Home IEM Reviews HIFIMAN RE-600S Review & RE-400 Comparison

HIFIMAN RE-600S Review & RE-400 Comparison

by Stuart Charles Black
Published: Last Updated on
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Before we get into the HIFIMAN RE-600S Review and comparison to the RE-400, grab a snack, sit back, and relax homie…

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Introducing the HIFIMAN RE-600S, a high-quality in-ear monitor (IEM) that we’ll be comparing to its predecessor, the RE-400.

These IEMs offer audiophiles and music enthusiasts a chance to experience exceptional sound quality in a compact and portable form.

In this comparison, we’ll review the RE-600S and explore the differences and similarities between these two models to help you make an informed choice for your audio needs.

What’s in the Box?

With the RE-600S:

  • A small circular zippered pouch for the earbuds.
  • An ungodly amount of ear tip assortments.
  • The Ear Buds.
  • A super nice carrying box complete with even more tips.
  • A User Guide.
  • A set of small filters in the form of circular dots. Place these over top of the driver to alter the sound. I found that these really made the sound signature even better.

With the RE-400:

  • The Ear Buds.
  • A small circular zippered pouch for the earbuds.
  • 8 ear tip assortments including 1 already included on the buds themselves.
  • A plastic see-through case that houses everything.
  • A User Guide.
  • The same set of small filters from above.



There’s really not much to it. Because they are IEMs, there isn’t a whole lot to talk about.

The cable on both is a rough type of fabric, but it feels pretty solid.

I’ve seen this same type of configuration on some of HIFIMAN’s 400 series headphones, and with those, it did kind of fray over time.

I’m not entirely sure if that will happen here, but it’s something to keep in mind.

The buds themselves on both are very lightweight, which is great for long listening sessions.

You’re never going to feel like you want to take them out due to them being too gargantuan.

Even so, they do feel a bit cheap and light.

This is also something to take into consideration.

Both cables split off into a Y, and each has a small plastic slider so that you can adjust the length between right and left, going into each of your ears.

Both also have a small plastic piece that connects the 2 wires, forming one and eventually terminating in a 3.5mm jack.

Each reads “HIFIMAN”, and each has the respective model named on the opposite side.

HiFiMan RE-600S Review

The difference is that the RE-400’s jack is an L-shape (similar to the HE-4XX’s), while the RE-600S is a straight termination.

The look and feel of both are nearly identical, save for a slight color discrepancy: The RE-600S’ buds are black, while the RE-400s are a white/grayish color.

All in all, the build on both is good, and I have no complaints, save for one: The nature of the cable will cause some slight static/interference but I’m not entirely sure where it’s coming from or what specifically is causing it.

It’s likely electronics-oriented, or the cable itself.

If you’re not wearing some type of material that could interfere with that, you’ll be fine.



This is where things, unfortunately, get dicey again. Like the TWS600s, the tip selection is good.

However, if you have ear canal sensitivity as I do, the buds are going to itch and become rather intolerable over a short period of time.

The good news is that sometimes the feeling will go away for a while, allowing you to listen to your favorite tunes.

I found that the longer I kept them in and tried to suffer through the discomfort, the easier it became.

Once you take them out for whatever reason and put them back in, the misery begins anew.

The good news is that if you do have this ear canal sensitivity, any of the white/clear buds have not bothered my auricles at all.

Just swap out the black ones for any of those and you should be fine.

That said, it’s fairly easy to get the buds into your ears, but once they’re in I found I was adjusting them fairly frequently because of a sort of perceived error – as if I put them in wrong.

When listening to music, you’ll sometimes notice that they need slight tweaks in order for the music to be fully represented properly. It’s hard to explain.

It could be the fact that I’m paranoid and nothing is actually wrong, so there’s that.

HiFiMan RE-600S Review

I guess what I’m trying to say is that they need to be situated just right at all times, and you will likely be making some slight modifications from time to time.

The actual tip issue is much more problematic, so for that, I will have to dock quite a few points.



This is where things really pick back up again.

My goodness.

I’m dead serious when I say that I really haven’t heard much else that’s more detailed and revealing than the RE-600S specifically with regard to IEMs or otherwise.

I also haven’t heard a lot of them, so there’s that as well.

It makes me sort of think that I’m actually missing out on details in some of my favorite headphones, which does kind of depress me and make me a sad frog.

Turn that frown upside down though; you’re in for a real treat with these puppies.

Everything and I mean everything gets a light shined on it.

You can hear so much subtlety and nuance in the human voice and that simply astonished me.

I mostly listen to the 89.7 The Classical Station from my stereo without headphones, so maybe this isn’t the fairest comparison.

But, putting these IEMs in revealed so much more going on than I could’ve ever imagined. Things like:

The subtleties of a person’s vocal inflection (I’m referring to the announcer).

The artists’ breaths and throaty sounds/noises. This was readily apparent in a lot of Classical pieces.

You can hear their unique exasperations and the way they breathe through their nose in between chords and passages.

It really is something to behold. I think the RE-600S does a bit better of a job revealing those qualities.

The way a hand or finger glides across the fretboard. The sound your fingers make when you change chords on a guitar, etc.

All kinds of stuff going on in the background.

For instance, in Mac Ayres’ “Lonely”, you can hear all sorts of car/traffic sounds coming through with incredibly good clarity.

With other headphones, I have a harder time making those sorts of things out. It sounds delightful!

Soundstage & Imaging


In continuation of the above points, I was equally impressed with the height, width, and depth of the image.

You can hear a lot of grunts and murmurs from the artists in question as well.

You’ll start to kind of believe that the sounds you’re hearing are coming from the outside of the IEM, which can be fairly startling at night.

I sometimes take them out to make sure I’m not about to be mauled by Freddy Krueger, even during broad daylight. It’s still pretty subtle though.

As far as the center image, it sometimes can seem a bit hollow or missing, but this isn’t always the case and is dependent a lot on the song.

For instance, during Alina Baraz’s “The One (feat. Jada)”, at 32 seconds it feels like something is going on way behind me, to the point where it almost sounds like someone knocking at the door in my apt. Pretty insane.

In Mija and Vindata’s “Better”, I could never make out what she was saying at the very beginning.

As everyone’s laughing, you can clearly hear her say, “I forgot my words.”

It comes through with crystal clear clarity and the song itself takes on a more revelatory quality.

The overarching theme is that both of these IEMs are incredibly revealing, even more so than some headphones I’ve heard (and I’ve heard quite a few).

Let’s get into specifics:

HiFiMan RE-600S Review


The bass here is very good. It’s definitely not boosted at all, but maybe slightly rolled off or a flat line.

I feel as though both of these IEMs bear a striking resemblance to the sound of the 400 series, and that makes sense when you consider the 400i, 400S, and 4XX all have HE in front of their name (vs. RE).

The entire sound can be summed up as non-fatiguing, mellow, smooth, relaxed, but incredibly detailed.

The bass punches, but it doesn’t sound artificial or cheap at all.

There’s no mid-bass bloat, and it transitions nicely into the lower mid-range.

Mid-Range & Treble

I think one of the biggest differences between the 400 series and these IEMs is in both mid-range and treble.

I feel like 9-10kHz on the 4XX specifically is too hot and essy. It gets on my nerves.

With the RE-600S and RE-400 Waterline, I’m not getting any of that.

It’s definitely more relaxed and sounds fantastic.

It does exactly what treble is supposed to do: provide some sparkle, but not get overzealous and out of line (like most headphones tend to do).

The mid-range is also done very well.

There’s some nice vocal presence, and I don’t feel like the mid-range is at all pushed back or too forward.

If I had to guess, there’s probably a bump in the presence regions, similar to the 400 series.

In listening to Plini’s Handmade Cities and Sunhead, I found the Soundstage to be very good – more so than in listening with other headphones.

Things just tend to open up like a flower, with the spacing and separation of particular interests (a running theme in this article).

The Filters

I tried the RE-600S with the supplied filters from the RE-400, and I found that the overall sound gets tamed down a bit and sounds a bit more realistic and syrupy.

The treble and vocals are subdued just enough to where everything sounds a tad more refined, natural, and effortless.


Amplification & Genre Pairing


Both of these IEMs are extremely efficient and have a low Impedance, so you don’t necessarily need to splurge on an Amp/DAC.

I was running both primarily out of the AudioQuest DragonFly Red, but even that’s overkill. I use one because I own it.

If you wanted to get an Amp/DAC with these, I would get a FiiO K3 or Q1 MK II and call it a day.

Both are a fine match for an IEM like this.

You can run DSD files, both have a bass boost and gain, and both can hook up to another amp via line out in case you ever decide to upgrade to some more demanding headphones.

Realistically though, you can use these with your phone and be completely fine.

Out of 100 on the DragonFly Red, I rarely went over 15-16 in terms of volume on my laptop, and they get plenty loud enough even with my crappy phone.

They just don’t need a lot of power at all.

Audioquest DragonFly Red

Just your standard issue flash drive 😉

As far as genre is concerned, I enjoyed all sorts of music with them, ranging from Hip-Hop/Rap, EDM, Classical, Jazz, Rock, Progressive, etc.

Due to their great Imaging and Instrument separation, Soundstage, and overall balanced sound, they will do well with pretty much anything.

It’s a frequency response conducive to long listening sessions.

Aside from the comfort issue, I don’t ever feel the need to take them off because of musical fatigue.

It’s the type of sound that you can chill with for hours.

Whether you enjoy analyzing music or simply listening to it, the RE-600S is a fantastic choice.

The 400 is a bit less refined and resolving, but the differences are fairly subtle.

I also found the RE-400 Waterline a bit more brash sounding, as if it’s not quite as sure of itself as the 600S.

Video Review & Comparison

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Final Verdict

I really wish I could give these an A+. Outside of the comfort issue (and it’s a fairly major concern), this is a pretty great IEM.

It reminds me of a Tin Audio T2 as well as something like a Status Audio CB-1. Very relaxing but still incredibly detailed.

I think I will give the RE-600S an A-. Instead of getting a perfect 100, I’d wager it deserves about a 90-92.


As of this update, I’ve been searching around and it doesn’t look like the RE-600S is available anymore.

The RE-400 is still around but does suffer from some build quality issues per my renewed research since the time of this posting.

Because of that, I’m going to recommend what is actually my current favorite IEM: the Tin Audio T2, packing a serious punch for only around $50.

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Well that’s about it for today my friend! enjoyed this HIFIMAN RE600S Review and came away with some valuable insight.

Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!

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All the best and God bless,





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