Sennheiser IE400 PRO Review









IE400 Pro: Transparent and Musical



Sennheiser Electronic GmbH & Co. is a German audio company founded in Wedemark (Germany) in 1945, which specialized in the development and production of a wide range of hi-fi products, such as in-ear monitors, headphones, microphones, telephone accessories and aviation headsets for personal, professional and business applications.

The Sennheiser IE400 PRO that I will now review for you belongs to the new IE PRO Series product lineup along with the IE40 PRO and IE500 PRO and features the new developed 7mm wideband transducer.




I would like to thank Sennheiser and Metan Teknik A.Ş. for providing me this sample for review purposes. I am not affiliated with Sennheiser or METAN Teknik A.Ş. beyond this review and these words reflect my true and unaltered opinions about the product. 


Some Web & Social Media Links:



The actual price for the Senneheiser IE400 PRO is 349,95 USD.


Package and Accessories:

The Sennheiser IE400 Pro is coming in a rectangular box which is, which is wrapped with a cardboard that is featuring the visual of the IE400 Pro and some brandings/details about it.

The main box is in black and the top cover features the Sennheiser Logo.

This box is including the following contents/accessories; 

  • 1 pair x Sennheiser IE400 Pro In-Ear Monitor
  • 1 pcs x Detachable Cable with “patented cable duct”
  • 3 pairs x Foam Ear tips (size S/M/L)
  • 4 pairs x Silicone Ear tips (size S/M/L, one came pre installed)
  • 1 pcs x Zipper Case
  • 1 pcs x Cleaning Tool
  • 1 pcs x 6.3mm Headphone Adaptor


The Sennheiser IE400 Pro is coming with lots of accessories which are all of high quality.

The box is including some special foam and silicone ear tips.

It comes also a zipper case, 6.3mm Headphone adaptor and a small cleaning tool.

The zipper case with the Sennheiser logo on the top is of high quality and a safe place to store your IEM and accessories.




Design, Fit and Build Quality:

The Sennheiser IE400 Pro has transparent plastic monitor housing which is available in two (2) different color options, which are the CLEAR and SMOKY BLACK variants. The overall build quality of the IE400 Pro is fine but doesn’t look as solid and premium as other IEMs on the market with a metal or acrylic shell.

The internal parts of the IEM are clearly visible on my review unit which came in the CLEAR variant.

On the front of the monitor shell that we describe as faceplate is the Sennheiser logo which printed in black color and a small vent.

On the back of the Sennheiser IE400 Pro is the sound nozzle which has small openings on the top.

On the top of the monitor housing is the patented female connector and near to the connectors are the Left & Right indicators, which is in red on the right monitor and in black on the left monitor shell.

The right monitor shell sports model description which is printed in black color.

The Sennheiser IE400 Pro is coming with a detachable cable which has a soft rubber coating in black color and features the “patented cable duct” system.

The housing of the male connector is made of plastic and sports a red ring indicator as Right (R) monitor marking. The cable sports on both sides flexible ear guides, which offers extra comfort for longer listening periods.

This cable of the Sennheiser IE400 Pro features also a plastic y-splitter with Sennheiser logo and small chin slider.

The 3.5mm Gold plated TRS headphone jack is L angled and has a black plastic housing, which sports the Sennheiser logo on the back.



Fit, Comfort & Isolation:

The plastic housing of the Sennheiser IE400 Pro is quite ergonomically and is comfortable to wear without any pressure or hurting of my ear channels, even after some long listening periods. The noise isolation of the IE400 Pro is above average pretty good and ideal for the use in noisy environments like bus, metro or train.



Technical Specifications:
  • Model             : IE400 Pro
  • Transducer     : 7mm Diameter Dynamic Driver with TrueResponse Technology
  • Impedance     : 16Ω
  • THD                : < 0.08 %
  • Freq. range     : 6 Hz – 19 kHz
  • SPL                  : 123dB/mW (1kHz / 1 Vrms)
  • Attenuation    : up to 26 dB
  • Weight            : 18g
  • Cable length   : 1.3m




According to Sennheiser’s official specs, the IE400 Pro has an impedance of 16 ohms and a sensitivity of 123 dB. It can operate on relatively weak sources such as Smartphone’s, Tablets, and smaller DAPs, and is able to archive fairly high volume levels without the need of an external amplifier.



Equipment’s used for this review:

IEM’s              : Sennheiser IE400 Pro, Custom Art FIBAE Black, FiiO FA7
DAP&DAC’s  : iBasso DX220, QLS QA361, Cayin N5II, xDuoo XD10 Poke



Albums & tracks used for this review:
  • Tingvall Trio – Bumerang (Flac 16bit/44.1kHz)
  • Liquid Tension Experiment 2 – Acid Rain (Flac 16bit/44.1kHz)
  • Opeth – Damnation (Wav 16bit/44kHz)
  • Metallica – Sad but True (Flac 24bit/96kHz)
  • Megadeth – Sweating Bullets (Flac 24bit/96kHz)
  • Slayer – Angel of Death (Flac 24bit/96kHz)
  • Elton John – Your Song (Flac 24bit/192kHz)
  • David Bowie – Black Star (Flac 24bit/96kHz)
  • Dave Gahan – Kingdom (Flac 16bit/44.1kHz)
  • Eric Clapton – Unplugged Album (Flac 24bit/96kHz)
  • B.B. King – Riding With The King (Flac 24bit/96kHz)
  • First Aid Kit – My Silver Lining (Flac 16bit/44.1kHz)
  • London Grammar – Interlude (Live) (Flac 24bit/88kHz)
  • Aretha Franklin – I Say a Little Prayer (Wav 16bit/44.1kHz)
  • Diana Krall – So Wonderful (DSF)
  • Laura Pergolizzi – Lost On You “Live at Harvard and Stone” (Wav 16bit/44.1kHz)
  • Rush’s – Leave That Thing Alone (Flac 16bit/44.1kHz)
  • Gogo Penguin – Raven (Flac 24bit/192kHz)
  • Otto Liebert& Luna Negra – The River (DSF) – Binaural Recording
  • Vivaldi – Le QuarttroStagioni “The Four Season” (Wav 24bit/88kHz)
  • Armin Van Buuren – Vini Vici (Spotify)
  • Lorde – Royal (Flac 24bit/48kHz)
  • Tom Player – Resonace Theory (16bit/44.1kHz)
  • Massive Attack – Angel (Flac 24bit/192kHz)
  • Portishead – The Hidden Camera (MP3 320kHz)




The Sound:


The Sennheiser IE400 Pro is an In-Ear Monitor with a W shaped sound signature which has a close to neutral tonality and a balanced presentation. The subbass is pronounced, while the midbass are pretty linear. The midrange is fairly flat while the upper midrange and treble region is pronounced and controlled.


The Bass:

The bass of the IE400 Pro has a W shaped character which means the subbass shows more intensity and quantity compared to the midbass region which is more linear in its presentation.

Due to the dynamic drive, the Sennheiser IE400 Pro is showing a natural, slightly warm and clean subbass presentation. It shows good depth and moderate extension, while the emphasis is not too low or too high. The subbass quantity is sufficient for any kind of music and one other plus point is that it doesn’t constrict the scene.

The midbass region of the Sennheiser IE400 Pro has an emphasis which is slightly below compared to the subbass. It shows a good level of slam and should be enough in quantity for most users with the exception of extreme bass lovers like the so called bass-heads.

The IE400 Pro is an In-Ear Monitor with the ability to perform specific subbass and midbass notes, which will make you happy while listening to instruments like the contrabass or drum up to artificial bass sounds.  Contrabasses, for example, have a good depth and speed, while percussion instruments are played at a close to their naturalness warmth.

The bass is in general pretty high in resolution and moderate in its speed and this ability makes the IE 400 Pro successful with a wide Variety of genres.


The Midrange:

The IE400 Pro offers a quite neutral, balanced, clear and open sounding midrange presentation with a fairly flat character. It sounds neither too upfront nor too recessed and the for a more natural W shape sound signature the midrange has been tuned pretty linear.

Male vocals have a slightly thick, fairly clear and quite lively tonality and doesn’t showing any negative situations like muddiness or mixings. The lower midrange depth of male vocals is on an average level.

The female vocal presentation of the Sennheiser IE400 Pro shows a good detail retrieval and extension due to well pronounced upper midrange. Female vocals have a close to neutral tonality along with a very transparent and clear presentation. Female vocals are represented in quite controlled, sibilance free and emotional way.

The Sennheiser IE400 Pro has a good vocal and instrument separation. Instruments have a very clear and transparent tonality along with good extension and brightness levels. For example, Instruments like violas have good depth, while guitars and pianos have good speed and extension. The neutral air between the instruments is making the IE400 Pro to a fairly airy and spacious sounding IEM.


Upper Midrange & Treble:

The Sennheiser IE400 Pro is an In-Ear Monitor with a strong upper midrange with a fairly neutral and transparent character. The upper midrange transitions are in general controlled and soft with exception of genres like metal music. In situations where the piano is played in higher notes, I didn’t experience any unnecessary brightness and sharpness in the upper midrange and treble region, the extension and transitions remained also highly controlled.

The IE400 Pro has a natural, soft and neutral treble presentation, which is neither sharp nor aggressive and sounds what should be.

The lower treble range (presence) is well pronounced, which is the main reason that Instruments like Hi-Hats are shown with good intensity, extension and definition. The emphasis tends to diminish slightly from control from the lower treble to the upper treble (brilliance) range. The extension of the Ride and Crash cymbals extends very easily to 10 kHz and beyond. For example, in Megadeth’s Sweating Bullets, the upper strings of the cymbals are extending up to 17 kHz and can be quite easily heard up to the 10 kHz range.

The cymbals in Jazz Music are generally much more pronounced and have a stronger extension than in genres like Metal music. Instruments like the big ride cymbals in “Tingvall Trio’s – Bumerang” song are pronounced and are showing good extension, while the tonality of the cymbals is a bit thick and dark in this song.



The Soundstage:

The Sennheiser IE400 Pro has a suitable soundstage for accurate placement of instruments and vocals. The sound stage is quite airy and spacious, while the stage has slightly more width than depth.




Some Short Comparisons:


Sennheiser IE400 Pro versus FiiO FA7:

The FiiO FA7 has a pretty U shaped sound signature where the midrange is behind the strong bass and sharp treble range. The general tonality is warmer than neutral, with a warm & entertaining bass and slightly warmish midrange and treble tonality.

Both the FiiO FA7 and the Sennheiser IE40 Pro are showing a good subbass depth, while the FA7 has slightly more quantity and intensity compared to the IE400 Pro. The midbass region of both In-Ear Monitors has good impact and a strong slam effect. The Sennheiser IE400 Pro is superior in terms of bass control and speed.

The midrange of the FiiO FA7 is laid back do to the fairly U shaped sound signature. The midrange of the FiiO FA7 has a warmer tonality than those of the Sennheiser IE400 Pro that is showing a more neutral and transparent tonality.

The lower midrange of the FA7 has more depth which makes is slightly more successful in terms of male vocal detail and depth. The Sennheiser IE400 Pro on the other hand is superior while listening to female vocals. Female vocals have better extension and detail retrieval while listening to the IE400 Pro. The upper midrange of both IEM’s is pretty controlled without any unnecessary sharpness. The upper midrange of the Sennheiser IE400 Pro is slightly more transparent, airy and detailed compared to the FiiO FA7.

The treble range of both In-Ear Monitors is energetic, lively and shows good extension. The lower treble range (presence) of the FA7 is more pronounced than its upper treble range (brilliance). Both the lower and upper treble region of the Sennheiser IE400 Pro is more pronounced and detailed compared to those of the FiiO FA7. The IE400 Pro is superior in terms of treble quantity and extension.

Both In-Ear Monitors have a suitable soundstage for a accurate instrument and vocal separation. The Sennheiser IE400 Pro is superior in terms of soundstage width, while the FiiO FA7 has slightly more depth.



Sennheiser IE400 Pro versus Custom Art FIBAE Black:

The FIBAE Black is a warm, musical and smooth sounding In-Ear Monitor with deep and strong bass, soft and musical midrange, controlled and mildly pronounced upper midrange and treble presentation.

The Custom Art FIBAE Black is slightly better in terms of subbass depth and quantity, while the same situation exists in the midbass region. The Sennheiser IE400 Pro on the other hand is superior in terms bass speed, tightness and resolution.

The Custom Art FIABE Black has a pretty warm and soft midrange presentation. The transparency and airiness of this region is on a moderate level, while the Sennheiser IE400 Pro offers a more neutral, clear and transparent midrange character compared to the FIBAE Black.

The Custom Art FIBAE Black is slightly more suitable for male vocals due to the lower midrange depth, while the Sennheiser IE400 Pro is more successful with female vocals because of the better upper midrange tuning.

The upper midrange and treble region of the Sennheiser IE400 Pro is superior in terms of extension and detail retrieval, while the Custom Art FIBAE Black has the upper hand in terms of musicality.

When it comes to the soundstage performance, I can confirm that the Sennheiser IE400 Pro is superior in terms of soundstage width, while the Custom Art FIABE Black has slightly more depth. The IE400 Pro sounds more spacious and airy compared to the Custom Art FIABE Black.



The Sennheiser IE400 Pro is coming in a beautiful packaging with lots of accessories and shows a good sound balance which is tuned in between a fun and reference type of presentation. The IE400 Pro will appeal to audiophiles as well as to music lovers with its fast bass response, transparent midrange and treble with good resolution.



Pros & Cons:
  • + Fast and Detailed Bass
  • + Clarity of the Midrange
  • + Treble extension
  • + Spacious Soundstage


  • – Plastic Shell
  • – Slightly lack of Midbass



You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *