HiFiMAN’s 400i headphones: Waiting For The Man

3rd November 2015

Offering a redesigned headphone design at a competitive price, Paul Rigby reviews HiFiMAN’s 400i headphones

Surely HiFi-MAN is asking for trouble with this new design?  A pair of audiophile quality headphones, priced at £360, is placing the 400i right up against some strong, nay legendary, designs such as the Sennheiser HD650. It’s a tough mission but HiFiMAN is famed for its attention to detail, so I was looking forward to tackling the 400i design within a full review.

The 400-series has always been an attractive design. It was the first mass produced orthodynamic headphone. That is, you could produce it on a machine. Before this important evolutionary step, they were all hand-made. The machine-lead production meant that the price could be brought down.

When I say that the 400i is ‘new’, I really mean ‘new’. You might think that adding a letter ‘i’ to the respected 400 moniker indicates that the 400i now totes nothing more than a pair of go-faster stripes and multi-toned horn to annoy the neighbours on a Sunday morning. Not so, as UK distributor and headphone expert, Mark Dolbear stated, “It’s a totally redesigned headphone. to begin with, it is 30% lighter and uses single-ended drivers. Sometimes you have headphone drivers with magnets on both sides of the diaphragm. These only have magnets on one side, it helps the efficiency so it’s easier to drive, they aren’t fighting against two magnetic poles.”



Dual magnets are also less efficient. For example, a dual magnet-driven HE6 needs a 3.5-4W per channel amp to drive them. Which is quite a lot.

Now, before you leap off your chair, yes, the original 400 also uses a single magnet but the 400i improves that inherent technology. But that’s not all, “The chassis has been redesigned with a new headband assembly and ear pads to improve comfort and sound (the pads have been designed to be more porous to allow the ear to breath more easily but also to enhance sound quality).

One of the major additions to the 400i design is the cable, “It’s a crystalline metal creation with oxygen free copper and silver cable. The latter opens up the sound stage a lot more when compared even to to the 500. The 400i cable is much more expensive to make, though, so it only comes with a 2m cable as standard. A lot of people use headphones while sitting near to a computer so the requirement for a longer cable is reduced.”


I can understand that cost point but I found the shorter than normal cable length an issue. Fine if you are by a computer, as Dolbear states but I tend to do most of the headphone listening sitting by my reference hi-fi which features a comfy chair that is  a little way away from it. At 2m, my headphone listening is not as comfortable as I would want it. That can be solved, though, the cables are detachable (to allow for upgrades – great idea) which allows you to add a longer 400i cable. The problem is that Hi-FiMAN do not feel that a 3m cable option is necessary. I disagree…strongly. After all, 3m is what most people are used to. No, Hi-FiMAN only offer 5m and 8m as replacement lengths. Problem is, if you jump from 2m to 5m then you will need to pay an extra £200.

In addition, I dislike the fiddly rotating nut design that connects the cable to the chassis. It’s awkward and tricky to attach.


There is good news regarding cable position, though, “The old cable used to fit to the head directly underneath,” said Dolbear “The 400i is slightly out to the front, coming out at around 7 o’clock position. For people with larger shoulders that means that the cable doesn’t sit on those.”


Arguably the most popular and most significant competitive design to the 400i in its £360 price-point is the Sennheiser H650 (although you can find HD650s at a lower price if you shop around – no doubt the same will be said of the 400i models in the fullness of time). The long-standing HD650 model has many supporters in the audiophile sector. In fact, many of my fellow journalists use them as mid-price reference hardware. I’m one of them. It seemed an obvious decision to compare the 400i headphones with the HD650, so that’s what I did.



Turning firstly to jazz on CD and the Tina Brooks album, True Blue. The first impression from the 400i was the extra bass presence. Yes, the HD650s handle bass well and can certainly drive any music with its fast and clear suite of lower frequencies but there was a lack of deep presence, broad heft and weight when compared to the 400i. That was the one principle, over-riding element of the 400i’s personality. Because of this, the entire soundstage was set a little lower, weighed a tad by the lower frequencies.

In terms of the overall presentation, the 400i phones had a much more relaxed delivery. The 650s could sometimes seem a little tense, almost as if they were giving you music while all their muscles were clenched. The 400is sounded very relaxed and at ease which helped the music to flow. What the HD650s provided that the 400is did not was a sense of precision and sharpness in terms of treble and upper midrange. That’s not to say that the 400i phones lacked accuracy, its just that the 650s excelled. The Sennheisers were sharp and quick off the mark.



The HiFiMAN phones may have lacked a slice of extra precision but they did offer more detail and musicality. That extra bass meant that the double bass was pushed further forward in the mix and became more dominant in the track but also the trumpet and sax were richer and fuller. Via the 650s, the trumpet did verge slightly on blooming or, during crescendos and at higher volumes, became ever so slightly forward in nature. With the HiFiMAN phones, that was never an issue. In addition, the 650s presented both the trumpet and sax within a narrow band of aural information, the HiFiMAN had the ability to grab hold of these narrow boundaries and pull them apart, giving both trumpet and sax more body and authority.

Replacing the CD with Porcupine Tree’s Four Chords That Made A Million track, this prog rock CD offered plenty of dynamic opportunities for the respective phones to show off their wares. In the early part of the track, there is no heavy bass, just main vocals, double track vocal effects, secondary percussion and guitars. This is quite a busy introductory sequence and many varying frequencies are vying for your attention. It was the HiFiMAN phones which did the best job of separating those frequencies into recognisable noises.

The soundstage was widened and each instrument within was separated enough to allow the ear to better delineate what was going on. While the HD650s were fast, dynamic and supremely agile, the HiFiMAN phones enriched  the detail with lower frequencies as well extra focus. For example, the rather subtle double tracked vocal, repeating the title of the song in this sequence, was clearly stated by the 400i phones.

When the heavy bass finally hit, while the bass guitar was more dexterous in the hands of the HD650, the HiFiMAN gave that guitar a larger role in the track, adding bulk and weight to its performance and giving it extra drive.

Bass, always punchy within the HD650s, was given extra mass by the 400is. Treble was offered a broader soundstage to perform by the latter while the extra focus allowed subtle secondary percussive effects to be more easily sought and located by the ear.

Moving to vinyl and a slice of Bing Crosby with the track, April Showers, a mono pressing played with a top-of-the-range Myajima Zero cartridge. Here, the HiFiMAN showed what a balanced performer it is, offering elements from all of the sonic spectrum instead of impressing in just a few. One example was the rather stilted Crosby vocal on the HD650s which sounded like the man was singing from a decent quality radio. The HiFiMAN added welcome lower frequencies that gave Crosby a more naturalistic quality, adding warmth and emotion to his delivery. The added focus and detail also enabled the ear to hear the delicate piano strikes, giving the rain effect from the song title at the beginning of the track a fuller and more informative response. In fact, with the HD650s, I originally thought that this effect was possibly a glockenspiel, which shows how tonally accurate the HiFiMAN phones are.


Reading the above, you might conclude that I have been overly critical or even positively derisory of the Sennheiser HD650s. Not so. I believe that the HD650s are not only an excellent pair of headphones but one of the very best designs in their price range. Hey, I wouldn’t be using them as a reference if I didn’t believe in them.

The problem, if it is a problem, is that they now compete with a new, upgraded 400i design from HiFiMAN that, no doubt, offers more. So much more, in fact. Yes, the HiFiMAN designs lack the precision and agility of the HD650s and, if you are the sort of person that requires exactitude within the upper mids, then the Sennhesiers are your babies. The 400i headphones, however, provide a much better balanced playback with greater emotion and focus as well as a much better insight into the music itself. Its level of detail is more than admirable. Providing a broad soundstage, the music is not only presented to you in a large, epic, fashion but listening to music on the 400i phones is an event. The representational and realistic manner of its approach to music lowers any listening fatigue to almost zero while its inherent musicality is wholly involving.

HiFiMAN 400i Headphones

Price: £360

Website: www.electromod.co.uk

Tel: 01494 956558

GOOD: balanced, bass, emotionally involving, focus & detail

BAD: lacks measure of precision and agility, cable length and cable connections


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Origin Sovereign Turntable

12” Enterprise arm

Miyajima Zero cartridge

Icon Audio CD-X1 CD player

Aesthetix Calypso Pre

Icon Audio MB845 Mk.II monoblocks

Quad ESL-57 speakers with One Thing upgrade

Sennheiser HD600 headphones

Icon Audio HP8 Mk.II headphone amplifier