[linrad] m-audio firewire 410 and other sound systems

[Jeffrey Pawlan <pawlan.com; jpawlan@xxxxxxxxxxxxxxxx>]

Some here have reported that they experienced no luck using the m-audio Firewire
410 box with winrad, linrad or other software for use with the SDR radios. I
bought one of these a few yers ago just for this purpose and am finally trying
it with several computers and with linrad and winrad in particular.

The firmware or basic operating system within this box and also within most
firewire sound boxes is loaded at boot time. It is not actually resident in the
product! This is the big show stopper when trying to use them under linux. Since
m-audio has no interest in providing a linux driver, you would need to make a
bootloader that can load the firmware even though the driver was written for
windows.

Under windows 2000, the newer driver on the m-audio website did not work for me.
I had to dig out the original CDROM that came with the product and scroll down
to the folder labelled firewire410. This driver is annoying difficult to load,
at least under 2000. You need to begin with the soundbox disconnected. Then
after loading once you need to reboot with the box connected to your firewire
port. You then need to reboot no less than three more times to get it to work.

I tested the firewire on two very different computers. First I installed in on
an old 800MHz notebook that does not have a firewire port. I used an Adaptec Duo
Connect pcmcia card which I had to install first. Once I got the 410 driver
working, I was able to test it with several audio programs as well as with
winrad. It worked in every case, but was found to be a bit unstable owing to the
extra interface layer of the pcmcia card and its driver. Whether in winrad or in
Audition, occasionally it would disconnect itself. I had to unplug the firewire
cable and rec-connect it. I know that hot plugging a firewire cable is not a
great idea. It worked with both input and output on the 410 and also worked with
the notebook's ESS Allegro as the output device.

I then installed the driver on a desktop computer with a Gigabyte motherboard
that has a firewire port on-board. Again, I did this under win2K. The driver was
just as annoying to install as it had been on the notebook. When done, the 410
worked well with winrad. I tried it as the input and with the delta44 as the
output, and then with the delta44 as input and the 410 as the output. It worked
well both ways.

While I am on the subject of audio interfaces, I want to report that I also
tested two others. I tested the m-audio Mobile Pre which is a low cost USB
interface. My notebook and most of them have stereo out but only mono input. So
by using the Mobile Pre I can operate portable and have decent two channel audio
sampling. It also works fine with winrad as the input device and with the ESS
Allegro chip as the output.

I did some extensive testing and found that similar to reports of the creative
usb products, there is a sample delay between the channels which means that you
will need to compensate for this in winrad using the I&Q phase and amplitude
balance. The phase difference is actually a little beyond what winrad can fully
compensate for at this time.

Finally, I tested a new highend 192KHz sound system made by Emu called the
1820m. It is quite good and works well with winrad in both wmme and in asio
modes. I tested it under win2K and also XP. The mixer application they provide
is far too complicated for our needs and the documentation is incomplete. But
the hardware is excellent and soon winrad will have a 192KHz sampling selection.
The 1820m will provide a flat 160KHz of display in I & Q mode.

73,

Jeffrey Pawlan  WA6KBL


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