Introduction
The iSound BT-3500 Bluetooth headphones provide a wire-free audio experience. Designed with rugged construction and extra soft over-ear cups, these headphones feature matched 40mm drivers for pure bass and crisp treble, delivering a full-bodied music experience. On-board volume and track controls enhance the wireless functionality, complemented by a crystal clear, anti-echo microphone for true hands-free calling. Enjoy up to 15 hours of continuous play between charges, making these headphones suitable for various audio uses.
What's in the Box
Upon opening your iSound BT-3500 package, you should find the following items:
- iSound BT-3500 Wireless Headphones
- User Guide
- Charge Cable

Image: Front view of the iSound BT-3500 Wireless Headphones and their retail packaging, showing the headphones, brand logo, and key features.
Product Features
- Wireless Connectivity: Bluetooth 5.0 for stable and efficient connection.
- Extended Playtime: Built-in rechargeable battery offers up to 15 hours of continuous play.
- Superior Audio: 40mm drivers deliver full lows and clear highs.
- Integrated Microphone: Answer calls with the built-in microphone, featuring anti-echo technology.
- Convenient Controls: On-board controls for music playback and volume adjustment.
- Comfortable Design: Over-ear cups made from soft material for extended wear.
Setup
1. Charging the Headphones
Before initial use, fully charge your iSound BT-3500 headphones. Connect the included charge cable to the charging port on the headphones and the other end to a USB power source (e.g., computer USB port, USB wall adapter). The LED indicator will show charging status and turn off or change color when fully charged. A full charge provides up to 15 hours of playtime.
2. Bluetooth Pairing
- Ensure the headphones are turned off.
- Press and hold the Power button on the headphones until the LED indicator flashes rapidly, indicating pairing mode.
- On your Bluetooth-enabled device (smartphone, tablet, computer), go to the Bluetooth settings.
- Search for available devices and select "BT-3500" from the list.
- Once connected, the LED indicator on the headphones will stop flashing and may glow solid blue.
- If prompted for a password, enter "0000".
The headphones will automatically attempt to reconnect to the last paired device when powered on.
Operating the Headphones
Controls Overview
The iSound BT-3500 headphones feature intuitive on-board controls for managing your audio and calls.
- Power Button: Press and hold to power on/off. Short press to play/pause music or answer/end calls.
- Volume Up (+): Short press to increase volume. Long press for next track.
- Volume Down (-): Short press to decrease volume. Long press for previous track.
Music Playback
After pairing with your device, open your preferred music application. Use the on-board controls to manage playback:
- Press the Power button once to play or pause music.
- Long press the Volume Up (+) button to skip to the next track.
- Long press the Volume Down (-) button to go to the previous track.
- Short press Volume Up (+) or Volume Down (-) to adjust the volume.
Making and Receiving Calls
The built-in microphone allows for hands-free calling when connected to your smartphone.
- Answering a Call: Press the Power button once when a call comes in.
- Ending a Call: Press the Power button once during a call.
- Rejecting a Call: Press and hold the Power button for 2 seconds when a call comes in.
- Redialing Last Number: Double-press the Power button when not on a call.

Image: Rear view of the iSound BT-3500 Wireless Headphones, highlighting the location of the control buttons on the earcup.
Maintenance
To ensure the longevity and optimal performance of your iSound BT-3500 headphones, follow these maintenance guidelines:
- Cleaning: Use a soft, dry cloth to clean the headphones. Do not use liquid cleaners or aerosols.
- Storage: Store the headphones in a cool, dry place away from direct sunlight and extreme temperatures.
- Battery Care: Avoid fully discharging the battery frequently. Charge the headphones regularly, even if not in use, to maintain battery health.
- Avoid Moisture: Do not expose the headphones to water or excessive moisture.
- Handle with Care: Avoid dropping or subjecting the headphones to strong impacts.
Troubleshooting
| Problem | Possible Solution |
|---|---|
| Headphones do not power on. | Ensure the headphones are fully charged. Connect to a power source using the charge cable. |
| Cannot pair with a device. |
|
| No sound or low volume. |
|
| Microphone not working during calls. |
|
Specifications
| Feature | Detail |
|---|---|
| Model Name | BT-3500 |
| Connectivity Technology | Wireless (Bluetooth) |
| Bluetooth Version | 5.0 |
| Audio Driver Size | 40 Millimeters |
| Earpiece Shape | Over Ear |
| Battery Life | Up to 15 Hours |
| Control Type | Media Control, Call Control |
| Special Feature | Microphone Included, Noise Cancellation (for microphone) |
| Material | Plastic, Soft Material (Ear Cups) |
| Product Dimensions | 3.25 x 7.5 x 8.5 inches |
| Item Weight | 14.4 ounces |
| UPC | 845620056514 |
Warranty and Support
For warranty information or technical support, please refer to the documentation included with your product or visit the official iSound website. You may also contact iSound customer service directly for assistance with your BT-3500 Wireless Headphones.
Manufacturer: iSound
Website: Visit the iSound Store on Amazon





