The next photo shows a few of the 120V Voltair cards of which our half-sized component runs 21 total.

For listeners who insist on high-quality external filtering in the analog domain, options are scare. Bryston and Pass no longer make theirs. According to my survey, we're down to JL Audio, Wilson Audio, M2Tech, Exposure—German Physiks and Hornsolutions go digital—and spl. None of them offer remote control. All are priced ~3K and up. Only today's comes in black, silver and red.

For the right user, could this be the ace they were waiting on to finally win their game of perfect mains/sub integration?

To find out for myself, I contacted Sascha Flocken, their VP of communications. Like Benchmark Media, Manley Labs, Weiss and others, this German firm enjoy a very developed presence in recording and mastering studios. As reported by and, their Professional Fidelity range of which today's deck is part also serves those home listeners who prefer resolution, dynamics and linearity. An online shop creates finger-surfing access. Lest you thought the company name means sound pressure levels, it's Sound Performance Lab whose beginnings under founders Hermann Glier and Wolfgang Neumannn date back to 1983.  The tour and following interview paint the picture.

My takeaway from both was that spl's engineering department operates as its own entity. Unlike small high-end boutiques whose chief bottle washer wears all the hats, they don't get bogged down by repetitive production demands. They do R&D and nothing but. It explains their catalogue's astounding depth including full-bore mastering consoles.

Also relevant to today's Crossover could be that spl were granted a rare 14-point patent on filter design in their early days which their Vitalizer popularized with over 80'000 units sold.

Let's find out how their Voltair Crossover behaves in an audiophile listening den of iniquity.