Playback Lag When Recording Due to USB Latency Compensation

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They're two different buffers. The USB Buffer Size setting on the device is the hardware level buffer for the Fractal unit. The setting in your DAW is the software side buffer on the computer. Both are running at the same time and both contribute to the overall round trip latency you get with USB.
 
Just to add to Mr Fender’s explanation, this thread is not about the asio buffer, it is about the usb buffer in the AxeFX. Also, the sizes of those buffers are independent, so there is no need to make them the same.
 
Ozone 8 causes this for me. It's not enough to disable it. I have to delete the plugin from the master bus, save, close and reopen the session.
 
Note: as of AxeFX III DSP firmware version 20, you can now reliably change the USB buffer size in the I/O -> Audio page on the Axe-FX. Setting this value to 16 will give most people good audio alignment when recording. There are some new latency problems when using DSP firmware version 20 that hopefully will be fixed soon, but simply setting that parameter to 16 is a good fix for the recording alignment problem in many cases.
 
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GlennO said:
Note: as of DSP firmware version 20, you can now reliably change the USB buffer size in the I/O -> Audio page on the Axe-FX. Setting this value to 16 will give most people good audio alignment when recording. There are some new latency problems when using DSP firmware version 20 that hopefully will be fixed soon, but simply setting that parameter to 16 is a good fix for the recording alignment problem in many cases.
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I never changed that - it was set to the default of 256. What are the implications of lowering this value to 16? Any negatives, that is.
 
A smaller buffer means lower latency, but requires more DAW CPU to keep up. It's a trade off. Basically, set is as low as you can without any artifacts or dropouts.
 
siin82 said:
I never changed that - it was set to the default of 256. What are the implications of lowering this value to 16? Any negatives, that is.
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There are no implications that I'm aware of for the AxeFX III. I believe this is different than on the AxeFX II where that parameter did make a difference due to more shared processing duties. With all due respect to Mr Fender, this will make no difference to the cpu load in the DAW.

If it doesn't have any implications, or even if it does, it should probably be set to 16 from the factory. Otherwise, new users will continue to be confounded when trying to record with an Axe-FX.
 
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Oh yeah, that's the hardware side buffer. The ASIO/DAW buffer size is the one that affects the DAW CPU load. I would assume the overall USB performance of your computer would be the limiting factor for the USB buffer size. Perhaps machines with a slower USB chipset or buss speed might need a higher value? Still the same should hold true for setting it. Set is as low as you can without causing any dropouts or artifacts. In many interfaces, the hardware side buffer is not even adjustable.
 
GlennO said:
Note: as of AxeFX III DSP firmware version 20, you can now reliably change the USB buffer size in the I/O -> Audio page on the Axe-FX. Setting this value to 16 will give most people good audio alignment when recording. There are some new latency problems when using DSP firmware version 20 that hopefully will be fixed soon, but simply setting that parameter to 16 is a good fix for the recording alignment problem in many cases.
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what are the new latency problems related to fw20?
 
Here is what I know of the status of this problem as of DSP firmware 20. This is what I've observed testing on MacOS:

1) In one way, DSP firmware version 20 is an improvement because you can now set the usb buffer size to 16 to fix the latency problem and it will stick when you reboot. That provides good alignment when recording in most cases. It also provides decent latency when using the Axe-FX as an audio interface. Yay!

However, the more basic issue remains the same as it has for four years: A user buys an Axe-FX III, studies the manual to learn how to record, records some audio, finds the audio timing is way off, and concludes the Axe-FX USB I/O is useless. Until something is done about that, I'm not sure the issue can be considered resolved.

As it is, the user is expected to possess some arcane knowledge about configuring the Axe-FX for recording. That's proven time and again to be an unreasonable expectation. It would be a big help if something could be added to the user manual that mentions this problem and points the user to a solution. But, it's been four years and no such addition to the user manual has appeared.

A better solution would be to make the Axe-FX work correctly right out of the box. The buffer size should probably default to 16 from the factory. Or, better yet, unless there's a good reason to make that buffer size adjustable, it should be fixed at 16 and not be changeable.

In addition, I'm seeing some new problems when using DSP firmware 20:

2) The I/O latency for a buffer size of 16 is at one value for the first 4 minutes after you reset the usb channel (which occurs when launching your DAW, rebooting the Axe-FX, connecting the USB cable, etc.). After 4 minutes, it steps down by exactly 128 samples.

3) Changing the usb buffer size parameter to 16 from the audio menu will result in a different latency than either of the two values from issue #2.

4) Importing a preset screws up the latency. Repeatedly importing the same preset causes the latency to jump around to seemingly random values.
 
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