First attempt to capture digital output fails - HELP

[Stringtheorist]

I got together the hardware necessary to send the digital output from my Ultra into the optical input on my Mac, and recorded a sample clip in Transcribe! (Stereo, 16bps, 44.1kHz). This is the result.... a horrible garbled mess. (Even the pitch of the guitar strings is wrong... sounds like I've detuned.) Can anyone offer any suggestions at all as to what could be wrong?

BTW, the hardware I'm using is an RCA coaxial cable into a coaxial->optical converter into an optical cable into the Mac.

By way of comparison I also ran an analogue signal out from unbalanced Out 1 and captured a second clip (also attached). Ignore the compression artifacts caused by converting to mp3.

[attachment=1:3kpo6fan]digital.mp3.zip[/attachment:3kpo6fan]
[attachment=0:3kpo6fan]analogue.mp3.zip[/attachment:3kpo6fan]

 

[chris beaver]

you used 44.1kHz, iit should be 48khz not 44 hence the pitch change

 

[Stringtheorist]

Oops. I thought 44.1 was standard but I must admit I didn't check the Ultra's output spec first. Many thanks Chris. I'm going to try it again now.

 

[Stringtheorist]

This isn't working. I keep setting it 48kHz and it sounds OK briefly but then the signal in Transcribe cuts out. When I go back to record I get the same sound as before. There is obviously a problem using this program. I'm going to have to test with something else. Anything out there for Mac that's good (and free) for quick recording?

 

[Charlie Wardick]

You still have a clocking problem. The Axe must be the clock master. Whatever is connecting to Axe output will need to have its clock source set to syncronize external or spdif.

 

[Stringtheorist]

You still have a clocking problem. The Axe must be the clock master. Whatever is connecting to Axe output will need to have its clock source set to syncronize external or spdif.

How do I do that? :?

I entered the Audio MIDI setup panel. I set the master to 48kHz and retried Transcribe but the exact same thing happened. When I returned to the Audio MIDI setup it hadn't saved my changes! A second after I alter the setting in the drop-down box it reverts to 44.1! WTF?! :x

 

[moshwitz]

A second after I alter the setting in the drop-down box it reverts to 44.1! WTF?! :x

Check the settings on your soundcard or the sound properties setting in your OS for a default setting,,and try setting that to 48.

I'm not a MAC guy, but I know some soundcards will have a setting that lets you override or follow the settings of the DAW software that you use.

hope that can help.

MOSHON
DAVE

 

[Stringtheorist]

Check the settings on your soundcard or the sound properties setting in your OS for a default setting,,and try setting that to 48.

I think that's what I just tried. It doesn't retain the setting.

 

[Zer0th]

(Stereo, 16bps, 44.1kHz)

I assume you're saying 16bit? The S/PDIF output of the Axe is 24bit.

48kHz
24bit
Axe clock master

 

[joegold]

You still have a clocking problem. The Axe must be the clock master. Whatever is connecting to Axe output will need to have its clock source set to syncronize external or spdif.

How do I do that? :?

I entered the Audio MIDI setup panel. I set the master to 48kHz and retried Transcribe but the exact same thing happened. When I returned to the Audio MIDI setup it hadn't saved my changes! A second after I alter the setting in the drop-down box it reverts to 44.1! WTF?! :x

In Audio MIDI setup look for the item "Clock Source" and set it to "Device" rather than Mac.
It should get the clock speed directly from the Axe. I.e. No need to enter 48k in AM Setup.

If that doesn't work, and you really need to record via S/PDIF, then you might need to buy an external audio interface after all.
Probably not a bad idea anyway. Speaking as someone who has used the internal audio on all my Macs until very recently, I'm quite happy I got an interface. Makes things work much better.

 

[joegold]

You still have a clocking problem. The Axe must be the clock master. Whatever is connecting to Axe output will need to have its clock source set to syncronize external or spdif.

How do I do that? :?

I entered the Audio MIDI setup panel. I set the master to 48kHz and retried Transcribe but the exact same thing happened. When I returned to the Audio MIDI setup it hadn't saved my changes! A second after I alter the setting in the drop-down box it reverts to 44.1! WTF?! :x

In Audio MIDI setup look for the item "Clock Source" and set it to "Device" rather than Mac.
It should get the clock speed directly from the Axe. I.e. No need to enter 48k in AM Setup.

If that doesn't work, and you really need to record via S/PDIF, then you might need to buy an external audio interface after all.
Probably not a bad idea anyway. Speaking as someone who has used the internal audio on all my Macs until very recently, I'm quite happy I got an interface. Makes things work much better.

Actually, I just realized that when using the Mac's internal audio card the Device selection for Clock Source is unavailable. You're gonna need an interface. Sorry.

 

[joegold]

]

Actually, I just realized that when using the Mac's internal audio card the Device selection for Clock Source is unavailable. You're gonna need an interface. Sorry.

And even if you did have an external audio interface, the advice I gave you would have been wrong.

Selecting "Device" as "Clock Source" merely selects the external audio interface's clock rather than the Mac's internal audio clock for driving the external interface.

My Presonus Firebox came with a little piece of software that allows me to select an external clock source.
I.e. Selecting the external clock is a feature/function of the external audio interface and its software implementation, not of Audio MIDI SetUp.

Unless Apple changed something in AU SetUp with the new Snow Leopard OS release, I think you're out of luck.

 

[Stringtheorist]

Unless Apple changed something in AU SetUp with the new Snow Leopard OS release, I think you're out of luck.

Sorry, I lost you half way through that. Are you saying I need to get an interface or that an interface won't make any difference? Which one did you get?

 

[joegold]

Unless Apple changed something in AU SetUp with the new Snow Leopard OS release, I think you're out of luck.

Sorry, I lost you half way through that. Are you saying I need to get an interface or that an interface won't make any difference? Which one did you get?

I'm saying that it looks like you can't slave the Mac's internal audio to the Axe's clock.
So if you want to record vi S/PDIF out from the Axe you'll need an external audio interface.
I've been using the Presonus Firebox.
Bought it used for a real good price.
I'd be happier if it was compatible with Pro-Tools, but that's not a real big issue for me.

 

[Stringtheorist]

I'm saying that it looks like you can't slave the Mac's internal audio to the Axe's clock.
So if you want to record vi S/PDIF out from the Axe you'll need an external audio interface.
I've been using the Presonus Firebox.
Bought it used for a real good price.
I'd be happier if it was compatible with Pro-Tools, but that's not a real big issue for me.

So are you using the Firebox with a Mac? Is that through the 9-pin computer jack? How do you interface that with the optical in?

This is frustrating. I have no need for 6 analogue inputs anyway; I only want to record the Axe. I guess the spdif in/out is the critical bit for me. Would prefer a stereo coaxial input and a s/pdif optical output so I can still use the Axe digital out.

Really, how is anyone supposed to make use of the Axe digital out? I haven't yet found an interface that takes a stereo coaxial input. The best interface for me seems to be the Edirol FA-66 (which has optical I/O) but I still can't see how I'd input a digital signal from the Axe's coaxial jack.

Why is this so difficult? :x

 

[chris beaver]

I'm saying that it looks like you can't slave the Mac's internal audio to the Axe's clock.
So if you want to record vi S/PDIF out from the Axe you'll need an external audio interface.
I've been using the Presonus Firebox.
Bought it used for a real good price.
I'd be happier if it was compatible with Pro-Tools, but that's not a real big issue for me.

So are you using the Firebox with a Mac? Is that through the 9-pin computer jack? How do you interface that with the optical in?

This is frustrating. I have no need for 6 analogue inputs anyway; I only want to record the Axe. I guess the spdif in/out is the critical bit for me. Would prefer a stereo coaxial input and a s/pdif optical output so I can still use the Axe digital out.

Really, how is anyone supposed to make use of the Axe digital out? I haven't yet found an interface that takes a stereo coaxial input. The best interface for me seems to be the Edirol FA-66 (which has optical I/O) but I still can't see how I'd input a digital signal from the Axe's coaxial jack.

Why is this so difficult? :x

dosent your Presonus Firebox has spdif?. if so you dont need to buy anything, how have you tried to hook it up with this? btw coaxial is stereo in one cable ive never heard of a mono coaxial cable

edit, im not sure i read that right, do you allready have a usb or firewire sound card?

 

[Stringtheorist]

dosent your Presonus Firebox has spdif?. if so you dont need to buy anything, how have you tried to hook it up with this? btw coaxial is stereo in one cable ive never heard of a mono coaxial cable

edit, im not sure i read that right, do you allready have a usb or firewire sound card?

It's not me that has the Firebox, it's Joegold. I'm just using a cheap analog->digital converter (following advice on this forum). Clearly I now need to shop for an interface but I don't think the Firebox is the best one to go with a Mac.

 

[chris beaver]

[/quote]
It's not me that has the Firebox, it's Joegold. I'm just using a cheap analog->digital converter (following advice on this forum). Clearly I now need to shop for an interface but I don't think the Firebox is the best one to go with a Mac.[/quote]

http://www.soundslive.co.uk/product.asp?id=5061 this focusrite one is very good for the price it has excellent preamps, to do any kind of serious recording you really need a good soundcard anyway so don't see it as a bad thing that you may need one. this card will do digital and analog.

btw, i wouldn't be too concerned about using the digital outs as the difference in audio is hardly if at all noticeable when using quality preamps verses digital out. if your using bad preamps obviously there would be a big difference. personally i prefer using my preamps as i like the very slight colour they add it works for me, i would love to see the axe fx include some kind of recording desk preamp models to add different colours at the end of the chain, that would be the icing on the cake

 

[markus]

I'm using an M-Audio Fast Track Pro. It has 2 xlr analog inputs, and spdif in/out on the back. There is also midi in/out on the back as well.
I've never had any issues with this device. Works really well. I'm almost positive it is compatible with a Mac, as well.

Mark

 

[joegold]

I'm saying that it looks like you can't slave the Mac's internal audio to the Axe's clock.
So if you want to record vi S/PDIF out from the Axe you'll need an external audio interface.
I've been using the Presonus Firebox.
Bought it used for a real good price.
I'd be happier if it was compatible with Pro-Tools, but that's not a real big issue for me.

So are you using the Firebox with a Mac? Is that through the 9-pin computer jack? How do you interface that with the optical in?

This is frustrating. I have no need for 6 analogue inputs anyway; I only want to record the Axe. I guess the spdif in/out is the critical bit for me. Would prefer a stereo coaxial input and a s/pdif optical output so I can still use the Axe digital out.

Really, how is anyone supposed to make use of the Axe digital out? I haven't yet found an interface that takes a stereo coaxial input. The best interface for me seems to be the Edirol FA-66 (which has optical I/O) but I still can't see how I'd input a digital signal from the Axe's coaxial jack.

Why is this so difficult? :x

The Firebox has RCA S/PDIF I/O via break-out cables.
Like i said, it also has a software utility that allows me to slave it to an external clock which is a requirement of the Axe digital output.
Several audio interfaces have RCA S/PDIF I/O.

You can still record the Axe into your Mac without an external audio interface, just not via S/PDIF.
The audio on the new Macs is pretty good too. 24 bit is available on my iMac. Used to be stuck at 16 bit.
The AD converters probably aren't all that hot though.

With all due respect...This isn't really that hard. You might need to educate yourself a bit more on modern recording techniques and gear.

Nobody here could help you properly with S/PDIF directly into the Mac, I guess, because nobody does it that way. It looked like it should be possible via the TosLink jack. But evidently it isn't.
Live and learn.
It does seem like an oversight by Apple though, to not include the option for external clock control.
It might be that other methods of S/PDIF I/O do not require the host to be driven by the external clock. I.e. It may be partly due to the idiosyncrasies of the Axe's digital I/O system.

It sounds like your recording activities will not be geared toward professional product anyway, or you wouldn't be shying away from buying an audio interface.
Why do you care so much about using S/PDIF?