Home Studio - USB Audio Devices
 

I'm looking at setting up a home studio of sorts. At the moment I'm using a pair of headphones as the microphone input and regular speakers out. I would like to use an actual microphone in, probably a USB microphone since the USB slots are a little more durable than my 1/8" mic in port(s).

I'm currently having issues where recording a new track and playing back a prerecorded track at the same time bleeds into the newly recorded track. Even though the output is to a pair of in ear headphones that shouldn't be that audible to the microphone. Especially since the input level of the headphones is fairly low, even with mic-boost on and mic and gain at 80%. With a trombone playing mere inches from the microphone. Surely my headphones shouldn't be having a 10% to 25% bleed in effect in those given conditions.

Anyway, I'm looking at getting a USB Microphone or USB based device like the M-Audio Fast Track Pro or Tascam Fireone or Presonus Firebox. And I need to know if I can use these under linux before I buy them. And whether or not using a USB microphone input would resolve my audio bleed issue.

I've also considered using one computer to playback and another to record, which should resolve the bleed issue. But I've heard that there's timing issues between cards and that it would be difficult to merge the two or more tracks and have everything line up all the way through.

Anyway, do I need special drivers for a USB microphone? I'm looking at getting one at a pro level 20Hz-20kHz of quality. Or an XLR to 1/8" adapter of sorts. Although I'm leaning towards a USB interface since the slots seem more durable than a 1/8" plug. Are there special kernel modules I need to include in a custom kernel to support these things? Are the usb/firewire audio input devices even supported?

At the moment I'm using Audacity and Ardour to record the tracks. If that helps.

Most of my soundcards are low end onboard stuff. Which in theory supports 48000Hz stereo input and stereo output. Some more so than others as I have several computers at my fingertips. The headphones only input mono. But I've got various microphones on order, including some stereo ones with 1/8" plugs.

For all intents and purposes I'm wanting to setup a studio quality recording ability as much as a poor mans budget can get. And I need to know if USB audio input devices will function and function well under current linux's. Is this a viable option?

It looks like some of it is handled with the --with-cards=usb-audio for alsa. As I look at other portable options like the Zoom H4 or MAudio MicroTrack.

Does anyone know if the mBox2 mini works under linux? It looks to be along the lines of what I'm looking for to bridge the gap between microphone and computer. There's no digidesign alsa module, but there is a usb-audio module. I am unsure of the extent that usb-audio would be able to utilize this hardware unit, if at all.

http://www.digidesign.com/index.cfm?...14&itemid=4962

At the moment I've gotten a few of these mics and get fair results with them. Certainly worth the price tag, if only for their portable-ness.

http://www.giant-squid-audio-lab.com/

Ultimately I'd like to connect something like this to my PC for recording purposes.

http://www.wesdooley.com/aea/R84.html

Suggestions?

It looks like some M-Audio USB devices have some support. At least the debian package midisport-firmware seems to indicate some useability for some devices.

It looks like the tascam US-122 or US-144 is along the lines of what I'm looking for. It is even listed in the alsa-project.org sound matrix. Anyone have any experience with either of those devices?

http://freebob.sourceforge.net/index...ported_Devices

I guess some firewire devices are supported.

I was leaning towards a tascam 144, but it appears there's no linux driver. The older 122 can be made to work, but the newer 122L uses a different chipset and tascam doesn't seem interested in developing a linux driver. So I guess those are out. I guess I'm looking for a firewire adapter for a compaq presario expansion port 2, as well as a mic interface device.

Some reports of an Edirol UA-25 working in linux. And it appears to be most of what I want. Aside from stereo input, and 1/8" inputs. I seemed to have missed the part of the alsa-project.org that says that if a USB device is "class compliant" it is supported. I guess there's a usb-audio spec and as long as the USB device is compliant, it "should" work.

Meanwhile I guess I've come across a suitable substitute. My new desktop has a high definition audio card(nVidia MCP61). Which takes care of stereo input (1/8"). And 24 bit sampling and up to 192kHz sampling rates. And the best part, not a lot of extra noise like my laptop has. I haven't tried full duplex yet. But with alsa 1.0.14 it works. And with alsa 1.0.15rc2 the mixer settings even has a mic boost setting.

A few issues with recording mono with a stereo input on a 64 bit system, but that may just be a versioning issue. It seems to be fine if I run a 32 bit knoppix LiveCD. Or even when chroot'd into a knoppix install. Just not on my AMD64 Debian sid install yet.

I've successfully managed to get an Edirol FA-66 firewire card working on openSuse 10.2 using the jack server and freebob drivers.

FreeBoB

Jack user docs

Getting firewire audio working on linux

Easy,

Perps.

As previously stated, I do not currently have firewire ports. And exanding the walmart laptop to have firewire ports is probably not worth the cost.

Anyway, here's what I've acquired in the meantime.

PCI --- M-Audio Delta 44
http://www.m-audio.com/products/en_us/Delta44-main.html

USB --- M-Audio MobilePre
http://www.m-audio.com/products/en_u...eUSB-main.html

And in the process of acquiring these, I've learned that most computers provide a bias voltage to your computer mics. These devices do not provide this voltage. So that pair of headphones or 1/8" mic you've been using on your computer as a microphone will probably not work on these devices. With that being said, the devices do work in linux.

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Specs:
M-Audio Delta 44 - 24 bit @ 96kHz - 4 channels in & 4 channels out (all 1/4" plugs) - builtin 10 channel mixer (not that I've used that yet)

M-Audio MobilePre - 16 bit @ 48kHz - 2 channels in & 2 channels out - Various interfaces in and out, but they all tie into the same 2 channels - Phantom 48V power for XLR only.

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Cons:
The MobilePre isn't as beefy as I'd like it to be spec wise. And there is no bias voltage to power unpowered electret type mics. The noise ratio isn't as bad as the onboard sound, but it's not studio quality either IMO.

The Delta 44 only has 1/4" inputs and outputs. So I've spent as much on adapters as I did for the device.

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Pros:
The Delta 44 sounds soooooo good. Even though spec wise it's not as beefy as the onboard soundcard. I find myself rummaging through my CD collection to rediscover how good my CDs should have sounded all along. This device is full duplex, it says so on the box. Which means that I can record and playback completely different tracks without having them bleed into the other. What the mic picks up is what gets recorded.

The Mobile Pre is powered by the USB bus. So no extra cords. It works in linux so I guess it's class compliant. It has multiple interfaces so you can record from almost anything. Except from devices requiring a bias voltage.

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Conclusion:
I need to get some real microphones now. At the moment the only mic I have that works with the new hardware is an old optimus one that probably cost less than it did to fill my gas tank in 1995 when I probably got the mic. The optimus is powered by one AAA battery.

Craigslist rocks. I picked up both of these units used for less than 50% of the MSRP.

I guess I should follow up some more. I got an Audio Technica 4033a mic and an Art Tube MP preamp. So my recording sources are now 4033a -> Art Tube MP -> Delta 44 -> PC or 4033a -> M-Audio Mobile Pre -> PC. The Delta 44 yields better results if only because it allows higher sampling rates.

I still haven't gotten the batterybox for the bias voltage dependant PC mics I own. But I am seriously considering getting it, since my new audio devices don't have their own bias voltage for external mics.

I'm still amazed at how much difference there is between onboard sound and these other devices I got. The Delta 44 makes even my decade old GNT-500P sound like a high end system. On my 150W stereo out to my Magnaplanar speakers, it is simply amazing. Even though I bought the speakers used over a decade ago. And got the stereo used to help settle an old debt about the same time.

So I guess if you take it all in stride:

$200 AT4033a mic
$50 Art Tube MP preamp
$100 Delta 44 soundcard
$400 Walmart Computer
$80 M-Audio Mobile Pre (for mobile recording mainly)
$120 adapters, cables, mic stand, and other support hardware.
$150 stereo
$450 speakers

---- total ----
$1,550 for everything.

As I recall a time when a new PC cost more than that. And as I look at higher end preamps where that's the low end of the spectrum.