When it comes to getting a new set of in-ear monitors (IEMs), it's normally a big investment and you want to get it right first time so, we generally spend lots of time doing research! Musicians I know often find themselves navigating through various specifications, recommendations, and graphs full of numbers and opinions on social media too. With so many options things can get overwhelming, but there is one design feature that stands out, making a significant difference, especially in less expensive IEMs. The humble Crossover. But whats the big deal?
In our opinion, this key aspect of a Custom In Ear Monitors spec is more powerful than any other stat and can really help you work out which set of Customs is for you. Even more telling than how many drivers you have and it can really change your on-stage experience.
Why is this so important? Well by the end of this article, hopefully it will all make sense!
In this blog, we delve into the intricate world of Custom In-Ear Monitors, shedding light on how IEM companies design their products. As a professional musician and engineer, I've discovered that the crossover is a crucial element to assess when anticipating how a Custom IEM will react on stage. I'll provide practical tips on optimizing your IEM experience and discuss the four main levels musicians should be aware of.
Now, although DCA has fantastic industry partners, this information applies to both Universal or Custom In Ear Monitors. Lets start at the beginning.
What is a Crossover exactly?
Let's start by understanding the fundamental concept of a crossover. It is intricately linked to the number of speakers or drivers in your In Ear Monitors. Whether you've used a powered PA speaker or encountered speakers and subwoofers at a venue, you've already benefited from a crossover.
Imagine having Custom In Ear Monitors with only one speaker driver inside each earpiece. In this scenario, a single source is responsible for delivering 100% of the sound, both punchy low notes and sparkling highs simultaneously. I'ts very difficult fort one speaker to do both of these jobs accurately as they are vastly different sounds. So single-driver In Ear Monitors like the Shure 215 for example, will sound quite full, but cutting in the mid-range and probably lack detail in highs as there are limits to what one speaker can do.
How do manufacturers improve this?
Option 1: Just add more speakers
The ACS Evoke 2 (here in Blue) is an excellent example of this approach. By spreading the workload across multiple speakers, each driver doesn't have to work as hard and it's really cost-effective way of getting more out of your Custom In Ear Monitors, delivering a great punchy sound especially on a tight budget. However, this method can still have it's limitations in terms of detail and sound range (40Hz - 18kHz) when pushed as the sound still all emanates from one type of source. So it's better, but this doesn't fully solve the problem. What next?
Option 2: Introduce a Crossover
So let’s take the same example here we now have 2 speakers. This time let’s make one speaker responsible for the slow-moving, power-thirsty low frequencies and one to take care of the faster more directional Mids and Highs. So what a crossover does is split the signal coming into the IEM and send it to the correct speaker. Rather than one speaker doing 100% of the work and covering the whole frequency range, two can do 50% each.
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We call this a 2-way crossover as the sound is split into 2 parts: Lows and Mid-Highs.
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This makes the sound feel a lot wider, helps preserve dynamics gives you better separation between instruments. The IEM now doesn’t have to work as hard to let things like vocals and keys cut through the mix more as they’re not being muddled up and squashed by the bass and kick drums as much for example!
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So with this, IEM manufacturers can then choose the best speakers for the job! So the Lows can be done by a Low frequency specific sub driver and the highs can be a much smaller High Frequency driver. This also then allows IEM designers to choose how loud or quiet certain parts of the sound is, shaping the tone of the In Ear and that changes how it feels on stage. SO then it can be tuned to be more bass heavy, or flatter sounding like a reference monitor. More on that later on the Blog and our Youtube Channel!
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But as Musician – with customs especially, this is where I’d recommend everyone to start with IEMs if you can!
So we have a 2 way, more separation and things are a little more dynamic – what’s next...?
Option 2. Let's Take This a Step Further! Introducing a 3-Way Custom In Ear Monitor Crossover
Moving beyond the two-way crossover, the three-way crossover is the most common in my view and the best for most people with the same concept as before, but even more control and a wider sound!
So if you look at even the simplest EQs on small mixing desks, usually the EQ section (green knobs on this picture) is split into 3 bands – low, mid and high. This gives you a broad range of control allowing your to increase or reduce the more problematic highs and lows independently of the mid-range frequencies. 3 way crossovers use the same principle.
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In this scenario for IEMs. Generally you’ll have 3 speaker drivers in each ear. One for the Lows, Mids and Highs.
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2-Way Vs 3Way: The Real world difference on stage for Custom In Ear Monitors
What does this mean on stage compared to the 2Way? Well simply, when things get louder and more complex (like a full band mix for example) from a sound point of view you will have even more separation as now there are compartments for more instruments as each speaker is only doing 1/3rd of the work!
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So the low driver can handle the fundamentals of your Kick drum, Bass Guitars and synths, the Mid is now able to reproduce the presence of vocals, snare drums, guitars and strings, with the High-frequency driver can focus on doing all the super-fast transient airy, musical detail of those upper registers. In practice, this feels like there is a place for everything. And as you’ve compartmentalized the sound a bit more, you’ll find the dynamic range of the Ears (how clear it remains at different volumes) significantly better.
Enhanced Dynamic Range: Vocalists take note!
I'm a vocalist myself, but any singers out there, trust me that Mid driver is your secret weapon! To be able to pitch properly you need your vocals to cut to get over your head voice and the occlusion effect. With a 2 way system, you can – but you’ll compromise on detail in the mix and when things get loud and dynamics change in choruses and crescendo sections, you’re IEMs won’t be able to reproduce much else other than just your voice. With a 3 way system, that seperation means you can run your vocal slightly lower and the band/accompaniment will sit ‘around’ your voice.
Fun Fact: Not every custom in ear monitor with 3 drivers have a 3-way crossover. In Ear monitors like the Ultimate Ears UE7 and the JHAudio JH7 only have a 2way crossover. We like our UE7s, we toured them for years but the 64Audio A3t and ACS Evolves offer alot more space and clarity in mixes in our opinion!
Again as before – a 3Way XOver allows for greater tuning capabilities. Great examples of 3 way IEMs I’ve used are the ACS Evolve Ambients, which have a really flat reference sound, against the 64Audio A3t which uses the X-Over to lift the Bass  and highs slightly to make a clear and defined but definitely a more enveloping sound!
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If I had to run out the door to a show with no idea what I would be doing, playing or how good the mix would be.
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I would be grabbing a set of IEMs with a 3WayXover.
3. Then the 4-way Crossover
For premium custom IEMs in the £1000+ range, the four-way crossover adds an extra layer of control by introducing a lower mid-frequency driver. This setup, involving lows, low-mids, high-mids, and highs, offers enhanced control over the upper mids, providing a distinct advantage for drummers and bass players.
Control and Separation
With four speakers handling specific frequency bands, the four-way crossover delivers more separation, control, stereo width, and dynamics.
Beyond a 4-Way Crossover?
What lies beyond a four-way crossover? The exploration into five-way and higher crossovers becomes a matter of sound design and personal preference. While some IEMs boast seven drivers with a seven-way crossover, there may be a point of diminishing returns! At this point we reckon the application of different tech like Kinetic Bass by FIR Audio or APEX by 64Audio are killer ways of really enhancing the sounds from an IEM!
In Conclusion...
Understanding the role of crossovers is pivotal in selecting the right IEM for your needs. Whether it's a two, three, or four-way crossover, the principle remains: split the signal for more separation, control, and a better understanding of where your instrument sits in the sonic spectrum.
In the complex world of IEMs, the crossover is a simple part of the spec sheet that can really elevate your on-stage experience. As you navigate the diverse options available, keep in mind the balance between drivers and crossovers to find the perfect match for your musical journey.
Most importantly... go out and Experience the Difference for yourself!
To appreciate the nuances of crossovers, consider booking a Free Demo session at DCA in the UK. This hands-on experience allows you to feel the impact of various crossovers before making a decision.
Thanks for reading, Miles (Founder - DCA)