.  But it's a pain as many times I want to work in 44.1k in Logic with my 48k GP.

So my question is, shouldn't the Fireface UC be able to convert in real time and let me use my GP at 48k and Logic at 44.1k?  If not, is there an RME product that will do this?  There is a drop down selection under Clock Mode where I can choose the sample rate, but it won't let me do this.  Not sure how this relates to using different devices with different clock rates.

Thank you!

  • ramses
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Re: Sample Rate Problem / Question re Fireface UC and Logic Pro X

Sorry, but this is the normal case. If you work with a certain sample rate in a DAW project, then all connected digital devices need to synchonize on that sample rate.

Or you need to use a sample rate converter (SRC) to be able to work with 48 kHz with your guitar processor while the rest is using 44.1. Or you need to work with 48 kHz and finally downsample to 44.1 if this is your target frequency. It can also be the case that your guitar processor is unable to get clock from digital link, then it could be the case that you need to make this device to the clock master. Depends on the capabilities of the device.

Other alternative is to connect the guitar processor analog, then you have no issues with clock ...

An ADI-2 Pro has a built-in SRC. You could deploy such a device in front of your UC.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • U2GT
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Re: Sample Rate Problem / Question re Fireface UC and Logic Pro X

Thank you so much!  I greatly appreciate the prompt response. 

The challenge I have is the guitar processor is connected to my computer so that Logic can sent it midi messages.  If I'm not recording, why can't Logic be in 44.1k mode?  The Fireface is set as the input/output device, not my guitar processor.  I just want one track to send midi messages to the guitar processor but not record anything.  Strange that I can't play a track in Logic at 44.1k while sending midi messages to another device.  Is this because the midi messages on the midi track are still processed in some form at 44.1k?  Maybe that's what I didn't understand.

Thanks again.

  • ramses
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Re: Sample Rate Problem / Question re Fireface UC and Logic Pro X

I think this has not much to do with whether you are recording or not.
The whole setup needs to work at one sample rate.

USB is a digital transport, which also has needs a clock.
You can not connect the UC by 44.1 and the GP by 48 kHz.

If the GP only supports 48 kHz, then you need to work in 48 kHz.

If working at 48 kHz is too much of a burden for you, then the easiest and least expensive way to overcome this is
- to use the analog outputs of your GP
- to implement MIDI connection between UC and GP
to be able to get rid of the USB connection with the 48 kHz between GP and Apple.

If you want to record digitally then you need
- a SRC between UC and GP
- MIDI cabling between GP and UC (so that you do not need USB to send MIDI between Apple(LPX) and GP)

I never had such a setup, so this is purely based on "brainwork(tm)" ..
Maybe others who also have such a setup can please comment to it .. thanks.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13