DiGiCo (UK) Ltd
USB 2.0 Audio Driver
Driver Release 1.0.0

Readme Revision2  2012-08-21

Operating system required:
* Windows XP (32bit or 64bit)
* Windows Vista (32bit or 64bit)
* Windows 7 (32bit or 64bit)

* Mac OS 10.7.4 or better
* Mac OS 10.8 or better

Recommended hardware specification:
* 2GiB RAM, Intel Core 2 Duo 2GHz CPU or equivalent.

This is an audio-only release of the USB Audio Driver for Windows 
and Macintosh to support DiGico's UB MADI.

By using an SD7-derived FPGA and a powerful dual-core 500MHz CPU, UB MADI
can simultaneously send and receive up to 48 channels of any incoming 48kHz
MADI or AES/EBU stream, automatically detecting the input type and configuring
itself to decode it within milliseconds of a connection, requiring no
configuration software.

This driver provides 48 channels of input and 48 channels of output at 48kHz
over USB 2.0 using ASIO or CoreAudio .
UB MADI automatically detects and selects the following input stream formats:

* 24 bit 48kHz AES-10 [MADI] (32, 56, 57 and 64 channel frame size)
* 24 bit 48kHz AES-3 [AES/EBU] Stereo Audio
* 48 kHz Word Clock (for synchronising UB MADI in a playback-only scenario)


In order to use UB MADI with your chosen ASIO-based digital audio workstation,
simply select 'UB MADI' in the DAW's audio device settings dialogue.
Just ensure that 48 channels of input and 48 channels of output are enabled
in the same dialogue.

N.B. Some DAWs require you to first select ASIO as the audio system.
The UB MADI ASIO driver allows ASIO and Core-AUDIO-compliant applications
to set the driver buffer length (and so latency) themselves, therefore no
control application is provided.

In most DAWs this is referred to as the 'block size' or 'buffer
size' and is measured in samples.

One sample at 48kHz is 20.8uS, so for example:
For a 20ms buffer, set the block size to 960 samples
For 10ms, set it to 480 samples
For 5ms, set it to 240 samples


Although virtually every computer built in the last 10 years includes at least
one USB 2.0 socket, not every machine will be capable of sustaining 96 channels
of 24 bit audio throughput. Care must be taken by engineers to make sure their
systems are suitable before using UB MADI in a live or production environment.

Usage Recommendations:

48 channels of audio requires around 7MB/s of write bandwidth to the recording
medium. Whilst this is much lower than the peak throughput of modern disks, if
your DAW does not use interleaved file access it may exceed the random access
of some hard disks, especially those found in older laptops.

For a successful recording:

1) Use 7200RPM or faster disks where possible, or preferably use a modern
solid-state disk.
2) Ensure you have significantly more capacity than is actually needed for the
recording.
3) Use a newly formatted disk if possible, or otherwise ensure disk
fragmentation is low (not necessary for solid state drives)
4) Do not use USB external hard disks on the same bus as UB MADI, i.e. through
an internal or external USB hub.
5) Quit all unnecessary applications, such as virus scanners, and disable
unnecessary hardware, such as wifi adaptors.

If UB MADI is being used either for playback only or recording only, select a
large audio buffer (such as 1024 samples) in your DAW's audio device settings.
Whilst modern computers, especially those running Mac OS, are capable of stable
operation with significantly smaller buffer sizes, using a larger buffer in
situations where low latency is not a priority will increase reliability in
the event of processing spikes.

Before any professional recording or playback situation, always test the
complete system for an extended period of time.


Two small system changes are recommended to improve stability of Windows when
recording or playing back high channel count audio streams such as those
provided by UB MADI:

1) Disable unnecessary visual effects.
In order to change this, right-click on My Computer and click on Properties.
Then under the Advanced tab click on the Performance Settings button. Select
Adjust for Best Performance and click Apply.
2) Prioritise processing for background tasks.
By default Windows prioritises graphical applications, but audio processing
and buffering counts as a background task.
In order to change this priority, again right-click on My Computer and click
on Properties. Then under the Advanced tab click on the Performance Settings
button. Under this window's Advanced tab change Programs to Background
Services.


F.A.Q:

Q: Can I use UB MADI as part of an aggregate device on a Mac?
A: No, UB MADI should not be used as part of an aggregate device, either with
another UB MADI or another device such as the computer's internal audio
hardware.
Aggregating UB MADI with another device may result in audio loss or distortion.

Q: Can I use UB MADI as a clock master when an input is present?
A: No, UB MADI will always slave its internal clock to an incoming signal and
will not output a different clock to that present on its input.
Care must be taken not to form a clock loop, where the device attached to
UB MADI's input is slaving to UB MADI's output.
This will cause the system clock to fall until it reaches the limit of UB MADI's
input receiver and audio distortion may occur; always ensure the device feeding
your UB MADI is a clock master, or is slaving to a device other than UB MADI.

Q: Does UB MADI support sample rates other than 48kHz or varispeed operation?
A: No, only fixed 48kHz is supported at this time.

Q: What happens to the MADI channels above channel 48 in the MADI stream?
A: On the input these channels are simply discarded; only the first 48 are
received and transmitted to the computer over USB.
On the output, those channels above 48 are transmitted as silence.

Q: When my UB MADI is synced to an AES 3 stream or a MADI stream with less than
48 channels I still have access to a full 48 channels of I/O in my DAW. Why does
it not reflect the actual input?
A: UB MADI always sends 48 channels to the computer and receives 48 from it.
This is to prevent the audio driver and DAW from having to reconfigure if the
input or output MADI formats change.
The LED on the device itself will always tell you the detected input audio format.

Q: What do the LED colours mean, and why do they pulse?
A: The multi-colour LED next to the USB socket changes depending on the input
format and device status:

Red:		I have not (yet) booted correctly. [This is always displayed whilst
booting]
Rainbow cycle: 	I am not receiving a valid input and so running on my own clock.
My output format is Digico standard MADI (48kHz 56 channels).
Blue: 		I am receiving AES-10 compliant MADI, transmitting it to the computer
and using it to clock my output, which is the same as the input format.
Purple: 	I am receiving AES-3 compliant AES/EBU audio, transmitting it to the
computer and using it to clock my output, which is Digico standard MADI (48kHz
56 channels).
Green: 		I am receiving a 48kHz word clock signal and using it to clock my
output, which is Digico standard MADI (48kHz 56 channels).

The LED pulses during normal operation to show that the on-board CPU is active
and has not stalled.



For support, please contact your local distributor or send an email to:
ubmadi@digiconsoles.com