Campfire Audio IO In-Ear Monitor Headphones - Official Thread

Yea. Umm things could have been handled a little bit better with the mixed opinions.

All the new changes look great! :smiley:


In reading the HF IO thread today, I recognize common keywords for the 2 BA profile even in the good reviews. I’ve come to believe that BA IEMs need something greater than 5 drivers to both span the full frequency range and smooth out the sharp peaks.



Mr. Stark, I don’t seal so good.
Sorry, couldn’t resist. Doesn’t seem like people are having much of a seal issue with these and they’ve definitely piqued my interest. Might end up being my first pair of CAs if I can swing it. @antdroid, looking forward to your impressions of them. You’re the swing vote for me.

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After all the recent drama, I must say I m also very much looking forward to your opinions!

To get this out of the way first…

Well, drama-wise – my measurements match pretty much what was posted earlier if you like to interpret graphs. The yellow/green curves are from reddit user malvinnvn and mines are the red and blue ones using different tips. I tried to match the same tips and settings he did, but unfortunately the Symbio tips I had, which is what he used, didnt fit the coupler. He sent me his exported data for comparison sake.

Listening Impressions:

In terms of listening, I find these not the best things for vocals, and specifically female vocals have a weird haze to it. Cymbals also exhibit this behavior. It has a low fidelity sound to it – a veil. I think some of the more negative impressions on head-fi have some merit, in terms of how I am hearing it. The bass and low end sounds great for my preferences and that is an improvement over the Orion. Male vocals don’t exhibit the same issues as females, though there still is a weird tinny-haze to them occasionally.

Treble is much more extended than Orion, from memory, and has a little bit of sparkle like Andromeda, though not as distinct and detailed. To me, it sounds like a really odd sounding mix of Orion and Andromeda with some weird mids that makes it not currently recommended for listening to vocals. It may perform better in instrumental music, which I havent dived too far into yet.

I’ve been A-Bing back and forth with Andromeda, Solaris and IO. Listening to Fleetwood Mac, Norah Jones, Chvrches, Chris Stapleton, U137, Radiohead, Massive Attack, and Cocteau Twins. Of those, U137 and Massive Attack sound pretty good, and they are more instrument/beat driven than vocal.

I think if I was blindly listening to these without a reference point, I’d still find it a little off, but could get used to it. But when put into perspective with another IEM which have more coherent mids, these sound a little off.

I’ll continue to post more impressions a little later.

Addition: Fit-wise, the longer Solaris-style bore makes this shell much more comfortable for me than the Andromeda/Orion and previous generation Campfires. I barely feel these on my ears and the sharp edges don’t touch the back of my ears anymore.

Also: Thanks for @taronlissimore for sending me this community preview unit to test out!


I actually had half a post written yesterday with impressions as I spent the weekend with the SR15, Io and Polaris 2 but then I remembered we sent you a unit.

Impressions are pretty spot on with what I hear. I think a lot of the disappointment around the Io is that people were hyping it up as a mini-Andromeda when there was nobody official that actually marketed it as a mini-Andromeda so the hype was too real. I think once they have been on the market for a month or two and people’s expectations are more in line with reality they will be talked about in a more positive light. Even though they aren’t mind-blowingly good, I find I am enjoying them for what they are. I do want to some A/Bing with the Astell&Kern Billie Jean since it’s another 2 B/A that has a different tuning. The weird timbre that is described isn’t as noticeable to me on most tracks but that could be because of music choices or my ears (since I sat beside twin-prop plane engines for 5 years).

The Io (as well as the Polaris 2) both have a much smaller shell then the Andromeda which is also immediately noticeable. Definitely the most comfortable Campfire IEMs to date.


From what I’ve seen the IO shares the same shell as campfire’s other premier offerings they are pretty comfortable to wear as they aren’t that heavy; I’ve had these since they were first released and in my opinion they seem to shine in the indie, or rock genre. Generally music that involves the heavy use of acoustic instruments. I would not recommend these earphones for edm or hip-hop. The IO seems to be lacking in bass, but I think that’s to be expected due to the IO being a dual balanced armature setup.

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Welcome @Neardanger!

These are very comfortable. I think the new longer nozzle helps with comfort for me the most as the previous iteration with the shorter nozzle tended to fall out or not fit quite snug without pinching the sharp edges with my ears.

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After listening to IO for a bit more tonight, I decided to try to play with EQ settings. Here’s a setting that I feel puts it closer to my personal preferences, with a little small added bass boost.

First photo is settings for EqualizerAPO. Second photo is the Room EQ Wizard equalizer simulation tool.

The blue line is the harman Target curve, which I don’t particularly care for too much, but is a good reference point for me since I do like parts of that curve. The darker red line is the IO stock Frequency Response, and the lighter Red is the simulated EQ response.

I generally like the sound of this, but it’s still just slightly off, probably from so much EQ. The 2.88KHz FR gain can be changed from +10 to +14 depending on preferences. Maybe even as low as +9. I chose +13 for now.

I threw in a Low Shelf Filter just to see how it handles subbass EQ. It requires quite a boost to be very noticeable.

Untitled.png Untitled2.png

The idea of this EQ is to bring the mids more forward to a more natural sound to me. I feel like a lot of the “haze” I was calling it earlier gets lifted. There’s still some artifacts left, but vocals, and more-so female vocals, are now not trapped behind the drum kit (and behind the curtains too), and brought back to the center of the stage. Male vocals join in for the ride. Guitars have more zing to them, and cymbals and hi-hats crash more naturally to me, as you can now hear them from outside a sheet of cloth. (again, these are my impressions).

With this EQ active, the spaciousness of the original sound profile, and extended treble and nice smooth bass puts this one above the Etymotics for me since that one is very closed-in sounding, and I prefer a wider soundstage. Despite the EQ though, I still hear traces of haziness and don’t know if that’s inherent in the design or if it’s distortion from too much EQ work, or both.


Hi and welcome @Neardanger.

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Great work as always @antdroid.

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Hey all. Still spending some more time with these to make my comments more legit and insightful.
Bare with me. The I0’s tuning is quite unique to me. It is hard to form exacting comments and opinions at this point of only 2 weeks of listening just on my way to work and back.

Talk soon. Hope all is well and happy Friday! :smiley:


Check out @antdroid’s full review of the IO, just posted on!


Great review @antdroid! We still need to meet up soon… probably next week! I should have more bandwidth for a lunch meeting or coffee meeting.

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Thanks! The IO is a very unique tuning, and I’ll give CFA credit for trying something new here. If the mids were tuned more like Orion, this would be a slam dunk top rated IEM for me.

Yea, this week has flown by and what not. I may be a bit busy next week but I can probably find time to meet up. Do you want to check out the IO too?


I think I’m good on IEMs :wink: they really just aren’t my thing… I wouldn’t want to waste anyones time trying to review them lol.

If not next week I am free the beginning of the following week… but I would have to check my schedule…

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Hi guys! I’m new here, just purchased a pair of Solaris myself today but am just having fun reading impressions/reviews in the meantime. I think there’s a small typo in your review @antdroid when referring to the andromeda having a dynamic driver for the bass - I think you possibly meant Solaris? Cheers.


Ah! good catch. Yea I mixed my IEM specs up. Maybe @Torq can help and edit that line out. I do find the IO to feel tighter/quicker than both Andromeda and Solaris in the bass kick department.

Also - Welcome to the forum and thanks for the immediate help :smiley:


Done! :wink: