"A volume control for your ears." That's what Dutch company Knops promises with its eponymous unpowered noise control ear plugs, which give you the ability to choose between four levels of noise filtering. We put them through the uncompromising test of an aggressively loud children's show.

The first step setting on the Knops ear plugs leaves your ears basically open. It's not quite the same as pulling them out altogether – the world sounds slightly odd and your chewing gets very loud – but it's perfectly fine for conversations and interferes minimally with what you'd normally hear.

Rotate the outer ring around to the first step, and the gramophone-shaped earpiece gets a 10-decibel attenuation filter attached to the inner end of it. The second step puts a 20-decibel filter on, and the final step kicks it up to 30 decibels of attenuation.

These filters have been designed to have as close to a flat EQ profile as possible, so they don't knock all the top end off your hearing the way that, for example, a set of foam earplugs can. Rotating the rings around through the different positions very much feels like choosing between four different volume options for the outside world.

In practical terms, you can fit your Knops with a range of different ear tips to suit different ear shapes, and they come with a fairly chunky zip-up case about three inches (8 cm) in diameter.

I had a chance to take them out for a field test this weekend when I took my son to see an aggressively loud, full-band children's show at a nearby town hall. The volume in the room fell short of a rock concert, but not by much; hearing protection was definitely on the menu, and I brought along a set of Etymotic ER20 flat-spectrum 20-dB earplugs to try the Knops against.

Audio quality-wise, I'd give the Knops a roughly equal score with the Etymotics. Both brands do an excellent job of reducing overall volume and protecting your hearing, without muffling the critical top-end trebles that give you some clarity about what's happening on stage. You can still feel the bass, which gets you plenty hyped, but you can hear what the singer's up to as well and enjoy a bunch of detail in the sound without having your ears creamed by sheer volume.

The ability to turn the volume up and down meant I was able to set different volumes for different tunes – let a little more in on something quiet, go right to the full 30 dB when things got crazy – and open up one ear completely to talk to my kid between songs. With a foam plug or something like the Etymotic, you're pulling the plugs out and sticking them back in. With the Knops, you're twisting the little dial. It's a convenience.

Another big difference is in the looks; while the Etymotic gear is transparent and fairly small, Knops are big and bold. The silver ring around the knob on the outside makes it look like you've got some sort of innovative new piercing that's stretching your ear holes instead of your lobes.

The final sticking point for most people will be price. Foam ear plugs cost a buck or two a pair, and Etymotic ER20s go for around US$14 a pair. Knops start at €59 (US$69) and go up substantially if you want to add niceties like knurled or gold-plated rings.

Having the two next to one another, I'd reach for the Knops pretty much every time. Hearing protection is important to me, the ability to bump it right up to a full 30 dB filter is terrific, and the volume dial does exactly what it says on the tin. Having huge, bold ear protection doesn't seem to invite criticism these days the way it used to back when I was playing in bands – "hey, look at this pussy who wants to be able to hear his grandchildren" – and I'd consider them a very nicely designed and executed piece of gear.

Given what concert tickets cost these days, maybe 70 bucks worth of really nice hearing protection isn't such a kick in the butt. They certainly feel like they're built to last. Check out a video below.

Product page: Knops

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