Sennheiser IE 400 PRO Review – Best Of The Pro Series
Pros — Smooth, cohesive, organic sound through fast driver; ultra-low distortion; unparalleled ergonomics; perfect channel matching; 2-year warranty; Made in Germany.
Cons — Sennheiser pricing (watch for sales); a bit too punchy and bassy for some; proprietary cable connectors (but they work reliably).
EXECUTIVE SUMMARY
The Sennheiser IE 400 PRO earphone produced in Germany is a well balanced, gently forward-dipping V-shaped, slightly warm sounding single-dynamic-driver earphone that also impresses by its low distortion and great comfort and fit. It is the second-highest priced but best sounding model of their IE PRO series imo.
INTRODUCTION
The world’s most competent (and now retired) headphone reviewer Tyll Hertsens once called Sennheiser the world’s most competent headphone manufacturer. Their standard staples such as the HD 25 and the HD 600 have delighted us for – yep – decades, and these models still belong to the top of the competition. And Sennheiser have brought us the so often copied earbud.
Sennheiser is a 75-year-old company out of Northern Germany that holds the highest reputation not only in headphones but also in professional microphones (and other products). With the advent of the iPhone in 2008, Sennheiser started developing iems – and they have always stuck to the single dynamic driver because of the cohesive sound and the low harmonic distortion.
Sennheiser’s most recent PRO line comprises three models, the $99/€99 IE 40 PRO (produced in China), and the $ 349/€349 IE 400 PRO and $599/€599 IE 500 PRO (both truly “Made in Germany”).
Biodegraded and I had reviewed the Sennheiser IE 40 PRO [here] and the Sennheiser IE 500 flagship [here] very carefully and in great detail. While I approved the IE 40 as a good sounding budget model, we both were more weary with the IE 500 PRO, which sound congested due to the complete absence of an upper midrange.
The Sennheiser IE 400 PRO and IE 500 PRO, although differently priced, share the same design and even the same 7 mm dynamic driver, but they differ in their tuning. From the sparse useful information on the internet, it appears that the Sennheiser IE 400 PRO is a much better sounding earphone than its more expensive sibling. I therefore approached Sennheiser asking for a loaner to test this. Let’s see what I could find out.
SPECIFICATIONS
Company Website: https://de-de.sennheiser.com
PHYSICAL THINGS AND USABILITY
The unpacking experience of the Sennheiser IE 400 PRO is exactly the same as in the Sennheiser IE 500 PRO and so is the ergonomics. I have tested over 250 earphones and can say that these Sennheiser line sports the best ergonomics out of the lot, perhaps shared with the now discontinued UE900s. The shells are small, they fit snug in my ears, they do not stick out (“bed use”), they are comfortable, and the material feels nice on the skin. And they seal well, which is expected as they have been designed as stage monitors. In fact, you never have the feeling that you have something in your ears – which is also partially contributed to the flexible memory wire. Isolation is very good once again – I have always liked Sennheiser’s silicone tips.
The cable with its round cross section is not too rubbery – and better than the braided version in the IE 500 Pro in that it does not tangle at all. Being black – it is not a grease and dirt magnet. There is some microphonics, though. The connectors are proprietary – you cannot attach a third-party cable – but they are sturdy and reliable. Like all Sennheiser iem cables, this one also comes with a chin slider.
Like their two PRO siblings, the Sennheiser IE 400 PRO, with their very low impedance of 16 Ω work well with just a phone – and the included silicone eartips – a Sennheiser standard – fit my ears well.
EQUIPMENT USED: iPhone SE (1st generation) and MacBook Air, alone or with Audioquest Dragonfly Black 1.5 dac/amp; stock cable and stock eartips.
TONALITY AND TECHNICALITIES
My tonal preference and testing practice
The sound of the Sennheiser IE 400 PRO can be described as medium-warm, gently V-shaped, organic, smooth and cohesive, with a bass punch that creates a mild veil. The driver is noticeably speedy.
The Sennheiser IE 400 PRO’s frequency response curve looks unusual compared to most earphones I have measured, independent of price. The good: it pays off, the sound is very good. The graph is forward dipping which indicates a warm signature. The odd part lies in the upper midrange (2-4 kHz) which appears to be below neutral. Such a graph shape should result in a lack of sparkle and a congested and muted – however rich- sound in the vocals department. The good: this does not happen. Yes, the vocals are rich and intimate, but nothing sounds muffled. Sennheiser must have solved this issue with their tuning in the treble – unfortunately, any coupler (ours included) yields unreliable results in this area so that we can only consider this segment or our graph as semi-quantitative.
But what is obvious is a set of peaks in the upper treble that produces overtones which fuel the midrange with the right sheen and sparkle without making them aggressive. The competition, especially from Asia, frequently boosts the upper midrange (2-4 kHz), which results in aggressive, sharp vocals. This signature is popular in the far east. Sennheiser relies on realistic reproduction that comes with fine British German understatement.
I find the overall sound signature very cohesive, and therefore agreeable, which, together with the organic timbre and the good comfort/fit provides for a pleasant, non-fatiguing listening experience. Stage and headroom are very good for a single dynamic driver, and so is detail resolution. The driver has just the right speed to delight the listener with a realistic attack/decay through the frequency spectrum.
The low end of the Sennheiser IE 400 PRO is well extended and boosted quite a bit above neutral, mainly in the sub-bass area, but this does not affect the vocals of the lower midrange. Although not evident in the graph, mid-bass can be a bit much at times. In terms of quality, the low end is reasonably well focused and medium tight with a natural speed but not as articulate as in the Sennheiser IE 500 PRO sibling. It is punchy, could be a bit sharper and can be perceived as marginally boomy in some tracks.
Moving into the lower midrange, vocals are soft and smooth, intimate, well-sculptured, and N A T U R AL. Very very appealing to my ears. V-shape? Vocals too distant? Just turn the volume up: distortion is minimal and much smaller than what your are used to, even at the highest volumes. There is no hint of harshness as in most of their Chi-Fi colleagues. That’s because the upper midrange is so well behaved. Downside of the tame upper midrange: vocals do not have the biggest sparkle around and it cuts into the transparency…but enough to be appealing.
The highs are very extended into the 15 kHz area recovering some sparkle and sheen but also creating some splashiness in cymbals.
The stage is wider than deep, it deserves a bit more depth. The overall presentation is very accentuated – but detail resolution, layering, and separation are good however somewhat limited by the 7 mm dynamic driver. Sound is as organic as it could be. The Sennheiser IE 400 PRO shine through their coherence and agreeable, inviting sound rather than through their nitty gritty technicalities.
WHY WOULD I WANT IT (OR NOT)?
We at audioreviews.org haven’t had much of a chance reviewing German gear. And that’s exactly where your money is in Sennheiser products: German quality control. Any of the Sennheiser earphones I have measured have impeccable channel balance. The Sennheiser IE 500 PRO and IE 400 PRO are “Made in Germany”, which remains one of the world’s highest quality seals. As a reviewer, I have been disappointed more than once with poorly designed and poorly manufactured, faulty products, that had been thrown on the market prematurely. The other advantage of the IE 400 PRO over their Chi-Fi competition is that they incorporate long (and real) professional experience, that much R&D went into them, and that this product has been so well designed that it is here to stay (on the market). The Chinese competition frequently floods the market with half-baked earphones prematurely, uses their clientele as guinea pigs, and an “improved” version, labelled as “Pro”, will follow so closely that the early adopters are being disgruntled. Sennheiser have the solidity and maturity of a company that they also don’t change their tuning unannounced so that the customer can rely on what they have to expect.
SENNHEISER IE 400 PRO COMPARED
The >$300 4 BA +1DD Anew X-One [here] is superior in most technical aspects (staging, imaging) but does not have offer the same cohesion and degree of natural reproduction, as well as the ergonomics and comfort. It also does not offer the Sennheiser IE 400 PRO’s low harmonic distortion and rigorous quality control (channel balance).
The Sennheiser IE 400 PRO graphs similar to the much cheaper Sennheiser IE 40 PRO [here], but do they sound similar? The main difference lies in the refinement: the IE 40 PRO’s low end is less articulate and slower/less tight and the model also lags in the midrange, particularly the vocals department. The IE 400 PRO reproduces voices more natural, richer, and adds more transparency. The Sennheiser IE 500 PRO [here], in comparison to the other two sounds congested and dull because of its lack of upper midrange/lower treble, but it has a more articulate and layered low end. It also loses against the IE 40 at 1/6 of the price. The $250 JVC HA-FDX1 [here] (with green/least perceived bassy filters) are more upper midrange forward and neutral with a flatter and less extended however realistic bass compared to the warmer Sennheiser IE 400 PRO. The JVCs also have a natural timbre.
CONCLUDING REMARKS
The Sennheiser IE 400 PRO are not only the clear winner against their siblings imo, they are also very good earphones per se. Price aside (sale price is ok), the only criticism could be the boosted bass, which was just fine to my sensible ears. Imaging is immersive, and the overall sound (“Klangbild”) is coherent and pleasant. These are a safe choice not only for expert hobbyists, but also for music lovers who are not so familiar with/overwhelmed by the market’s offerings. It will be difficult to find somebody who would not enjoy these. On top of that Sennheiser give you the piece of mind that their products are well quality controlled and equipped with a 2-year warranty.
Until next time…keep on listening!
You find an INDEX of all our earphone reviews HERE.
DISCLAIMER
The review unit was loaned to me by Sennheiser Canada upon my request. I thank them for that as well as some German Sennheiser audio engineers for discussion.
Our generic standard disclaimer.
You find an INDEX of our most relevant technical articles HERE.
