Audio-Technica System 9 ATW-901/H VHF Wireless System User Manual

1. Introduction

The Audio-Technica System 9 is a four-channel frequency-agile VHF wireless system designed for reliable performance and clear, natural sound quality. This system is ideal for various applications requiring a headset microphone, offering ease of setup and operation. It includes the ATW-R900 receiver and a body-pack transmitter with a headset microphone. The system operates on user-switchable VHF channels (169.505, 170.245, 171.045, and 171.905 MHz).

2. Package Contents

Verify that all items listed below are present in your package:

ATW-R900 Receiver
ATW-T901 Body-Pack Transmitter
Headset Microphone
Power Supply for Receiver
Two AA Batteries (for transmitter)
User Manual (this document)

Audio-Technica System 9 ATW-901/H Wireless System components including receiver, body-pack transmitter, and headset microphone.

Figure 1: Audio-Technica System 9 ATW-901/H Wireless System components. This image displays the ATW-R900 receiver, the ATW-T901 body-pack transmitter, and the associated headset microphone, illustrating the complete system.

3. Setup

Receiver Placement: Position the ATW-R900 receiver in a location free from obstructions and away from other electronic devices that may cause interference. Ensure the dipole antenna has clear line-of-sight to the intended operating area.
Receiver Power Connection: Connect the supplied AC adapter to the receiver's DC input jack and plug the adapter into a standard AC power outlet. The power indicator light on the receiver will illuminate.
Audio Output Connection: Connect the receiver's audio output to your mixer or amplifier. Use either the balanced XLR output or the unbalanced 1/4" output jack, depending on your audio equipment.
Transmitter Battery Installation: Open the battery compartment on the ATW-T901 body-pack transmitter. Insert two fresh AA batteries, observing the correct polarity (+/-) as indicated inside the compartment. Close the compartment securely.
Headset Microphone Connection: Plug the headset microphone's connector into the input jack on the body-pack transmitter. Secure the connection if applicable.
Channel Selection: Both the receiver and transmitter have user-switchable VHF channels. Select one of the four available channels (169.505, 170.245, 171.045, or 171.905 MHz) on both the receiver and the transmitter. Ensure both devices are set to the same channel for proper operation.

4. Operating Instructions

Power On: Turn on the receiver first, then the body-pack transmitter.
Verify Connection: Observe the RF indicator light on the receiver. It should illuminate, indicating a successful wireless link with the transmitter.
Adjust Volume: Speak into the headset microphone at a normal speaking level. Adjust the volume control on the ATW-R900 receiver to achieve the desired audio output level. Monitor the AF peak indicator; it should flash only during the loudest audio peaks, not constantly.
Operating Range: The typical operating range is up to 200 feet (60 meters) in an open environment without interfering signals. Maintain line-of-sight between the transmitter and receiver for optimal performance.
Power Off: When finished, turn off the body-pack transmitter first, then the receiver. This helps prevent audio pops or other unwanted noises.

5. Maintenance

Battery Replacement: Replace the AA batteries in the body-pack transmitter regularly, especially before critical performances, to ensure consistent performance. Low battery power can lead to signal degradation or unexpected shutdowns.
Cleaning: Clean the exterior surfaces of the receiver and transmitter with a soft, dry cloth. Do not use harsh chemicals or abrasive cleaners. For the headset microphone, gently wipe the microphone element with a slightly damp cloth if necessary, ensuring no moisture enters the grille.
Storage: When not in use for extended periods, remove the batteries from the transmitter to prevent leakage. Store the system in a cool, dry place, away from direct sunlight and extreme temperatures.

6. Troubleshooting

Problem	Possible Cause	Solution
No sound or weak sound	Transmitter or receiver not powered on. Batteries in transmitter are dead or low. Incorrect channel selected on transmitter/receiver. Receiver volume too low. Microphone not connected to transmitter. Audio cable from receiver to mixer/amp is faulty or disconnected.	Ensure both units are powered on. Replace with fresh AA batteries. Verify both units are on the same channel. Increase receiver volume. Ensure headset microphone is securely plugged into the body-pack. Check audio cable connections and try a different cable.
Intermittent signal or crackling sound	Interference from other wireless devices or electronics. Operating beyond effective range. Low transmitter battery. Obstructions between transmitter and receiver. Incorrect channel selection.	Change to a different operating channel. Reduce distance between transmitter and receiver. Replace transmitter batteries. Relocate receiver for better line-of-sight. Ensure both units are on the same, clear channel.
Distorted audio	Receiver volume too high (AF peak indicator constantly lit). Microphone gain too high (if adjustable). Input level on mixer/amplifier too high.	Reduce receiver volume until AF peak indicator only flashes on loudest sounds. Adjust microphone gain on transmitter (if available) or mixer. Lower input level on connected audio equipment.

7. Specifications

Operating Frequencies	VHF High Band, 169 MHz to 172 MHz (4 user-switchable channels: 169.505, 170.245, 171.045, 171.905 MHz)
Modulation Mode	FM
Maximum Deviation	+/-10 kHz
Dynamic Range	≥90 dB (A-weighted), typical
Total Harmonic Distortion	<1% (at 1 kHz, +/-10 kHz Deviation)
Operating Range	200' (60 m) typical open range environment with no interfering signals
Operating Temperature Range	40° F (4° C) to 110° F (43° C)
Frequency Response	80 Hz to 13 kHz
Receiver (ATW-R900)	Non-diversity, single-channel, advanced dipole antenna, volume control, AF peak, RF, and power indicator lights. Balanced XLR and unbalanced 1/4" output jacks.
Transmitter (ATW-T901)	Body-pack, requires 2 AA batteries.
Microphone Form Factor	Headset
Connectivity Technology	XLR (receiver output)
Enclosure Material	Metal
Item Weight	1 Pound (System total)
Item Dimensions	7 x 1 x 4 inches (Receiver)

8. Warranty and Support

This Audio-Technica System 9 ATW-901/H Wireless System is covered by a 1-year limited warranty from the date of purchase. This warranty covers defects in materials and workmanship under normal use. For warranty service or technical support, please contact Audio-Technica customer service. Keep your proof of purchase for warranty claims.

For further assistance, visit the official Audio-Technica website or consult your local dealer.

Audio-Technica ATW-901/H