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Can Someone Tell me One Good Reason

Why the Axe FX II can't be set to slave off of a master clock?
All I ask, is one "good" reason.... :)

In my studio, I have an Apogee Symphony 8x8 I/O. The Symphony's internal clock is said to be equivalent to the Apogee Big Ben, a great clock, but can not be set up to slave off of the Axe Fx II. As such, trying to utilize the AES input and output results in minor cracks and pops at 48kHz.

I have been using an analog input for the signal to the Symphony, but it really burns my bottom that I can't utilize a digital in/out.

Jake
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
If you set the Input Source to AES/SPDIF it derives its clock from the input stream. Not sure why you are getting pops.
 
If you set the Input Source to AES/SPDIF it derives its clock from the input stream. Not sure why you are getting pops.

Starting with the Output from the Fractal Axe FX II

1. Symphony I/O is set to 48 kHz Sample Rate.
2. Axe FX II input source is set to Input 1 - Guitar plugged into front Inst. jack.
3. SPiDF/AES Source set to AES

Axe FX AES signal being fed to Symphony I/O AES 1/2 and routed to Output 1/2 ---> Protools 11.
Pro Tools 11 Recorded audio has slight clicks and pops. Switching to all analog input from Axe FX II obviously does not have the digital artifacts.

Not even concerned with re-routing back to the Axe yet. Need to get output AES signal to Symphony issues cleaned up first. So I hope this explains what is happening.

Here is an audio link where you can hear the artifacts.
https://soundcloud.com/uncle-feng/axe-aes

Thanks
 
Last edited:

rdnzl

Inspired
If you set the Input Source to AES/SPDIF it derives its clock from the input stream.
Would it be possible to have a separate clock source setting: "Clock source: Internal / Digital In" ?

This would be very useful for us studio guys. We could leave the Axe clock slaved to S/PDIF and use the digital output all the time while still being able to switch the input between front panel for recording and S/PDIF for reamping.
 
Would it be possible to have a separate clock source setting: "Clock source: Internal / Digital In" ?

This would be very useful for us studio guys. We could leave the Axe clock slaved to S/PDIF and use the digital output all the time while still being able to switch the input between front panel for recording and S/PDIF for reamping.
That would be a great feature.
 
If your apogee doesnt have SRC you may need to set its clock to AES in.
Unfortunately, Apogee Symphony does not allow itself to be clocked eternally in USB Mode. I believe one option for doing this is in Audio Interface Mode using Thunderbolt. Need to check into it a bit more. But with USB, can't do it. :(
 
A quick update;

As suspected, utilizing Thunderbolt to connect the Apogee Symphony to the Mac and changing the clock source to AES/SPDIF. As soon as the unit was connected via Thunderbolt and the clocking changed, the digital pops and clicks disappeared.

Haven't worked on re-amping yet...
 

sprouseod

New Member
As you know there are many high end clocking devices out there which have a much more accurate sample rates than most digital devices. These are used as your master clock source with units such as Lavry, Apogee, Lucid, etc. However, it is my understanding the the AXE-FX will not accept an external clock., it has to be the master clock If i'm wrong please correct me on that. As a previous PT studio guy I'm not sure how the Axe-Fx clock compares to others. Maybe someone from Fractal can comment on the clocking of the unit. I can tell you that I compared the Axe-Fx to the Digi 002 a while back and the Axe Fx crushed it. But then again Digidesign was never known for the quality of its hardware
Richard
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
The Axe-Fx will derive its clock from the AES/SPDIF when using Digital In. In Analog In it uses its internal clock.
 

sprouseod

New Member
Maybe I've missed it. Where do you find the dig in setting? Does it take up one of the 2 inputs? Can you still have an analog input such as a guitar signal? I assume the master clock needs to be set at 48k?

thanks
richard
 

Bakerman

Axe-Master
Input select is in the I/O menu. Using digital in disables analog input 1, including front input. It's still possible to use input 2 then but global pitch & envelope detection only work on input 1. Clock source needs to be 48k for Axe to function as intended. (It will actually sync to anything in a certain range including 44.1 but this will affect times & frequency response.)
 

kartman

Inspired
That would be a great feature.
I'm new to Axe FX II but I'm having this issue with PreSonus 1818VSL. Their driver allows me to select 48kHz sampling and slave to the SPDIF clock supplied by the AxeFX. All good, right? Except that every time I reboot the studio computer, the dumb driver reverts to "internal clock" and I get the random pop/clicks that others are mentioning. I asked PreSonus about this and the blew me off, saying that this is "normal behaviour"... Yeah, normal for their crappy driver and a good excuse for brushing me off! Not impressed....

Short of losing the front instrument input on my AxeFX by setting to "Digital In", have any firmware updates offered the option to slave to an external SPDIF clock source?

Many thanx.
 
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