The Hidizs H2 has some general audio specifications listed so let’s start there. We already mentioned the rated power output of 8mW which again does not seem like much but this unit seems underrated and seems to have the ability to power most IEMs in my collection to volume levels that I would describe as almost unsafe. It does seem louder and cleaner than my Android phone.
Distortion seems low in listening tests and is rated at 0.008% at 1 kHz and that seems right to my ears and the one area which I would consider its weakest besides power output is the SN ratio of a rated 92 decibels which is still acceptable for Hi-res audio. Dynamic range seems adequate.
The H2 frequency response hit me with a somewhat common low-powered device frequency response curve that restricts bass response below 20Hz which is done at the DSP level of the BT chip.
This is a smart thing to do at the tuning level because it acts as a subsonic filter that cuts those lower rumbling frequencies which not only hurts sound quality by wasting valuable amplifier power and causing sound anomalies but also hurts battery life.
I ran a tone sweep on this device and that demonstrated the low-frequency cut-off and that it also was free from noise in the upper frequencies which I find quite uncommon for a Bluetooth device even nowadays. For the record, I did most testing with the FiiO BTA30 and using the LDAC codec.
So the bass response is pretty solid and clean enough and digs just deep enough to be enjoyable with a flat toned frequency presentation overall beyond the bass response, with a good amount of high-frequency extension for a Bluetooth device especially at the higher quality codecs, and presents it all with a somewhat open and airy soundstage. Imaging was fairly precise as well.
I did connect the Hidizs H2 with a USB wire to my PC and ran the output to higher quality amplification like the Topping A90 and the iFi ZEN CAN Signature which will also be reviewed soon and obtained pretty decent sound quality.
The Hidizs H2 works well as a standalone DAC. A more expensive DAC will sound better of course because there is a touch of harshness in the midrange and some in the high frequencies when you use the H2 as just a DAC and use high volume levels.
Perhaps a touch more of deep bass would have been more pleasant-sounding due to the lack of deep bass presence. It would also warm up the sound signature.
But to be honest, for the asking price and if we overlook and exclude the Bluetooth section altogether, I would say with confidence that there is a good fifty-dollar DAC here that has a surprising amount of accurate imaging while retaining a decent frequency balance with low distortion. Hiss was not an issue either.
The Bluetooth range on the Hidizs H2 is somewhat of a mixed bag but not too shabby and rather common. The rated specifications are approximately 10 meters, but with UAT or LDAC, the listed range drops to 4 meters but I got slightly different distances.
I got approximately 28 feet which is less than specified on APTx, AAC, or SBC but with LDAC, I was able to go further out than the rated 4 meters which translates to about 16 feet and I got 19 feet. I was unable to try the UAT range but I assume is similar to LDAC. I would say the listed ranges are more or less there.
Latency was not much of an issue and the H2 does better than most with less than a 0.2-second delay which is the average for today’s Bluetooth devices. Of course, that varies with the codec being used. The APTx LL is the best if latency is of major concern to you and the H2 has it available.
Let’s go through a small list of full-sized headphones to see how they pair together with the Hidizs H2 Starting with the Hifiman Sundara. These full-sized Planar Magnetic cans are not the most efficient and seem to like lots of power and I would not use a less efficient can than this one with the H2.
What is most affected by this combo is dynamic range and the bass seems to take a rear seat due to a lack of drive power. The rest of the frequencies come through just fine and you even get most of the microdynamics and detail. Volume suffers as well and if you like loud, you will constantly desire more volume.
So yea, what about a more efficient can like for example the Phillips SHP9500? This full-sized headphone is very efficient and prefers clean power over high voltage output and does very well with the H2. If you have a very short 3.5mm dual male wire you could go minimal wireless with the SHP9500 and I recommend this combo or a similar combo with the Hidizs H2.
Volume was adequate just do not expect concert levels and I still feel this device is better suited for sensitive IEMs. Bass was again, just adequate but the rest of the frequency range came through quite pleasantly on the SHP9500 with plenty of detail especially up on the top end while using LDAC.
I could go on for hours talking about how well the Hidizs H2 pairs up with most IEMs. For the sake of time, we will stick to a chosen variety. We’ll use a single dynamic, a dual driver, and a multiple driver hybrid IEM starting with the Hidizs MS2.
The Hidizs MS2 is a smooth-sounding and polite set that retains those characteristics with the H2. There is a touch of harshness around the upper midrange to the lower treble when paired with the H2 that is not present on the MS2 while using better amplification. Volume was at a good level with this two-driver dual voice coil setup.
I also got to pair the H2 with the recently released Kinera Norn which is a five-driver IEM with a Tesla magnet-driven dynamic driver and four BA drivers and I got very good results in clarity, bass response, and cleanliness. Both these IEMs will be reviewed here soon so stay tuned.
Another set I paired with the H2 was the single driver FIIO FD5. The volume level was higher with this IEM due to the high sensitivity of the driver and this made a good pair. Bass was somewhat impactful. The midsection was clean and high frequencies were clean enough although I think the highs are the weak point of the FD5, not bad, just the weak point.
To throw another set in the mix I pulled out the TRI I3 which is a 3 driver hybrid with a dynamic, a BA, and a planar magnetic driver. These are the hardest to drive optimally from the bunch due to the Planar driver but I was surprised to get a very pleasant midrange response, good bass, and sharp highs but lost around a few decibels of volume compared to let’s say, the FD5.
The Hidizs H2 is a rather unique device for a particular need that turns out to be one of the most versatile pieces of hardware I have. The small size and all the abilities it has, make it a high-value item in my opinion and quite a bargain for what Hidizs is asking and for all this device does.
The Hidizs H2 is an extremely tiny device that accepts a Bluetooth transmission up to LDAC and UAT plus all the rest including APTx LL with a one-touch NFC connect feature, a built-in microphone with CVC, Built-in volume control with full phone media control, and voice prompts, a headphone amplifier which doubles as a line drive plus a USB DAC amplifier dongle all in one.
It also can go anywhere you need quality audio wireless with no need to set up complicated network boxes and for the asking price, I honestly do not know of any device that does so much so well for such a small investment.