Sennheiser HD 490 PRO700286 · HD 490 PRO (standard, not PRO Plus) · wired- Nominal impedance
- 130 ohmThis one: 120 ohm
- Weight
- 260 gThis one: 240 g
HEADPHONES
Sennheiser HD 400 PRO
HD 400 PRO · wired · Sennheiser part 700047
- Acoustic design
- Open-back
- Wearing style
- Over-ear (circumaural), open-back wired studio headphones
- Nominal impedance
- 120 ohm
The HD 400 PRO (article 700047) is Sennheiser's open-back, around-ear wired studio headphone. It uses angled 120 Ω dynamic transducers with a polymer-blend diaphragm, velour ear pads and a detachable single-sided cable, and both a 3 m coiled and a 1.8 m straight cable come in the box. It weighs 240 g without the cable. Sennheiser lists a two-year warranty.
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THE ACTUAL PRODUCT
Compare with Sennheiser HD 490 PRO
Specifications checked 27 Sept 2026Manufacturer specifications, not a hands-on test.
The nearest checked headphones by key specifications, with what differs from the Sennheiser HD 400 PRO. The first matches the Compare button above.
Sennheiser HD 490 PRO700286 · HD 490 PRO (standard, not PRO Plus) · wired
Beyerdynamic DT 990 PRO 250 ohm459038 · 250 ohm · coiled cable- Nominal impedance
- 250 ohmThis one: 120 ohm
- Weight
- 250 gThis one: 240 g
Beyerdynamic DT 900 PRO X729906 · 48 ohm · black- Nominal impedance
- 48 ohmThis one: 120 ohm
- Weight
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Key strengths
Two cables come in the box — a 3 m coiled cable and a 1.8 m straight cable — plus a 3.5-to-6.3 mm adapter, so desk and studio setups are covered without buying accessories.
Angled 120-ohm dynamic transducers use a polymer-blend diaphragm, and the headphones weigh 240 g without the cable.
Ear pads and both cable types are listed as replaceable spare parts.
Before you buy
It uses an open acoustic principle, and Sennheiser publishes no ambient-noise attenuation figure for it.
The specification sheet gives 110 dB SPL at 1 kHz / 1 V RMS. A separate feature statement gives 120 dB SPL without a measurement reference, so the two figures cannot be treated as the same test. The transducer diameter is not stated.
The supplied cables use a 3.5 mm plug, with a 6.3 mm adapter included in the box.
Every specification. With its source.
Full specifications
Exact configuration: 700047 · HD 400 PRO · wired
21 specifications in 6 groups. Values are manufacturer specifications unless a row says “Measured result” or “Calculated from cited specifications”.
Design & fit
5 items
- Acoustic design
- Open-back
- Wearing style
- Over-ear (circumaural), open-back wired studio headphones
- Weight
- 240 g
Without cable, per the specification sheet and manual; the product page gives the same 240 g without stating a basis.
- Ear pads
- Velour; replaceable
- Serviceability
- Replaceable ear pads and components; ear pads, coiled cable and straight cable listed as spare partsSource
Connections & battery
6 items
- Wired / wireless connections
- Wired; detachable single-sided cable: 3 m coiled cable with 3.5 mm jack plug and a 1.8 m straight cable supplied, plus a 3.5-to-6.3 mm adapter
Replacement coiled and straight cables are listed as spare parts.
- Supplied plug and adapter
- 3.5 mm jack plug with 6.3 mm adapter
- Cable arrangement
- Detachable, single-sided cable; coiled 3 m and straight 1.8 m cables supplied
- Cable length
- 1.8 m
Supplied straight cable. A separate 3 m coiled cable is also supplied; the source does not specify whether its length is relaxed or extended.
- Battery life
- Not listed by the manufacturer
The retained exact sources do not explicitly establish battery life or that no battery is required for operation. Do not infer a not-applicable operating requirement from analogue/dynamic construction or a battery-included No row.
Source - Coiled cable rated length
- 3 m
Separate supplied coiled cable. The source states 3 m but does not establish its relaxed/extended measurement basis. A 1.8 m straight cable is also supplied.
Audio specifications
6 items
- Nominal impedance
- 120 ohm
- Voltage-referenced sound pressure level
- 110 dB SPL (1 kHz, 1 Vrms)
The specification sheet states 110 dB (1 kHz / 1 V RMS). The UK page technical table labels the same conditioned figure Max. sound pressure level; this record preserves the voltage-referenced claim without independently certifying a maximum. The separate 120 dB feature statement gives no reference and is not assumed to use these test conditions.
- Driver construction
- Angled 120-ohm dynamic transducers with a polymer-blend diaphragm
Sennheiser does not state the transducer diameter on the pages and documents read.
- Rated frequency range
- 6–38,000 Hz (−10 dB)
- Rated total harmonic distortion
- <0.05% at 1 kHz, 90 dB SPL
- Advertised SPL without stated reference
- 120 dB SPL
UK page feature statement. Frequency, input voltage/power and measurement reference are not stated; the 120 dB claim is not labelled maximum. Do not compare it numerically with the specifically conditioned 110 dB at1 kHz/1 Vrms claim or use it as a comparable sensitivity/maximum-output input.
Source
Calls & noise control
2 items
- Active noise cancellation
- Not listed by the manufacturer
The complete exact sources establish an open dynamic wired design but do not explicitly negate active noise cancellation. Open construction and omission of ANC do not establish a false capability.
- Microphone
- Not listed by the manufacturer
The complete exact sources list the headphone and accessories but do not explicitly establish absence of a microphone. An omitted microphone and a stereo headphone plug alone cannot become a sourced false capability.
In the box
1 item
- In the box
- HD 400 PRO headphones, 3 m coiled cable with 3.5 mm jack plug, 3.5 mm to 6.3 mm adapter, 1.8 m straight cable, quick guide, safety guide
Operating limits
1 item
- Operating temperature
- −15 °C to +55 °C
Relative humidity up to 90%.
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