AKG WMS470 Instrumental Wireless Set BD7 500 to 530 MHz Guitar System

AKG WMS470 Instrumental Set BD7: A Wireless Channel for the Player

The AKG WMS470 Instrumental Set is a complete analog UHF wireless instrument system in the Band 7 configuration, covering 500.1 to 530.5 MHz at 50 mW of effective radiated power with a PT470 bodypack and an MKG L instrument cable in place of a microphone. Its carton holds an SR470 stationary receiver, the PT470 bodypack transmitter, the MKG L instrument cable, 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. What separates this set from the vocal sets in the same family is simply what plugs into the transmitter: a guitar lead rather than a capsule. It exists so a guitarist, bassist or horn player can leave the cable behind and still land on the same console channel.

What the MKG L Cable Does Between an Instrument and a Pack

Supplied with this set is the MKG L instrument cable, a short lead terminating in a 3-pin locking mini connector at the transmitter end and a 1/4 in (6.3 mm) jack at the instrument end. That combination is the whole reason a bodypack system can replace a guitar cable: the pack presents a 3-pin locking mini input rather than a jack socket, so the lead has to translate between the two, and the locking collar means a player cannot pull the connection apart with a sharp turn on a dark stage. Length matters as much as the connectors, because a bodypack lead only has to reach from a guitar strap to a belt, and a long lead would leave a loop of cable swinging where it can catch on a strap button or a mic stand. Guitarists and bassists notice the difference within one song, and horn and woodwind players using a clip-on pickup with the same locking termination plug straight in without the jack lead at all.

Setting Bodypack Gain for an Instrument-Level Signal

Gain staging at the pack is the single most consequential adjustment on any bodypack channel, because the PT470 has to accept sources whose output levels differ by tens of decibels. A magnetic guitar pickup produces a modest signal, an active bass with a preamplifier on board produces a much hotter one, and a piezo pickup on an acoustic instrument sits somewhere in between, so a pack gain control exists to bring all of them to the level the FM transmitter expects; setting it too low buries the signal in the noise floor of the radio link, and setting it too high clips inside the transmitter before the console ever sees the audio. The practical method is to play the loudest passage of the loudest song and back the gain off until the pack stops indicating overload, then leave the console fader to do the mixing. A bassist who has ever heard a wireless channel sound thin and gritty on the low notes has heard the wrong answer to that question, and it is fixed at the pack rather than at the desk.

Band 7 Placement and Copying the Carrier by Infrared

Band 7 occupies 500.1 to 530.5 MHz, and inside it the receiver commands 30.5 MHz of switching bandwidth, subject to local regulations, which is the span across which a carrier can be moved without new hardware. This part of lower UHF 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. Setting the actual carrier is done optically rather than typed twice: the receiver finds a frequency using enhanced automatic setup with channel preview and an environment scan, and the infrared link then copies that frequency straight into the pack while it is held in front of the receiver. Manual entry is where multichannel systems fail, since one wrong digit produces a channel that looks correct in the rack and dies on stage, and an optical handshake removes that possibility entirely.

The Belt Clip, Cable Dress and Moving Without Thinking About It

Physical detail decides whether a player forgets the pack is there, and the BC400 belt clip supplied with this set is where that starts. A belt clip holds the transmitter against a belt, a strap or a waistband so the pack sits still rather than swinging from a pocket, and once the pack is fixed the short MKG L lead can be dressed under a guitar strap with a little slack at the instrument end to absorb movement. Strain is the enemy here, since the repeated flexing at a connector is what eventually kills any instrument lead, and a locking connector plus a fixed pack position takes most of that flexing out of the system. Worship guitarists stepping off a riser, musical theatre pit players moving between positions, and function-band horn sections walking into an audience all rely on that arrangement holding for a whole show without a thought.

Interfacing the Receiver and Who Buys an Instrument 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, which is exactly the flexibility an instrument channel needs, since the destination may be a console microphone input, a line input, or the front-panel input of a guitar amplifier or an active wedge. Transmitter 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, while pilot-tone code squelch with a threshold adjustable from -80 to -100 dBm keeps the output muted whenever the pack is off. Up to 48 simultaneous channels are available when several frequency bands are combined, and the platform accepts WMS4000 antenna and charging accessories. Electric guitarists and bassists, horn players with clip-on pickups, acoustic players with piezo systems, worship bands cutting cable runs across a platform and rental houses stocking one instrument channel all buy this set for the same reason: it arrives complete, including the lead.