Another technique for minimizing noise under marginal operating conditions is known as squelching. When the level of the incoming RF signal drops below a certain threshold, the system becomes prone to interference and may even pick up spurious signals. In older systems, the squelching threshold is a manual adjustment. The WMS 61 and 81 systems use a pilot tone sent from the from the transmitter, which “instructs” the receiver to adjust its reception level accordingly so that noises due to improper squelch action are vastly minimized. The receiver goes into muting silently, and only when the transmitted signal drops below usable level.

Basic System Description:

Both systems include handheld transmitters with a choice of five head units, a flexible bodypack with both microphone and line input capability, and a half-rack width, single rack unit receiver. The WMS 81 series also had a unique wireless receiving unit for use with portable video cameras.

A. Handheld transmitter: The HT61 and HT 81 units are virtually identical. As you hold the unit in your hand, you will note that there is no antenna pod or dangling wire. In this system a dipole transmitting antenna is contained completely within the unit. Gently turn the base of the transmitting unit counterclockwise and remove it. Also remove the black ring that fits just above the base of the unit. When you have done this you will see 4 operating controls, the battery compartment and a listing of the transmitting frequency bands and a corresponding frequency set number. Let’s look at these in turn:

1.Channel selector: This is a recessed control that can only be accessed by a small flat-blade screwdriver (contained in the shipping package), and these channels are indicated 1 through 9 and A through F for a total of 15 channels. The channel number or letter must agree with the corresponding setting on the receiving unit, and the frequency set number must agree on both handheld unit and receiving units. (Note: When changing frequency on the transmitter, turn the unit OFF, set the new frequency, and then turn the unit back ON. The power must be off for the circuit to accomplish the frequency change.)

2.Gain setting: This control is just below the channel selector and is adjusted by a small screwdriver so that the optimum signal-to-noise ratio of the transmitted audio signal is achieved.

3.Power On-off: This switch is located just to the left of the gain control. When it is switched on an external red LED indicates to the microphone’s user that the transmitter is operating. The red LED also serves as a modulation indicator; normal maximum peaks in the spoken signal will result in a slight increase in the brightness of the LED and thus is an indication of good transmitting level.

4.Microphone On-off: This switch is located to the right of the gain control. For normal operation this switch must be in the ON position.

5.Battery compartment: Just below all of the controls is the battery compartment. Two AA batteries will provide up to 12 hours operation; thus, it is not necessary to turn the system power on and off at any time during a normal program or performance. When the batteries need to be replaced, simply pull on the two cloth ribbons to remove them. It is important to use high quality alkaline batteries. Generic batteries of lesser quality can drop in voltage, prematurely causing the transmitter to cease operating in as little as 15 minutes.

When the batteries are in fresh condition, the red LED/status light on the microphone case will glow dimly; when the status light is illuminated brightly, there are approximately 90 minutes of battery performance left, and the batteries should be replaced as soon as possible. In the event that the status light does not light up at all, the batteries are dead and must be discarded. When installing new batteries, use extra caution to ensure that they are oriented correctly.

6.Channel listing: For convenience, the 15 individual frequency bands are listed for each set, and the master set number is located at the top of the listing.

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AKG Acoustics WMS61, WMS81 manual Basic System Description
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WMS61, WMS81 specifications

AKG Acoustics has been a leading name in professional audio equipment for decades, renowned for its innovative designs and superior sound quality. The WMS81 and WMS61 are two notable products in their wireless microphone systems, designed to meet the demanding needs of live performances, presentations, and broadcasting. Both systems offer exceptional performance, ease of use, and advanced technology, making them ideal choices for musicians, public speakers, and audio professionals.

The AKG WMS81 is notable for its precision and reliability. One of its main features is its advanced frequency management technology, which ensures a stable connection by automatically scanning for the clearest frequencies. This minimizes the risk of interference during live performances. The WMS81 also includes a high-quality handheld transmitter with an AKG D5 microphone capsule, known for its excellent feedback rejection and vocal clarity. This makes it particularly suitable for dynamic performances where clarity and volume are essential. Additionally, the WMS81 offers a wide frequency response, ensuring that every nuance of the performance is captured.

On the other hand, the AKG WMS61 is a versatile system that provides excellent sound quality and flexibility. It features a compact bodypack transmitter designed for use with lavalier or headworn microphones, providing hands-free operation that is perfect for presentations or theater performances. The WMS61 includes a diverse selection of frequency channels, enabling users to operate multiple systems simultaneously without interference. Its sturdy construction ensures durability, which is essential for the rigors of touring and frequent use.

Both systems utilize AKG's renowned audio technologies, including their high-frequency response and low distortion characteristics. Another key feature of these systems is the automatic frequency selection capability, allowing users to easily find the best available channel in crowded RF environments. They also both come equipped with an efficient battery management system, offering extended operational time to ensure reliability during long events.

In summary, the AKG WMS81 and WMS61 wireless microphone systems are excellent choices for anyone looking for high-quality audio performance in a wireless format. Their robust features, advanced technologies, and user-friendly designs make them suitable for a wide range of applications, from live performances to corporate events. With AKG's commitment to innovation and quality, both systems promise to deliver exceptional sound and reliability for audio professionals and enthusiasts alike.
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