The following review has been thoughtfully crafted by Mr. Indranil Mitra from Kolkata, a cherished supporter, customer, and friend of The Audio Store. We express our gratitude to Mr. Indranil for generously sharing his personal insights into the Sennheiser IE 900 IEM. It is important to note that this review is entirely unbiased, reflecting Mr.Indranil's genuine experiences and preferences. No benefits or exchanges have influenced the content of this review. His valuable contributions significantly enhance our blog, and we sincerely appreciate his unwavering dedication to the audio enthusiast community.
Firstly, I would love to thank The Audio Store for sending this unit out for review, especially Pritam & Pankaj Ji for entrusting me with his own personal unit.
Anyone who knows me, knows that I am fond of good ol' senny. HD600 and HD650 are some of my favorite headphones ever. Coming to their recent IEM lineup, the IExxx, i have all the three - IE200, IE600 and IE900.
The IE900 is the flagship of the bunch. Speaking of build, the IE600 and IE900 is on a league of their own. IE600 is made out of a zirconium shell and the IE900 solid metal. IE200 is an all plastic build but that is still damn durable (think of their plastic chassis audiophile headphones, that last over 40 years with no sign of dying). The fit is actually slightly different among the three. IE600 fit the best in my ears, then came IE200 and then IE900. The IE900 has a slightly bigger chassis than the other two. But this is all speaking comparatively. The IExxx lineup is the smallest form factor IEM i have ever seen and worn and they are THE MOST comfortable IEMs I have ever used. They just vanish in your ears compared to other IEMs. The IE 900 has its design carved out of the machining marks that looks quite sophisticated but it may grate against your ears when pushed in too deep, just one thing to keep in mind.
Speaking of sound, the 3 IEMs couldn't be any more different. I will tell you straight away that the IE 200 has the most "conventional" type of tuning among the 3. But it is nowhere near the capabilities of its elder brothers. Don't get me wrong, the IE200 is absolutely a steal deal for its price but there is no comparison with the IE 600 and IE 900.
Firstly, the IE 900 seems to be the first IEM i have heard that actually has an "out of head" headstage, which is comparable to headphones. Simply, no other IEM I have heard yet could ever achieve this. The famed Campfire Andromeda is known for its soundstage, but that simply sounds narrow in comparison. IE900 is seriously wide and for some, it may replace some headphones.
IE900 seems to continue the list of superlatives with its bass response. Goddamn, that bass extension, that bass punch is just so addictive. It's so detailed, so controlled with such a visceral attack that it puts a grin on my face. Needless to say, no IEM i've heard even comes this close to this kind of attack (specially not BA setups). Compared to the IE600, the IE 900 has more physical quantity of bass but the IE 600 still has very good extension which is very resolving (better in terms of quality and quantity compared to most of the other IEMs), but the IE 900 out-resolves it with more attack. The IE 900 wins in the bass department, plain and simple.
When it comes to midrange, both the IE 600 and IE 900 are quite neutral to my ears, not too forward not too laid back with great detail retrieval. The IEM industry is flooded with cheapo stuff with subpar tunings, made by some bloke in a shed probably. Not here. Both the IE 600 and IE 900 provide lovely midrange. But of course don't expect the kind of resolution and texture in the midrange that the HDXXX lineup of their headphones provide. A/B'ing against the HD 660S2, the midrange is significantly more detailed with a largely substantial more texture. But hell, the HD 660s2 doesn't have the addictive and visceral bass response of the IE900 (just open back dynamic things sadly...). But it is not surprising, HDXXX lineup is still probably the undisputed leaders of midrange in the industry. Things get VERY interesting from upper midrange and treble onwards and this is where the camps are going to be divided. If you are a graph chaser, the IE 600 has the adequate ear gain according to traditionally accepted target curves, the IE 900 falls short in this regard. Through my years of listening, I have learnt that I prefer lesser ear gain that what the target curves suggest. This is all personal preference as everyone's HRTF is unique. Thus, I absolutely love the tamer upper midrange of IE900. But make no mistake, both the IE 600 and IE 900 are very bold and "risky" tunings done right.
The IE 600 has a unique character in its lower treble which gives it a characteristic sparkle in the treble. Usually this is a classic recipe for disaster in my experience but I was proven so wrong. The tuning in the treble while yes boosted, is done so tastefully that its hard to put the iem down. In this regards, the IE 900 is smooth in this region, no added spice. But the behaviour is flipped after the lower treble. In the IE 600, the treble smoothed out after this region with no quirks, while the IE 900 picks up in the upper treble with some peaks. This is the only drawback of the IE 900 in my opinion. As a person who is very sensitive to upper treble peaks, I was kind of disheartened with the treble response of the IE 900. But the practical side got the better side of me and I immediately whipped out EQ to fix this.
I knew I had to tailor the treble to my tastes as the rest of the sound of IE900 is simply sublime. And good news, I have developed a PEQ setting for my own unit which I am leaving below. It is not fine tuned but it makes the experience vastly, if not almost perfect for me. Acknowledging that unit variance is a thing, and that the HRTF varies wildly for frequencies above 10kHz, I recommend you to do a sine sweep and find the peaks yourself and develop your own EQ if the treble bothers you. But here goes mine :-
Preamp -1.0 dB
5800Hz Gain= -2.0 Q=3.
7100Hz Gain= -4.0 Q=3.
11000Hz Gain=-2.0 Q=2.
With this EQ, the IE900 is a high end IEM that I'd probably buy for myself (and I don't personally prefer IEMs in the first place), it's that good. It surpasses the IE600 to my ears, with a tuning that is more versatile and simply more technical on all fronts. All 3 installments in this lineup are tremendous for the price. But yeah, the IE900 is truly special (with some EQ).