AKG WMS470 Presenter Wireless Set BD7 500 to 530 MHz Headworn Lavalier

AKG WMS470 Presenter Set BD7: Two Microphones on One Wireless Channel

The AKG WMS470 Presenter Set is a complete analog UHF wireless presenter system in the Band 7 configuration, covering 500.1 to 530.5 MHz at 50 mW of effective radiated power and unusual in shipping two microphones rather than one. Its carton holds an SR470 stationary receiver, a PT470 bodypack transmitter, a C555 L head-worn condenser microphone, a CK99 L lavalier condenser microphone, a BC400 belt clip, the RMU4000 rack mount kit, a universal power supply with US/UK/EU adapters, one AA size battery and two BNC UHF antennas. Audio runs 35 to 20,000 Hz within plus or minus 3 dB at a typical 120 dB-A signal-to-noise ratio and less than 0.3 percent distortion at 1 kHz at the receiver. Both microphones terminate in the same 3-pin locking mini connector, so a presenter chooses a style at the last minute rather than at the purchase order. One channel therefore serves two entirely different speaking habits.

Two Microphones, Two Different Published Responses

Supplied with this set are the C555 L head-worn condenser and the CK99 L lavalier condenser, and they are genuinely different microphones rather than two shapes of the same one. C555 L is a pre-polarized condenser on a behind-the-neck headband whose boom can be worn on either side, measuring 80 Hz to 20,000 Hz with 25 mV/Pa sensitivity and a 120 dB maximum SPL, and it carries a flexible capsule shock mount and a moisture shield. CK99 L is a cardioid clip-on lavalier with a metal clothing clip, a 125 degree pickup angle, a published 150 Hz to 18,000 Hz response and 8.8 mV/Pa sensitivity into a 200 ohm source impedance. Both draw their operating current from the pack and both terminate in a 3-pin locking mini connector, which means a lecture theatre can hand a nervous first-time speaker the discreet lavalier and give the visiting keynote the headband that holds a fixed working distance, using exactly the same channel.

Working Distance Is Why the Two Sound So Different

Placement, not electronics, produces most of the audible gap between a head-worn microphone and a lavalier on the same pack. A head-worn capsule sits an inch or two from the corner of the mouth and stays there when the speaker turns to a whiteboard, so the level arriving at the capsule barely changes and the gain the system needs is low; a lavalier clipped at the sternum sits eight to twelve inches away, loses roughly six decibels every time that distance doubles, and swings in level whenever the speaker turns their head. Lower required gain is what buys headroom before feedback in a room with ceiling loudspeakers over the presenter, which is why head-worn microphones dominate in rooms that fight for level. Lecturers who pace and write on boards, trainers who work a flip chart, and worship speakers who move away from a lectern all sound markedly steadier on the headband, while a seated panellist or a keynote in a suit is usually better served by the lavalier.

Why the Receiver Has Two Antennas

Diversity reception is the reason the SR470 carries two 50 ohm BNC female antenna sockets rather than one, and it is the least understood feature on any wireless receiver. A radio wave inside a room does not arrive by a single path; it reflects off walls, glass, metal trusses and bodies, and where two paths meet out of phase they cancel, producing a null a few inches across in which a single antenna hears almost nothing, which is exactly what a presenter walking across a stage occasionally steps into. Microcontroller-controlled space diversity solves it by comparing both antenna paths continuously and taking whichever is stronger, and because two antennas separated by some distance are almost never in the same null at the same instant, the dropouts a single-antenna system suffers simply stop. Placing the two supplied antennas apart and in line of sight of the presenter is the whole technique, and in a lecture theatre with a metal-framed ceiling it is the difference between a channel that works and one that crackles at one spot on the floor.

Band 7, Switching Bandwidth and What That Number Buys

Band 7 occupies 500.1 to 530.5 MHz, and within it the receiver commands 30.5 MHz of switching bandwidth, subject to local regulations. Switching bandwidth is the span of spectrum a system can be retuned across without changing any hardware, and it is the specification that decides whether a wireless channel can be moved when a television station, a neighbouring venue or a visiting production crew occupies the frequency it was set to; a narrow-bandwidth system stranded on a busy frequency has to be replaced, whereas 30.5 MHz of headroom means the answer is a menu change. This part of lower UHF also sits well below the 600 MHz line that spectrum authorities in the United States redrew when upper UHF was reallocated to mobile broadband, so a plan built here is not working against a restricted edge. For an institution that will keep a room in service for a decade, that retuning room is the specification that matters most.

Interfacing, Runtime and Who Deploys a Presenter Channel

Audio leaves the SR470 on a balanced XLR switchable to -30 or 0 dBm and on an unbalanced 1/4 in (6.3 mm) jack reaching plus 9 dBu, so the channel lands cleanly on a console microphone input, an installed mixer, or the line input of a room amplifier. Endurance follows the cell fitted, giving 7 hours from an alkaline AA, 8 hours from an NiMH rechargeable or up to 14 hours from a lithium cell, which is easily a full teaching day, and pilot-tone code squelch with a threshold adjustable from -80 to -100 dBm keeps the output silent whenever the pack is switched off between sessions. Up to 48 simultaneous channels are available when several frequency bands are combined, and the platform accepts WMS4000 antenna and charging accessories. Lecture theatres, corporate training rooms, conference centres, houses of worship with a changing roster of speakers, museums running docent-led tours and broadcast presenters who need hands free all buy this set because one channel arrives able to suit two speaking styles.