Review: Heir Audio Hiso | Gifted


Heir Hiso sounds warm-ish, giving a full bodied sound on it’s own terms. The bass driver is big, which I mentioned earlier and that results a warm meaty sound on mid and bass sections. But the great thing is highs are articulate and well accented, so I would not consider Hiso a dark IEM. Still, it has some darkness in it and I’m going to explain that below. It’s overall a good all rounder and a sweet IEM.


It’s mid-bass oriented and that sometimes can be problematic with wrong synergy. On the contrary, with the right source it sounds so sweet especially with electro guitars and such. Be careful though, as this specialty can be very congested sounding with a mismatch. Also the bass is a little soft and that’s because of the suppressed subbass. Lows don’t hit very hard and they don’t reach very low. Is it bad? No. It all depends on you and your listening preferences. Because the sweet midbass can be a pleaser with Classic Rock, Jazz or Blues. Even so I have to say, in my opinion this IEM doesn’t need this amount of midbass. Moreover, when you tone down that part in the EQ a little bit, Hiso takes a more pleasing approach with a less stressful way. I liked it much more this way and I recommend to tone down the midbass, or I recommend a good matching source, like a flatter kind of DAP than my ZX2.

When I tried it with my Fostex HPA-4 DAC/AMP, I realized it’s more consistent this way. The sound is more coherent and that mid-bass thing is almost gone. Still it needs to be just a little less, but it’s OK. So as usual, source – earphone combination comes into play here. Most of the time they need to be opposites. With my ZX2 it’s warm + warm with Hiso, but with Fostex it’s a little bit flat + warm, so that’s a much better and fitting combination.

I wouldn’t consider Hiso’s bass negative, but it’s very dependent on the source so one should be cautious. You can find yourself flicking the midbass sections of the EQ. Also I noticed that it gets better when the driving power is stronger but more on that in technical aspects.


Dark and thick is what I would say about them and that is good for my taste. Some may not find it pleasing but it’s beautiful for me. Mids are one of the  great parts of this IEM with a warm approach. Not too forward though, they still maintain some distance. When you think about the whole spectrum, midbass presence makes Hiso sing stressful sometimes. That of course depends on the setup as I mentioned above. Nevertheless, mids are very very satisfying and I loved getting the sweet thick tones out of it. When I focus on the instruments and vocals they come so sweet to me in terms of tonality. I usually place importance on mids and that is hard to find around this price range, but seems like Heir’s done it. I can’t say any negative thing here, as I heard worse mids out of more expensive IEMs.


Now I think this is the best part of Heir HISO. The thing that I hate about the In-Ears around lower price levels, is the aggressive and sibilant trebles. Whenever I try a budget or mid-fi IEM, I simply hesitate because of that, as I think high end IEMs achieve better performance in terms of cohesiveness and control. HISO breaks the routine here with a great treble response. It’s not super detailed of course and that’s a straightforward comment for this price, but I’m not talking about the detail retrieval or a superb technicality. Instead I highlight the beautiful articulation, control of sibilance and good extension. It’s a pleasure to listen to and if anything is harder to find than good mids in sub-300 $ USD range, that’s obviously this qualitative treble response. I found that in HISO and what else one should expect for the price?


Overall HISO shines through with it’s cohesiveness, nice and sweet sounding mids and articulated treble. On the technical side of things, one should be aware of the technical limits of this IEM. Well, there are 2 BA drivers and you shouldn’t expect a god-like separation or great resolution. When I compare it to the IEMs with similar price levels though, I need to say it doesn’t fall behind. Thanks to the great treble response that I mentioned, HISO gives a high-resolution feeling to the listener. Separation is not great and I think that’s partly because of the mid-bass presence, but still if you match it with a flat source I think you won’t be disappointed.

It has a fairly good soundstage. Width is quite good especially and positioning of elements is clear. Length of the stage is not very strong though. Detail level is very nice for a warm sounding IEM at this price. All you need is a good source that can unveil these qualities.

I noticed that if you give some good power, HISO sounds better. So despite being a small and pretty IEM, it excels. Straight from my DAP it wasn’t the best, then I switched to my desktop DAC/AMP and it sounded better. When I flicked the gain switched though, it even sang better, especially the bass quality was better with a tighter beating. I suggest that more power can feed the bass driver more properly, so that it gets more controlled with higher quality. I highly recommend using a good powered source with this IEM, possibly with the addition of a portable amp (one of Heir’s?).


vs. LZ-A4LZ is bassier and it has much more subbass presence with a strong punch. The soundstage is better with it as it has a distinctive speaker feeling with the open-back design. HISO has more mid-bass when compared. Positioning on the Heir is better and the resolution is similar. HISO has warmer and fuller mids, LZ’s mids are thinner and laid back in comparison. LZ feels V-Shape sounding when comparing head to head.

vs. Aedle ODS-1: ODS-1 has a very similar bass character to HISO. It has the same mid-bass significance which I found a little bit too much on Aedle. Mids are also identical in terms of tonality, but technically Heir is better with a better seperation from other freq’s. Aedle has laid back treble when compared to Heir, which has better extension and articulation. Stage performances are around the same.

vs. Oriolus Forsteni: I haven’t posted the baby Oriolus’ review yet but I wanted to include it here. Forsteni has better seperation and resolution, narrower stage, a tad thinner mids and better controlled bass overall. Trebles are similar in terms of timbre and extension, but because of the better seperation Forsteni feels a little more refined.

vs. Earsonics ES-2Dark and thick mids, fairly good soundstage and good tonality are the shared points between the two. ES-2 has a little less treble accentuation, and a better controlled mid-bass. High are better with the HISO especially in terms of definition.

vs. Noble SavannaMuch flatter and brighter, Savanna is a flat monitor. So they’re very different from each other. HISO is more musical with a smoother and warmer response, on the other hand Savanna has better resolution and micro details. They’re the exact opposites. I think the only resemblence is the forward mids, but in different tonality.


For 329$ USD you get a great looking, durable and a very portable IEM with a warmish sound and a good quality treble, which is so hard to find at these price levels nowadays. Bass excels better with more power but if you’re an enthusiast like us, you won’t face much problems finding a good portable amp or a straight powerful DAP.

Also the fit is great and that’s essential for a IEM. To be honest this is one of the best IEMs for the price, you just need to find a good synergy with some driving power. Nice job from Heir Audio with this.

I hope we can receive more products from Heir. I’m curious about their amps and cables, and hopefully they can provide their higher level IEMs for us to review.

4.3/5 - (21 votes)

A keen audiophile and hobby photographer, Berkhan is after absolute perfection. Whether it is a full-frame camera or a custom in-ear, his standpoint persists. He tries to keep his photography enthusiasm at the same level as audio. Sometimes photography wins, sometimes his love for music takes over and he puts that camera aside. Simplistic expressions of sound in his reviews are the way to go for him. He enjoys a fine single malt along with his favourite Jazz recordings.

Be first to comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.