EDL IE 900 Audiophile in-Ear Monitors with X3R Technology, and Upgrade Option to Micro-Tesla Drivers



  • Technology                 : Unique X3R technology
  • Transducer principle   : Single Dynamic Driver with Pressure Chamber
  • Impedance                  : 16 Ω
  • Frequency Response : 5Hz-48kHz (-10dB)
  • SPL                             : 123 dB (1 kHz, 1 Vrms)
  • THD-N                        : <0.05% (94 dB, 1 kHz)
  • Housing Material        : One-piece precision-milled aluminum
  • Cable Length              : 125cm
  • Weight                        : 4gram
SKU: EDL IE 900 Audiophile in-Ear Monitors Categories: , Tags: , ,


This is a custom product built by Earphone DIY Labs with Sennheiser IE900 shell with X3R Technology and TrueResponse Transducers (Drivers). We proudly provide the upgrade option to our Micro-Tesla Drivers which got 100% positive feedback from thousands of users, and work seamlessly with X3R.  

Key values for you: 

  • Innovative X3R technology unique to the IE 900. As displayed above, the X3R is a unique triple-chamber absorber system and acoustic vortex removes masking resonances for a refined and extended treble. 
  • Larger-than-life sound from 7mm TrueResponse Transducer, crafted specifically for in-ear listening using the entire frequency spectrum for critical hearing of all elements of the source
  • The upgrade option with 8mm Mirco-Tesla drivers which outperforms the original 7mm TrueResponse Transducer design, choose of thousands Earphone DIY Labs users
  • Equipped with para-aramid reinforced cables with gold plated MMCX connectors which possesses a special recessed and robust design to ensure reliability even after over 500 attachment cycles
  • Selection of silicone and memory foam ear adaptors in 3 sizes (S/M/L) and adjustable ear hooks to ensure an optimal fit and high noise isolation
  • Product includes: 3 connecting cables with MMCX connectors; single ended 3.5mm and balanced 2.5mm & 4.4mm, silicone & memory foam sets (S, M, L), carry case, cleaning tool and user manual

Note we are working on getting a DIY kit ready for experienced DIYers.  Question about shipping? Check in the shipping service. 

Also note IE900 cannot work with regular MMCX cables (Shure/SONY spec).  Even looks very similar, Sennheiser customized its MMCX connector with an additional protection which blocks any non-Sennheiser cables to be connected.

Know more about IE900

We recommend this video for a very objective review of IE900.

And in case you need a subjective review, here is a good one at Sennheiser IE 900 Review – Flagship Dynamic Driver IEM (headphones.com)


The IE900, like Sennheiser’s other IEMs, is utilizing a single-dynamic driver. Though, what Sennheiser has done for the IE900 is that they’ve implemented their new X3R transducer,  combining their refined 7mm Extra Wide Band Transducer with a triple-chamber absorber system. So, with its cutting-edge design, how does the IE900 perform?

First Impressions

Well, I know I’ve given some of my thoughts away in the “First Look” video I made for the IE900, but to briefly recap, I think it sounds rather good. In fact, it’s probably the most enjoyable listening experience I’ve personally had in an IEM thus far. It’s not without its flaws, of course, but it’s got a very nice presentation that is surprisingly spacious, with a good tonality, and even great dynamics. Whilst I will say that it immediately struck me as having a slightly bright frequency response, it wasn’t offensive or harsh, and it actually had a very good midrange and low-end response. 


Admittedly there haven’t been many (yet!), but of the IEMs I’ve had the opportunity to listen to, the IE900 has my favorite bass response. It’s got a very generous bass shelf under 120hz, which gives the subass region a lot of presence, energy as well as a deep rumble. However, it’s not overbearing over other frequencies, and instead feels both enjoyable and clean. It’s perhaps a bit more elevated than what I would personally consider to be “neutral-sounding,” but it makes for a bass region that is fun, and the IE900 is undoubtedly very capable at keeping its bass reproduction tight and controlled. Additionally, it is worth noting that like on other IEMs using a dynamic driver, the bass is punchy and has some satisfying kick to it. 


The midrange on the IE900 is one that I think is accurate, with a tonality and balance that reminds me of the HD800S, and the HD 560S; two headphones of which midranges I’m fond of. Throughout, the mids are linear with an organic voicing that keeps the fundamentals of vocal and instrument lines natural-sounding. Occasionally I felt as though the IE900 was just a little forward at around 3.5K when compared to my Vérité Closed, or even to my HD600, but I’m fairly sensitive to the upper midrange, so I think that for most listeners it won’t be an issue. Regardless, it’s a great depiction of the midrange; brass instruments carry their energetic bite, and electric guitars have their distinct buzz and growl. 


The treble range is where I think that some listeners might have some trouble with the IE900. As I mentioned earlier, the highs do have a bit added brightness to them. In the lower-to mid treble, it sounded to me as though there was fairly broad elevation centered around 6K or about maybe 4-5dB. This, in combination with a narrower peak at around 8.5K, I felt really highlighted the overtones and harmonics in that region which made for a treble range that did sound ever so slightly unnatural in its brilliance, and it did also introduce some sibilance. Again, this didn’t make the IE900 harsh or piercing in the way that “peaky” headphones such as the DT 1990 Pro are, but over extended listening sessions it could become a little bit fatiguing or distracting. 

This elevation aside, I still think that the treble range on the IE900 is pretty good. Since the elevation is not narrow, it doesn’t stand out or make the highs feel particularly uneven. Additionally, I really appreciate the IE900’s excellent treble extension, as it has nice air qualities above 10K that properly nuance the glisten of vocals and the splash of cymbals. 


For its detail retrieval and overall sense of clarity, I found the IE900 to deliver very good performance. Even compared to the similarly-priced, balanced armature CFA Andromeda 2020, the IE900 to me seems to deliver a cleaner image of the music, with all vocal and instrument lines having a defined structure, and adequate texturing. 

Soundstage, Imaging, and Layering

The IE900 has truly outstanding spatial qualities, and I think that they may just be where it shines brightest. Since it’s an IEM that works with an extremely compact enclosure, no, it doesn’t have the kind of soundstage that you’d get from an over-ear headphone. Still, it feels remarkably more open and spacious than other IEMs I’ve listened to, which makes for a listening experience that is nowhere near as confined as what you’d expect from an in-ear headphone. For imaging, it easily discerns the positioning and directionality of sound, revealing the location of sound cues accurately. Additionally, it’s got equally good image distinction and layering. Instrument lines retain their distinction even through busy musical passages, which I also think is something that strongly contributes to the IE900’s perceived clarity. 


As mentioned earlier, the IE900’s dynamic driver delivers engaging dynamics that heighten the musicality of the listening experience. Low tones are fast and punchy, whilst upper registers have a satisfying bite and defined attack. Overall, the IE900 provides a good sense of tactility that gives instruments a more realistic and energetic presence, and in this regard it’s among the better IEMs I’ve heard. So, if you’re looking for an IEM with a good sense of punch and slam, I think you’ll enjoy the IE900.


The slightly emphasized treble region may be a bit of a put-off for some listeners, but as a whole I think the IE900 is a very good IEM. It’s one that I’ve personally really enjoyed listening to, as it’s got excellent technical performance, a good tonal balance, and great comfort–undoubtedly a well-rounded headphone that I’d gladly recommend.

One more thing I should note, is that in a high-end market that’s continuously steering towards multi-driver and hybrid solutions, the IE900 is an outstanding option for listeners who really enjoy the kind of presentation that a single dynamic driver has. If this is something that, like me, you value in your listening experience, then you may want to keep this one on your shortlist. 

About X3R technology

[Quoted from Sennheiser – Headphones & Headsets – Microphones – Business Communications]

Created for an intense listening experience: the new IE 900 is Sennheiser’s audiophile in-ear flagship model

The One-Driver Principle

Refined for Accuracy

Developed with an audience of high-fidelity sound enthusiasts in mind, the IE 900 makes even the subtlest nuances of sound audible. This reproduction of a wide frequency range with low distortion is the result of Sennheiser ́s one-driver principle and the development of their X3R system, a refined version of the company’s own, in-house developed and produced, 7 mm TrueResponse transducer. What refines the X3R technology is the three Helmholtz resonator chambers which are precision-drilled into the elegant aluminum chassis of the IE 900 and placed between the diaphragm and the nozzle. To further smoothen the treble, Sennheiser integrated an acoustic vortex. This is a complex shape that maximizes acoustic friction so that excessive energy is scattered. The effect is measurable and audible and serves to make the treble as smooth and pleasing as possible.

Refined for Accuracy

“The X3R system enables the listener to hear more details in their music which is what audiophile listening is all about. The three resonator chambers smoothen the frequency response at high frequencies in the area from 6 to 10 kilohertz, reducing the so-called masking effect. This means that you can better hear frequencies above 11 kilohertz – the details”, says acoustic engineer at Sennheiser, Andre Michaelis and continues, “the challenge here is to perfectly balance the three chambers to get the correct response. You need to tune chamber by chamber and then make sure they are perfectly balanced together to achieve the correct frequency response. This process requires advanced acoustic engineering”, Andre Michaelis adds.

This complete harmony of systems is at work to unlock the details buried within every track. That each earpiece houses three resonator chambers, pinpoint and tame the resonance peaks that mask a recording’s unique textures. The frequency smoothing brings the listener ever closer to a perfect sound experience—the reproduction of an entire moment captured through sound. Further, the process of milling each aluminum earpiece yields unmatched precision of the Helmholtz resonators for maximum effectiveness of the resonator system.
According to Jermo Koehnke, Product Manager at Sennheiser’s audiophile team, it is the tuning of the X3R systems resonator chambers that make the IE 900 truly stand out and why they offer such exceptionally good high frequency translation.

Tuned Like a Sports Car

What options can I choose from?

You can choose from 2 driver options.

  • 7mm TrueResponse drivers, sounds very similar to IE800 XWB (Extra Wide Band) drivers. See the frequency measurement vs. IE800 below. 
  • Or upgrade to Micro-Tesla Drivers


Why shall I upgrade to Micro-Tesla Drivers

This is a 8mm driver powered by Micro-Tesla drive technology with ultra-wide-band(5~46Khz) performance. It’s our flagship product, which outperform all the high-end micros drivers we have ever tested(including the original IE800). If you are looking for the extreme experience, we are proud highly recommend it.

  • The Micro-Tesla drive technology is characterized by maximum magnetic field strength greater than 1Telsa, focusing on the air gap inside the dynamic driver unit in a micro drive unit, which is 2 or 3 times the conventional IEM drivers.
  • Ultra Wide Band means the driver performs excellently from 5Hz to 45KHz, which greatly exceeds the ordinary IEM 20~20Khz range.
  • The main benefits to users are
    • Ultra-high density of the bass. With precise volume, the bass is well controlled and deeply extend to subwoofer area. It’s the most powerful and balanced bass we’ve ever tested among dozens of high-end drivers!
    • Ultra-low distortion in the middle. The human voice is precisely pinpointed and sounds like it should.
    • Unmatchable treble. If you haven’t tried a top level IEMs like IE800, T8iE, you may feel it is too bright in 1 second but then you will know it’s only because the high resolution can make details crystal clear – your ears are a little bit overloaded.

For the measurements using IEC711 coupler, ARTA and customized sound card,  see below.

Frequency response
Cumulative Spectrum Decay (i.e., the waterfall diagram)
Energy decay
Burst Decay


Impulse Response

The MMCX cable

We provide 1 pcs of unbalanced Para-aramid Reinforced cable with 3.5mm connector. 

How if I have special requirements?

Please leave your requirements in the ordering note and we’ll handle them accordingly, or contact our service account for any issue. 

Additional information

Weight 0.1 kg
Dimensions 15 × 10 × 3 cm
Driver options

7mm TrueResponse Transducer (Drivers), 8mm Micro-Tesla Drivers


There are no reviews yet.

Be the first to review “EDL IE 900 Audiophile in-Ear Monitors with X3R Technology, and Upgrade Option to Micro-Tesla Drivers”

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

You may also like…