1. Product Overview
The Koss QZ-99 Noise Reduction Stereophones are designed to provide an isolated listening experience by reducing ambient sounds. They feature Pneumalite™ ear cushions and a secure headband for effective passive noise isolation. Integrated controls allow for convenient volume adjustment and stereo/mono switching.
These headphones are suitable for environments where external noise reduction is beneficial, such as with racing scanners or metal detectors, or for focused audio listening.
Key Features:
- Passive Noise Reduction system isolates the listener from ambient sounds.
- Neodymium magnet structures for clear audio reproduction.
- Closed Pneumalite™ ear cushions and an extra-secure headband create a sealed listening environment.
- Volume control located on the ear cup for easy level adjustment.
- Stereo/Mono switch for enhanced flexibility.
- Single-entry, 8-foot coiled cord for extended reach and tangle resistance.
2. Setup and Connection
2.1 Unpacking and Inspection
Carefully remove the Koss QZ-99 headphones from their packaging. Inspect the headphones and cable for any visible damage. Ensure all components, including the 8-foot coiled cord and the 3.5mm jack, are present and intact.
2.2 Connecting to an Audio Source
- Locate the 3.5mm audio jack on your audio device (e.g., laptop, desktop, tablet, cellphone, music production equipment).
- Insert the 3.5mm plug of the Koss QZ-99 coiled cord into the audio output jack of your device.
- If your device requires a 1/4-inch adapter, use the provided adapter by screwing it onto the 3.5mm plug.
Image: The 3.5mm audio jack, 1/4-inch adapter, and the in-line stereo/mono switch on the Koss QZ-99 cable.
2.3 Adjusting for Comfort
Place the headphones over your ears. Adjust the headband to ensure a snug yet comfortable fit. The Pneumalite™ ear cushions should fully enclose your ears to maximize passive noise reduction and sound quality.
3. Operation
3.1 Volume Control
The volume control knob is located on one of the ear cups. Rotate the knob clockwise to increase the volume and counter-clockwise to decrease it. Adjust to a comfortable listening level.
3.2 Stereo/Mono Switch
An in-line switch on the cable allows you to select between stereo and mono audio output. Set the switch to "STEREO" for standard stereo sound. If your audio source is mono or if you prefer a mono output, slide the switch to "MONO".
Video: A product overview demonstrating the features and controls of the Koss QZ-99 headphones, including the adjustable fit, on-ear volume control, and the stereo/mono switch.
4. Maintenance and Care
- Cleaning: Use a soft, dry cloth to clean the exterior of the headphones. Do not use liquid cleaners or solvents.
- Ear Cushions: The Pneumalite™ ear cushions are designed for durability. If they become worn or damaged, contact Koss customer support for replacement options.
- Storage: Store the headphones in a clean, dry place away from extreme temperatures and direct sunlight. Avoid tangling the coiled cord.
- Cable Care: Do not pull on the cable to disconnect the headphones from an audio source. Always grasp the plug firmly.
5. Troubleshooting
5.1 No Sound or Low Volume
- Ensure the 3.5mm plug is fully inserted into the audio source.
- Check the volume control knob on the ear cup and turn it clockwise to increase volume.
- Verify the volume settings on your audio source device.
- Test the headphones with a different audio source to rule out device-specific issues.
5.2 Distorted Sound
- Reduce the volume on both the headphones and the audio source.
- Ensure the audio cable is securely connected and not damaged.
- Check the stereo/mono switch position. Incorrect settings for certain audio sources can cause distortion.
5.3 Poor Noise Isolation
- Adjust the headband to ensure the ear cushions form a complete seal around your ears.
- Ensure the ear cushions are not damaged or worn, as this can compromise the seal.
6. Specifications
| Feature | Detail |
|---|---|
| Model Number | QZ99 |
| Noise Control | Sound Isolation (Passive Noise Reduction) |
| Frequency Response | 40-20,000 Hz |
| Sensitivity | 102 dB |
| Impedance | 60 Ohms |
| Connectivity Technology | Wired |
| Headphones Jack | 3.5 mm Jack (with 1/4-inch adapter) |
| Cable Feature | 8-foot Coiled Cord |
| Control Type | Volume Control (on ear cup), Stereo/Mono Switch (in-line) |
| Ear Placement | Over Ear |
| Material | Metal (frame) |
| Item Weight | 15 ounces (425 Grams) |
| Product Dimensions | 8.63 x 4.13 x 8.38 inches |
7. Warranty and Support
7.1 Legal Disclaimer
The product warranty does not cover misuse of the product. Please refer to the official Koss website or your purchase documentation for complete warranty terms and conditions.
7.2 Customer Support
For technical assistance, replacement parts, or further inquiries, please contact Koss customer support. Contact information can typically be found on the Koss official website or within your product packaging.
