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Two white in-ear buds and matching charging case on a plain surface

Sennheiser

Sennheiser CX400TW1 White in-ear headphones

SKU CH-V1HN-4S90A MPN CX400TW1 White

True wireless in-ear headphones with 7 mm dynamic drivers, Bluetooth 5.1, aptX support and up to 20 hours total playtime

  • TypeIn-Ear
  • ColorWhite
  • Driver Unit7mm dynamic driver
  • Frequency Response5Hz-21KHz
  • THD<0.08% (1kHz / 94dB)
  • Power SupplyUSB charging via USB-C socket at charging case
  • Superior sound from 7mm dynamic drivers with built-in equalizer
  • Up to 20 hours total playtime with charging case
  • Bluetooth 5.1 with SBC, AAC and aptX codec support
  • Customisable touch controls for music, calls and voice assistant
  • 5 hour full charge, 10 minutes gives 1 hour playtime

True Wireless In-Ear Headphones

The Sennheiser CX 400BT True Wireless are Bluetooth 5.1 in-ear headphones built for listeners who want high-fidelity audio without cables. They use 7mm dynamic drivers and support SBC, AAC and aptX codecs for broad device compatibility.

Charging Case and Touch Controls

Each earbud weighs 6g and the white charging case weighs 37g, holding a 420mAh battery that extends total playtime to 20 hours. A USB-C socket on the case provides a full charge in 1.5 hours, while ten minutes of charging adds one hour of listening. Customisable touch surfaces handle music, calls and voice assistant commands.

Compatibility and Fit Check

Verify that your source device supports Bluetooth 5.1 and at least one of the listed codecs for best performance. The ear-canal coupling relies on a secure seal, so buyers who cannot achieve a comfortable fit with in-ear designs should consider a different form factor.

Highlights

  • Superior sound from 7mm dynamic drivers with built-in equalizer
  • Up to 20 hours total playtime with charging case
  • Bluetooth 5.1 with SBC, AAC and aptX codec support
  • Customisable touch controls for music, calls and voice assistant
  • 5 hour full charge, 10 minutes gives 1 hour playtime

Specifications

BrandSennheiser
SeriesCX 400BT True Wireless
ModelCX400TW1 White
Part Number508901
TypeIn-Ear
ColorWhite
Driver Unit7mm dynamic driver
Frequency Response5Hz-21KHz
THD<0.08% (1kHz / 94dB)
Power SupplyUSB charging via USB-C socket at charging case
Sensitivity107 dB SPL (1 kHz / 1 mW)
ConnectorYes
Ear CouplingEar canal
Weight6g (single earbud) / 37g (charging case)
Wireless TypeBluetooth 5.1
Profiles: A2DP, AVRCP, HSP, HFP
Codecs: SBC, AAC, aptX
BatteryBattery type:
Built-in Lithium-Ion rechargeable batteries
left/right earbud: 55 mAh, charging case: 420 mAh
Charging time:
Approx. 1.5 hrs for fully charged
After 10min charging 1 hrs music playtime
After 60min charging 5 hrs music playtime
Operating TimeUp to 7 hrs music playtime with earbuds
Up to 20 hrs music playtime with charging case
Microphone Frequency Response100Hz-10KHz
FeaturesSuperior Sound
7mm dynamic drivers and built-in equalizer
Customizable touch controls
Fully adaptable controls for music, calls and voice assistant
Codec Support
SBC, AAC and aptX: Wide range of Bluetooth audio codec support
Battery life
Up to 20h hours music playtime
Ergonomic design
Optimal comfort and secure fit with 4 ear adapter sizes
Voice Assistant Support
Enjoy speech optimized calls and voice assistance
Package ContentsCX 400BT True Wireless 2 earbuds
Charging case
USB-C charging cable
Silicone ear adapter sets (in size XS/S/M/L)
Shipping weight0.20 kg
Package size168 × 112 × 46 mm

Questions about this item

What Bluetooth version does the CX400TW1 use, and what codecs are supported?

The earbuds use Bluetooth 5.1 and support SBC, AAC and aptX codecs for wide device compatibility.

What are the dimensions and weight of the charging case?

The charging case weighs 37g and houses a 420 mAh battery; individual earbuds weigh 6g each.

How do I pair the earbuds for the first time, and what step is often missed?

Remove both earbuds from the case to enter pairing mode automatically, then select "CX 400BT" in your device's Bluetooth menu.

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