This is a nice little product. It’s really good for IEM/headphones that are highly sensitive (really low impedence) or for amps (amp/dacs) with non-linear volume controls.
Having said that, I bought the iFi Uno amp/dac which has a very non-linear volume control and it makes using my Thieaudio Legacy 4 IEMs (9.5 ohm of impedence) very tricky. At, say, the 9 o’clock position - very little volume. At 10 o’clock, slight volume increase. At 10:30, BOOM! - instant deafness! :-) With higher impedence devices, it isn’t quite as dramatic but it’s still either all or nothing. The iFi IEMatch+ assures that the user will have a much greater range of volume adjustment to find the perfect level.
The iFi IEMatch+ is also pretty effective at attenuating really bright or sibilant IEM/headphones which means it also should easily drop any background noise well below the threshold of human hearing. Having said this, you can also buy the Match if you simply want to have a smoother and less fatiguing sonic signature. Attenuating the frequencies down by -12db (in ‘High’ setting) can allow for a greater volume input without introducing (audible) harshness and distortion. However, the ‘Ultra’ setting (-24db) is quite low and I can’t think of an IEM that can take advantage of that, which is not to say there aren’t any. Maybe the next version of the Match can have attenuations of -6db and -12db, which could work better when you need some reduction and times where you need a little more.
Overall, the IEMatch+ is highly recommended, whether you need to tame highly sensitive IEM/headphones or just want a warmer, richer sound.
Great. Eliminates hiss and also attenuates RFI noise from phone. (For reference: iPhone 13—> Mojo 2 —> Andromeda)