Introduction
Thank you for choosing the HIFIMAN RE400 In-Ear Monitor Earphones. These earphones are designed to deliver high-fidelity audio with advanced ergonomics for a comfortable listening experience. This manual provides essential information on setting up, operating, maintaining, and troubleshooting your RE400 earphones.
Package Contents
Please check the package to ensure all items are present:
- HIFIMAN RE400 In-Ear Monitor Earphones
- Interchangeable Silicone Ear Tips (various sizes)
- Carrying Case
- User Manual (this document)

Image: HIFIMAN RE400 earphones with included accessories, including multiple ear tips and a protective carrying case.
Product Overview
The HIFIMAN RE400 earphones are engineered for superior sound quality and comfort. They feature an 8.5mm Titanium driver with a Neodymium magnet, ensuring precise audio reproduction. The cabling is made from Crystal and Copper, designed to maintain signal integrity. The advanced ergonomic design provides a secure and comfortable fit for extended listening sessions.

Image: Front view of the HIFIMAN RE400 in-ear monitor earphones, showcasing their compact design.

Image: Side view of the HIFIMAN RE400 earphones, highlighting their ergonomic shape.

Image: The HIFIMAN RE400 earphones connected to their 3.5mm audio jack, showing the cable design.
Setup
1. Connecting to an Audio Source
- Locate the 3.5mm audio jack on your audio device (smartphone, tablet, computer, MP3 player, etc.).
- Insert the 3.5mm plug of the RE400 earphones firmly into the audio jack until it clicks into place.

Image: A close-up of the durable 3.5mm audio jack, ready for connection to an audio device.
2. Fitting the Earphones
- Identify the left (L) and right (R) earphones. These are typically marked on the earphone housing or cable.
- Select the appropriate size of silicone ear tips from the included set. A good fit is crucial for sound quality and comfort. Experiment with different sizes to find the best seal for your ears.
- Gently insert each earphone into your ear canal. Adjust until you achieve a comfortable and secure fit, ensuring a good seal to maximize bass response and noise isolation.

Image: Close-up of the HIFIMAN RE400 earphones showing the 'L' and 'R' markings for proper ear placement.
Operating Instructions
The HIFIMAN RE400 earphones are designed for straightforward operation:
- Audio Playback: Once connected to your audio device, simply start playing your desired audio content.
- Volume Control: Adjust the volume directly from your connected audio device.
Maintenance and Care
To ensure the longevity and optimal performance of your HIFIMAN RE400 earphones, follow these care guidelines:
- Cleaning: Regularly clean the ear tips with a soft, damp cloth. Ensure they are completely dry before reattaching. You may also gently wipe the earphone housings with a dry, soft cloth.
- Cable Care: Avoid sharp bends, twists, or excessive pulling on the cable. When storing, coil the cable loosely to prevent tangling and damage.
- Storage: Store your earphones in the provided carrying case when not in use to protect them from dust, dirt, and physical damage.
- Avoid Extreme Conditions: Do not expose the earphones to extreme temperatures, humidity, or direct sunlight. Keep them away from liquids.
Troubleshooting
If you encounter any issues with your HIFIMAN RE400 earphones, please refer to the following common solutions:
- No Sound:
- Ensure the 3.5mm jack is fully inserted into your audio device.
- Check the volume level on your audio device.
- Test the earphones with a different audio device to rule out device-specific issues.
- Inspect the cable for any visible damage or breaks.
- Distorted Sound:
- Lower the volume on your audio device.
- Ensure the ear tips are clean and properly seated on the earphones.
- Check for any debris in the earphone nozzles.
- Uncomfortable Fit / Poor Noise Isolation:
- Experiment with different sizes of ear tips to find the best fit for your ear canals.
- Ensure the earphones are inserted correctly and creating a good seal.
If the issue persists, please contact HIFIMAN customer support for further assistance.
Specifications
| Model Name | RE-400 |
| Driver Type | Dynamic Driver |
| Driver Size | 8.5 mm |
| Impedance | 32 Ohms |
| Connectivity Technology | Wired |
| Headphones Jack | 3.5 mm Jack |
| Cable Material | Crystal and Copper |
| Item Weight | 4.2 ounces (0.26 Pounds) |
| Product Dimensions | 6.69 x 8.6 x 0.79 inches |
Official Product Video
Video: An official overview of the HIFIMAN RE400 In-Ear Monitor Earphones, detailing their features and design.
Warranty and Support
HIFIMAN products are sold through authorized retail partners to ensure high levels of service. Products not sold by authorized partners may not be verified as authentic and will not receive the HIFIMAN manufacturer's warranty or factory service. Please verify your purchase with an authorized HIFIMAN retail partner.
For specific warranty details or technical support, please refer to the warranty card included in your package or visit the official HIFIMAN website.





