Acurus Act4

Acurus Act 4 - 16 Home Theater Processor. Used as a demo in our theater. Has maybe 80 hours on it. Comes with factory rack ears. Always in a smoke free environment. Works like new because it is as close to new as possible. Comes with remote, power cord, original two layer box.
Here is some info / review: The Acurus ACT 4 is the latest high-end multichannel AV pre-amp and processor from the US manufacturer Indy Audio Labs. There are actually two versions – the ACT 4-16, which I'm reviewing here, and the more expensive ACT 4-20, which was released recently. The main difference is that the ACT 4-20 has 15.5 configurable channels, while the ACT 4-16 is 'limited' to 13.3.

Those extra four channels of processing aside, both appear to be identical with support for Dolby Atmos and DTS:X immersive audio formats, and Hi-Res Audio. There's also HDMI 2.0b and HDCP 2.2, so the ACT 4 can pass 4K/60p and High Dynamic Range (HDR10 and Dolby Vision). The ACT 4-16 isn't cheap though, costing a hefty £12,300 as at the time of writing (July 2018).

There are some genuinely impressive pre-amps and processors at the high-end of the market, so the ACT 4 will need to deliver an exceptional performance if it's to hold its own. The Acurus ACT 4 definitely looks the part, with the kind of elegant design, solid build quality, and slick features that often differentiate products at the higher-end of the market. Thanks to a large 7" central display that is not only informative, but also a touchscreen interface, the ACT 4 has a very cool front facia that creates a pleasingly minimalist effect.

I've been arguing for manufacturers of AV receivers to take this approach for years. You don't need loads of buttons and connections on the front: an on/off button, a volume dial and a touchscreen covers everything. That's exactly what the ACT 4 does, with an illuminated power button on the left, a touchscreen in the middle, and a large volume dial on the right.

Performance

In terms of its performance, the Acurus ACT 4 was rock solid with no problems in terms of operation. The processor was fast, responsive and stable, with no issues in terms of stability. It also performed extremely well as a pre amp and using the touchscreen was an absolute joy.

As a processor the ACT 4 is superb, decoding and rendering both Dolby Atmos and DTS:X very effectively to deliver an open but detailed soundstage with precise steering of effects and plenty of surround presence. Of course I was partnering it with exceptional amplification and speakers in the shape of the dARTS Theatre System, but even so the ACT 4 remains a great processor regardless.

As always I started with the Amaze trailer from Dolby's Atmos demo disc. The ACT 4 did an excellent job of delivering the multitude of effects such as birds, thunder and rain, resulting in an impressively immersive experience. I then moved on to the Atmos soundtrack on the Blu-ray of Gravity, which has a highly directional sound design making it ideal for testing a system's steering and tonal balance. The ACT 4 steered the voices and effects around the room seamlessly, resulting a very three-dimensional experience.

The absence of any built-in room equalisation meant I had to rely on my own skills but thanks to a carefully designed home theatre, a degree of familiarity with the room itself, and plenty of experience in managing the bass response, the result was a suitably balanced and smooth low frequency presence. I used my go-to bass test disc – Blade Runner 2049 – and the ACT 4 handled the massive low frequency notes at the start of the film very well, delivering them with plenty of control and precision.

I recently picked up A Quiet Place, and this film has quickly become one of my favourite soundtracks. For a film that is essentially about not making any sound, the mix is incredibly active all of the time. There is an amazing amount of subtlety with the silent scenes punctuated by wind rustling through the leaves or soft footsteps on sand. However when someone accidentally makes a loud noise or the monsters arrive, the dynamic range of the soundtrack is incredible. The entire soundstage just bursts in to life, with plenty of use of the overhead channels and massive amounts of bass energy to give the scenes greater impact. The ACT 4 handled this amazing soundtrack with real skill and authority.

Moving on to DTS:X soundtracks, the recent 4K Blu-ray release of Jurassic World delivers a great example of what the format is capable of, and the ACT 4 handled it extremely well. This is an active and immersive sound design, especially during the jungle scenes. There's also effective use of the overhead channels, with dinosaur sounds emanating from the trees above the protagonists. The sound designers make full use the bass to give the dinosaur roars a more visceral impact, but within all the action and effects the dialogue remains clear and focused.

The ACT 4 includes the Dolby Surround and DTS Neural:X upmixing algorithms and using the 4K Blu-ray of Dunkirk, I was able to compare the two. Both delivered the impression there were overhead channels, even though I know the 5.1 soundtrack obviously wasn't mixed that way. As a result I felt engulfed by sounds, whether it's the rattling inside the Spitfire cockpits or the troop ship filling with water as it sinks. It's entirely up to you which of the two you choose, and if you have a 7.1.4 set-up it really doesn't make any difference, but if you have a 7.1.6 set-up then you might prefer to use Dolby Surround because it will make use of all the channels.