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Sennheiser CX 400 II Precision Review | 93 Data compared

Avg. price: ~£20
Form factor: in-ear
Connectivity: wired
Battery life: N/A hours
Active noise cancellation (ANC): no

Sennheiser CX 400 II Precision review. Compare 93 technical specifications and user reviews to see how it ranks among headphones and if it is worth buying.

5.0

Good

4.3

Poor

7.7

Very good

0.2
Gaming
Score components:
35.0%
0.0
Audio latency
25.0%
0.0
Low-latency game mode
20.0%
1.0
Can be used as a headset
12.0%
0.0
Noise-canceling microphone
8.0%
0.0
Battery life
2.1
Travel
Score components:
28.0%
1.0
Active noise cancellation (ANC)
24.0%
0.0
Battery life
18.0%
10
Weight
16.0%
0.0
Multipoint support
14.0%
0.0
Ambient sound mode
0.2
Calls
Score components:
28.0%
0.0
Noise-canceling microphone
24.0%
1.0
Can be used as a headset
18.0%
0.0
Multipoint support
16.0%
0.0
Battery life
14.0%
0.0
Companion app
4.0
Workout
Score components:
28.0%
10
Weight
24.0%
1.0
Water resistance
20.0%
4.0
IP rating
16.0%
0.0
Battery life
12.0%
1.0
Can be used as a headset

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Verdict

The Sennheiser CX 400-II Precision is a wired in-ear headphone featuring high-end dynamic speaker systems with neodymium magnets, delivering a bass-driven yet natural sound reproduction across a 17 Hz to 22,000 Hz frequency response range. Key technical specifications include a low 16-ohm impedance, a sensitivity of 114 dB, and a 1.2-meter symmetrical cable ending in a 3.5 mm angled gold-plated jack. Its main strengths lie in its superior passive noise isolation, high-resolution musical detail, and extensive accessory package, which includes a cable clip, winder, and carrying pouch. However, some users have noted cons such as a midrange that can be overshadowed by the mid-bass, a lack of an inline microphone for calls, and concerns regarding long-term cable durability.

Technical Specifications of Sennheiser CX 400 II Precision

Overall score

5.0

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Popularity

What it is: An indicator based on the number of reviews received by the headphones.

When it matters: When you prefer headphones that have already been chosen and reviewed by many other users.

Sound

4.4

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Active noise cancellation (ANC)

What it is: Reduces background noise using active technology

When it matters: When blocking office, travel, or aircraft noise is a priority.

Importance: HIGH

Driver type

What it is: Type of speaker driver technology used

When it matters: When the underlying sound character and driver technology matter to you.

Importance: MEDIUM

dynamic

Driver size

What it is: Diameter of the speaker driver unit

When it matters: When you want extra hardware context behind how the headphones may handle bass weight, scale, or overall presentation.

Importance: MEDIUM

Number of drivers

What it is: Total number of speaker drivers per earcup

When it matters: When multi-driver designs are part of your buying criteria.

Importance: LOW

Lowest frequency

What it is: Lowest audio frequency the headphones can reproduce

When it matters: When deeper bass extension matters for your music or movie listening.

Importance: MEDIUM

Good value: <=10 Hz

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Calls & Controls

2.9

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Noise-canceling microphone

What it is: Built-in microphone reduces background noise during calls

When it matters: When you take calls in busy spaces and want your voice to stay clearer.

Importance: MEDIUM

N/A

Can be used as a headset

What it is: Shows whether the headphones can handle voice chat and calls in addition to normal audio playback.

When it matters: When one pair needs to cover music, calls, meetings, and gaming chat.

Importance: MEDIUM

Number of microphones

What it is: Total number of built-in microphones

When it matters: When call pickup quality and beamforming support matter to you.

Importance: LOW

Good value: >=2

Boom microphone

What it is: Includes detachable boom microphone for voice clarity

When it matters: When you need stronger voice clarity for gaming, streaming, or work calls.

Importance: LOW

N/A

Microphone SNR

What it is: Signal-to-noise ratio of the microphone

When it matters: When call clarity matters and you want your voice picked up more cleanly instead of buried in background hiss.

Importance: LOW

Good value: >80 dB

N/A

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Connectivity

6.2

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Connectivity

What it is: Available connection methods (wired, wireless, Bluetooth, etc.)

When it matters: When the headphones need to match how you listen across wired and wireless devices.

Importance: HIGH

Bluetooth version

What it is: Version of Bluetooth technology supported

When it matters: When wireless stability, efficiency, and feature support matter more than treating Bluetooth as a box-check spec.

Importance: MEDIUM

Good value: >=5.0

N/A

Maximum Bluetooth range

What it is: Maximum wireless operating distance from source device

When it matters: When you move around rooms and want fewer dropouts from your source device.

Importance: LOW

Good value: >=10 m

N/A

Audio latency

What it is: Delay between audio and video in wireless mode

When it matters: When you watch video or play games and need sound to stay in sync.

Importance: HIGH

Good value: <60 ms

N/A

Multipoint support

What it is: Supports simultaneous connections to multiple devices

When it matters: When you switch often between a phone and a laptop during the day.

Importance: MEDIUM

N/A

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Features

2.7

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Ambient sound mode

What it is: Allows external sounds to pass through for awareness

When it matters: When you need to stay aware of traffic, voices, or announcements.

Importance: MEDIUM

N/A

EQ support

What it is: Allows customization of sound profile via equalizer

When it matters: When the stock tuning is not enough and you want to shape bass, mids, or treble to match your taste.

Importance: MEDIUM

Companion app

What it is: Dedicated mobile app for customization and updates

When it matters: When software customization, updates, and extra controls matter.

Importance: MEDIUM

N/A

Adjustable ANC levels

What it is: Allows adjustment of noise cancellation intensity levels

When it matters: When you move between quiet rooms, offices, streets, and public transport and do not want one ANC setting for every situation.

Importance: LOW

Good value: >=4

N/A

Voice assistant support

What it is: Compatible with voice assistants like Siri, Alexa, or Google Assistant

When it matters: When hands-free control is part of your daily routine.

Importance: LOW

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Battery

1.0

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Battery life

What it is: Playback time on a single charge

When it matters: When you commute, travel, or work long shifts and do not want charging breaks to interrupt listening.

Importance: HIGH

Good value: >45 hours

N/A

Battery life with ANC

What it is: Playback time with active noise cancellation enabled

When it matters: When you plan to keep noise cancellation on for most of the day.

Importance: HIGH

Good value: >40 hours

N/A

Charging time

What it is: Time required for a full battery charge

When it matters: When you often need the headphones ready again after short breaks.

Importance: MEDIUM

Good value: <=2 hours

N/A

Quick charge

What it is: Provides quick playback time with short charging period

When it matters: When a short top-up needs to deliver useful playback before you leave.

Importance: MEDIUM

N/A

Battery capacity

What it is: Total energy storage of the internal battery

When it matters: When you are estimating how much battery headroom the design may have before relying only on the official runtime claim.

Importance: MEDIUM

Good value: >=720 mAh

N/A

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Design

8.3

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Brand name

What it is: The manufacturer or brand of the product.

When it matters: When you prefer a specific ecosystem, support network, or design philosophy.

Importance: MEDIUM

Sennheiser

Form factor

What it is: Overall design type of the headphones (over-ear, on-ear, in-ear, etc.)

When it matters: When comfort, portability, and isolation depend on the overall headphone style.

Importance: HIGH

in-ear

Weight

What it is: Total weight of the headphones

When it matters: When long listening sessions make wearing comfort more important.

Importance: MEDIUM

Good value: <150 g

Acoustic design

What it is: Type of acoustic design (open-back, closed-back, semi-open)

When it matters: When you need the right balance of isolation, leakage, and soundstage.

Importance: HIGH

closed-back

Clamp force

What it is: Amount of clamping pressure applied to the head

When it matters: When comfort and fit security matter during long sessions.

Importance: MEDIUM

N/A

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Sennheiser CX 400 II Precision vs the average headphone

Why is Sennheiser CX 400 II Precision better than the average headphone?

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94.5% lower weight
Sennheiser CX 400 II Precision is lighter than the average headphone (12 g vs 218 g). The average pair of headphones weighs 218 g.
What it is: Total weight of the headphones
When it matters: When long listening sessions make wearing comfort more important.
Importance: MEDIUM
Good value: <150 g
Sennheiser CX 400 II Precision is lighter than the average headphone (12 g vs 218 g). The average pair of headphones weighs 218 g.12 g vs 218 g
12 dB/mW higher sensitivity
Sennheiser CX 400 II Precision has a higher sensitivity than the average headphone (114 dB/mW vs 102 dB/mW). The average headphones have sensitivity of 102 dB/mW.
What it is: Sound pressure output level per unit of input power
When it matters: When you plan to use weaker sources like phones, handhelds, or entry-level dongles and still want enough volume.
Importance: MEDIUM
Good value: >=106 dB/mW
Sennheiser CX 400 II Precision has a higher sensitivity than the average headphone (114 dB/mW vs 102 dB/mW). The average headphones have sensitivity of 102 dB/mW.114 dB/mW vs 102 dB/mW
Direct 3.5 mm plug
Sennheiser CX 400 II Precision includes a direct 3.5 mm plug, the average headphone does not. 38.8% of headphones have a 3.5 mm male connector.
What it is: Shows whether the headphones end in a built-in 3.5 mm male plug instead of relying on a separate detachable cable.
When it matters: When direct wired compatibility with older devices or adapters matters.
Importance: MEDIUM
Sennheiser CX 400 II Precision includes a direct 3.5 mm plug, the average headphone does not. 38.8% of headphones have a 3.5 mm male connector.
In-line controls
Sennheiser CX 400 II Precision includes in-line controls, the average headphone does not. 36.4% of headphones support in-line controls.
What it is: Controls available on in-line remote of wired cable
When it matters: When your wired setup depends on cable-mounted buttons or call controls.
Importance: LOW
Sennheiser CX 400 II Precision includes in-line controls, the average headphone does not. 36.4% of headphones support in-line controls.
0.2 % lower distortion
Sennheiser CX 400 II Precision has a lower total harmonic distortion than the average headphone (0.1 % vs 0.3 %). The average headphones have total harmonic distortion of 0.3 %.
What it is: Percentage of harmonic distortion in audio output
When it matters: When cleaner sound reproduction matters at louder volumes.
Importance: LOW
Good value: <=1%
Sennheiser CX 400 II Precision has a lower total harmonic distortion than the average headphone (0.1 % vs 0.3 %). The average headphones have total harmonic distortion of 0.3 %.0.1 % vs 0.3 %
4.5x cheaper
Sennheiser CX 400 II Precision is cheaper than the average headphone (£20 vs £90).
Sennheiser CX 400 II Precision is cheaper than the average headphone (£20 vs £90).£20 vs £90
2,000 Hz higher treble extension
Sennheiser CX 400 II Precision has a higher highest frequency than the average headphone (22,000 Hz vs 20,000 Hz). The average headphones reach a highest frequency of 20,000 Hz.
What it is: Highest audio frequency the headphones can reproduce
When it matters: When treble extension and overall frequency reach matter to you.
Importance: MEDIUM
Good value: >=24000 Hz
Sennheiser CX 400 II Precision has a higher highest frequency than the average headphone (22,000 Hz vs 20,000 Hz). The average headphones reach a highest frequency of 20,000 Hz.22000 Hz vs 20000 Hz
11 dB SPL higher sound pressure level
Sennheiser CX 400 II Precision has a higher sound pressure level than the average headphone (114 dB SPL vs 103 dB SPL). The average headphones reach a sound pressure level of 103 dB SPL.
What it is: Output loudness level of the headphones, usually measured in dB. It helps compare how loud a model can play under similar conditions.
When it matters: When you need a rough idea of how loud the headphones can get before you pair them with a weaker source.
Importance: LOW
Good value: >=108 dB SPL
Sennheiser CX 400 II Precision has a higher sound pressure level than the average headphone (114 dB SPL vs 103 dB SPL). The average headphones reach a sound pressure level of 103 dB SPL.114 dB SPL vs 103 dB SPL
94.5% lower weight
Sennheiser CX 400 II Precision is lighter than the average headphone (12 g vs 218 g). The average pair of headphones weighs 218 g.
12 dB/mW higher sensitivity
Sennheiser CX 400 II Precision has a higher sensitivity than the average headphone (114 dB/mW vs 102 dB/mW). The average headphones have sensitivity of 102 dB/mW.
0.2 % lower distortion
Sennheiser CX 400 II Precision has a lower total harmonic distortion than the average headphone (0.1 % vs 0.3 %). The average headphones have total harmonic distortion of 0.3 %.
2,000 Hz higher treble extension
Sennheiser CX 400 II Precision has a higher highest frequency than the average headphone (22,000 Hz vs 20,000 Hz). The average headphones reach a highest frequency of 20,000 Hz.
11 dB SPL higher sound pressure level
Sennheiser CX 400 II Precision has a higher sound pressure level than the average headphone (114 dB SPL vs 103 dB SPL). The average headphones reach a sound pressure level of 103 dB SPL.
Direct 3.5 mm plug
Sennheiser CX 400 II Precision includes a direct 3.5 mm plug, the average headphone does not. 38.8% of headphones have a 3.5 mm male connector.
In-line controls
Sennheiser CX 400 II Precision includes in-line controls, the average headphone does not. 36.4% of headphones support in-line controls.

Calls & Controls

Why is Sennheiser CX 400 II Precision worse than the average headphone?

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Fixed cable
Sennheiser CX 400 II Precision has a fixed cable, while the average headphone has a detachable one. 62% of headphones have a detachable cable.
31 mm smaller driver size
Sennheiser CX 400 II Precision has smaller driver size than the average headphone (9 mm vs 40 mm). The average headphones use a driver size of 40 mm.
Not headset-ready
Sennheiser CX 400 II Precision is not headset-ready, while the average headphone is. 84.7% of headphones can be used as headsets.
1 fewer microphones
Sennheiser CX 400 II Precision has fewer microphones than the average headphone (0 vs 1). The average headphones have 1 microphones.
No voice assistant support
Sennheiser CX 400 II Precision does not support voice assistants, the average headphone does. 60.8% of headphones support voice assistants.
8 years older release date
Sennheiser CX 400 II Precision was released earlier than the average headphone (2,009 vs 2,017). The average headphones were released in 2,017.
February 2009
31 mm smaller driver size
Sennheiser CX 400 II Precision has smaller driver size than the average headphone (9 mm vs 40 mm). The average headphones use a driver size of 40 mm.
What it is: Diameter of the speaker driver unit
When it matters: When you want extra hardware context behind how the headphones may handle bass weight, scale, or overall presentation.
Importance: MEDIUM
Sennheiser CX 400 II Precision has smaller driver size than the average headphone (9 mm vs 40 mm). The average headphones use a driver size of 40 mm.9 mm vs 40 mm
No voice assistant support
Sennheiser CX 400 II Precision does not support voice assistants, the average headphone does. 60.8% of headphones support voice assistants.
What it is: Compatible with voice assistants like Siri, Alexa, or Google Assistant
When it matters: When hands-free control is part of your daily routine.
Importance: LOW
Sennheiser CX 400 II Precision does not support voice assistants, the average headphone does. 60.8% of headphones support voice assistants.
Fixed cable
Sennheiser CX 400 II Precision has a fixed cable, while the average headphone has a detachable one. 62% of headphones have a detachable cable.
What it is: Cable can be removed or replaced
When it matters: When you care about easier cable replacement, simpler storage, or the option to swap to shorter, longer, or upgraded leads.
Importance: MEDIUM
Sennheiser CX 400 II Precision has a fixed cable, while the average headphone has a detachable one. 62% of headphones have a detachable cable.
Not headset-ready
Sennheiser CX 400 II Precision is not headset-ready, while the average headphone is. 84.7% of headphones can be used as headsets.
What it is: Shows whether the headphones can handle voice chat and calls in addition to normal audio playback.
When it matters: When one pair needs to cover music, calls, meetings, and gaming chat.
Importance: MEDIUM
Sennheiser CX 400 II Precision is not headset-ready, while the average headphone is. 84.7% of headphones can be used as headsets.
1 fewer microphones
Sennheiser CX 400 II Precision has fewer microphones than the average headphone (0 vs 1). The average headphones have 1 microphones.
What it is: Total number of built-in microphones
When it matters: When call pickup quality and beamforming support matter to you.
Importance: LOW
Good value: >=2
Sennheiser CX 400 II Precision has fewer microphones than the average headphone (0 vs 1). The average headphones have 1 microphones.0 vs 1
8 years older release date
Sennheiser CX 400 II Precision was released earlier than the average headphone (2,009 vs 2,017). The average headphones were released in 2,017.
February 2009
What it is: Official release or launch date of the model
When it matters: When you want a newer model for fresher features, longer support life, or simply to avoid buying into an older generation.
Importance: LOW
Good value: >=2020
Sennheiser CX 400 II Precision was released earlier than the average headphone (2,009 vs 2,017). The average headphones were released in 2,017.2009 vs 2017
4.5% lower user score
Sennheiser CX 400 II Precision has a lower user score than the average headphone (7.66 vs 8.000).
What it is: A rating that combines user reviews and the total number of reviews received by the headphones.
When it matters: When you want to understand how headphones perform in real listening and how reliable they are in terms of comfort, audio quality, battery life, and long-term use.
Sennheiser CX 400 II Precision has a lower user score than the average headphone (7.66 vs 8.000).7.66 vs 8
3.6% worse value for money
Sennheiser CX 400 II Precision has worse value for money than the average headphone (6.50 vs 6.736).
What it is: An indicator that combines the headphones' overall rating with their cost.
When it matters: When you are looking for headphones that offer a strong balance of performance, features, and price.
Sennheiser CX 400 II Precision has worse value for money than the average headphone (6.50 vs 6.736).6.5 vs 6.74

Calls & Controls

Graphic comparison of Sennheiser CX 400 II Precision and

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Third-party reviews

United Kingdom

United States

(Reviews last updated: June 2026)

What customers like about Sennheiser CX 400 II Precision?

Punchy, bass-driven sound quality that is impressive for the price range
Generous accessory bundle including a carrying pouch, cable winder, and various ear tip sizes
Effective passive noise isolation due to a snug in-ear fit
Lightweight and comfortable design suitable for long listening sessions
Integrated manual volume control slider on the cable for convenience
Excellent value for money as an upgrade over stock earbuds

What customers dislike about Sennheiser CX 400 II Precision?

Durability concerns, with reports of cable failure or one earbud stopping after several months
Mids can be overshadowed by the prominent bass response
The volume slider is sensitive and can be accidentally moved by clothing
Cable noise (microphonics) can be distracting during active movement
Symmetrical cable design lacks the flexibility of asymmetrical 'J-cord' styles
Bass-heavy profile may not suit audiophiles seeking a neutral sound

Expert reviews

reference-audio-analyzer.pro

[Undated Technical Report]

Sennheiser CX-400 II Technical Report and Measurement

The Sennheiser CX-400 II is a low-impedance, closed-back, in-ear headphone model evaluated through a simplified entry-level audio analysis report. According to the measurement data, the headphones feature a voltage sensitivity of 126.09 dB/V SPL, an average impedance of 19.17 ohms, and a power sensitivity of 108.91 dB/mW SPL. While the testing highlights that the frequency response...Read more

head-fi.org

05/05/2010

Sennheiser CX 400-II Stereo Ear-Canal Headphones - Black [Head-Fi]

The Sennheiser CX 400-II is a durable, entry-level, wired in-ear monitor praised for its comfortable design, excellent passive noise isolation, and a generous accessory package that includes multiple ear tip options and a carrying case. Sonically, the earphones deliver a warm, robust sound signature characterized by a powerful, controlled bass and clear mids, making them suitable...Read more

totallydubbed.net

29/03/2012

Sennheiser CX 400-II Review - Totally Dubbed

In the Totally Dubbed Sennheiser CX 400-II review, the earphones received a high final rating of 9/10 due to their excellent value for money at a purchase price of £18. The reviewer highlighted several major pros, emphasizing their exceptional comfort (rated 10/10) and small size, which allows them to get "lost" in the ears and enables users to sleep while wearing them. Additional...Read more

headset.net

06/04/2026

Sennheiser CX 400-II Precision Stereo In-Ear Headphones Review: Would you also like to see current Sennheiser alternatives that are now considered suc...

The Sennheiser CX 400-II Precision wired in-ear headphones offer a high-quality audio experience with an effective noise-isolating design that seals out environmental distractions. They feature a 3.5 mm jack, a 1.2-meter cable, and an integrated inline volume slider, making them highly compatible with multiple devices. Sound performance is remarkably detailed across all frequencies,...Read more

connect.de

25/09/2009

Sennheiser CX 400 II Headphones - Connect

The Sennheiser CX 400 II is a €70 in-ear headphone package that offers a rich selection of included accessories. The bundle features a transport pouch, a cable clip, a cable winder, six different ear adapter pairs, and an integrated volume slider that functions as a fine-tuner rather than covering the entire volume range. During the sound test, the headphones impressed with a rich,...Read more

hifitest.de

02/09/2009

Sennheiser CX400II In-Ear Headphones Review

The HifiTest review highlights the Sennheiser CX400II as a highly capable, compact pair of in-ear headphones priced at around 70 Euros. The reviewer notes several prominent pros, starting with the generous inclusion of six pairs of ear tips, which makes it quick and effortless for users to find the right fit for their ears. Another practical design choice is the included shirt clip...Read more

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