During last summer’s InfoComm show, AKG introduced the DMSTetrad, a four-channel 2.4 GHz digital wireless microphone system for live sound, corporate events, church and industrial installations. It is designed to be set-up quickly and be simple to use. And from a first glance at the receiver, it is indeed very streamlined looking with a knob, a volume pot and three LEDs per channel. Pretty straightforward.
The package I got for review contained a body pack transmitter with a C111 LP head mic (they refer to it an ear hook microphone), along with two handheld mics with transmitters. The two handhelds were the D5, one of AKG’s workhorse dynamics and the P5, their Perception series counterpart.
The system includes the four-channel receiver and two antennas which can be mounted on the rear of the unit, or front-mounted when using the included rack-mount kit. Both antennas have high-frequency mounts with fine threads — rather than BNC connections — so any chances of expanding the system with optional external antennas or combiners seems unlikely.
In’s and Out’s
The rear panel has four individual XLR outs for each of its channels, as well as a summed mono output that takes the signal from each mic and lets the user create a simple mix using the front panel volume pots for each channel. These controls attenuate both the feed-to-mono and the main outs for each channel simultaneously and could definitely be useful for quick mixes to a powered speaker or two for quick in/out industrial gigs, panel discussions, etc. Also on the rear panel is a port for the external 12 VDC wall wart supply and a switch for engaging the interference protection feature.
The front panel also includes three status LED’s for each channel indicating clipping (overload), link (used when locking a transmitter onto that channel) and a battery LED that flashes when the transmitter has less than one hour of power remaining.
Speaking of batteries, the transmitters (handhelds and body packs) all operate for six hours on two AA alkaline batteries, and all transmitters automatically shut down whenever the receiver is powered down — a useful feature.
In The Field
After attaching the antennas to the receiver and loading the batteries into the various transmitters I fired it up. One thing I noticed was the wire spring retaining clips that hold the two AA batteries in place on both the D5 and P5 battery compartments. They seemed flimsy and would sometimes get in the way while putting the covers back on during battery changes. And on a few occasions, the clips popped out entirely. Putting the clips back into place was a no-brainer, assuming they didn’t fall onto the ground on a dark stage. Perhaps AKG can address this in a future version. I found that aspect somewhat incongruous, being as everything else about these mics seemed very solid in their design.
Upon powering up, I saw that the body pack showed up right away as connected to channel one. I’m assuming it came factory programmed that way. The handhelds needed to be linked in. I consulted the enclosed quick start guide (something more companies should provide with new gear) and followed the procedure for channel recognition. It took a few tries to lock in, but both mics did connect. I felt that the quick start guide could have been a little more detailed about the procedure. Once running, the system sounded great and all receiver-to-transmitter assignments are retained, even when the batteries are removed and the transmitter is unplugged.
Having worked with both of these mics in the wired versions, I had an idea of what they should sound like. Both are supercardioid with a fairly tight polar response, excellent off-axis rejection of unwanted stage noise and high feedback immunity when wedges were placed off to the side. The D5 sounded as it should with a smooth, well-rounded frequency response, extended HF response and very effective internal shock protection against handling noise and stage bumps. Taken from AKG’s popular Perception line, the P5 had a more aggressive sound (a good thing with certain vocalists and musical styles) and exhibited some noticeable handling noise. I was surprised by the performance of the C111 LP earhook mic/beltpack combo, which offered a clear and natural sound with excellent intelligibility.
One thing I missed on the receivers was knowing what frequencies were actually being used. I work in a lot of venues where other wireless units are in use. And I understand that this unit will seek out unused bands in its range, but I can’t rely on other units doing the same and it would be nice to know exactly what frequencies we are on. All the literature included with the unit and on the packaging just said it was 2.4 GHz. I went to the website looking for the manual. It wasn’t really obvious where it was. I had a hard time finding it, although I eventually found it here: akg.com/pro/p/dmstetradsystem
The manual lists the following as the frequencies they switch between: 2.404 to 2.420 GHz; 2.430 to 2.446 GHz; 2.454 to 2.470 GHz
The DMSTetrad has several interesting features. One of the features of this system is the DROCON or DROpout CONcealment technology that can accurately extrapolate the missing bits of signal to hide dropouts. It’s also equipped with 128-bit AES standard encryption to prevent tapping of the audio signal for high-security situations. There is also an interference protection switch to combat other equipment that operate in the 2.4 GHz range such as Wi-Fi, Bluetooth devices.
One thing I found a bit over the top was the naming of every component in the system with its own acronym. The receiver is the DSRTetrad standing for Digital Stationary Receiver. The Bodypack is the DPTTetrad (Digital Pocket Transmitter), and the handheld mics are the DHTTetrad, appropriately enough short for Digital Handheld Transmitter.
Overall I found the DMSTetrad a great system for introducing users to the world of digital wireless and a good choice for installations or portable applications where user friendliness is a major concern. Something that will certainly appeal to most users is the affordable system pricing, which begins at $699/street for a D5 handheld with a four-channel receiver, making it an ideal starting block for stepping up to a larger rig simply by adding additional transmitters on an à la carte basis.
