NNNN loudspeaker presets and the people behind them

Espen Evensberget, Øivind Stuan and Sverre Holm in the anechoic chamber at NNNN HQ.

Øivind Stuan

Øivind has been enthusiastic about sound systems ever since he accidentally headbutted his dad’s SEAS DIY loudspeakers as a preschooler. His first paycheck as a teenager went straight into a DIY loudspeaker kit. In the years that followed, he designed passive crossovers for multiple loudspeakers in collaboration with his late mentor Kjell Morten Berg. The measurement sessions were sometimes performed in large auditoriums or even small airplane hangars to get large enough distances for gated stepped sine measurements with reasonable low-frequency extension.

His first experience with professional crossover design software was with LEAP 4 from LinearX. As long as the measurements were trustworthy, the tool allowed for very efficient design and optimisation of crossover layouts and component selection. Being DOS-based and running on a 90MHz Pentium also provided a satisfyingly snappy user experience.

Like many of his peers, Øivind spent several years building car audio systems with custom-designed passive crossovers, but the compromises involved eventually led to him moving on from that specific area of audio systems.

While passive crossovers have their charm, Øivind has grown to prefer active crossovers for their ease of tuning, in particular, the possibilities offered by digital signal processing. That said, nearly sixteen years of professional audio product development has taught him that DSP is still no replacement for getting the basics right in terms of acoustical design and mechanical integration.

These days, he works primarily as a software developer for audio systems at Cisco, touching on most parts of the signal processing chain, though his favourite part of the code is the audio processing subsystems directly related to the acoustical design. His favourite place at work is, of course, the anechoic chamber, especially during the final measurements for a new loudspeaker system design, where the individual driver responses come together to form a cohesive whole, typically ending in an extended listening session to enjoy and rediscover his favourite playlists.

Having known Rune for many years, he’s also picked up an interest in horn-based loudspeaker designs, so far peaking with the construction of a 5.5m long corner-loaded folded horn subwoofer with a 1m² mouth area for home theatre use.

Øivind holds a bachelor’s degree in electrical engineering and a master’s degree in acoustics from the Norwegian University of Science and Technology. When he is not working on sound systems, he enjoys mountain unicycling and judo.

Øivind and the second ON2 pair

Øivind at Cisco

Espen Evensberget

Espen was born in 1954 and has a background in social sciences and computer science from NKSH (Norges kommunal- og sosialhøgskole) and UiO (University of Oslo). He has long experience in the publishing industry in the Gyldendal Group and later as a business advisor for business and strategy development.

Espen has always harboured a passionate interest in music and audio, ever since his schooldays when he built and maintained the school’s discotheque and sound equipment, mostly constructed from DIY components from KEF, SEAS, Peerless, and Josty Kit. Later on, he had various summer jobs in audio: maintaining PA/stage equipment, developing large simultaneous interpretation systems, and even a brief spell in the soon-to-be-famous Electrocompaniet, doing PCB soldering and repair work on their celebrated Two-Channel Audio Amplifier.

At home, Espen’s basement has gradually evolved from a rehearsal room (with drums, bass, and keyboards) to an electronic and speaker workshop, complete with acoustical treatments and lots of measuring equipment. He has himself designed and built many amplifiers for hi-fi and guitar, and probably more than 100 speakers: firstly with passive filters, then with purpose-built analog electronic filters, and eventually with digital signal processing. Even if digital filters offer the greatest flexibility and possibilities, there are still use cases when a well-designed passive filter has merit.

Over time, Espen’s main area of interest has become filter design, simulations and measurement theory, especially large horn-based speaker systems. For many years, Espen was very active in the DIY community doing design, simulation/measuring, and tuning for many well-known large horn systems in Norway: among them systems for Leif Christensen, Dag Alveng, and others. Within this small community and given our common interests in horn speakers, it was natural to meet up with Rune.

These days, Espen has retired from his day job as a business consultant and is (finally) devoting most of his time to audio and music. When not working on sound systems, he is often found outdoors, deep in the woods, or high up in the mountains fly-fishing for trout and char.

Espen with a the filter he designed for ON8

Sverre Holm 

Sverre Holm was born in 1954 in Oslo and, due to an early interest in audio and electronics, studied electrical engineering at NTNU in Trondheim where he obtained a PhD in 1982. Since 1995, he has been a professor of signal processing and acoustic imaging at the University of Oslo. He has published in, among others, IEEE Transactions on Acoustics, Speech and Signal Processing, and the Journal of the Acoustical Society of America, and written the book Waves with Power-Law Attenuation(Springer, 2019).

Sverre has a very interesting journey within audio that you can read more about here:
https://nnnn.no/a-norwegian-journey-in-audio-and-acoustics/

Sverre with Bjørn Magne Idland

Sverre at SEAS in 2006

Rune Skramstad (NNNN CTO) 

Our CTO Rune Skramstad started out with passive crossovers, analog line-level crossovers and electronic analog crossovers in the early ’90s, but his life changed when he got hold of a DSP loudspeaker management system in 1999. Suddenly, trial and error was fast-paced and fun. Passive heavy-duty subwoofer filters that had to be cooled down with ice bags were suddenly a thing of the past for high SPL applications.

In the ’90s and early 2000s, the Norwegian Altec Lansing distributor/engineer Per Grov and the Norwegian d&b and Zeck distributor Magnar Bergo (Drammen Lyd) played an (involuntary) mentoring role. They shared their experience with a young loudspeaker designer, sound engineer, and DJ (Rune), who asked endless questions about loudspeakers and loudspeaker processing, trying to absorb knowledge and experience like a sponge.

From 2006 onwards, measurement expert (Smaart, TEF, SIM II, Audio Lense and more), sound engineer and musician, Atle Aamodt, along with physics professor Sverre Holm, took over the mentoring role in a more formal way in a loudspeaker company called Paragon Arrays.

More on Rune’s history to come…

Rune in younger days