by John Gatski
Things sure have changed for home recordists. No more cassette decks, reel-to reels. Even digital DAT decks and standalone CD recorders are old hat. Today, the computer is king for laying down audio tracks. Whether a handheld recorder (a mini-computer), desktop or the omnipresent laptop, you can record audio on it.
Since the computer is not exactly equipped with direct connections that can link to your favorite microphone or music instruments, companies have been motivated to create all sorts of do-dads to facilitate the recording through the computer — from single channel USB and Firewire A-to-Ds, D-to-As to complex multichannel preamps and processors that link through the same ports.
USB is the most popular of computer interfaces. Although several companies have developed single-channel, low-cost USB microphone interfaces, very few have high-resolution 24-bit, 96 khz capable products. That is where CEntrance comes in.
CEntrance, the developer of the high-end USB high resolution transmission technology in high-quality DACs, such as Benchmark and Bel Canto, now offer its own economical, good audio quality solutions to home or pro recordists: the MicPort and the AxePort.
Priced at $149, the MicPort Pro is a single-channel mic pre amp-to-A/D converter via USB interface with built-in phantom power and a pretty darn good headphone amp — all running off the 5VDC feed from the computer USB port. The AxePort is similarly priced and designed to link your electric or acoustic electric guitar directly to the computer via USB.
The MicPort Pro is housed in a robustly-built, aluminum cylindrical enclosure with an XLR female connector on one end and mini-USB jack on the other. It has small potentiometers for mic gain and for headphone gain. The headphone port of entry is an 1/8th inch jack. The MicPort Pro also features phantom power, supplying voltage to run 48V condenser microphones. An external light ring (software defeatable on AxePort) indicates the MicPort Pro Pro is on. It is supplied with a 6-ft. USB cable, and USB drive with optional software.
The AxePort is housed in a cool-looking, blue cylinder with 1/4-inch guitar port on one end and USB mini-connection on the other. It also contains a headphone jack and has rotary knobs for instrument and headphone gain; it comes with its USB cable, belt clip and optional software.
Spec-wise, the MicPort Pro is fairly flat to 20 khz Plus, minus 1.5 dB)) and signal to noise is more than -121dBV (A-weighted, 150-ohm source) and dynamic range is listed at 104 dB. Not too shabby specs for such a low, price compact interface.
CEntrance designed the ‘Port products to operate with the USB 1 protocol because the basic version of USB does not need additional drivers for Mac or PC (keeping it simple to use), and it provides enough bandwidth for 24-bit/96 kHz performance.
I used the MicPort Pro with my MacBook Pro laptop, and a number of microphones including a Audix SCX-5 condenser (the lollipop-looking one), a Shure SM-27 condenser, an Audix I-5 dynamic and a Shure KSM-141 instrument condenser microphone.
The MicPort Pro was easy to set up for recording. After plugging in the cable from the MicPort Pro to the USB port on the Mac, I selected the CEntrance MicPort Pro icon in Leopard’s Audio/MIDI settings and set the word length/sample rate to 24 bit/96.
I then opened my recording program, Bias Peak 6.0 — a full-featured, easy-to-record/edit stereo program for pros or home recordists. I selected the MicPort Pro option in Peak’s Audio/I/O menu, set the word length to 24-bit, the sample rate to 96 khz. After I set the appropriate gain on the MicPort and the master gain in Peak, I auditioned the audio before clicking the mouse on record. Not quite as easy as adjusting the knobs on the cassette deck, but not too difficult.
First up, the Audix SCX-25 — one of my favorite mics for recording acoustic guitars. I adjusted the gain on the mic and the master gain on Peak, as well as selecting the 24/96 kHz high resolution option.
I recorded a Gibson Super Jumbo SJ200. The full, but brash sound of the maple and spruce wood recorded quite nicely through the Audix/MicPort Pro combo. I also recorded the Gibson and two small Martins to equal satisfaction with the Audix, as well as the other Shures.
This under-$150 miniature mic pre/A/D produced professional-quality recordings. It is not noisy with normal amounts of gain, (only wide open can you hear a hiss). It is quieter as some stand-alone mic pre, and mixers I have used. Way quieter than many of the digital handhelds when cranked at 3/4 gain or more.
The built-in headphone amp comes in handy if you want to monitor the mic signal with zero latency (the signal path is pre-computer). It also sound good; it drove my AKG 701s, 271s and various Grado and Ultrasone cans without any strain. The low-impedance AKGs needed a little more gain, but it worked. I am impressed.
The AxePort worked similarly. I plugged in the SJ200 (with its Fishman pickup) and recorded a clean, high-res track at 24-96 kHz. it was a nice direct way to get your guitar sound into the computer with nice sound. I also plugged in a Les Paul and got a great, clean rhythm tome with both pickups engaged. Direct-to-recorder electric rhythm guitar can be a refreshing break from the sonic dirt and the mud of signal-path manipulation in today’s amplifiers.
How about stereo? No problem. If you have two USB ports on your computer, just take two MicPort Pros, or an AxePort and a MicPort Pro and make two-channel recordings.
To get two USB inputs to work simultaneously for stereo on the Mac, you have to enable the Aggregate Device setting in the Audio/MIDI menu after selecting the desired inputs (two MicPort Pros with mics, or an AxePort and MicPort Pro/mic). You also have to engage the Aggregate Device setting in your recording program to complete the setup. For device aggregation with Windows, CEntrance offers its unique driver, available as a free download.
I used two Audix I-5 dynamics and recorded my Martin OO18V. The 24/96 stereo recording sound was pretty close to other preamps I have used on that guitar and those mics. Smooth and detailed with a bit of midpeak, just like the I-5 always sounds.
Just for kicks, I plugged a Les Paul with Seymour Duncan Seth Lover custom humbuckers into the AxePort for right channel recording, then I plugged in a Shure KSM-141/MicPort combo into another USB port for left channel audio. I placed the mic four inches from the 17th fret. The stereo track consisted of the Les Paul’s mic’d acoustic sound and the humbuckers, directly fed to the right channel. I had to crank the gain a bit on the MicPort Pro to get the mic channel to balance with the pickup level, but it worked — creating a very cool, clean, chorusy electric guitar sound in stereo. No outboard mixer needed.
Overall, the MicPort and the AxePort are useful sonic tools for a variety of recording tasks — scratch recordings, adding extra tracks to multitrack mixes, or just recording your evening plunking sessions. Its price should not scare away the novice recorder, and the quality will even make pros happy. It is not going to beat a $2,000 preamp, but it sure puts a lot of $500 mixer preamps to shame — in terms of noise.
My only complaint with the CEntrance products are the USB cables. Low-cost, USB cables are not really meant for gregarious recording activities. The supplied ones worked okay, but one had a lot more noise than the other. Online, I found a higher-quality, 2-meter cable with thicker gauge wire and a ferrite core for extra noise reduction. The company, NTC Distributing, (Model UH22MB2412-DSI) sells it for $10. This cable felt more robust and fit tighter in the CEntrance USB connectors. Monster Cable has one for $19.
The other thing I noticed when using these interfaces with USB cables, mic stands and headphones in close quarters — cable movement noise. Noise that is picked up in the recording. If you buy the AxePort, you can use the belt clip to route the cables away from strumming hands, etc.
I love the MicPort Pro. It does exactly what the folks at CEntrance said it does — allows the operator to feed high-res audio directly to the computer via the USB port; you can record music, recorded voice or any other desired audio task. For guitar players, the AxePort allows the same easy interface. This tandem of MicPort Pro/AxePort mini-interfaces gets a full-size Stellar Sound award from the Everything Audio Network. For more information go to www.centrance.com.