At first glance, you might mistake Campfire Audio’s Solstice In-Ear Monitors for earbuds. They’re not. In-Ear Monitors (IEM) are what earbuds want to be when they grow up. And if you can swallow the high price, the Solstice puts every other earbud to shame.

Over the past few years, I’ve reviewed some excellent over-the-ears headphones and earbuds, topping out at models costing as much as $600. But, to be truthful, I’m not quite as big a fan of earbuds, though I’ve also tested some that offer excellent sound. That was before Campfire Audio offered me a custom-fitted pair of Solstice monitors. These suckers will put a substantial dent in your wallet, priced at a budget-watering $1,499. That’s not earbud price territory. But if you have a large enough wallet, be prepared to open it wide–the Solstice IEMs are worth it.

What’s the difference?

There are some very substantial differences between earbuds and In-Ear Monitors. One is price. For the most part, in-ear “headphones” at this price are for monitor use, either on stage or in a recording studio. Some examples are the Audeze Euclid and the Sennheiser IE 900. Even high-end earbuds tend to top out at $600-$700. Another significant difference is the driver technology used to produce the sound. Higher-end monitors tend to have more sophisticated drivers and extended frequency response.

Finally, it’s rare to find a wireless IEM, as the most common wireless technology for earbuds uses Bluetooth, which has a slightly detrimental effect on sound quality, something that you don’t want when laying out megabucks for near-perfect sound. And when you see a performer wearing in-ear monitors moving around a stage, they are almost certainly wearing a wireless receiver operating at radio, rather than Bluetooth, frequencies.

Solstice IEMs: Stick ’em in your Ears

While Campfire Audio has a range of IEMs, the star of the show are the Solstice phones. These are custom-fitted, and I had to get molds made of my ear canal. This required the services of a local audiologist and is pretty much the same process as having a set of custom in-canal hearing aids made. Campfire Audio has a list of audiologists who can make the molds, but most local hearing aid centers will do it for a fee—in my case, $60.

The process involved an audiologist mixing a silicone goop and stuffing it into my ear. The most uncomfortable part of the process was biting down on a plastic block (which positions the ear canal) for about 10 minutes while the goop solidified. The audiologist popped them out of my ear, examined them to make sure they were what was needed, and put them in a box, which I mailed to Campfire Audio (they supplied the mailing label). A couple of weeks later, I received a package with the custom Solstice monitors. Considering that every pair of these IEMs are handmade, waiting a week or two doesn’t seem like much of an ask.

Small earbuds, and especially in-ear monitors, use dynamic drivers, balanced armature drivers, or a combination (hybrid drivers) of these sound-producing elements. This model features five balanced armature drivers and Campfire Audio’s T.A.E.C. (Tuned Acoustic Expansion Chamber) modeled 3D printed interior enclosure. Essentially the company custom 3D print the monitor interior to enhance the performance of the five drivers.

As part of my testing, I compared the sound quality between the Solstice and a pair of Campfire Audio’s Andromeda 2020 IEMs, which are almost identical except for the custom fit of the Solstice, and priced at $1099. I also did some comparative listening between the Solstice and high-quality Meze Classic 99 headphones.

I’ll be honest. Even switching back and forth between the Andromeda and the Solstice in the same listening session, I didn’t hear much of a difference playing the same setlist with each IEM. The most significant difference I noticed was the degree of audio isolation between the universal-fit Andromeda and the custom-fit Solstice. That’s what you’re paying the extra $400 above what similar models cost. Additionally, the Solstice IEMs had just slightly more bass punch, a result of audio coupling due to the closer fit of the custom phones.

How I Tested

To help test the performance of the Solstice, I relied on AudioCheck, which provides a multitude of tests for determining the response of headphones, earbuds, and even room speakers. It’s not perfectly scientific, as it relies on your ears’ responses to make the ultimate decisions. But it does make for a good testing ground.

In my testing, I used lossless music from Amazon Music HD Ultra and the AudioCheck test tones. I also listened to the same song on Spotify ((which is not lossless), YouTube where available (which has even less quality than Spotify on many tracks), and Amazon Music HD Ultra, which has greatly enhanced bandwidth.

While many of the CDs I own aren’t lossless, there was a noticeable difference in quality listening to the same tracks using a pair of high-quality Meze 99 Classic over-the-ear headphones and the Solstice. The Solstice provides a crisper listening experience even on standard definition tracks. The particular over-the-ear headphones I used provided rich sound, with a noticeable greater bass response. Still, compared to the Solstice’s flat response, it did somewhat color the reproduction.

Keep in mind that great quality IEMs deserve equally great quality music sources. This is especially important when trying to match the stated frequency response of the music source to that of the IEMs. Campfire Audio states the response of the Solstice from ranges from 8Hz to 20kHz, so you should get great audio definition with pretty much any music source. But if you plan to spend this much money on a set of IEMs, you should also splurge on the streaming service(s) you use to get lossless audio.

The Bottom Line

The bottom line is that the Solstice In-Ear Monitors sounded fantastic on almost every track I listened to, whether from CD and lossless streaming audio tracks on Amazon Music Ultra HD audio streaming service or the performance in the tests on AudioCheck. The Solstice has virtually flat response from low bass to high treble. According to Campfire Audio’s description, they claim a slight roll-off on the low mid-level, but it wasn’t something I could detect in my testing.

This flat response is especially noticeable in tracks of live performances, even those recorded years ago. The IEMs also provide excellent spacial capabilities, allowing you to audibly place where a performer of an instrument is on a virtual stage when listening to some live performances (depending on the original recording quality, of course).

The most significant difference between the Solstice IEMs and similar Campfire Audio IEMs with the same driver and tuned enclosure configuration is the comfort level and the amount of audio isolation that the Solstice provides. The custom-fit Solstice does take a bit of getting used to; they are tightly molded to your ear canal shape.

And while the audiophile fit doesn’t protrude as far into the ear canal as the artist fit, the custom-fit does provide more of a disconnect from the sounds around you. One thing I found that took a bit of time to get used to was the cable routing, which goes up over and in the back of the ear. This is almost ubiquitous in stage performance IEMs, and I found it slightly uncomfortable having the wire run down the back of my ear for the first several minutes I used the IEMs. After that short while, I forgot about it.

The bottom line is that these IEMs sound terrific. One caveat though. Before you spend this much money on in-ear monitors, make sure that your music source is good enough to make use of the incredible range these phones offer. But if you’re an audio purist, or have a production studio in your dwelling,  these beautiful IEMs will fit the bill. And if you’re going to wear the IEMs for hours on end or need the audio isolation for performing or producing, the additional cost of the custom-fit Solstice is very much worth it.

Rating: 9/10

Price: $1,499

Here’s What We Like

• Mind-blowing audio response
• Fancy leather carry case
• Litz wire cord

And What We Don’t

• Expensive
• No 1/4-inch plug adapter