Disclaimer: This pair is owned by James too!
Better known as a portable version of Widing ME-10EX, iHX is the very first IEM from the french company, Novodio. Compared to the original ME-10EX, Novodio iHX, which was released in January 2012, is of higher sensitivity and lower impedance. And most importantly it is way cheaper, priced at 39,90 €.
Perhaps the most distinguished feature of iHX is the proprietary 3D sound stage technology. Just like how a human HRTF works in a loudspeaker environment, a bit of signal from each channel is mixed into one another in order to create a natural stereophonic sound image, according to the manufacturer. In other words, they implemented an analog version of crossfeed into iHX. Since this kind of pseudo 3D simulation is usually realized by a DSP process, their approach is absolutely brilliant, only if the claim turns out to be real.
CON: The problematic ringing at 4~5 kHz is now even greater, and the bass response is an overkill. The graphs can't even be plotted properly. And finally, the manufacturer intentionally inverted the right channel's polarity only, in order to achieve the claimed "3D effect"... Let me assure you: That is an audible acoustic disaster, not a "3D effect"!!! Shame on you, Novodio.
ON SECOND THOUGHT #5: James asked a few question in regarding to Widing ME-10EX & Novodio iHX brothers when he shipped the items:
1. Do WIDING ME10EX and Novodio IHX share the same driver, just with different impedance?Answer #1: It is quite obvious that while the basic design philosophy is identical, the electrical design of their drivers is entirely different. Here's the comparison of some measurement parameters of both IEMs.
2. Why does the Novodio's bass sound tighter (and closer to the WIDING) when I add 100ohms? Adding output impedance should have the opposite effect on damping, no?
Widing ME-10EX VS Novodio iHX
And adding resistance in between a headphone and an amplifier output decreases damping of the driver, resulting in frequency dependent attenuation. Thus, an additional 100 Ω on iHX should yield a boost of 0.6 dB at 4.8 kHz due to loss of damping, and that's about all there's to affect.
Impulse response compared between 0 Ω VS 100 Ω
Distortion compared between 0 Ω VS 100 Ω
CSD from 200 to 20,000 Hz compared between 0 Ω VS 100 Ω
CSD from 20 to 200 Hz compared between 0 Ω VS 100 Ω
Not only the distortion figure remains the same even with additional 100 Ω, time-domain characteristics remain unstirred. Moreover, the said tonal change, which James describes as "tighter" damping, has not been observed at all.