44/48 kHz, USB Audio and Helix

[Mikael Hansson]

Hi bar,

I got the Line 6 Helix Rack this weekend and stumbled upon a few issues…

If you’re using it’s USB interface (8in/8out) you can easily send both the raw and the processed guitar to your DAW for recording. Combined with their Helix Native plugin, you can just fire up an instance of the plugin on the raw track, select the same preset and it will sound exactly the same as the processed recording. This is because the level of the raw recording is matched to the level hitting the hardware processing.

As I have another main interface, Focusrite Saffire Pro40, I tried setting up the Helix as an aggregate device. Setting it up wasn’t a problem but the Helix channels were nowhere to be found when I selected the aggregate device in Cubase. I found out that the USB Audio class compliant driver for the Helix requires running at 48 kHz so changing the aggregate device to that solved the problem…but:

I have never wanted to use 48 kHz since I only release 44 kHz material. Initially due to the CD format but is that even relevant anymore and do you really risk getting any artefacts converting from 48 kHz to 44 kHz?

Another thing is this lockdown to 48 kHz. The Helix supports 44, 48, 88, 96 kHz using their custom Mac driver which unfortunately has double the latency (about 20 ms total in/out) compared to the class compliant driver and it's supposedly only developed to alleviate problems that a minority of users experience.

Looking at the Apple USB audio tech specs doesn’t give any hint of why it shouldn’t be feasible to also make different sample rates available in the class compliant driver. Maybe someone here knows more about creating drivers for audio devices :-)

Other than that I’m very pleased. Luckily I got the rack version which has a guitar thru output making it easy to record the raw sound on another channel, but then I have to match the level by ear when running it through the Helix plugins…and if you’re not using the USB audio you miss out on sending stuff back to the Helix for processing (it’s a big a** multi fx if you want with several parallel multi fx lines available)

/Micke