LINK: ACS Custom  |  PRICE: £139-£159  |  FAQ: ACS support

While writing about the Flare Audio Isolate ear plugs, I got looking at some of the high-end custom solutions, particularly those on the ACS Custom website. A few YouTube videos later, and I was set on buying a pair as an upgrade from the ACS ER20s I’ve had for several years. The company offer a range of ear plugs with protection from a 10dB reduction right up to stripping 27dB from the environment.

After a bit of deliberation, I decided to go for the PRO17, which offer the best balance between manageable volume reduction and clarity for working with music. The PRO17s are recommended for most musicians, including DJs, as well as other people who frequent clubs. If you tend to work with massive sound systems, or work with amplified sound, the website recommends the PRO26.

Or as ACS put it:

“The standard for amplified musicians, DJ’s, vocalists, sound engineers, clubbers and gig-goers.”

I then thought:

“What better way to test these out than at a filthy techno rave?” So I did, and here are my impressions.

In a nutshell

UK engineered and fabricated, bespoke custom fit ear plugs with a -17dB filter, designed to protect your (and only your) ears from hearing damage (what about your twin? Ed).

ACS custom moulded earplugs (4)

In the box

Along with your soft silicone ear plugs with fitted filters, you get the usual instructions and care guide, a little wire loop tool to clean wax out of your plugs, some ‘comfort cream’ ear lube, and a zip-up carrying case for it all.

Making them

Since the PRO17s are completely made to your ear shape, you’ll need a trip to the local audiologist to have them take an impression mould of your ear canals to send off to the ACS factory. The options I chose for my earplugs were a fluorescent blue, added grips (to better remove them), no cording, with laser etched text.

After ordering my PRO17s from the ACS website, I was sent an ‘impressions certificate’ which asked me to find my local specialist (in my case, Boots Opticians) and book an appointment. My visit consisted of a quick hearing test, followed by the ear impressions. Each ear gets a little bit of sponge on a string stuffed down the canal, then the silicone is syringed in using a mini version of those bathroom silicone sealant guns. These impressions are then sent off to ACS HQ to be 3D scanned and kept on record in case you need them again, as well as used for your custom plugs.

The whole process takes a couple of weeks from your appointment to receiving your plugs (dependent on the workload at ACS), but the appointment itself only takes half an hour. In theory, your finished ear plugs should be sent to your audiologist, who will then organise to show you how to fit them, though I ended up receiving them for some reason. Note from ACS: orders are sent to the audiologist or direct to the customer, depending on what is specified.

Should you find yourself needing more (or less) protection, you can also easily buy and fit different filters. While the filters aren’t exactly cheap at £50 for the pair, it’s much more affordable than having to buy another set of custom plugs. Note from ACS: We offer a 60 day free of charge filter exchange, so if the filters chosen do not give the correct protection they can be sent back and swapped for a higher or lower attenuating version.

ACS advises getting a new impression of your ear hole once every four years, as you grow older and your ear changes shape, though I suspect that as long as the plugs are comfortable and fit well, you’ll get a lot more mileage out of them.

ACS custom moulded earplugs (5)

Ear lube

I really want to talk about this. Yes, you get a tube of ‘ear lube’. I assume you can use it for other purposes, but I have no intention of finding out. It’s mostly there to use the first few times you put your plugs in. All you do is take a small dot of cream on the tip of your finger, and coat the end of the ear plug before you stick it in and twist.

Comfort and fit

One of the most important features on ear plugs is how snug they are for long periods. The barb-style ear plugs tend to have a good isolating fit and stay in your ears, but cause a fair amount of discomfort, almost like having an ear infection. Foam based plugs provide a good seal, but tend to fall out and they blocked sound is much less transparent, which is less-than-ideal for music.

Getting these things in your ears is a bit more complicated than just shoving them in. Since they’re fairly rigid and shaped like your ear canal, you have to twist the plugs in as you push. You won’t be able to push them in too far, so any resistance means they’re snug and ready to use.

And you can wear these things for hours. I have worn them for an entire night of running a party, DJing, blocking out a screaming toddler — all sorts. They’re so comfortable in the ear that I put them in one morning when the child decided 06:00 was an appropriate time to bounce about the house, and promptly fell blissfully asleep for another three hours.

ACS custom moulded earplugs (1)

Sound quality

With only the ear plug sets I tested with the Flare Audio Isolates to stack the PRO17s up against, it seems like a bit of an unfair comparison. Obviously, the closest competitor in the group is the silicone barb style ER20s, which are also from ACS. The quality of the sound of those was a step above the Flares and the others I tested, due in part to the fact they filtered sound.

While the PRO17s is yet another step beyond the ER20s, it’s nowhere near as much of a leap. They do sound better. And the fact they sit in your ear more snuggly means the sound hits the filter more than via leakage or through resonating when the plugs are scraped by something.

Owner’s experience

Having purchased these for myself, I got to experience an aspect of ownership that you don’t tend to as a reviewer: customer service. Before committing to the purchase, I contacted ACS with a couple of questions regarding which of their ear plug options would be best, and got a swift reply from a couple of cheery and helpful people.

When I received and tested the plugs initially, I found that they’d slip out when I moved my jaw, even though they felt snug. Another email sent, and they offered to receive them back to add some extra thickness to help create a tighter fit. Sorted!

ACS custom moulded earplugs (3)

The bottom line

When compared to the much cheaper off-the-shelf solutions, the quality of the PRO17 ear plugs is night-and-day. From the level of service, to the build of the product and the audio quality, you really do get what you pay for, as long as you are willing to pay it.

The biggest difference is with comfort. If you need hearing protection for long periods, that stays in firmly, don’t even bother with the cheap options. Go for the custom silicone ear plugs, and you’ll forget you have them in. But there’s also an improvement in quality of sound too, which is probably actually linked with the comfort thing. Sound is much more obviously reduced across the board, similar to the ER20s I pitted against the Flares, but clearer.

The only criticism I could level at the PRO17s, would be about portability. The ear plugs themselves are tiny, but are designed to stay in your ear or the protective case, which, while convenient, is just too big to carry in a pocket. Having the options of a flatter or shorter hard-case would be really useful.

In the end, I’m sure people will ask “how can I justify that much money for little blobs of silicone?”, but I’d say to them: “how can you not?”. I liken ear protection for DJs to a skater or cyclist wearing a helmet. It’s just something you shouldn’t skimp on, because once your hearing is gone, no amount of modern medicine will get it back, just like brain damage.


You get everything you need, plenty of customisation, and it’s all top notch. Great customer service, too. It ain’t cheap, but frankly, keeping your ears protected is priceless.
Ease of use
Value for money
Great comfort and fit
You get ear lube
Lots of customisation options (for a price)
An essential bit of kit for professional DJs
£140 is a steep ask for a lot of people
You have to use ear lube
Zip up pouch is a bit bulky for your pocket
Can be fiddly, and a risk of losing one is costly


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