Most portable audio interfaces are compact and inexpensive, and they offer limited features. With the Traveler, however, MOTU gives the mobile recordist the same combination of professional features and affordability that it has brought to commercial and project studios. The Traveler features as many as 20 simultaneous inputs, flexible onboard sync, a choice of power sources, and the ability to operate as a standalone mixer.
FIG. 1: The MOTU Traveler includes a full complement of analog and digital I/O in a mobile, bus-powered package.
In the Bag
MOTU designed the Traveler to be easily transportable (see Fig. 1). Its rack ears, unlike those of MOTU's other audio interfaces, are not initially attached. That makes the Traveler easy to throw in a bag or a suitcase with a laptop and other location-recording essentials.
The Traveler's dark blue front panel furnishes everything you need to make quick adjustments and change settings on the fly, even in time-critical location-recording situations. Each of the first four channels has a push pot and a 48V phantom-power switch; pushing the knob toggles a -20 dB pad. Taking the pad into account, the mic preamps have a maximum gain of 73 dB, adjustable in 1 dB steps. Six additional push pots let you control the device's setup and the built-in CueMix DSP monitor mixer. The Volume push pot adjusts the headphones and the main outputs; just push in the knob to toggle its function, which is reflected in the main display.
The center of the faceplate contains a multipurpose LCD that displays parameters graphically. To its right, another display presents a dozen 4-segment LED meters showing the analog, S/PDIF, and AES/EBU input levels. LEDs indicate analog output and ADAT I/O activity. Unfortunately, there's not enough space on the front panel for output or ADAT metering.
The rear panel has four Neutrik combo XLR/TRS jacks for inputs 1 through 4, which accept mic, line-level, or high-impedance instrument inputs. The other four inputs are balanced/unbalanced TRS line-level jacks, as are the eight analog outputs. All analog I/O supports 24-bit, 192 kHz audio. The rear panel also has S/PDIF I/O (which is on coaxial connectors) and two optical connectors (which are capable of either ADAT or S/PDIF operation). Additionally, the Traveler features word-clock I/O, an ADAT sync input, and XLR inputs for AES/EBU I/O. The maximum sampling rate for digital I/O is 96 kHz.
On the Side
Because the Traveler jams so much I/O into its small case, its external power and MIDI ports are on the right side of the unit rather than on the backplate. The Traveler was designed to get bus power from its 6-pin FireWire port. If you have a laptop without 6-pin FireWire, or if you will be working on location with a portable 24V battery pack, you can use an optional DC adapter or the side-mounted 4-pin XLR battery port. A switch lets you enable or disable bus power.
On first blush, I feared the side ports would be blocked when the Traveler was rackmounted. Because it is smaller than the standard 19-inch rack width, almost two inches of clearance are between the Traveler's side and the edge of your rack — more than enough room for power and MIDI plugs. If you plan on rackmounting the Traveler and using the MIDI or power ports, you should insert those plugs before securing the device into the rack.
FIG. 2: CueMix DSP gives you an intuitive, mixerlike GUI for all of the Traveler''s I/O routing options.
CueMix to Go
The Traveler comes with CueMix DSP, MOTU's third-generation hardware monitoring software. CueMix DSP lets you control the Traveler's internal I/O routing (see Fig. 2). You can route any combination of inputs to any stereo output pair, change level and pan settings, and mute or solo your inputs. You can also engage a +6 dB software boost, toggle the reference level between +4 dB and -10 dB, and mute your master output. CueMix DSP's onscreen console provides preamp knobs, pad buttons, and a master fader with metering. I'd prefer to be able to route any input to any output, but CueMix includes four separate mix buses, so you can configure inputs to four output pairs and switch between them on the fly.
The CueMix DSP application is easy to use. The graphical user interface (GUI) looks like a standard mixing console with all the input channels displayed and the output pair serving as master output for the current mix bus. Moreover, the message center at the top of the interface identifies the control that you're mousing over and available configuration options. To cover every possible monitoring situation, you can save your own presets for instant recall.
Because mobile recording often means live recording, being able to configure as much as you can without a computer is a real time-saver. Happily, you can configure all CueMix DSP monitor routings and all internal parameters directly from the Traveler's front panel. You can even save presets directly from the front panel and use the Traveler as a standalone 8-output mixer.
By default, the main display shows a graphical representation of all the current mix's input faders from the onboard CueMix DSP. To adjust a channel's volume, push the Mix Bus knob to select from the four mix buses, turn the Cursor knob to move to the channel that you want to adjust, and turn the Value knob. You can access all the other CueMix DSP parameters by pressing the Mix knob and then scrolling with the Param knob.
You can access the basic setup options such as word clock and optical I/O format using the same knobs. The well-written manual clearly explains how to access virtually all of the Traveler's parameters from the front panel. For configuring the Traveler's SMPTE reader/generator, though, you'll need the included FireWire SMPTE Console application. That application lets you assign any analog input and output to handle timecode I/O.
FIG. 3: Based on MOTU''s Digital Performer, AudioDesk 2 offers a full-featured audio recording, editing, and mixing environment for the Mac.
Macintosh users get a bonus: the Traveler also comes with AudioDesk 2, MOTU's recording, editing, and mixing application derived from Digital Performer's audio features (see Fig. 3). AudioDesk 2 lacks Digital Performer's MIDI and software-instrument support, but it does offer a professional-quality multitrack audio recorder, comprehensive editing, and a full-function mixer, complete with support for third-party MAS plug-ins. AudioDesk owners can upgrade to Digital Performer for $395.
The Savvy Traveler
To test the Traveler's converters and preamps, I recorded a variety of sources such as electric and acoustic guitars and male and female singers. I also played various reference CDs that I know intricately through the Traveler's outputs.
The Traveler's instrument inputs run hot, even at a -10 dB reference level. When recording electric guitar direct through the Traveler, I still needed to engage its -20 dB pad, and then raise the gain to hear the best results. With condenser microphones, however, I got an excellent vocal level with headroom to spare. The 73 dB of gain that the Traveler's preamps delivered was more than enough for most mics and the other sources I tried, but it wasn't quite enough level for miking acoustic guitar with my Royer R-121 ribbon mic.
The preamps were quiet, even at high levels of gain, but they lacked a bit of high end and had a narrower low-end image than more expensive preamps. When I tested only the converters, however, the Traveler's outputs sounded clean and balanced, with a good stereo image.
I would expect an audio interface that has a feature set as extensive as the Traveler's to cost much more. I was very impressed with its performance and versatility, especially in light of its affordability. The Traveler is well designed and well executed, and anyone who is looking for a full-featured recording interface should definitely consider buying it.
Orren Merton is the author of Logic Pro 7 Power! (Thomson Course Technology, 2004) and Logic 7 Ignite! (Thomson Course Technology, 2005).
TRAVELER SPECIFICATIONS Analog Audio Inputs (4) Neutrik balanced/unbalanced ¼" TRS/balanced XLR combo, (4) balanced/unbalanced ¼" TRS Analog Audio Outputs (8) balanced/unbalanced ¼" TRS, (1) ¼" headphones Digital Audio I/O stereo coaxial S/PDIF, stereo AES/EBU, stereo optical (switchable S/PDIF or ADAT Lightpipe) Data I/O (1) MIDI In, (1) MIDI Out, (2) FireWire,word-clock I/O A/D/A Rates 44.1-, 48-, 88.2-, 96-, 176.4-, 192 kHz Digital Sampling Rates 44.1-, 48-, 88.2-, 96 kHz Maximum Preamp Gain 73 dB A/D Dynamic Range 112 dB (A-weighted) A/D THD+N <0.0017% (-95 dB) @ 1 kHz, -1 dBfs D/A Dynamic Range 109 dB (A-weighted) D/A THD+N <0.0015% (-96 dB) @ 1 kHz, -1 dBfs Crosstalk 109 dB @ 1 kHz (typical) Weight 3.8 lbs. Dimensions 14.75" (W) × 1.75" (H) × 9" (D)
PROS: Lots of simultaneously available I/O. SMPTE generation and sync. Optional DC adapter, optional external battery, or FireWire bus power. Front-panel CueMix DSP control. Excellent documentation. Bundled AudioDesk 2 software.
CONS: No front-panel output metering. Mic preamps lacking in high end.
EASE OF USE