Introduction
Welcome to the Monster Harmonic N21 Bluetooth Headphones user manual. These over-ear wireless headphones are designed to deliver powerful deep bass and crystal-clear audio, featuring Bluetooth 6.0 for stable connections, dual EQ modes, and a comfortable, foldable design. This manual provides detailed instructions on how to set up, operate, and maintain your headphones to ensure optimal performance.
Package Contents
Please check the box for the following items:
- Monster Harmonic N21 Bluetooth Headphones
- User Manual
- Type-C Charging Cable
- 3.5mm Audio Cable
Product Overview
The Monster Harmonic N21 headphones feature an ergonomic design with intuitive controls and a foldable structure for portability. Key components include:
- EQ Button: For switching sound modes and activating voice assistant.
- Power Button: For power on/off, play/pause, and call management.
- Volume Buttons (+/-): For adjusting volume and navigating tracks.
- Type-C Port: For charging the headphones.
- 3.5mm Port: For wired audio connection.
Setup
1. Charging the Headphones
Before first use, fully charge your headphones.
- Connect the provided Type-C charging cable to the Type-C port on the headphones and a USB power source (e.g., wall adapter, computer USB port).
- The indicator light will show charging status (specific light behavior not detailed, typically red for charging, off/blue for full).
- A full charge takes approximately 1-2 hours.
2. Bluetooth Pairing
To connect your headphones wirelessly:
- Ensure the headphones are powered off.
- Press and hold the Power Button until the indicator light flashes (usually blue/red alternately), indicating pairing mode.
- On your device (smartphone, tablet, laptop), enable Bluetooth and search for available devices.
- Select "Monster Harmonic N21" from the list.
- Once connected, the indicator light will typically turn solid blue or flash slowly.
3. Wired Connection
For a wired connection, use the 3.5mm audio cable:
- Plug one end of the 3.5mm audio cable into the 3.5mm port on the headphones.
- Plug the other end into the audio jack of your device.
- The headphones will automatically switch to wired mode, conserving battery.
Operating Instructions
Power On/Off
- Power On: Long press the Power Button for 3-5 seconds.
- Power Off: Long press the Power Button for 3-5 seconds.
Music Playback
- Play/Pause: Single tap the Power Button.
- Next Track: Long press the '+' button.
- Previous Track: Long press the '-' button.
- Volume Up: Single tap the '+' button.
- Volume Down: Single tap the '-' button.
Call Management
- Answer/End Call: Single tap the Power Button.
Dual EQ Modes
The headphones offer two custom-tuned EQ modes:
- Switch Mode: Single tap the EQ Button to toggle between Bass Mode and Vocal Mode.
Voice Assistant
- Activate/Deactivate Siri/Google Assistant: Long press the EQ Button for 2 seconds.
Maintenance
- Cleaning: Use a soft, dry cloth to clean the headphones. Do not use abrasive cleaners or solvents.
- Storage: When not in use for extended periods, store the headphones in a dry environment. The foldable design allows for compact storage.
- Environmental Conditions: Avoid exposing the product to direct sunlight for prolonged periods. Do not use this product in the rain or extreme moisture.
Troubleshooting
| Problem | Possible Solution |
|---|---|
| Headphones won't power on | Ensure the headphones are fully charged. Connect to a power source and try again. |
| Cannot pair via Bluetooth | Ensure headphones are in pairing mode (flashing indicator light). Turn off and on Bluetooth on your device. Move closer to the device. |
| No sound in wireless mode | Check volume levels on both headphones and connected device. Ensure headphones are properly paired. |
| Poor call quality | Ensure microphone is not obstructed. Move to a quieter environment. Check Bluetooth connection stability. |
| Automatic shutdown | This may occur if the battery is low. Recharge the headphones. |
| Restore factory settings | Refer to the full user manual (PDF) for instructions on how to perform a factory reset, if available. |
Specifications
| Feature | Detail |
|---|---|
| Product Name | Monster Harmonic N21 |
| Brand | MONSTER |
| Bluetooth Chip | Bluetrum |
| Bluetooth Version | V6.0 |
| Operating Frequency | 2.402–2.480GHz |
| HD Audio Codec | AAC, SBC |
| Transmission Distance | ≥10m (10m-20m) |
| Frequency Response | 20–20000Hz |
| Driver Size | φ40mm |
| Battery Capacity | 300mAh 3.7V |
| Charging Port | Type-C |
| Charging Method | Cable |
| Charging Time | 1–2 hours |
| Playback Time | Approx. 25 hours |
| Material | ABS, Plastic |
| Headphone Pads Material | Synthetic Leather |
| Waterproof | Yes |
| With Microphone | Yes |
| Voice Assistant Built-in | Yes (Apple Siri Support, Google Assistant Support) |
| Control Button | Yes |
| Volume Control | Yes |
| Sound Isolating | Yes |
| Earcups Type | Sealed |
| Impedance Range | up to 32 Ω |
| Sensitivity | 110dB |
| Resistance | 32 Ω |
| Max Output | 30mW |
| Vocalism Principle | Dynamic |
| Communication | Wireless+Wired |
| Connectors | Type c |
| Function | For Internet Bar, for Video Game, Common Headphone, For Mobile Phone, For Office, For Study |
User Tips
No specific user tips from reviews or Q&A were provided for this product.
Warranty and Support
For detailed warranty information, technical support, or further assistance, please refer to the official Monster website or the complete user manual PDF. A PDF version of the user manual is available for download at this link.
