The picture above shows the PUK Recording Studio control room 1, which my company designed and built in 1985 for John “PUK” Quist.

Elton John, George Michael, Depeche Mode and many other top artists went to Denmark to use this studio, normally for 6 months.

The room is 100 sq meter, and the big woofers are 30” (80 cm), each driven by 1000W amplifiers. They work up to 100 Hz, the 15” units cover the lower midrange from 100 Hz to 400 Hz. Above 400 Hz the system was later changed to 2 pcs 8” and a high power (1000W peak) ribbon tweeter, with a 1600 Hz crossover, when we did a second matching control room in 1987.

The crossover is 4 way active, 24dB/octave. Sensitivity is 99 dB for 2,83 Volt. Total power is 10.000 Watt. The electricity company set up a new transformer station only for this studio, and all wires were screened with lead.

But the story began many years before…

I was born in Copenhagen on the 12th of April 1953. I grew up in a family of science and engineering. My mother had a M.Sc. degree in Chemistry and she worked as a researcher at Denmark´s Technical University (DTU). My father had a M.Sc. degree in mechanics and he worked for the Danish Government analyzing work accidents. He developed large computer programmes to find the common cause of the accidents.

In 1972 I began studying engineering at Denmark’s Technical University. A few years later in my spare time I co-founded Audiophil, a Danish Hi-Fi importing company, together with Bo Christensen (Bo later founded Primare and BOW technology). Raymond Cooke, the founder of KEF loudspeakers, visited us and appointed Audiophil as the new KEF distributor for the Danish Market. The company grew rapidly and this dual work prolonged my studies by a couple years. In the beggining I spent 3 years on the fundamentals of a M.Sc.E.E, but because of my keen interest in loudspeakers, I changed to a more relevant new multi education.

Eventually I graduated as B.Sc.E.E engineer specializing in mechanics, production technology, electronics and acoustics. My dissertation paper written in 1980 focused on horn loudspeaker design.

Afterwards, I sold Audiophil to Per Lundgreen and founded a Pro-audio import company together with Peter Olsen and Susanne Kampmann. The enterprice expanded to a team of 14 employees and reached an annual turnover of 2 million EUR of Pro-audio equipment sales in Denmark.

In 1982 we began manufacturing a Pro-audio power amplifier SLT 250. It used 28 MOSFETs and produced 2x250W or 1×1000W in 8 Ohm. It became the standard in most danish recording studios and PA companies.

PUK recording studio

During 1985-1987 I designed and supervised the turnkey construction of the PUK recording studio, see http://www.pukstudio.com. “Studio Sound” magazine wrote, “It has focused the recording world’s attention on the most unlikely site for an innovative recording facility”. George Michaels “Faith” album was made at PUK and became the USA no. 1 for the whole year in 1987. Elton John’s best selling single “Sacrifice” was also recorded at PUK. Many other artists such as Depeche Mode have since then chosen PUK Recording Studio. PUK control room featured an impressive 10.000 W active 4 way loudspeaker system and a unique room acoustic design. It was developed together with Poul Ladegaard from Brüel&Kjær. (http://www.bksv.com/)

At least in part PUK’s success owed to a superior sound insulation between the different rooms and extremely low noise and sound levels in both the recording rooms and the monitoring rooms. This was accomplished by floating the rooms on separate foundations with “Rockwool” insulation plates descending several meters into the ground between the foundations. 3 layers off special very thick laminated glass in two independent frames ensured that the sound from the 10.000W loudspeaker system did not leak into the recording rooms.

Denmark’s Radio (DR) visited PUK and thereafter asked Poul Ladegaard and me to analyse and suggest improvements for DRs main control room. DR decided to purchase a special loudspeaker from us, as rebuilding the acoustics would have been too costly.

Denmark Radio (DR) Studio

Building custom listening rooms, power amplifiers and loudspeakers

I have since built many of these rooms. They integrate the loudspeakers with a room using my special acoustic design. Together they make a sound so life like, that Professor Robert E. Greene in “the absolute sound” magazine issue 124 called it “Exploring the boundaries of the possible”.

In 1990 I began manufacturing Hi-Fi Amplifiers based on our professional power amplifiers. They were called SiriuS and received highest praise in local magazines.

In 1995 I developed the SiriuS D 200, the world first Single MOSFET 200 W power amplifier. All other 200W analog transistor power amplifiers had to use 4 or more output devices in parallel for the positive signal path and 4 others for the negative signal path, all to share the power load. Even with careful selecting and matching, they would not be identical in effect deriving sound from a mixture of many different sounds. The SiriuS D 200 used only one device in the positive signal path, and only one device in the negative signal path of a push-pull power amplifier. By virtue of by passing the deficient parallel operation of the devices, it offered a pure and unique sound as well as a simpler manufacturing process.

Some years later I received an interesting offer from a NY law company. Their client wanted to buy the SiriuS trademark. So today the Sirius trademark belongs to the Sirius satellite radio company in USA (https://www.siriusxm.com/).

I found a nice new name for my amplifiers in Websters. “GamuT” was the new name which originally meant “The entire range of musical notes” in middle age Latin. The GamuT D 200 Single MOSFET power amplifier received many awards world wide, among them are: Golden Ear award 2000 in “the absolute sound”, USA. Editors Choice Best Buy 2003 in “the absolute sound”, USA. Editors Choice award “Hi-Fi Choice”, England, twice. Editors Choice award “Hi-Fi & Records”, Germany. Reference in “Revue du Son”, France. See more in Reviews on http://www.gamutaudio.com

In 2003 I sold GamuT to travel and research new technology including the iPod, Blue Ray and 802.11 N (Wireless audio and video) for CAT Science Park. (http://www.catscience.eu/)

Moving to Finland

Drawing from the recording studio design experience, I custom-build listening rooms, amplifiers and loudspeakers for rich music lovers around the world.

In 2007 and 2008 I worked in Kupio, Finland for Amphion loudspeakers (http://www.amphion.fi). I developed 18 new loudspeakers and expanded the export sales network.

My designs performed suberb in Hi-Fi magazine tests: Amphion Prio 520 became a Best Buy in “Hi-Fi Choice”, England Amphion Ion L became Best Buy in “Hi-Fi Choice”, England Amphion Helium 520 became Best Buy in “Hi-Fi Choice”, England Amphion Argon2 Anniversary became Best Buy in “Hi-Fi Choice”, England Amphion Argon 3L became Best Buy in “Hi-Fi Choice”, England.

The Amphion Prio 520 and the latest Prio 620 also received very good reviews in “Stereo“ Germany, outperforming other brands at the similar price point.

I was glad to see Amphions export sales go up by more than 100%. Due to shared parts inventory went down by 30% and inventory turnover doubled.

Unluckily, in January 2009 I broke a bone in my leg on the ice in the Kupio Airport. My doctor found a vitamin D deficiency in my blood test. Vital for bone strength, vitamin D is synthesized in exposure to sun and my body was not generating enough of it due to lack of sunshine – too bad for the pale Finland. I decided to move south.

I have spend a lot of my time in India. I was invited 3 times to give lectures at AES meetings in Mumbai and I have built one of my listening rooms with an active loudspeaker system for a client in Mumbai.

I have presented the following Audio Engineering Society papers at the AES conventions:

• “A Large Monitor Loudspeaker System Suitable for Digital Recording” Paper Number: 2312 Convention: 79 (October 1985);
• “24-Track Hard Disk Compared with 24-Track Tapemachine.” Paper Number: 3316 Convention: 92 (March 1992);
• “A Practical Guide to Acoustical Design of Control Rooms and Placement of Loudspeakers” Paper Number: 4252 Convention: 100 (May 1996).

In 2007 I also presented a paper titled “The advantages of using waveguides in Hi-Fi loudspeakers” at the High End 2008 show in Munich, which received positive mention in “Stereophile” magazine written by Paul Messenger, England’s most experienced loudspeaker reviewer.

Another project I embarked on was designing active loudspeaker system for an elegant Indian diner “Tote on the Turf” in Mumbai. Please visit it while you’re there.

Today – astounding, yet affordable audio solutions

Today I and my partners do development work for many famous High End companies. As you can see I have built some of the most expensive audio systems in the world. However, from the very start my deeper ambition was to create products which most music lovers could afford. I began my own Hi-Fi life with Sinclair, Dynaco and Linsley Hood DIY amplifiers and Peerless, and later Lowther horn loudspeaker.

My first step was to see if I can design a better sounding loudspeakers in the 1-2k EUR range. That’s how the new Amphion loudspeakers was born.

The next project, Parasound ZDAC priced at 475 USD, began as an USB DAC developed together with Thomas Holm of HOLM Acoustics ApS. Please see excellent reviews it received in the products page.

Best wishes

Ole Lund Christensen