Hardware Reviews

Quiescent Apex40, 50 & 60: splendid isolation

Quiescent Apex isolation devices www.the-ear.net

Quiescent Apex isolation devices

The Quiescent Apex range of component Couplers is distinctly different from the isolating products found elsewhere. For a start they are asymmetrical and their surfaces are carved out with curved paths that are seemingly random, they are also pretty chunky, the smallest Apex40 is 127mm (5 inches) wide at the widest part of the base. And finally they have a support point at one end of the block rather than in the middle.

Turn a Quiescent Apex of any size over and it appears to be a shell that’s filled with some kind of resin, it’s not clear what goes on within this internal highly damped part of the block but Quiescent describe it as a honeycomb structure and this combined with the shapes on the surface is said to provide an irregular path for disspipating vibration. The results produced by using three Apex Couplers under pretty well any component would suggest that this approach is rather effective.

Quiescent Apex isolation devices www.the-ear.net

They are not designed to combat airborne vibration and no mention is made of energy travelling through support racks, instead they are intended to deal with high frequency vibration produced by component resonance and eddy currents in equipment. It is well understood that component vibration is an issue but not many manufacturers attempt to do anything about it, Naim suspends circuit boards on springs in its higher end products and others attempt to damp vibration using various methods, but no one goes to these sort of lengths in their electronics apart from Quiescent.

The non-parallel sides and irregular surfaces of the Quiescent Apex Couplers combine with a honeycomb structure in order to cancel vibration channelled into the Coupler via the stainless steel spike atop each one. The larger the Coupler the more effective it is at reducing the energy produced within each component which in turn allows it perform in a more optimal manner. The range consists of three models: Quiescent Apex40, Apex50 and Apex60, the numbers indicate the height of these chunky blocks in millimetres, the footprint of each increases along with model, the Apex60 being 190mm wide at the longest end.

Quiescent Apex isolation devices www.the-ear.net

The Apex50 effect

My listening started with the Apex50 under a Moor Amps Angel 6 power amplifier, a 29 kilo beast that normally sits on four hard rubber feet atop an equipment rack that has damped spring suspension and thus is quite well isolated from energy travelling through the floor. Here three Apex50s managed to open up the soundstage and add definition to the image, it became apparent that this was achieved by lowering the perceived noise floor because quieter sounds were easier to hear. These feet allow the amplifier to produce greater purity of tone too, notes seem to be cleaner and there is more space between musicians. They did wonders for Michael Franks’ Art of Tea album on vinyl which had more groove, space, definition and solidity of treble.

Apex60s under the same amplifier took things even further in the same direction whilst improving dynamics, speed and power in the bass. The latter quality proved to be the most distracting with further listening as familiar tracks offered up more weight and depth in the bass than usual. This combined with greater detail and openness mean that going back to the amp alone made it sound rather dull and restricted.

Quiescent Apex isolation devices www.the-ear.net

I also tried the Quiescent Apex50s under my Rega P10 turntable which was already sitting on a suspended Townshend Platform, and given that the Quiescent Couplers are designed to tackle high frequency vibration I was surprised at the benefits accrued on this turntable. That said it’s a lightweight design that is probably better at channelling high frequencies than lower ones. The effect was greater depth and shape to notes, better timing that produced more bounce in the rhythm and there was also more sparkle to the electric piano. Playing a few more LPs it became apparent that the bass was also more substantial and solid.

Moving from Apex50 to Apex60 under the turntable enhanced both timing and dynamics, the sound gaining filigree detail and immediacy, the Art of Tea now sounded immaculate, the turntable revealing greater contrasts between tracks, dynamics and tone. This comparison was slightly skewed because the extra weight of the bigger Couplers allowed the Sesimic Platform to compress its springs which improves mechanical isolation from the rack below.

Quiescent Apex isolation devices www.the-ear.net

Putting Apex50 Couplers under a lightweight Auralic Aries LE streamer markedly improved timing, and this with a component that has a plastic case in which eddy currents would find it hard to reside. With the much more substantial Auralic Altair G1.1 streamer in its aluminium case the effect was a calming of the balance that allowed more detail to be presented in a better timed fashion which made the music more engaging.

Placing three Quiescent Apex60 Couplers under Tom Evans’ Linear A valve power amplifier had a different effect to that found with the Moor Amps, here there was a significant increase in image focus brought about by greater clarity and definition in the sound, the amplifier became more articulate, better able to reveal precisely what was going on in the mix. The change was not subtle at all and elevated this already remarkable amplifier another step or two up the high fidelity ladder.

Quiescent Apex isolation devices www.the-ear.net

Both my Lumin U2 mini streamer and an iFi Pro iDSD DAC enjoyed having a trio of Quiescent Apex40s beneath them if the results were anything to go by. In both cases the main benefit was an opening up of the soundstage bringing depth and three dimensionality to the imaging, with the streamer gaining more in depth and the DAC delivering better timing.

Apex Coupler conclusion

The Quiescent Apex Couplers are a development of similar devices made under the company’s previous brand Vertex AQ, I never tried those but reviewers of my acquaintance spoke highly of them. By working up from that point Quiescent have developed an isolation product that while it works on different principles to the usual variety and ends up being bigger, offers significant upgrade potential to almost any component. If you want to hear what your system is really capable of I recommend giving them a try, and remember, in this case bigger is better.


Type: isolation feet
Size HxWxD, weight:
Apex40: 40 x 125 x 122mm, 525g
Apex50: 50 x 145 x 140mm, 768g
Apex60: 60 x 190 x 182mm, 1760g
Warranty: 20 years

Price when tested:
Apex40 £740/set of 3
Apex50 £1,250/ set of 3
Apex60 £1,950/ set of 3
Manufacturer Details:

isolation feet


Jason Kennedy

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