Like many of the first generation of G5s, the line out on my server is very noisy. Because of this, I have been looking for a decent external audio interface for it for a while now.
Initially, I tried using an Edirol UA-5, but at the time the Mac OS X drivers were quite immature, causing frequent crashes and lockups. I did, eventually, find a successful way to use the device by taking the digital optical out from the Mac and feeding it to the optical in on the UA-5, effectively turning it into an external DA converter. This worked, but waisted a lot of the functionality (i.e. it was audio out only).
Even if I could solve the driver problems, the UA-5 has three other significant drawbacks:
- It uses USB1 to interface to the computer, which severely limits the amount of audio bandwidth it can handle. In particular, at 24-bit, 92KHz, it is capable of doing one stereo in, or one stereo out, but not both.
- It does not provide a midi interface, so if I wanted to do some “mobile” music using my laptop, I’d have to bring along a separate midi box. (Of course, I have this problem at home too, but what’s one more box shoved in behind the server?)
- It needs AC power, which is also potentially a problem for laptop music making. (And the wallwart for it is huge.)
Despite these issues, the UA-5 was working well enough that I had avoided doing anything more about audio interfaces until a couple of weeks ago, when Gordon Slater from the Divertimento Orchestra asked me about ways to improve the sound quality of the recordings he made of our rehearsals. He has been using using a Sony stereo mic plugged into a Griffin iMic connected to his MacBook. Theoretically, the microphone is reasonably high quality, which would seem to imply that the quality of the DACs in the iMic was the culprit, so once again I started looking at what was available.
A friend of mine, Terry Mask from the Digital Music Center in Ottawa, helped out with the following suggestions for low cost interfaces:
How about these options?:
Edirol UA25 (USB)
Edirol FA66 (Firewire)
EMU 0404 (USB2)
Presonus Inspire 1394 (Firewire)
Presonus Firebox (Firewire)
All the interfaces listed feature:
- limiting (except the Firebox, to my knowledge)
- 2 phantom-powered mic preamps
- mac support (although the 0404 is new to the Mac …)
- bus powered
If he’s interested in some inexpensive mics, the Behringer C2’s would probably be decent for this application.
In addition to the above, Terry mentioned that he had recently used a Yamaha GO46 on a recording session he had done and been very satisfied with the results. This box is a bit more expensive than some of the above ones, but has several nice attributes:
- It has 4 inputs (2 with very high quality mic preamps) and 6 outputs, at up to 24-bit, 192KHz.
- It has a built in midi interface.
- It is “bus powered” directly off of the firewire, with no wallwart required.
Did you spot the pattern? 🙂 Yup, I picked one up last week, and have been playing with it ever since. So far, the results have been good, but not completely without issue:
- I haven’t quite been able to get the latency down to where I wanted, topping out at around 8ms before it started to crackle. (If that didn’t make sense to you, the capsule summary is: that’s (effectively) the minimum time between when the computer tries to make a sound and when the sound comes out the speakers. If the latency is too high, for example, it makes it difficult to play software instruments in real time.)
- I ended up needing to put a ground loop isolator between the GO46 and my speakers. Believe it or not, the noise from the G5 was actually travelling down the firewire and leaking out in the resulting audio. Doh!
Despite these problems, I’m happy so far. I still need to do some test recordings, particularly of the cello. I’ll let you know how it turns out.
