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Acrylic Vs Soft Silicone: The Big Debate! Which is the Right Custom In Ear Monitor Material for you?


So investing in a new set of Custom in Ear Monitors is a big thing for 99% of people.

It can be daunting and expensive, especially when it’s new and you’re transitioning from cheaper Universal In Ear Monitors. But there is one massive, misunderstood choice that a lot of Musicians I see have to make and there’s a lot of misconceptions about it too (plus it heavily divides opinion with a lot of people being in either one – or the other camp!)

So I’m going to answer the question that I get asked a lot when we talk In Ears - and it’s generally the first thing people notice and ask when they look at or hold my own Customs!

So people often say to me, something along the lines of;

..."So you've got both... which is better - A soft shell or Hard shell Custom In Ear Monitor?

Surely a softer one is more comfortable?

How am I meant to know the difference, because they’re custom?

What are the actual real-world differences for you as a gigging musician or engineer? ..."

So luckily, if those are the kind of questions you've been asking yourself the answer to that question is actually pretty easy– and I’m sticking my neck out and saying with these 5 simple considerations, this is going to help definitively answer for once and for all - which is best for you: Hard Acrylic or Soft Silicone In Ear Monitor!

Lets do it...

Firstly, lets understand the materials... and your ear!

Before delving into the comparison, it's essential to understand the characteristics of each material. So you've porbably noticed your ear is pretty flexible - and inside your ear is no exceptin. Whenever you move your jaw, your ear canal warps and changes shape slightly. IN terms of fit, this is really imporatnt especially if you're a vocalist, or mayeb a woodwind or brass player who might move their mouth alot during a performance or have your jaw not in it's natural relaxed position!

ACS Custom Evolve Ambient Custom In Ear Monitors
ACS Evoke2 Custom In Ear Monitors in Trans Blue

Acrylic IEMs are rigid and designed to provide a snug fit for the ear canal and are often designed as a 'best fit' for your ear. So for 64Audio or FiR Audio, we'll always use a 1inch bite block to grab an open jaw impression ensuring whether your mouth is open or closed, you'll get a consistent seal and isolation. On the other hand, soft silicone IEMs are flexible, and the canal tip (the bit going into your ear) will move slightly, adapting to the shape of the ear canal as it moves, offering a more natural feel and enhanced comfort. So with this, an open jaw impression is only really needed if you're a vocalist, but mine are closed jaw impressions and still seal when I seal and hit those face-melting falsettos!

So with that bit of context, which is best for you?


Consideration 1: Comfort & Time

Comfort plays a crucial role with Custom In Ears, especially during extended wear but this is where the first misconception comes in! Acrylic IEMs, while rigid, are meticulously crafted to provide comfort and are perfectly smooth and can be worn for several hours without discomfort quite happily. I will often perform for several hours and still wear my 64Audio A18ts during pack down so around 4 hours, and they're really comfortable!

64Audio A18t Custom In Ear Monitors with Elm Burl and Trans Smoke Faceplates
My 64Audio A18t Custom In Ear Monitors with Elm Burl and Trans Smoke Faceplates - my buckletlist Customs!

However, silicone IEMs being flexible and softer makes them ideal for prolonged use. They'll also warm up slightly to your body temperature over a set, making them even more pliable which is nice! So if you're wearing IEMs up to 4 - 5 hours at a time, either is fine. If you're using them for a particularly extended period like stage managing or running communication lines (comms) for 5+ hours, soft silicone is probably the best way to go!

Consideration 2: Build Quality & Durability

ACS Custom Evolve Ambient Custom In Ear Monitors and Line6 Helix
My ACS Custom Evolve Ambient Custom In Ear Monitors at a gig

Now, in terms of build quality, both acrylic and silicone In Ear Monitors are excellent and are design with durability being a primary concern, especially for musicians on the road. Reliability is key after all!

One main difference however is how they make the shells strong. Soft silicone customs are actually solid, with drivers set inside them. This makes them pretty impact-absorbent, highly durable and can withstand accidental drops (or bounces off guitars) quite nicely.

FiR Audio Custom In Ear Monitors with Unicorn Poop and SpaceX faceplates at Dakin Custom Audio
FiR Audio Custom In Ear Monitors with Unicorn Poop and SpaceX faceplates at Dakin Custom Audio

Acrylic IEMs are the opposite, being a hard 3D printed material they're hollow, so while inherently more rigid, the reinforced thick walls to enhance durability, making them equally suitable for rigorous use. FIR Audio actually has the thickest acryllic shells on the market, meaning they are pretty bombproof!

Consideration 3: Technology & Customization

64Audio A4s Custom In Ear Monitors with Zebra and Gold labyrinth faceplates at DCA HQ
64Audio A4s Custom In Ear Monitors with Zebra and Gold labyrinth faceplates at DCA HQ

Acrylic and silicone IEMs offer distinct advantages in terms of technology and customization, however on this one at least, we think there's one clear winner!

Soft silicone custom In Ear Monitors, being solid tend to be a bit more limited in customization options. However ACS have learnt over the years how the material reacts and use the interaction between the Speaker drivers inside and thier silicone housing to deliver excellent frequency extension and resonance, all thanks to their unique material properties.

Acrylic IEMs however being a slightly simpler construction provide opportunities for advanced customization that you've probably seen, with all manner of weird and wonderful designs available to express yourself on stage! But if it's tech you love, then Acryllic has the win here too. Due to the hollow internals and separate faceplate, manufacturers like FIR Audio have capitalised on the strength of the material to integrate technologies such as bespoke tuned internal sound chambers, and reinforced pressure relief modules, as well as offering intricate designs on the faceplates. Shoutout to FIR Audio by the way for including all customisation in the price of the Custom In Ear Monitors - we love that!

FIR Audio Xenon6 Custom In Ear Monitors with Dark Horse Faceplates
FIR Audio Xenon6 Custom In Ear Monitors with Dark Horse Faceplates!

Consideration 4: Any possible negatives?

ACS Custom In Ear Monitors - Evoke2 Ambient
ACS Custom In Ear Monitors - Evoke2 Ambient

Each material has its drawbacks. Silicone IEMs may experience weaker points around cable sockets due to their flexibility, potentially leading to stress on internal wiring if you ever needed to replace the cable, however when changing the cable on my Evolves I've never experienced that issue - plus I never have to take the cable off. On the other hand, Acrylic IEMs, while sturdy, beng hollow can crack or shatter under extreme pressure. I watched once as my TM's Ultimate ears fell off their cable backstage once and scuttle into the darkness - only to hear a small 'crack' followed by an annoyed shout as it disappeared under his shoe... However, with proper care, both types of IEMs can provide years of reliable performance!

Consideration 5: Sound Quality of the Custom In Ear Monitor?

A soft silicone ACS Custom custom in ear monitor and 64Audio A3 hard acryllic custom in ear monitor

Ultimately, the sound quality is paramount and why we are all here! Now while both acrylic and silicone IEMs offer exceptional audio performance, every manufacturer has their 'House Sound' so as I say to all my clients, personal preference plays a significant role here and actually... there is no right or wrong!

I always recommend you experience and Demo both types of IEMs and get both sets in your hands to properly evaluate which one you prefer! We do demos all the time here and try our best to be transparent, challenge preconceptions and let you decide whats best.


So there you go...

The choice between acrylic and silicone custom in ear monitors is yours, and essentially boils down to personal preference and specific requirements. By considering factors such as comfort, durability, customization options, and sound quality, you can make an informed decision that aligns with your needs and preferences. Whether you opt for the flexibility of silicone or the customization options of acrylic, investing in custom IEMs ensures a tailored listening experience that will without question enhance your performance on stage - just take a bit of time to get them in your hands if you can!

Three FIR Audio Custom in ear Monitor demo units at Dakin Custom Audio
FiR Audio Frontier Series Demo Units at DCA

At DCA, we understand the importance of finding the perfect pair of Customs so we'd love to help you if you're considering it. With our extensive range of demo units and firsthand experience using them live, we're here to help you navigate the decision-making process and find the ideal solution for your live setup. Feel free to contact us today for any advice or to explore your options and embark on your journey to Custom In Ear Monitors!

Thanks for reading - Miles (Founder DCA)

Still need help?

We're here to help! We've gigged our custom in ear monitors enough here in the UK now that we do understand where they work... and more fundamentally where they don't! So if you're still. a little unsure and want some impartial advice on which might work best for you, feel free to reach out!

A wireless custom in ear moniotr pack sitting on Dakin Custom Audio's 3D Ear impression Station at Architect band's rehearsal before their tour with Metallica
Demo & Impression Day with Architects before their European Tour with Metallica



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