Cables

From selecting its own copper ore, drawing and refining its strands at a partnering mill and meticulously hand-fashioning its premium products, Germany’s In-akustik has been approaching cable construction with a passion since 1977. The pursuit of an air dielectric, preferable but less practical than PTFE, HDPE, PP or PVC, is a particular mission for this brand and one taken to its next level in the Referenz LS-4005 AIR. Priced at a not inconsiderable £7019 for a 3m stereo set terminated in bananas or spades (or £7799 for superior SBW connector types), this cable is still arguably the ‘sweet spot’ in its Reference range – the very new LS-8005 AIR being about four times the size and nearly three times the price...

Web of wires

Now in its fifth generation, In-akustik’s ‘Super Speed waveguide’ geometry has been expanded to encompass no fewer than 16x1.5mm² multistranded conductors, grouped as signal and return pairs and supported within a flexible polyethylene ‘nest’. Each of the 1.5mm² conductors comprises 24 OF-copper strands, wound around a solid PE core, and individually lacquer-coated to prevent non-linear surface-to-surface conduction. The helical layout of these conductors is designed to reduce parallel capacitance, minimise dielectric losses and optimise, or at least manage, the local electromagnetic fields. Cable diameter is a full 4cm, but it’s much lighter and more readily ‘dressed’ into position than many a less bulky but far stiffer high-end speaker cable.

Above: Rhodium-plated, tellurium copper terminations include a lockable ‘ball joint’ to make for easy installation

The LS-4005 AIR’s measured parameters are very close to the figures published by In-akustik itself – a moderate 0.13µH/m series loop inductance, and moderately high 217pF/m parallel capacitance, all combined with a vanishingly low 4mohm/m loop resistance, equivalent to a power loss of just 0.0043dB/m into 8ohm. Leakage is a superb >300Mohm, this also reflective of the idealised ‘air’ dielectric.

Taking the air

This flagship cable arrived while we had a series of spectacular loudspeakers available in our purpose-built listening room, including the Wilson Alexx Vfx, the Rockport Orion [HFN May ’25] and DALI Epikore 11 [HFN Feb ’25]. Powered by both Constellation Revelation 2 [HFN Jan ’25] and BAT REX 500 [HFN Feb ’24] amplifiers, the well-rounded quality of the LS-4005 AIR cable was immediately obvious.

Previous In-akustik speaker cables have typically demonstrated a slight edge [HFN Jan ’16], and while the LS-4005 AIR also puts its best foot forward it combines this with a wonderfully open, vibrant and fresh-sounding top-end. It’s super articulate but never bright, as illustrated by the snap of steel guitar sparkling within the otherwise warm and emotionally charged ambience of Tracy Chapman’s remastered ‘Fast Car’ Greatest Hits; Elektra 0812279 50132. This sense of an expansive, immersive musical ‘experience’ extends into the midband where Finnish group Club For Five’s a cappella cover of Dire Straits’ ‘Brothers In Arms’ [WEA 5051865611929; CD res download] sounded vivid but arguably a little larger than life. If you want to inject a little extra gas into a slightly small-scale system then this will likely do the trick, but with this grandstand sound also comes the merest softening of stereo focus.

Bass, too, is as extended and potent as the top-end is revealing, the LS-4005 AIR delivering the full, ominous impact of Black Sabbath’s ‘Into The Void’ Master Of Reality; Rhino/Warner Records; 96kHz/24-bit and ensuring Geezer Butler’s undulating bassline and Bill Ward’s drums enjoyed appropriate weight and scale.

If you’re after a big sound, the Referenz LS-4005 AIR pulls out all the stops.

Hi-Fi News Verdict
In-akustik has gone to extravagant lengths to realise as practical an ‘air dielectric’ cable as might be achieved without incurring either excessive weight or, indeed, fragility. So the Referenz LS-4005 AIR is both lighter and more physically flexible than its 4cm diameter might suggest. Its sound, too, is writ large with air and atmosphere, and proves more than competitive even at this heady price. But wait... There’s a solid silver version too!

Sound Quality: 88%