Fit and Comfort

Seen above is one of the included size M silicone ear tips installed on the right ear bud and inserted into an artificial ear mold. I have averagely sized ears, and the ear mold seen above about perfectly represents my own experiences. Size M silicone tips are my go-to for testing in general since foam tips are not included by some, as was the case here. The size of the ear buds is about average, but it is the design that makes for the best IEM fit I have had to date. It's a bold move to sculpt shells for universal IEMs such, especially when including size SS tips to cater to some of your audience in the east, but it has paid off to where I suspect many with average-shaped and sized ears will have a good time with the fit. These also weigh ~7 g each without the cable, so there is no physical fatigue, either. The excellent fit I had more or less accounted for any ear-tip issues, which had these work well in my ears with the stock ear tips. If the fit is good for you too, It's also quite easy to get a good seal with plenty of passive isolation, which should have the dynamic driver work better.

Audio Performance

Audio Hardware

I once again had to resort to photos on the product box, but they do a fairly good job illustrating the make up of the Ovidius RX-100 and acoustic chamber. Ignoring the bad English translation, we see this is a single dynamic driver (DD) and two balanced armature (BA) driver setup. The DD uses a 10 mm diaphragm inside what I believe is a cavity inside another for further isolation. The diaphragm uses some form of "nano carbon crystal molecules," which is such a general description that I don't see anything useful to discuss here. It is placed inside the shell, and the dual BA drivers appear to be a set of two as opposed to two individual units. These are, as Ovidius puts it, independently developed by the company with one for the mids and the other the highs, leaving the bass response to the dynamic driver. The BAs are inset in the sound tube, which is the de-facto nozzle here, which reminded me of the FiiO FH5s.

Driving the hardware takes no more than with your average IEMs, with a rated impedance of 36 Ω that is compensated for slightly with an above average sensitivity of 116 dB at 1 kHz, which I presume is 116 dB/mW and in turn works out to ~110 dB/mW. A standalone DAC/amp intended for high sensitivity earphones is not a bad idea thus, if only to run at lower volumes without clipping or a hiss, and going with one of the portable Bluetooth options we have covered before also makes this a wireless solution. The lack of a 3.5 mm audio jack for most phones these days is another reason to consider a DAC/amp that takes digital input and provides a 3.5 mm jack since you will otherwise have to use an adapter anyway, or even a dedicated DAP. If not on the go, space is less of an issue, but the relatively short cable might be a potential handicap if connecting to a PC as the audio source. While ~10 cm longer than average, that is not enough to really make a practical difference.

Frequency Measurement and Listening

I will mention that I have a general preference for a warm neutral signature emphasizing a slightly elevated bass and smooth treble range with detailed mids and good tonal separation. I also generally prefer instrumental music over vocals, with favored genres including jazz and classical music.


Our reproducible testing methodology begins with a calibrated IEC711 audio coupler/artificial ear IEM buds can feed into enough for more ideal isolation. The audio coupler feeds into a USB sound card, which in turn goes to a laptop that has ARTA and REW running and the earphones connected to the laptop through the sound card. I begin with an impulse measurement to test for signal fidelity, calibrate the sound card and channel output, account for floor noise, and finally test the frequency response of each channel separately. Octave smoothing is at the 1/6th setting, which nets a good balance of detail and noise not being identified as useful data. Also, the default tuning was used for testing, and no app-based settings were chosen unless specifically mentioned. Each sample of interest is tested thrice with separate mounts to account for any fit issues, and an average is taken of the three individual measurements for statistical accuracy. For IEMs, I am also using the ear mold that fits to the audio coupler for a separate test to compare how the IEMs fare when installed in a pinna geometry and not just the audio coupler by itself. The raw data is then exported from REW and plotted in OriginPro for easier comparison.


The IEC711 is such that you can't really compare these results with most other test setups, especially those using a head and torso simulator (HATS). The raw dB numbers are also quite contingent on the set volume, gain levels, and sensitivity of the system. What is more useful information is how the left and right channels work across the rated frequency response in the Ovidius RX-100 IEMs, or at least the useful part of it. The left channel was separately tested from the right one, and colored differently for contrast. I did my best to ensure an identical fit for both inside the IEC711 orifice, so note how the two channels are within +/-1 dB through the bass and mids until it gets to about 4 kHz, after which there was some channel imbalance. I listen to IEMs for a while, do measurements, and then play a mix of white/pink noise for a minimum of 15 hours to test for any burn-in effects before repeating the listening and at least a couple of measurements. So in this case, I had listened to these first and noticed something was potentially off in the presence region before the measurements verified it. After realizing this, I did notice it more, especially with jazz and classical music. In the price range these operate in, I don't expect individual checking and calibration, but do expect channel matching. It could be a case of the custom BA drivers in the sound tube being more susceptible to fit, but keep this in mind nonetheless. The good thing is that there is minimal difference going from the ideal IEC711 coupler cylinder orifice to the artificial pinna, with the peak shifts generally a measurement artifact.

There isn't much in the way of Ovidius describing the expected sound signature, with the same bad English translation somehow stating that these are best-suited to listen to good music in times of peace, and that the music will move you with emotions. Okay, then. I don't think I shed any tears this time around, but I did leave impressed with the Ovidius RX-100, so that's a good start. The tuning may look like a V-shaped signature, but really comes off more balanced than that. Yes, there is good bass energy, but primarily with detail in mind. I would not recommend this set for bassheads; it's got some sub-bass thump, but it is not pronounced enough to feel the drop in EDM and house music. That said, bass and double-bass guitars strum along nicely, with mid-bass being where things get groovy. Jazz and funk music in particular are really good, with male vocals benefiting from the added energy due to there being sufficient range and tonal separation with the dynamic driver.

So while tuning with the single dynamic driver is absolutely fine in my books, I am not sure if this hybrid design makes the most of it. As mentioned, macrodynamics are less than ideal, with no real impact behind the rumble you will feel. This is not a negative thing in itself, just that it may not be what you are looking for. For my specific tastes, this worked out fine since I prioritize detailed mids and balanced highs more, so I was curious to see how Ovidius' self-developed BA drivers worked out. I would have liked more range in the mids again, but do see what the company is going for. This comes off as a more mature take on the mainstream tuning, wherein the likes of even eastern pop music with a mix of instruments and higher pitched vocals are a very good fit. Think K-pop and baby metal for a better idea of where the Ovidius RX-100 shines. Notice how the tuning response starts going up from ~1 kHz? This is where pop and jazz again come into play for more western music. This then leads to the expected compensation for in-ear resonances, although it is somewhat brighter than I was expecting with the bass response it had.

It's not a bad thing as long as you are aware of it. Things certainly don't get shouty, and the smooth transition to the treble response helps. Once again, I think the use of the dual BA setup helped, with a steady and non-fatiguing tuning allowing for hours of enjoyable listening to instruments of all kinds. Percussion Instruments in particular shined for me, and second-order harmonics from guitar notes also hung around in a very satisfying manner. There are plenty of other IEMs that handle the treble response better, but I can't really think of many that are in the same price range as the Ovidius RX-100. I do think the tuning measurement of the left channel is more representative of the set as a whole since the changes going on aren't that big in reality. I found myself enjoying classical music and jazz a lot, which also reminded me that I wanted more. Imaging especially could be better as there was a slight haze when larger groups of instruments were playing. This was somewhat mitigated by the RX-100 having a fairly rounded soundstage, with the shell design possibly playing a role here, meaning that it was again reminding me of being quite good with the likes of smooth jazz playing with a fixed source in a more intimate setting. A full jazz band with 5–6 people spread out might be challenging imaging-wise, but not as much as as an entire orchestral performance in a concert hall.

Comparison to other IEMs

At this point, I have more IEMs tested to where I can do a couple of things when valid. Seen above are graphs where the first comparison is with IEMs of similar tuning in my collection, and then there is one with IEMs in a similar price range. In the former, I would undoubtedly go with the Ovidius RX-100; the FiiO FH5s did quite a few things well, but its resolution is lower in a couple of places, and that 8 kHz peak is not great at all. The different switches don't do much in that regard, including where the bass boost is really more of a mids and treble dip as we saw in the review of the same. The IKKO OH10 did get a nice price cut since the review, which does make it quite attractive, but it is physically fatiguing in all the ways the Ovidius RX-100 is not. The RX-100 is also more detailed and has more range in the mids for my preferences, and both are on par for technical deficiencies. When moving to similarly priced, tested IEMs, it's really not a fair comparison since all three are tuned so differently and intended for different use cases. For what it is worth, I would give the technical edge to DUNU.