Since about 2008 I’ve been using a Phonic Helix Board 24 Firewire mixer as a digital audio interface for multi-track recording, but also for digitising various analogue sources such as vinyl records, cassettes and the sound from Super 8 movies.
It’s a fully-featured mixing desk and it does an excellent job of pretty much everything – but when bolted into its wheeled flight case with amps for live use, it is large and heavy. It’s a great choice when I’m doing live sound or a multi-track recording, but overkill when I’m recording choral evensong with two microphones or capturing an LP from my turntable.
I’ve been pondering buying a small USB audio interface for a while but I finally bought one today when I saw an M-Audio M-Track on special offer.
It’s a simple but versatile device. It has two inputs (which can be coupled as one stereo input) and accepts either 1/4″ TRS jack or XLR input connectors. It provides 48V phantom power for mics that need it, switchable impedance for connecting guitars without a DI box and monitoring outputs that can be connected to an amp and speakers, or a pair of headphones. It is fully powered from the USB bus, including the phantom power so it can be used with a laptop without needing a mains connection.
On paper, the specs look competitive with the larger and much more expensive Helix device. It’s hard to draw a direct comparison since some of the Helix figures are given as ranges.
| Helix Board 24 | M-Track | |
|---|---|---|
| >90 dB | Signal-to-noise ratio | 97 dB |
| <0.005% | Total harmonic distortion | 0.005% |
| 10.5 kg | Weight | 0.7 kg |
| 445 x 212 x 432 mm | Dimensions | 155 x 124 x 51 mm |
| 16 | Inputs | 2 |
Of course specs on paper are only half the story, and it’s how these things perform in reality and how they sound that matters.
So far I’ve used the M-Track to record one church service and about 60 hours of vinyl. I am extremely pleased with the results. The dynamic range and noise are really very good and the sound is rich and full-bodied across the entire range of frequencies.
Anecdotally, I noticed that the frequency range of the M-Track seems to extend lower than that of the Helix. For the church recording test, I set up the recording microphones in the same way that I always do. In the raw recording, there was a strange buffeting sensation that was too low to hear, but loud enough to affect the dynamic range compression. I was stumped at first, until I realised that I was hearing the sound air convection currents moving around the church, disturbing the microphones at sub-sonic frequencies. This had always been happening, but the Helix had presumably been filtering out frequencies below 20Hz. When I set a high-pass filter at 20Hz, the problem disappeared. My condenser microphones have an optional wind-shield (below) which I hadn’t bothered using so far. I will start using those now to see if it avoids the problem!
For those who are interested in the details, the church recording was made with a pair of Behringer B-5 microphones, using the omnidirectional capsules. The mics were spaced about 1m apart and connected to the M-Track using balanced cable via the XLR connectors and powered via the M-Track’s phantom power. For more info on recording in churches, you might want to read my comparison of microphone techniques.
The vinyl records were captured using a Technics SL-3 turntable with Shure M92E cartridge and a Behringer PP400 phono preamp, connected to the M-Track via the unbalanced jack connectors.
Jonathan Gazeley 