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ACS T2 Dual Driver Monitor Review


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  • Exceptional sound quality
  • Silicone moulds are much more comfortable than hard shell customs


  • Expensive
  • Cable can't be replaced
  • Not as nicely finished or customisable as hard shell alternatives

Key Specifications

  • Review Price: £499.00
  • Custom silicone earpieces
  • Kevlar reinforced cabling
  • Customisable look with option for laser etching
  • Dual balanced-armature drivers
  • Waterproof, rugged case and soft pouch

What is ‘value for money’? When a product is cheap, well featured and well made it is easy to assess. It is good value for everyone. Where the problems start is when the price goes up. The Sony Vaio Z Series is the best portable laptop on the market, but at £2,400 is it good value for money? Perhaps. The Dyson Air Multiplier is the best desktop fan, but it costs £199. Is this worse value for money because it is ‘just a fan’? Ultimately value for money comes down to individual requirements and personal finances. The rule is it’s subjective. And if this is something of a drop intro apologies, but value for money is the fundamental quandary when reviewing ACS’s truly remarkable T2 monitors.

Let’s get it out of the way. If you want a pair of T2s you will have to find £499. For £510 you can buy a 16GB iPhone 4. For £569 you can take home a 40in Sony Bravia KDL-40EX503 television. Are we in ‘just a fan’ territory? Why on earth would you spend £500 on a pair of earphones? And here’s the hard bit: you should.

There are obvious caveats. Clearly you have to be seriously into your music. Unless you obsessively rip your music at the best possible bitrates (or still insist on buying the CD) then the T2s aren’t for you. If you don’t own a phone, a TV or decent laptop then prioritise – what are you thinking? Do you have a large mortgage to pay? An ex-wife to appease? Best stop reading now, because the next 1,200 words won’t make you feel better about your life. On the other hand if you ”can” consider spending £500 on a pair of earphones find a comfy chair and start stroking your credit card because you’re about to learn these are the ones to get.

First things first. What sets these apart from most other high-end in-ear monitors (IEMs), such as the Shure SE 535 or Sennheiser IE8s is the fact they’re custom moulded to perfectly fit the contours of your inner ear. This creates a better seal, reduces outside noise and preserves fidelity. Other companies such as Westone and Ultimate Ears also offer this service though ACS is one of the few to offer soft silicone moulds rather than hard plastic ones.

The rest of the monitor is no less bespoke. It can be laser etched with lettering or symbols of your choice. Clear, purple, red, blue, yellow or black finishes are standard options, but virtually any colour can be requested and the same goes for the Kevlar reinforced, anti-friction cable (its length can also be specified). Cable positioning is offered either at the top of the monitors (to feed behind the ears) or at the bottom to mimic a typical earphone arrangement – the former is generally better for avoiding pulling the phones out or damaging them when you snag the cable. A personally inscribed rugged case is supplied as well along with a soft carry leather pouch. £500? It’s a start…

Of course there is an interesting conundrum when buying a pair of T2s. If they are all custom made how do you try them first? Quite simply you can’t. You pay your money, get some impressions made at an audiologist – ACS’s dealer map will provide some suggestions (there are numerous partners nationwide) – and join the waiting list (manufacture and delivery usually takes two/three weeks). A 30 day return policy exists for unsatisfied customers and earpieces will be remade if there is a problem with the fit.

The first special thing you’ll notice when you use T2s is the fit. ACS makes the custom moulds for Etymotic’s HF2 and HF3 earphones amongst others and those moulds are roughly the same size as a regular earphone tip. For its own monitors things are rather different. The moulds are considerably larger filling the entire ear canal. The benefits to this are twofold. 1. You get a near perfect seal (27db of isolation) which loses the vast majority of environmental noise even before the audio starts and 2. The speakers are held entirely inside the ear resulting in a flush finish. This is convenient since you can rest your head against a pillow at the end of a long day and sleep comfortably when travelling long distances. The sheer level of sound isolation means without any audio T2s function as professional grade earplugs.

With such a snug fit putting the T2s in initially takes practice. A provided guide will walk you through it (an anti-clockwise twist works best) and you’ll be a pass master in no time. Because they’re made from medical grade 40 shore silicone they’re durable yet flexible so they adjust with jaw movements to maintain comfort. The silicon also heats quickly to body temperature meaning you’ll forget they are in within minutes. It’s impressive stuff, but the real lasting impression (pun very much intended) comes when you press play.

It is hard to know where to begin describing such an experience. ‘Ballistic’, ‘vast’ and ‘agile’ would all be good adjectives, but the overwhelming impression is that of emotion. For all their manufacturing refinement they produce a sound that feels like it was formulated in the sweat shed from an Ozzy Osbourne stage dive and the fires of Jimmy Hendrix’s burning guitar. In a sector split between some customers demanding surgical precision and others addicted to bass the T2s effortlessly please both. They are as much fun with Mozart, Pavarotti and Miles Davis as they are with Metallica, the Chemical Brothers and Eminem. Dual drivers provide incredible drive across low, mid and high ranges and two balanced armature transducers add exquisite detail with frequency response from 16Hz to 20KHz. The effect is like getting knocked out by a velvet boxing glove.

So how to they compare to the competition? An obvious rival would be Shure’s flagship SE535, which carries a £478.98 RRP, but can be found online for nearer to £400. The SE535 has been our earphone of choice, but there is a significantly wider soundscape to the T2s: a sense of cinema verses IMAX. The T2s also offer greater clarity and are more immersive. The fact the SE535s don’t come with custom moulds may make the comparison unfair, but Shure doesn’t offer them. You could get third parties ones but they lack the full ear mould of the T2s and their swanky flush finish, and they’ll still then set you back circa £500.

There are a number of other custom IEM manufacturers but several don’t operate in the UK and most only offer hard plastic moulds so again miss out on the comfort benefits of the T2s. What’s more, the silicone offers better sound isolation, further
reducing the need to crank up your music and hearing – one of the key benefits of custom moulds in the first place.

Even in noisy environments like the London Underground the T2s create a serene, calming silence for your ears to enjoy.


What price do you put on the best? The ACS T2 monitors may cost £500, but they represent a new high in earphone sound quality and audiophiles will be bowled over. The custom moulds fill the ear canal to create the perfect soundstage and the flush design is practical when you want to put your head down. Finally the bespoke seal means you will have never enjoyed listening to music at such low volumes. Your bank manager may not thank you, but your doctor, your heart and your soul most definitely will.

”Note:” Now is probably not the best time to tell you ACS makes a flagship triple driver £650 T1. We’ll have a review of this truly frightening creation soon.

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