A one-man workshop, then a partnership.

SPL stands for Sound Performance Lab, and the company has always been based in Niederkrüchten, a small municipality on the Lower Rhine near the Dutch border. Its own website says it has been developing audio equipment “since 1983.” The German trade magazine Studio Magazin, in a 2023 interview with Hermann Gier by its editor Fritz Fey, gives a slightly different start: in 1984 Wolfgang Neumann founded a sole proprietorship called Sound Performance Laboratory. We give both dates. Wolfgang Neumann has no documented connection with the Berlin microphone maker of the same surname.

According to the same article, Neumann soon met Hermann Gier, and in 1987 the two formed a partnership. In 1994 Peter Waschke, a figure from the audio-publishing world, joined them, and SPL electronics GmbH was formed with three partners. The SPL website now names Gier and Neumann as the founders.

The product that made the name came out of a setback. Gier told Studio Magazin that the pair had announced an exciter, but that Aphex held a German patent on its Aural Exciter, granted in September 1987, so they needed a new idea. He dates the decisive night to 18 February 1988: listening at two in the morning on cheap full-range speakers hung in the corners of the room, Neumann added a sub-bass filter and a mixing stage, and the timpani on a Jennifer Warnes recording suddenly sounded huge. “That was the birth of SPL and the Vitalizer,” Gier said. The magazine’s own timeline places the Vitalizer’s launch in 1987, so the two accounts do not quite agree.

The Vitalizer, the Transient Designer and 120 volts.

The Vitalizer became a family of processors. Reviewing the Vitalizer Mk2-T in April 1999, Sound On Sound’s Paul White described it as combining EQ with “a number of largely secret processes” and noted that the original Classic model was still in production. SPL calls the circuit patented.

In October 1998 White reviewed the Transient Designer, which shapes the attack and sustain of a sound regardless of its level, and called it “a unique dynamic processor” with “nothing else on the market like it.” Studio Magazin dates it, and the Atmos 5.1 surround microphone system made with Dirk Brauner, to 1998.

SPL’s technical signature is its 120-volt technology: audio circuits running on rails of ±60 volts, which the company says is four times the voltage of typical integrated op-amps. It was first used in the MMC1 surround mastering console and the PQ equaliser, then in stereo mastering consoles in 2005 and the Phonitor headphone amplifier in 2007, according to Studio Magazin. Reviewing the Phonitor in December 2008, Sound On Sound called 120V “SPL’s trademark” technology and explained the crossfeed and speaker-angle controls that imitate listening on loudspeakers. In March 2026 the magazine reported that Neumann had designed the company’s own discrete SUPRA op-amps for these circuits, and called the new Venos bus compressor “one of the best available.”

The Phonitor also led SPL into hi-fi. Studio Magazin reported that by 2012 half of all Phonitor sales were going into home listening rooms, and in 2014 the company started a hi-fi range called Professional Fidelity. Its studio hardware has also been released as software through Plugin Alliance.

Design and documentation.

Big consoles get the attention, but much of a modern studio’s signal path runs through equipment from smaller specialist makers. The seven companies in this guide each built a name in one link of that chain: summing, conversion between analogue and digital, microphone preamplifiers, or moving audio between systems.

Summing is where Dangerous Music began. The company says it was officially founded in 2001 with the release of its 2-BUS analogue summing amplifier. Its website gave an address in Edmeston, in upstate New York, in 2008 and 2014.

Conversion is central to several others. Lavry Engineering, whose range includes the Quintessence digital-to-analogue converter, gives its shipping address as Kingston, Washington. Crane Song, whose products have included HEDD converters, gave its address as Superior, Wisconsin, on its website in 2005. Burl Audio, which says it was founded in 2006, makes converters and microphone preamplifiers and describes itself as “based in Santa Cruz, California.”

Grace Design, a family firm that says it was founded by the brothers Michael and Eben Grace in the early 1990s, makes microphone preamplifiers and says its shop is in Lyons, Colorado. SPL electronics, which names Hermann Gier and Wolfgang Neumann as its founders, is based in Niederkrüchten, Germany, and uses the line “Sound Performance – Made in Germany.” DirectOut, from Mittweida in Saxony, works on the networking side, with MADI and audio-over-IP converters and routers that link consoles, stage racks and computers.

This guide sets out what can be checked about each brand — who founded it, who owns it, and what it says about where its products are made — and marks clearly what rests only on the company’s own word.

Front panels that read from left to right.

SPL is privately owned by its partners, and we found no outside takeover in the sources we checked. Studio Magazin reported that Peter Waschke retired in 2018 and handed over to Heinz Middelkamp, whose own company had been responsible for manufacturing all SPL products since the late 1990s. At the turn of 2022 and 2023 Wolfgang Neumann retired but stayed on as a developer and adviser, and the developer Bastian Neu took over his place as managing director and co-owner. The company’s legal notice now lists Gier, Middelkamp and Neu as managing directors.

On where its products are made, SPL says it manufactures “all devices in our own production facility in Niederkrüchten on the Lower Rhine, Germany,” and signs its website “Sound Performance – Made in Germany.” We give that as the company’s claim.

The look is unusually well documented for a studio brand. Gier told Studio Magazin that he has handled the product design himself from the start, with no formal training. At first the layouts followed wherever Neumann had placed the controls on the circuit board; later the two agreed a feature set first and Gier turned it into a design, preferring a signal flow that runs from left to right, input to output. Fey praised the “all-black design” of the mastering series. SPL’s Vitalizer Mk3-T, the company says, swapped its predecessor’s “golden robe” for the black of the Studio Series, and the Transient Designer 4 Mk2 has a 4 mm black anodised aluminium front panel with knobs milled from solid aluminium. Sound On Sound noticed a smaller habit in 2008 and 2014: rear-panel labels printed so that they can be read upside down when leaning over the rack from the front. For the hi-fi range, Gier said, SPL kept the Phonitor look because any other design would have meant losing “our only recognition feature”; its Performer s1200 amplifier comes in black, red or silver.

For a design guide, SPL shows how a small engineering firm can build a recognisable face from panel layout, finish and a few signature controls. Compare RME, another German studio-electronics maker, and Behringer. For this guide we use black, silver and a deep red with a sans, an unofficial interpretation; no product or logo is reproduced.

Keep SPL’s identity on hand — save it to a board in the Made Good inspiration library.