Sennheiser IE 100 Pro in-ear monitors review

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What is it?

In-ear monitors have been a core part of pro audio for decades now, and particularly central to the task of saving gigging musicians’ skins. They’re a lynchpin of modern live audio monitoring – a welcome reprieve from the feedback-y squall of the monitor wedge, and a vital barrier against the often-damaging sound levels on stage. In recent years, their appeal has broadened, as has their affordability.

Today, in-ear monitoring is much less a preserve of the touring pros, and more so an option for bands, musicians and artists of every stripe. Building a budget IEM rig for your band is easier and more cost-effective than ever, and building your own self-monitoring system is as easy as buying a splitter cable. DJs are even getting in on the action, with in-ear monitors being a welcome alternative to bulky DJ headphones for sound isolation and accurate sound reproduction. As such, there’s an extremely vibrant market for beginner-grade, entry-level and otherwise cost-effective IEMs – at the centre of which, you’ll find the Sennheiser IE 100 Pro.

Sennheiser’s IE 100 Pro are a set of wired in-ear monitors that set out to marry affordability with pro-grade monitoring accuracy, and throw in some viable sound isolation and hearing protection in the process. They are single-driver in-ears, each bud sporting a 10mm dynamic driver with a frequency range of 20Hz to 18kHz – plenty for a clean, natural sound that’s honest without being unpleasant.

Performance

Close up of Sennheiser IE 100 Pro earbuds and jack — (Image credit: James Grimshaw)

From first impressions and on build quality alone, the Sennheiser IE 100 Pro are a compelling pair. The earbud bodies are plastic, but they’re in no way thin or flimsy; they feel fully robust in-hand, without being too heavy to wear comfortably.

Being small of earhole, I elected to install the smallest size of provided ear tip. The IE 100 Pro ship with the medium tips attached, but replacing them proved to be remarkably easy – without being too easy. The new ear tips snapped into place, and felt extremely secure thereafter.

Putting the earbuds in and getting the cables settled feels as natural as tucking your hair behind your ears

The silicon ear tips provided with the IE 100 Pro are familiar in form and feel; they’re single-flanged, which is a small shame when other shapes with better fits are a possibility. I, personally, don’t love single-flanged ear tips much, for the fact there’s so much material contact in your ear – which can lead to sweatiness and irritation in short order, against the gentler yet tighter-fitting potential of a double flange. This is nitpicky stuff though, really, and especially so at this price.

Where the wires connect to each earbud, there’s a length of posable cable so you can route them comfortably around the back of your ear, and be sure that they stay when you move your hands away. Putting the earbuds in and getting the cables settled feels as natural as tucking your hair behind your ears. More generally, the IE 100 Pro are surprisingly comfortable at first ‘plug’; they slot gamely into place, and are very content to stay without much in the way of rubbing or discomfort.

My first test with the IE 100 Pro was at my desk, listening to audio streamed from Qobuz via my laptop’s headphone output, so as to get a sense of their sound profile. I was happy with what I heard, too. Queens Of The Stone Age’s Era Vulgaris was my go-to album, and the separation between parts was remarkable. I did find the sound itself to be oddly impersonal; it’s an analytical frame that gives a lot of definition and even preference to mids and high mids especially. Coupled with a bit of treble roll-off, it adds up to something that initially feels quite biased – but on further testing, makes perfect sense.

Sennheiser IE 100 Pro in their box

(Image credit: James Grimshaw)

Taking the IE 100 Pro out to the studio for a live rehearsal, much of the low end that I felt was getting short shrift simply made it into my body via other means. I wouldn’t use these for mixing at home, but they prove hugely beneficial for making mix decisions in loud rooms. That preference for upper-range information was not only analytically representative, but also hugely practical for filling in everything that gets attenuated by plugging your ears airtight with two plastic clumps.

Speaking of which, the isolation here is great. Even at home, typing on a keyboard and auditioning some DAW mixes, I couldn’t hear my own keystrokes, or even the slam of the front door when my wife returned home. In practice, I found it very easy to focus on what I was hearing in-ear against a loud PA system.

The final test, really, was the longevity test. After a certain point, you simply forget that they’re in there; I could easily have gone over an hour wearing them without needing to take a break, and that’s not really how any of us wear in-ears anyway. One time, I took them out after a long stint at the DJ decks, and my ears sort-of missed them.

Final verdict

I think the Sennheiser IE 100 Pro, ultimately, are excellent. They’re as comfortable as they could ever be at this price point, they do an excellent job of feeding you exactly what you need to hear in a loud, boomy environment, and they’re hardy enough that I’m not too worried about dropping them a bunch at soundcheck (though I’d be a little more worried if I stood on them).

There are some shortcomings to the IE 100 Pro; useful as the sound profile is, there’s still a little missing low end that could be useful elsewhere – and the high end does roll off in a noticeable way, though not in a gig-breaking way. If these are the kinds of things that are likely to get in your way on the IEM front, you simply need to be upping your budget. In my view, these exemplify value for money.