In-ear monitors, or IEMs, are an integral part of any professional live performance. They sound better and are much smaller than stage wedges, offering musicians a far more effective monitoring solution by delivering consistent sound no matter where they are on stage. Depending on your budget and intention, adding IEMs to your workflow can be either a modest upgrade to your setup or serious evolution of your production value. In this guide, we'll be going over the advantages (and disadvantages) of IEMs as well as some of the intricacies and nuances of their nature, setup, and capabilities, all with the intent of providing you with solid comprehension of how they work. We're here to help you understand exactly what you need to get your IEM system up and running—whether you're playing at the local dive bar or planning your big world tour!
What Are IEMs?
To the uninformed observer, IEMs are indistinguishable from normal wired earbuds; however, they offer a few key differences in their design and construction which elevates them to their preferential status in the world of stage performance.
1: Type of Drivers – Dynamic vs. Balanced Armature vs. Electrostatic
The most significant difference between IEMs and most consumer earbuds is the style and type of drivers they use to create sound. Typical earbuds will use a single dynamic driver that handles sound at all frequencies, whereas IEMs will often use multiple balanced armature (BA) drivers, each of which handle different frequency ranges, exactly like the way a typical PA loudspeaker projects sound using both a woofer for lows and a tweeter for highs (hearing aids notably use balanced armature drivers as well).
Super high-end IEMs often include electrostatic drivers which are often considered the best technology for producing ultra-high frequencies—models like the iBasso Epitome Professional In-Ear Monitors have as many as twenty drivers in each ear (and you'll be paying for them!).
The difference between a dynamic, balanced armature, and electrostatic driver comes down to science and design philosophy, and while I'd love to get into the specifics, there are better resources online that can dive into it deeper than I could—the sound is what we care about here.
2: Audio "Quality" of IEMs
I put the word "quality" in quotes because it's not a matter of whether IEMs sound better than earbuds—it's that they sound different. Consumer earbuds are often colored with a specific sound profile, usually boosting bass or accentuating treble to make sound more pleasant or engaging to the listener. IEMs do their best to not influence the sound they're reproducing—they are (ideally) designed to deliver a completely flat frequency response so that the performer can hear the music exactly as it's being recorded or amplified. This is mostly due to the balanced armature drivers they use:
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Because they are smaller than dynamic drivers, balanced armature drivers allow more space for the multiple drivers IEMs need.
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Since they're lighter, they naturally possess a superior response time which delivers far more accurate attack/decay times (they can stop and start faster) and enhanced clarity when dealing with higher frequencies
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Conveniently, they do not need air vents to function properly like dynamic drivers do, which allows for better sound isolation (see below).
The diminutive nature of balanced armature drivers is real and has its tradeoffs: because they move less air, bass impact and response is significantly dulled; because they're more physically delicate, harmonic distortion is introduced more quickly and severely as levels increase, and because it's a more sophisticated technology, they're more expensive to manufacture—a price the consumer will inevitably bear.
Electrostatic drivers overcome the distortion issue but will still suffer from lack of bass response; they're even more expensive than BAs and they'll usually need a separate amplifier (often called an "energizer" when it comes to IEMs … for whatever reason) to realize their full potential—a solid IEM receiver should have one built-in.
Some higher-end models like the Astell & Kern x 64 Audio XIO In-Ear Monitor Earphones will use a combination of driver types to compensate. This pair uses ten drivers per earphone—two dynamic drivers for the bass, six BAs for the midrange, and two more special proprietary drivers for the highs.
For listeners, these special types of drivers are a significant consideration and will depend on your budget, how you hear, and the kind of music you listen to—but for most professional musicians performing on stage, there's no question that IEMs are the superior choice.
3. Sound Isolation
IEM's use specific materials for their ear tips (usually silicone) that emphasize passive sound isolation, as opposed to the more porous and soft material most earbuds use (most consumer stuff instead relies on active noise cancellation for isolation, which makes more sense day-to-day).
A good pair of IEMs should be physically airtight and sit deeper in the ear canal: this effectively creates a seal that blocks out significantly more ambient noise and ensures a more secure fit than a typical set of earbuds. Shure's SE215 is a best-seller at B&H and a long-standing affordable favorite in the industry, reducing outside noise by -37 dB.
Another benefit of IEM's passive sound isolation is the natural hearing protection it provides, not to mention the ability for the performers to monitor at a lower volume—IEMs get finicky when you blast them, and professional musicians tend to be VERY PROTECTIVE of their hearing!
4. Form Factor and Design
Most wired IEMs will use an over-ear cable design which loops over and behind the ear, meant to maintain a secure fit and to prevent the performer from hearing any sounds from the cable rubbing against anything. These cables are often detachable as well, which allows the user to replace a less durable component and keep the (often quite pricy) drivers—good IEMs should last years.
5. Tuning and Personalization
Because each performer will have their own set of IEMs on stage, they can each have their own personalized mix of the performance – the drummer can cut their own signal (since they're sitting right behind the kit anyway) while keeping a click-track on and emphasizing the bass player and vocalist, while the guitarist could boost the kick drum and bass guitar to lock in with the groove – it comes down to style and preference. This can be done through a mixer with multiple aux outputs (more on that later).
Wired or Wireless IEM Systems—Which Should You Use?
Choosing between a wired and wireless system will come down to multiple factors, like your budget, playing style, and location (wireless systems use radio frequency transmission and may require you to buy licenses to transmit on certain frequency bands, more on that in the wireless section). Here's what you need to know about how these systems operate:
Wired Systems
A mono or stereo monitor feed is sent from one or two aux busses (respectively) from a mixing board, usually through a snake to a stage box—from that point you can connect a wired IEM system/amplifier like the Behringer Powerplay P2 or Polsen PMA-2B to the stage box/mixing desk via XLR or ¼" TS/TRS cable. These systems are usually belt-packs or stand-mountable boxes that you connect your personal IEMs to, often with built-in features like level/balance controls and mono/stereo toggles.
Wired systems are typically more affordable (some as little as $40) and won't be subject to transmission failures or battery drain. The number of wires attached to your body may be overwhelming and will definitely limit your ability to move around on stage—drummers and some bass players might not have an issue with this, but more ambulatory and dynamic acts will want more freedom.
Wireless Systems
Wireless systems remove the cabling and are becoming more common for performers. They allow for a far quicker setup and breakdown and allow more freedom of movement for the performers but come at a significantly greater expense, are harder to setup, and can run into some issues like dropout or battery failure.
Wireless IEM systems like the Sennheiser XSW IEM SET Stereo In-Ear Wireless Monitoring System come with a desktop or rack-mountable stereo transmitter with antennas that connect to a number of stereo IEM receivers (the bodypack) that you'd plug your IEMs into, often having the same onboard controls as wired systems. But to properly use an IEM system, you must know a bit about the way it transmits signal from the transmitter to the receiver:
Analog or Digital Wireless IEM System? Latency and Companders
All wireless IEM systems use the radio frequency spectrum to transmit signal, and despite the nearly universal transition from analog to digital, analog IEM systems remain best for most situations: digital systems need to use ADCs and DACs (analog to digital/digital to analog converters) to send audible signal, which creates latency and can make the monitoring situation untenable (the maximum acceptable latency is ~7 ms). Add that latency to the latency added by any sort of digital processing done at the mixing desk and you can quickly run into a serious problem.
But why do digital systems even exist then? Well, Analog systems need companders (compressor/expanders) to compress the signal from the transmitter enough so it can travel through the radio waves before being subsequently expanded at the receiver. This can seriously impact the quality of the audio (particularly with highs and lows). With high-end systems, the companders are so good that any quality drop-off is imperceivable, but lower end systems can't say the same. Price-point of analog IEM systems matters A LOT—so while digital systems have a higher price floor, they don't need companders, meaning even a less expensive system will deliver high quality audio (at the cost of latency, of course).
Radio
Both analog and digital systems run on UHF (ultra-high frequency) bandwidths, and to have multiple wireless receivers all work in the same room, each unit must be tuned to a frequency to not interfere with one another. In addition, depending on where you live and your locality's laws, you may need to purchase a license to use certain frequencies, or roll the dice on a free-to-use portion of the radio spectrum that might run into interference from other wireless devices—make sure you purchase a system with the correct frequency ranges for your country or state.
While I won't go into the specifics, cheaper units will typically have fixed frequency bands to choose from, which usually makes it easy to plug and play but can run into issues quickly if each band member is using different brands or models of systems. But, if each band member is fine with being sent the same mix, it's entirely possible to use only one radio frequency to transmit to all of the receivers—while the number of receivers able to receive the same signal from a transmitter is theoretically infinite, it will depend on the system as well as the radio frequency band itself.
Recently manufactured (and often lower-end) IEM systems may use the license-free 2.4GHz and 5.8GHz frequency bands that are commonly used with wireless systems—including Bluetooth devices—but (as of 2026) IEM systems will NEVER use Bluetooth because the technology can't overcome the significant latency it introduces.
Other Cool Things to Know
IEMs can be a rabbit-hole of a topic, and I've already waxed poetic on them for two-thousand words, so let's quickly rundown some other features and aspects of IEMs that are worth knowing about, especially if you're looking to purchase a pair for yourself:
Custom/Personalized Molding
If you have the desire and the budget, you can purchase the services of an audiologist or aural professional to create an impression of your outer ear canal and concha with medical grade silicon to be sent to a manufacturer of custom IEMs like 64 Audio or Ultimate Ears, who will deliver a set that fits perfectly into your ears specifically. This helps improve sound isolation and lessen the amount of level needed to drive the drivers and will prevent them from slipping or falling out of your ears during a performance. This can be a bit pricey and will take a while to receive, but this is a great option if you're going to be wearing IEMs a lot.
Ambient Ports/Active Ambient Monitoring
Some musicians will be worried about the seal IEMs can bring, basically expelling you from sensing the outside world—while I lean toward to the philosophy of "if you want it in your monitors, mic it up," wanting to hear the audience or the room in general is understandable, and the airtight seal can become uncomfortable and cause fatigue over time.
Those who want to hear the room can get IEMs with "ambient ports," essentially holes in the casings that break the airtight seal—64 Audio uses ATOM Venting technology to achieve this. Some ambient ports can come with different settings for how much sound you want to let in, but the main drawback is that once you add a port, the airtight seal is broken, and it will never have the same sound isolation—even if it's closed "all the way."
High-end IEM manufacturers like Sensaphonics build IEMs like the 3DME that use 3D sound technology built-into the casings to mitigate this. Instead of passive ambient ports, each IEM has a binaural microphone that picks up sound around you, able to be controlled and leveled so you can mix the ambient level with the mic levels while maintaining a true airtight seal. IEMs with this technology won't be cheap though.
True Wireless Conversion
IEMs with detachable cables can be converted into true wireless earbuds with wireless amplifiers like the FiiO UTWS5 True Wireless Bluetooth Amplifier. This product lets you ditch the cable while offering a built-in amplifier and DAC, so it's able to power even high impedance IEMs and stream audio at high sample rates. This is more for listeners, as Bluetooth adds latency making it unsuitable for playing live.
Conclusion
We hope this guide has given you some insight into in-ear monitoring and its advantages in stage performance settings. B&H has a wide range of IEM headphones and wireless systems at every price range, so if there's a specific product you want to know more about, reach out to our team of experts online or at the B&H Superstore!
