Acoustune HS1790TI Universal In Ear Monitor

thaslaya's star rating system:
☆☆☆☆☆ - Fantastic!
☆☆☆☆ - Recommended
☆☆☆ - There are buyers but not for me
☆☆ - Can't see the appeal
☆ - Product is a failure

Disclaimer:
These were lent to me by a friend for trial/review. All thoughts and opinions are my own.

Gear used:
●LG v30+
●Samsung Galaxy s22 Ultra
●Samsung dongle
●Hiby FC4
● Kiwi Ears Allegro
● iFi GO bar Kensei

Source:
Listening was done through Amazon Music HD or Ultra HD.

Introduction:
Founded in 2013, Acoustune is a Japanese based audio company and iem manufacturer that developed their own unique dynamic driver material called "Milinx". According to their site, it's a "medical synthetic base material, formed into a thin film". While Accoustune is not a prominent mainstream brand, some of their iems are instantly recognizable due to their unique shell design. The HS1790TI released in 2022 and currently retails around $750-799. They feature a single dynamic driver utilizing Acoustune's own Milinx diaphragm paired with the rigidity of titanium to prevent resonance. Thats a lot of tech lingo but let's see how they sound.

Build, fit, ergonomics:
The HS1790TI comes in an Acoustune branded box which contains a large carrying case, the iems themselves, a 3.5mm terminated Pentaconn cable, a smaller case, and a plastic holder for 6 sets of tips. The inclusion of both a large, hard travel case and a smaller, more pocketable one is great and more in line with what you'd expect to see in an expensive purchase. The shell showcases Acoustune's intricately crafted design that closer resembles something you might pull off the engine of a high performance race car than an iem. This style doesn't align with my personal taste but I can see why people could be drawn to them. The shell housing is made of titanium and has a great build quality with a nice weight balance. The fit is a bit difficult though as there are some edges and protrusions that caused me discomfort, particularly under my tragus. After some trial and error, I was able to get a fairly stable fit but I found myself having to readjust them over longer sessions. The nozzle length might be a bit on the short side at least for my ears. I would have liked them to be longer for a more stable, deeper insertion. The HS1790TI utilize Pentaconn connectors which makes cable rolling more difficult as it's less common than MMCX and 2 pin. The stock cable honestly feels a bit cheap and rubbery. The build quality doesn't match that of the precision machined shells and is better suited to a set under $200. It does come with a nice Acoustune branded leather cable tie though. Not all of the stock tips were included in the holder since this set is borrowed so I can't speak much on their quality and fit. I used my prefered Penon Liqueur tips as I find their seal to be best for me.

Sound impressions:
I woud describe the HS1790TI tuning as warm/neutral with boosted bass. It does a remarkable job of straddling the fine line between being too warm, making highs lack shimmer and sparkle, and having too much energy in the upper frequencies that can present as fatiguing and over detailed. The soundstage is on the average/narrow side to my ear sounds and comes off more intimate with vocals and mids taking center stage. Even though it can sound somewhat restricted, it never feels claustrophobic or congested and seperation is very good giving each note its own room to breath. It almost sounds a personal concert is being played just for the listener in a small venue. While they aren't necessarily hard to drive, they do respond well to power and benefit from amplification to bring out their full potential. I found them best paired with the more powerful iFi GO bar Kensei on Turbo mode compared to the Hiby FC4 and Kiwi Ears Allegro.

●Lows - Bass is big and subbass rumble reaches pretty low. The bass gets even bigger with high gain on the Kensei. It can get near basshead levels when pushed but never sounds bloated or overbearing. The sub bass is more prominent and the mid bass stays clean and doesn't bleed or hinder the mid frequencies. It's not the best performing bass as far as speed and tends to have a slower decay but it has great texture and a visceral quality that is more musical over technical. I would decribe them as thick and syrupy but in the best way, almost like being wrapped in a warm blanket.

●Mids - To my ear, vocals are the star of the show on the HS1790TI. They are so smooth, non-fatiguing, and inebriating and I could listen for hours. Both male and female artists sound fantastic without shout or sibilance. There is a fair amount of energy in the upper mids that could be just a tad much on certain tracks but that also depends on listening volume. The timbre is spot on and the mid frequencies have a very realistic and organic timbre. As I touched on in the lows section, the mids stay free from any bleed and have plenty of separation to shine on their own. That syrupy feeling carries over from the bass and the mids also sound rich and luxuriant.

●Highs - The treble takes a back seat to the other frequencies and that exactly matches my preference. There is plenty of detail to be heard but it's done in a musical way that keeps it from sounding cold and clinical. There's enough air and shimmer to satisfy most (maybe not the trebleheads out there) while also allowing the mids and bass to grab the spotlight and take center stage. Some of the more troublesome high notes, such as claps and cymbal splashes, stay free of any irritation for the most part. I did sporadically encounter just the smallest twinge of "hot treble" causing a slight unpleasantness but it happened so rarely that it was easy to overlook. This will also depend on listening volume but for me it didn't really retract from the overall product.

In conclusion:
Rating the Acoustune HS1790TI is difficult for me. One on hand, I absolutely love the tuning and it's definitely one of the best iems I've heard to date. But on the other hand, the shell design is not my style and the shape causes some difficulty with fit and comfort. Also at $750, it's not a cheap purchase. As most people in this hobby eventually discover, diminishing returns become very real as the price increases. Just because something is double or triple the cost doesn't mean it'll have double or triple the performance. For me this became fairly evident during my time with the HS1790TI. Don't get me wrong, they are absolutely great and could easily be endgame for a lot of people, myself included. But I've also experienced ~90% of their sound value in sets costing $300. That makes these a tough sell at $750. So what does a buyer for the HS1790TI look like? In my opinion it's someone who enjoys a deep, visceral bass, a smooth, vocal-forward midrange, and a tight treble that exhibits just enough air and sparkle without detracting from the other frequencies. Their tuning shines best with soft pop, soft rock, R&B, and other vocal centric genres. It also wouldn't hurt if the buyer loves the unique aestetics. After all, a lot of us listen with our eyes as well as our ears (at least I'm very guilty of this). Ultimately, I can recommend them if their tuning and design resonate with you. Thanks for reading and I hope I've been able to shine some light on one of the most unique iems I've had the pleasure of reviewing.


The Acoustune HS1790TI is endorsed by local wildlife.