Sennheiser CX 400BT True Wireless Owner Manual
Product overview
Charging case
- LED displays the charging process/charge status of the rechargeable battery of the charging case or of
the earbuds (when inserted into the charging case) - Input for USB-C connector for charging the rechargeable batteries
- LED button activates the LED display for 5 seconds
- Built-in rechargeable battery for charging the earbuds on the go
- Type plate
- Charging compartment for the left earbud L
- Magnetic holders
- Charging compartment for the right earbud R
- Charging contacts
Touch control panel- Changeable silicone ear adapters
- Left earbud L (secondary earbud, receives signals from the right earbud)
- Status LED
- Magnetic holders
- Charging contacts
- Microphones for phone calls
- Right earbud R (primary earbud, controls the Bluetooth connection to the smartphone and to the left
earbud) - Openings for acoustic optimization
- Built-in rechargeable battery
Touch control panelUsing the earphones
Information on the rechargeable battery, the charging process and the first use.The earbuds and the charging case each have a built-in rechargeable battery. The charging case allows you to store the earbuds safely at all times while they are being charged.Upon delivery, the rechargeable batteries of the earbuds and the charging case are in sleep mode and have to be woken up by connecting them to a power source once. Sennheiser recommends charging the earbuds and the charging case for a complete charging cycle without interruption before using for the first time.A complete charging cycle of the charging case and the earbuds takes about 1.5 hours. The quick charge function gives you approx. 1 hour of playback time after 15 minutes of charging.
Charging the rechargeable battery of the earbuds and the charging case
- Open the charging case by overcoming a slight magnetic resistance and insert the left earbud into the left charging compartment and the right earbud into the right charging compartment.
- Connect the USB-C connector of the USB cable to the USB-C socket of the charging case.
- Connect the USB-A connector to a corresponding socket of a USB power source (to be ordered separately). Make sure that the USB power source is connected to the power supply system.The rechargeable batteries of the earbuds and the charging case are being charged.
The LED of the charging case displays the charge status:
Care and maintenance of the earbuds/charging case
CAUTION
Liquids can damage the electronics of the product!
Liquids entering the housing of the product can cause a short-circuit and damage the electronics.
- Keep all liquids far away from the product.
- Do not use any solvents or cleansing agents.
- Clean the product only with a soft, dry cloth.
- You can clean the silicone ear adapters under lukewarm running water. Allow the ear adapters to dry at room temperature for at least 12 hours before putting them back on the earbuds.
- Clean the charging contacts on the earbuds and in the charging case from time to time using e.g. a cotton swab.
Replacing the ear adapters
For reasons of hygiene, you should replace your ear adapters from time to time. Spare ear adapters are available from your Sennheiser partner.
- Pull the ear adapter away from the in-ear sound tunnel.
- Mount the new ear adapter to the in-ear sound tunnel. Ensure that it locks into place.
Specifications
| Wearing style | true wireless stereo earphones |
| Ear coupling | ear-canal, closed-back |
| Frequency response | 5 Hz to 21 kHz |
| Transducer principle | dynamic |
| Transducer size | 7 mm |
| Sound pressure level (SPL) | 114 dB (1 kHz/0 dBFS) |
| THD (1 kHz, 94 dB SPL) | < 0.08 % |
| Microphone principle | MEMS |
| Microphone frequency response | 100 Hz to 10 kHz |
| Microphone pick-up pattern (speech) | 2-mic beamforming array |
| Power supply | built-in Lithium rechargeable batteries, 3.7 V earbuds: 54-60 mAh charging case: 400-420 mAh USB charging via USB-C socket of the charging case: 5 V , 600 mA |
| Operating time | 7 hrs with rechargeable battery of the earbud (test conditions: iPhone within 1 m distance, Bluetooth AAC codec, volume level 50 %, no EQ settings); 20 hrs with rechargeable battery of the charging case |
| Charging time of rechargeable batteries | approx. 1.5 hrs |
| Temperature range | operation: 0 to +40°C storage: –25 to +70°C |
| Relative humidity | operation: 10 to 80%, non condensing storage: 10 to 90% |
| Magnetic field strength | earbuds: 0.63 mT charging case: 101 mT |
| Weight | earbuds: approx. 6 g each charging case: approx. 37 g |
Bluetooth
| Version | Bluetooth 5.1 compatible, class 1, BLE |
| Transmission frequency | 2,402 MHz to 2,480 MHz |
| Modulation | GFSK, π/4 DQPSK, 8DPSK |
| Profiles | HSP, HFP, AVRCP, A2DP |
| Output power | 10 mW (max) |
| Codec | aptX®, AAC, SBC |
| Device name | CX 400BT TW LE-CX 400BT TW (Bluetooth Low Energy only) |
| Number of active connections | 1 |
Manufacturer Declarations
Warranty
Sennheiser electronic GmbH & Co. KG gives a warranty of 24 months on this product.For the current warranty conditions, please visit our website at www.sennheiser.com or contact your Sennheiser partner.
In compliance with the following requirements
- General Product Safety Directive (2001/95/EC)
- Compliant to Sound Pressure Limits according to country specific requirements
Trademarks
Sennheiser is a registered trade mark of Sennheiser electronic GmbH & Co. KG. Apple and the Apple logo are trademarks of Apple Inc., registered in the U.S. and other countries. App Store is a service mark of Apple Inc.Google Play and the Google Play logo are trademarks of Google LLC.The Bluetooth® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any use of such marks by Sennheiser electronic GmbH & Co. KG is under license. Qualcomm aptX is a product of Qualcomm Technologies International, Ltd. Qualcomm is a trademark of Qualcomm Incorporated, registered in the United States and other countries, used with permission.
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