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

[Ralf Mardorf]

On Sat, 2011-01-08 at 14:47 -0500, Mike Holstein wrote:
> On Sat, Jan 8, 2011 at 12:58 PM, Thomas Orgis <thomas-forum at orgis.org>
> 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.
>         
>         --
>         Ubuntu-Studio-users mailing list
>         Ubuntu-Studio-users at lists.ubuntu.com
>         Modify settings or unsubscribe at:
>         https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-users
>         
> 
> 
> do dought USB should be easier than firewire, i just know that this
> week i was preparing for an audio presentation at my LUG, and a simple
> little grey ground lift added to the plug on the laptop quieted down
> my firewire interface, and not the USB interface i wanted to use
> (because of the size). i can only speak from experience, and i feel
> that an external USB interface (something like a 2 channel interface
> without preamps) is probably not a significant enough step up from an
> internal interface. you can get some nice USB devices though. i really
> like the ZOOM
> H4 http://www.samsontech.com/products/productpage.cfm?prodid=1901 .
> the preamps and onboard mics are very nice quality, and the standalone
> recording feature could be nice. i dont think the quality of firewire
> vs USB can be challenged. i have a presonus firepod that is literally
> plug and play in ubuntu with ffado. the USB device i use needs the
> madfuloader, and can be a little more challenging to get up and
> running, this is again *in my experience. i have several texas
> instruments firewire chipsets that i like to use, and are supported
> well. i have a VIA chip set that is not bad either. when
> trouble-shooting xruns on a firewire or USB device, i think its
> helpful to look at the output of:
> 
> 
> cat /proc/interrupts
> 
> 
> running that in a terminal can help determine what devices share IRQ
> values. i try and set my firewire card to its own IRQ in the bios
> (when possible). ive found that using a different USB port on certain
> laptops can really help isolate a USB audio device, and reduce xruns.
> 
> 
> i didnt mean to step on any toes earlier about the quality of USB
> devices. although, you might want to take into consideration that if
> you were to visit a professional studio, the likely-hood of seeing a
> USB interface in a rack somewhere, or in the signal path at all would
> be rather unlikely.

FWIW you can make any USB jack head of the USB jacks by rtirq, e.g.
change RTIRQ_NAME_LIST="rtc snd usb i8042" to RTIRQ_NAME_LIST="rtc snd
usb3 i8042"