AKG Acoustics WMS 450
Mar 1, 2008 12:00 PM, By John McJunkin
Easy-setup mic system fills the gap between plug-and-play and high-end applications.
The AKG Acoustics WMS 450 wireless-mic system is intended for applications for which super-simple, plug-and-play solutions aren't quite sufficient, but for which expensive, high-end systems would be overkill. A key notion underlying this product is ease of setup and use. It offers a number of options for use in live-sound, house-of-worship, and conference applications. Five WMS 450 packages are available: the C 5 condenser mic, the D 5 dynamic mic, the headworn C 555 L MicroMic, the Presenter package with a C 407 L lavalier mic, and the Guitar package with a 1/4in. phone plug for electric guitar. I spent some time with the C 5-mic version.
The system uses a 1/2RU SR 450 receiver, which allows you to use multiple systems without sacrificing a lot of rack space. Its front panel is very simple, with a pushbutton power switch, a volume knob, and three menu-navigation buttons, all straddling a two-color, backlit LCD display. This display has a bar graph to indicate the field strength of the received signal, a five-digit multipurpose alphanumeric display, and a bar graph-style VU meter indicating the level of the received audio. The front panel also displays the transmitter's battery status, which I really liked. It's nice to have a heads-up if a battery is about to die. LEDs above the LCD display indicate various states of operation.
The rear panel is every bit as simple, with an XLR-balanced output, a 1/4in. unbalanced-output jack, BNC connectors for the unit's two antennas, and a slider switch that inserts a 30dB pad. Finally, the rear panel features a locking, threaded DC-power input jack that accepts the input of the unit's line lump power supply. I really appreciate the locking mechanism, which prevents users from accidentally yanking the power. The receiver can catch signals in seven bands that range from 650MHz to 865MHz, and it exhibits a 35Hz-to-20kHz audio range. Also, the receiver is compatible with AKG WMS 4000 antenna splitters, power supplies, and high-quality antennas, so it can be integrated into a pretty sophisticated system. Another unexpected, but very nice, feature at this price is a rehearsal function for finding dead spots.
The HT 450 transmitter that I test-drove is based on the capsule of AKG's recently introduced C 5 handheld condenser mic, which I have used a bit and have found to be a very good mic for handheld vocal use. The HT 450 C 5 provides all the expected resolution of a condenser mic, but it is tough and easily used in for live sound or in a house of worship. It sports a heavy-duty, wire-mesh windscreen that nicely tames plosives and one of the most robust internal shock mounts I've seen. The wireless version's transmitter operates in the 650.1MHz-to-680MHz band, and it can be set to any number of preprogrammed frequencies or tuned directly in 25MHz increments. Up to 12 channels can be used simultaneously in multichannel applications.
The mic sports a LCD display to show you various attributes of operation, including battery status. The bottom of the mic has three charging contacts for use with the AKG CU 400 charging base. It also has a rechargeable 1.2V NiMH battery, which will typically last 8 hours. To keep operation and maintenance very simple, the mic can also be powered by a garden-variety 1.5V AA battery, which provides about 6 hours of use.
One particularly clever and welcome feature of the mic is the infrared communication between the transmitter and receiver, which vastly simplifies setup. The actual audio signal is handled in the radio domain, but control communications between the transmitter and receiver happen in IR. After connecting and switching on the receiver, I was able to establish a channel with just a few button pushes. The receiver then established an IR link and alerted the microphone to the frequency, to which the mic immediately adjusted. I appreciate the simplicity here. In the process of setting up a channel, a few keystrokes established the country of operation, and I was able to just scroll through the various countries to quickly arrive at legal operation.
One minor complaint about the mic: Its switch is countersunk, which is probably intended to prevent a vocalist from inadvertently powering down in the middle of a performance. It's recessed so far and in such a narrow channel that it is difficult to mute it quickly with your thumb. I realize this is a trade-off. We don't want the mic accidentally turned off, but we also want to be able to quickly and easily mute it. To be sure, this quick-muting capability is not as critical with a handheld mic as it would be with a headworn mic. On the positive side, the mute switch is dead quiet. One other minor issue: The mic's casing is constructed of a high-quality plastic that is a bit slippery for handheld use. There could be a bit more grip. The good news here is that there's really no handling noise to speak of, which is largely due to the mic's robust internal shock mount.
The mic's cardioid pattern contributes strongly to its high gain-before-feedback. It also features the AKG PB 1000 Presence Boost Adapter. This plastic device is attached directly onto the mic's capsule to acoustically boost intelligibility frequencies. I was pleased with its effect — vocals cut through the mix a lot more effectively, and speech was much more intelligible as a result. Overall, I was thrilled with the way the mic sounded — full, warm, and with plenty of resolution in the high end, as you'd expect from a condenser mic. The transmission to the receiver is very quiet, and the receiver itself does not contribute much noise to the signal path. The published total harmonic distortion (THD) for the receiver is less than 0.3 percent and less than 0.7 percent for the HT 450 transmitter — a nice, clean signal that really sounds good. I would definitely trust this system to provide a clean, robust signal anywhere a vocal is necessary.
In addition to some previous exposure to the AKG C 5 capsule, I have also had experience with the D 5, and it is a very solid, good-quality dynamic mic. I would guess that the D 5 version of the WMS 450 system is similar in operation and quality to the C 5 version. Again, based upon prior experience with AKG products, I would bet the C 555 and C 407 mics (in the headworn and lavalier versions of the system, respectively) are very solid and provide a high-quality signal to your mix. Those two systems, along with the Guitar version, ship with the PT 450 body-pack transmitter, and they probably would exhibit the same simple setup and operation.
If you require a moderately sophisticated system that simplifies setup and delivers quality sound, I would definitely recommend taking a look at the AKG WMS 450.
Company: AKG Acoustics
Product: WMS 450
Pros: High-quality sound and simple setup, even for multichannel applications.
Cons: Recessed mic switch is hard to access, mic casing feels a bit slippery.
Applications: Live sound, house of worship, conference.
SR 450 receiver
Bandwidth: 35Hz to 20kHz
THD: <0.3% @ 1kHz
S/N ratio: 120dB (A-weighted)
HT 450 transmitter
Bandwidth: 35Hz to 20kHz
THD: <0.7% @ 1kHz
S/N ratio: 120dB (A-weighted)
RF output: 50mW maximum ERP
Battery life: 1.5V AA - 6 hours. 1.2V NiMH - 8 hours
John McJunkin is the principal of Avalon Podcasting in Chandler, Ariz. He has consulted in the development of studios and installations and provides high-quality podcast-production services.
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