Chiming in on the 'cheap-usb-audio-interface' conversation

[Ralf Mardorf]

On Sat, 2011-01-08 at 18:58 +0100, Thomas Orgis wrote:
> Am Sat, 8 Jan 2011 11:34:59 -0500
> schrieb Mike Holstein <mikeh789 at gmail.com>: 
> 
> > in my experience, USB devices can sometimes
> > pick up as much electrical interference as internal sound cards on laptops.
> 
> I have to spoil the specific take on USB interfaces: "Hey, I hear it when you move the mouse!" That's what I got with someone listening with headphones to the main output of my Edirol FA-101. I'm glad that you don't get that on the recordings (I _think_), just superimposed on the analog output portion.
> But still, I am mightily pi**ed about the lack of protection from such issues (our dear friend Improper Grounding again, I guess) even when shelling out several 100 € for the gear.
> 
> Be it USB or any other digital interface, I guess you can have luck and the bad sort of which. I do not see a technical argument why a USB-connected device should suffer more than a device connected via FireWire (both being bus-powered, even) ... you can get bitten on both camps. For simple recording tasks, I really like the io|2 -- no comparison in bitchyness to the FireWire setup. I ended up angrily smashing a dual socket mainboard with a hammer because it featured a southbridge bug that just so might be the reason for reliable FireWire audio being impossible -- even using a PCI controller with a "good" FireWire chip. I strongly suspect that a USB interface would have worked just fine. Perhaps not ultra sharp latency, but without all the fuss.
> 
> That being said, by current setup with ubuntu studio 10.04 and the FA-101 on a custom PC worked without major hickup the last few weeks ... but I very well remember having to reboot the machine (or at least modprobe-cycle firewire) because the firewire subsystem got stuck because of just another subtle driver issue. The FA-101 is a rather old device, but still tricky. No comparison to just having snd-usb-audio loaded and off we go -- with the added plus that it works without JACK, too. To be fair: USB interfaces may not like being put behind a hub... so they're not _totally_ trivial;-)
> 
> 
> Alrighty then,
> 
> Thomas.
> 
> PS: To be a bit more on topic again; I did not test the MIDI performance of any of my USB or FireWire interfaces (uh, would that work with the FA-101?). I am using an Alesis ControlPad with in-built USB for triggering drums via MIDI ... but I don't play seriously enough on that one to judge.

Full ACK. Usually the digital noise should be very silent, but some days
ago I had loud digital clicks here too, IIRC when unmuting my DX7 at the
analog mixer. I never had this before. Perhaps some cables or devices
changed their position or some shielding get broken or ... anyway, even
if everything is in good shape, when turning the loudness of the amp to
it's maximum, there will be digital click noise by my PCI cards. This
noise shouldn't be audible at levels, we play music, even when it's
very, very loud. I guess USB is more safe against noise, but a
non-shielded PCI card. A trick should be to use unbalanced audio devices
with the balanced IOs of the analog mixer and a single-sided shielding.
Until now I didn't need to test it, the digital noise was borderline,
resp. quiet ok silent.