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COMPUTER AUDIO REQUIREMENTS
Regardless of the type of computer you will use to playback audio from, it must have at least one avail-
able USB port. The m905 ships with a standard USB type A to type B cable. The type A connector plugs
in to the computer and the type B connector to the USB m905 input.
The m905’s asynchronous mode USB DAC supports standard driverless operation on Mac OSX since
version 10.x.x. Sample rates up to 192kHz are supported. For Windows PC computers, users will need to
download and install a free driver on their computer. This driver can be found on our website:
http://www.gracedesign.com/support/support.htm
On Mac computers driverless operation is supported by the OS. The m905 will automatically show up
in your computer’s list of supported audio devices as ‘Grace Audio Device’. In most cases, simply choose
that as your audio playback device and the system will work.
Different operating systems may pose their own set of complications in setting up the m905 as the
audio playback device. In the event that ‘plug and play’ operation does not occur, you will need to look
at some specific setup variables for your OS. In this case, we will direct you to a very well written and
comprehensive docu ment by our friend and colleague Charlie Hanson from Ayre Acoustics.
http://www.ayre.com/usb.htm
This is an invaluable resource for computer/USB audio setup information for most all current operat-
ing systems, and we strongly urge you to familiarize yourself with the information pertaining to your
specific OS.
Another excellent resource is Wavelength Audio’s website: http://www.USBdacs.com
In the event that you have any setup issues which aren’t addressed by these resources, feel from to
contact us directly at 303.443.7454 Monday through Friday 9 – 5, MST.
USING THE m905 FOR DAW PLAYBACK
With the extremely high quality audio playback achieved with this USB interface, the m905 can be great
option as an stereo output device directly from your digital audio workstation. For playback only, this
will work very well. However, using it in conjunction with other USB audio devices connected to your
workstation computer’s USB will require some adjustments to your computers audio settings and for
best results, some external clock routing between audio devices.
For Mac OS X, this is achieved by setting up the m905 in an ‘aggregate audio device’ setup, with the
m905 as the output device.
For Win 98 – Win 7, you must use ‘asio4all’ drivers- http://www.asio4all.com/. There is currently no sup-
port yet for windows 8.
With both of these setups, if you are using multiple I/O devices, you will need to pay careful attention
to clocking. In Mac / Core audio aggregate setups, you are able to set which device is the clock master.
However, this means that other devices will be sample rate converted, which we do not recommend.
15 Updating Firmware
The m905 utilizes three different unique processors for system and digital audio control. As indicated
in the system SETUP menu, the three processors are RCU (remote control unit processor), ACU (audio
control unit processor) and XMOS (digital audio control processor). Over time firmware updates may
become available. These can be found and downloaded from the Grace Design website at http://www.
gracedesign.com/support/support.htm. Each processor firmware is independent of the other and may