HifiMan first taste of success in the IEM world comes when RE0’s price was lowered to $99 during the Black Friday sale a few years ago. It was an instant hit and really set the bar high for what $100 can buy. However, the new $99 RE400 isn’t just here to repeat that success - according to Fang, the boss of HifiMan, it is meant to set a new reference point to what he believes audiophile IEM should at least be able to measure up to. It is an ambitious goal no doubt, so does it sink or swim? Spec Driver: 8.5mm Dynamic with Titanium Diaphragm Impedance: 32 +/- 3.2 ohm Sensitivity: 102dB/mW Rated power: 10mW Maximum power: 30mW Frequency response: 15 ~22 KHZ Cable: 1.35m OFC Accessories and Build Quality Being a preview sample, the IEM comes without the final package and thus we won’t be looking into that. Accessories wise, you should find a pair of small eartips, a pair of small bi-flange and a pair of big bi-flanges. There is also a hexagon-stick shaped cable managing tool. As said, this is not the final packaging so you might or might not find more accessories inside the retail package, but it is supposed to have replacement filters and shirt clip as well. The build quality of RE400 is HifiMan best-to-date yet. The cable from the Y-splitter up is similar to that used on RE262 / RE272, which is soft, good quality and doesn’t seem to harden easily. The cable from Y-splitter down is covered with fabric sleeve to increase its tearing resistance, but unavoidably also makes it more microphonics. It isn’t terrible but the use of shirt clip is recommended. The new housing is really small and unique to HifiMan so far. The nozzle diameter is however still the same as older models so you can use aftermarket eartips like MEElec or Sony Hybrid. However, HifiMan does recommend the stock small bi-flanges as it is said to be the best pairing. The small bi-flanges are another HifiMan’s first as it is developed specifically for the new RE400 / RE600 series. Overall it is quite comfortable and isolation is about average (-20dB or so) Sound Quality The IEM has been given over 50 hours of burn-in before the review. Different from the more analytical RE272 and RE0 (RE252 to a lesser extent) or the more euphonic RE262, RE400 is one that seems to carry the least flavoured sound, or should I say the least ‘wow factor’ in its sound. Don’t get me wrong, it is an excellent IEM in its own right. But if you have owned HifiMan’s IEM in the recent past, RE400 might not sound that impressive at first. Instead, it seems to be tailor to suit a more ‘matured / polite’ group of listener, so to speak. It isn’t reference flat, but there is a sense of neutral in its presentation – warm, calm, almost like a Westone UM3X type of stage monitor while still has a good degree of musicality in its presentation. Bass runs deep down to the 20Hz region, well bodied and comes with good low end rumbling. It is however not quantitatively a bass monster. At most, I’ll refer it as a bit more than neutral. Mid is sweet, detailed and textured. It is thick but not overly so. It can almost be called a mid-centric sound if not for the well complimented bass. Obviously mid are what’ll grab the listener’s attention first and the strength of RE400. Treble extends high, but mostly in a gentle fashion so all the sparkles tend to be just half-a-step behind the rest of the frequency. Analytical listener need not apply, especially if you are a fan of RE272 or RE0. RE262’s fan on the other hand might find RE400 to be closer to their heart, but it doesn’t quite have the same euphonic feeling. Soundstage is above average but not excessively wide as the whole presentation is neither upfront nor very far away, rather it is immersive and surrounding like sitting in the third role of a small theatre. As far as comparing to HifiMan last generations of IEM, the RE0, RE-ZERO, RE262 and RE272 – I think it is safe to say RE400 is ahead of RE-0 and RE-ZERO as far as overall technical ability goes. But it is not quite that obvious when it is compared to RE262 and RE272. Neither of the three IEM has any real weakness, so to speak – but RE262 excels in vocal fluidity while RE272 is as close to perfect reference-flat as any universal IEM that I know of. RE400 on the other hand doesn’t seem to have a particular area that makes it stands out. Then again, it is a sound that can hardly be hated. It is after all the first jack-of-all-trade in HifiMan’s line-up since they have stepped into the IEM market and it is a competent sound that could easily be placed amount the upper tier. Verdict RE400 is nicknamed the ‘waterline’ for its design goal as a reference line among audiophile IEM. For a less-than-$100 IEM that has SQ that rivals many that are priced twice or thrice as expensive in the upper tier, I think Fang has gotten his point across the IEM world. We have seen some really excellent sub-$200 upper tier IEM in the past couple of years, but few if any ever go below the $100 mark – but here again HifiMan has come to reconquer the land with RE400 as they once did with RE-0, and I think it is only fair to recommend it with a [5/5] Sonic Diamond for their effort. A thank to HifiMan for the sample.