CX 400BT True Wireless True wireless stereo earphones Model: CX400TW1, CX400TW1 R, CX400TW1 L, CX400TW1 C Instruction manual Use the search function, the navigation (left) or the following links: Start “Product overview” “Getting started” “Using the earphones” “FAQ/If a problem occurs ...” “Specifications” Sennheiser electronic GmbH & Co. KG Am Labor 1 30900 Wedemark Germany www.sennheiser.
Important safety instructions Important safety instructions ▷ Read this instruction manual carefully and completely before using the product. ▷ Always include this instruction manual when passing the product on to third parties. ▷ Do not use the product if it is obviously defective or makes loud, unusual (whistling or beeping) noise. ▷ Only use the product in environments where Bluetooth® wireless transmission is permitted.
Important safety instructions Only use rechargeable batteries and chargers recommended by Sennheiser. Only charge the product / rechargeable batteries at ambient temperatures between 10 °C to 40 °C/50 °F to 104 °F. Do not heat the product / rechargeable batteries above 70 °C/140 °F. Avoid exposure to sunlight and do not throw the product / rechargeable batteries into fire. When not using the product / rechargeable batteries for extended periods of time, charge them regularly (about every three months).
Package contents Package contents Earbud R for right ear (CX400TW1 R) and earbud L for left ear (CX400TW1 L) Charging case with built-in rechargeable battery for the earbuds (CX400TW1 C) USB charging cable with USB-C and USB-A connector, approx. 0.25 m Silicone ear adapters (size XS, S, M (pre-mounted to the earbuds) and L) Quick guide Safety guide Online you can find: • this detailed instruction manual and additional information (www.sennheiser.
Product overview Product overview Charging case CX400TW1 C 7 8 6 9 1 2 3 4 5 7 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 fo
Product overview Earphones CX400TW1 R and CX400TW1 L 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 6 | CX 400BT True Wireless
Product overview Overview of the LED indications of the charging case When a USB cable is connected, the LED of the charging case permanently displays the charging process: Charging case Charging case WITH WITHOUT earbuds earbuds inserted inserted LED pulses yellow ... earbuds and charging case are being charged ... charging case is being charged lights up green ... earbuds and charging case are fully charged ... charging case is fully charged flashes red ...
Product overview Charging case Charging case WITH WITHOUT earbuds earbuds inserted inserted LED lights up green ... earbuds are fully charged and the charging case can still charge at least one complete cycle pulses yellow ... earbuds are being charged via the rechargeable bat– tery of the charging case lights up yellow ... earbuds are fully charged, the charging case cannot charge another complete cycle lights up red ... rechargeable bat...
Product overview LED Meaning; the earbuds... flashes red-blue for approx. 1 ... are in Bluetooth pairing mode minute 3x flashes blue 3x ... Bluetooth pairing or earbud pairing successful 3x flashes red 3x ... Bluetooth pairing or earbud pairing failed lights up blue ... are connected to a device via Bluetooth (primary earbud (R) is connected to the smartphone, secondary earbud (L) is connected to the primary earbud (R)) lights up red ...
Product overview 10 | CX 400BT True Wireless Voice prompt Meaning/earbuds... “Recharge headset” ... Rechargeable battery is almost empty. Recharge the rechargeable battery. “Call rejected” ... incoming call rejected “Call ended” ... call ended “Volume min” ... volume set to minimum “Volume max” ...
Getting started Getting started 1. Waking up the earbuds and the charging case and charging the rechargeable batteries R L USB-C USB-A 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. ▷ Insert the earbuds into the charging case. ▷ Connect the USB-C cable to the charging case and to a USB power source (> 14).
Getting started ▷ You can choose between 4 different ear adapters in size XS, S, M and L (> 20). 1 Left Right L R ▷ Assign the right earbud to your right ear and the left earbud to your left ear. ▷ Insert the earbuds at a slight angle into the ears and twist them slightly into the ear canal so that they sit comfortably and snugly in the ear canal. 3. Connecting the earphones to a Bluetooth device “Pairing“ L R 3s Connect the earphones to your smartphone via Bluetooth (> 16). 4.
Using the earphones Using 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. Rechargeable battery Operating time with fully charged rechargeable batteries Earbuds approx.
Using the earphones Charging the rechargeable battery of the earbuds and the charging case 1 R L 2 3 USB-C USB-A 1. 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. The earbuds are magnetically pulled into the charging compartments. 2. Connect the USB-C connector of the USB cable to the USB-C socket of the charging case. 3.
Using the earphones Connecting the earphones to a Bluetooth device To be able to use the Bluetooth wireless connection, you must register both devices (earphones and e.g. smartphone) via the device settings of your smartphone. This process is called pairing. If operation differs from the steps mentioned, also refer to the instruction manual of the Bluetooth device you are using. When you switch on the earphones for the first time after initial charging, they automatically switch to pairing mode.
Using the earphones The right and the left earbud also use a Bluetooth wireless connection. Both earbuds are paired with each other upon delivery. If you are using a different earbud (e.g. a spare earbud), the two earbuds must also be paired with each other (> 17). Pairing the earphones with a Bluetooth device 1 2 “Pairing“ max. 1 m/40 inch 3s 3 4 ************ “Pairing successful“ ********* CX 400BT TW 3x ON 1. Take both earbuds out of the charging case and insert them into your ears (> 20).
Using the earphones Switching the connection to paired Bluetooth devices/“Connections” To selectively switch the audio connection to paired Bluetooth devices using the “Connections” function, you require the Smart Control app (> 19). ▷ In the Smart Control app, tap “Connections”. The list of Bluetooth devices paired with the earphones appears. ▷ From the list, select the paired device to which you want to connect the earphones. Make sure that the desired device is switched on and Bluetooth is activated.
Using the earphones 4. Simultaneously touch and hold the right and the left touch control panel for 10 seconds until you hear the voice prompt “Pairing” and a beep. The LEDs of the earbuds flash green and red. The earbuds are in earbud pairing mode. If pairing was successful, you hear the voice prompt “Pairing successful” and the LEDs of the earbuds flash blue 3x. ▷ Now pair the earbuds with your Bluetooth device (> 16). 1 2 USB-C USB-A Bluetooth off 3 L R 4 “Pairing“ “Pairing successful“ max.
Using the earphones Installing the Smart Control app To make full use of all the settings and functions of the headphones, you need to have the free Sennheiser Smart Control app installed on your smartphone. Download the app from the App Store or Google Play and install it on your smartphone. Alternatively, you can use your smartphone to scan the following QR code or to call up the following Internet site: www.sennheiser.
Using the earphones Selecting suitable ear adapters for optimum fit of the earbuds XS S M L Click The perceived sound quality including bass performance and the best possible noise cancellation of the earphones depends to a large extent on the correct fit of the earbuds in the ear. ▷ 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.
Using the earphones Switching the earphones on WARNING Danger of hearing damage due to high volume levels! Listening at high volume levels can lead to permanent hearing defects. ▷ Before putting the headphones on, adjust the volume to a low level (> 22). ▷ Do not continuously expose yourself to high volume levels. “Power On“ L “Connected“ ▷ Take both earbuds out of the charging case and insert them into your ears (> 20).
Using the earphones ▷ Insert the earbuds into the charging case to switch them off. As soon as the earbuds are inserted into the charging case, they switch off and are being charged (> 14). You can also switch off the earbuds manually (idle mode) via the Smart Control app. The earbuds automatically switch to idle mode if no paired Bluetooth device can be found within 15 minutes.
Using the earphones Using the voice assistant/voice dialing ▷ Tap the touch control panel of the right earbud 1x. The available voice assistant of your smartphone is activated (*depending on the system or app on your smartphone: Siri, Google Assistant, ...). ▷ Ask the voice assistant your question or make a request. To cancel the voice assistant/voice dialing: ▷ Tap the touch control panel of the right or left earbud 1x. ON/OFF Siri, Google Assistant ...
Using the earphones Left touch control panel Tap 2x Function Plays the previous track in the playlist Playing the next track ▷ Tap the touch control panel of the right earbud 2x. Right touch control panel Tap 2x Function Plays the next track in the playlist Making calls using the earphones The call functions are only available when the earphones and the smartphone are connected via Bluetooth. Some smartphones and telephony apps (e.g.
Using the earphones Right or left touch control panel Function Tap 1x Accepts a call Tap 1x Ends a call Voice prompt “Call ended” Tap 2x Rejects a call Voice prompt “Call rejected” Tap 1x Accepts an incoming call and ends the active call Tap 2x Rejects an incoming call and continues the active call Using the Auto Call function If you take the paired earbuds out of the charging case during an incoming call, the call is automatically accepted and you can use the earbuds directly for making calls.
Using the earphones Charging case Charging case WITH WITHOUT earbuds earbuds inserted inserted LED 26 | CX 400BT True Wireless lights up green ... earbuds are fully charged and the charging case can still charge at least one complete cycle pulses yellow ... earbuds are being charged via the rechargeable bat– tery of the charging case lights up yellow ... earbuds are fully charged, the charging case cannot charge another complete cycle lights up red ... rechargeable bat...
Using the earphones Adjusting sound effects/the equalizer To be able to use the sound effects/equalizer, you require the Smart Control app (> 19). ▷ In the Smart Control app, select the desired sound effects via the equalizer. You can use predefined presets or define your own settings. The sound effects are stored in the earphones. These sound settings are active even without using the Smart Control app, i.e. when you are using a different Bluetooth device.
Using the earphones Storing or transporting the earphones in the charging case Store the earphones in the charging case to prevent damage to the earphones when you are not using or transporting them. The earphones are automatically charged in the charging case so you always have the full battery life to work with. ▷ 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.
Care and maintenance of the earbuds/charging case 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.
Care and maintenance of the earbuds/charging case Information on the built-in rechargeable battery Sennheiser ensures and guarantees that the rechargeable battery performs at its optimum upon purchase of the product. If, upon purchase or within the warranty period, you suspect that the rechargeable battery is obviously defective or if a charging error/battery error is displayed (> 7), stop using the product, disconnect it from the power supply system and contact your Sennheiser partner.
FAQ/If a problem occurs ... FAQ/If a problem occurs ... Current list of frequently asked questions (FAQ) Visit the CX 400BT True Wireless product page at www.sennheiser.com There you will find a current list of frequently asked questions (FAQ) and suggested solutions. Your question has not been answered or the problem persists? If a problem occurs that is not listed in the FAQ section or if the problem cannot be solved with the proposed solutions, please contact your Sennheiser partner for assistance.
FAQ/If a problem occurs ... L R 5s Resetting the earphones to the factory default settings If the function of the earphones is disturbed and a reset (> 31) does not improve, reset the earphones to the factory default settings. This deletes, among other things, all pairing settings. The Smart Control App allows you to reset the earphones to the factory default settings via the settings menu.
Specifications Specifications CX 400BT True Wireless Model: CX400TW1, CX400TW1 C, CX400TW1 L, CX400TW1 R 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.
Specifications 34 | CX 400BT True Wireless Device name CX 400BT TW LE-CX 400BT TW (Bluetooth Low Energy only) Number of active connections 1
Manufacturer Declarations 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.
Manufacturer Declarations aptX is a trademark of Qualcomm Technologies International, Ltd., registered in the United States and other countries, used with permission. Other product and company names mentioned in the user documentation may be the trademarks or registered trademarks of their respective holders.
