GR55 tip for USB digital line-in on Mac without sacrificing fidelity

[Per Boysen <perboysen@gmail.com>]

Hi,

This is a tip for those using a Roland GR55 guitar synth and a Apple
computer for amplification/recording. The tip is that you can pipe the
GR55 into the Mac digitally through a USB cable without having to set
up the GR55 as the external audio interface for the Mac. Many good
audio interfaces sound better then the GR55, both on the input side
for digitizing the guitar's analog pickup outputs and on the output
side when sending the mix to monitoring or PA. By going digitally
through USB we are sidestepping the lousy AD/DA conversion of the GR55
so you get the GR55 synths as digital line-in and still can plug your
guitar etc into the better audio interface you hopefully have. This
means the GR55 is active as an audio interface together with your
normal interface and on a Mac and you can make this routing possible
by creating an Aggregate Device in the Audio MIDI Setup Utility (look
for it in "Applications/Utilities"). Under the audio tab you click the
little plus signe down left and create your own Aggregate Device where
you can combine many physical interfaces. In my case over here I'm
combining my RME Fireface400 with the GR55. Now, when launching an
audio application (like Mobius standalone, Logic, Live...) you open
its preferences and select your new Aggregate Device as its audio
interface. In my case what happens then is that the audio application
detects 20 incoming channels instead of the usual 18 of the RME box.
Channel 1 - 18 are the usual RME channels while channel 19-20 is the
USB stereo feed from the GR55. The sound is much better compared to
when I used analog guitar cables from the two GR55 outputs into a
stereo input of the RME. And less to schlepp around.

Greetings from Sweden

Per Boysen
www.perboysen.com
http://www.youtube.com/perboysen