Product page: https://campfireaudio.com/shop/io/

MSRP: $300

Driver specifications: 2BA

Where I can imagine listening to the Polaris V2 at my own personal time, I refuse to entertain any fantasy that involves me listening to the IO outside professional intentions.

I have endured 2 hours of listening with this thing, swapping tips and sources to eliminate every variable that could make the IO sound bad. And with every variable exhausted, I thus came to the conclusion: the IO is inherently bad.

Right right, you want an explanation. There are two aspects that kill the IO as a competitive IEM in the market: the resolution and its tonality (and as an extension, its timbre). I’ll start with the easier of the two to explain.

The IO simply struggles at surface level detailing. The attack function of its transients are rather blunted and dragged out, resulting in notes that lack definition and cleanliness. The decay seems to be fine per usual BA expectations, so it seems that the heavy smearing that I’m hearing is due to the less-than-stellar attack. The end result is an IEM that sounds like a fuzzy, low resolution image, barely being able to separate quick percussive hits prevalent in metal genres.

All that would’ve been fine if it at least sounded correct, but the IO fails the hardest in timbre and tonality. The simplest answer is that the IO sounds wrong, though to explain why it is so requires an analysis of its frequency response that I shall now touch on, at the risk of being called a dirty measurbator by the brave and attractive people on the internet.

The IO has its “pinna gain” at 1.7kHz, which is essentially the middle-of-nowhere in the context of academic neutrality. Hammershoi & Moller’s Diffuse Field peaks at roughly 2.5kHz, and the Harman research’s own approximation of Diffuse Field peaks even later at 3kHz. This is another problem with the IO in that its “pinna gain” is of such a high Q-factor that it begins to dip where it was supposed to maintain SPL, resulting in a peak that does not correspond with any academic definition of neutral. Subjectively, it sounds like an odd emphasis in harmonics that shouldn’t be emphasised, and there is barely any bite and energy due to the suppressed upper midrange.

You could argue that academic research on neutral does not necessarily prove how good an IEM would sound, to which I would agree wholeheartedly. Again, I am only defaulting to interpreting the graph because there is literally no other way to explain why the IO sounds this wrong. I have physically heard it and I would personally be satisfied with the statement of “The IO is bad because it sounds wrong”, but I know that many of my readers would not be satisfied with such a copout answer so here is my somewhat-objective explanation on why it is so.

The IO is still listenable and me critically listening to it for 2 hours should be proof of that. But it is far from being even decent.