“Sonic neutrality is our obsession”
What Hi-fi? caught up with PMC co-founder Peter Thomas to discover all about his hi-fi journey
Peter Thomas co-founded PMC in 1991 with his former BBC colleague, Adrian Loader. From not-so-humble beginnings supplying the BBC with monitoring speakers, PMC has since grown into one of the most successful specialist loudspeaker manufacturers on the planet. What
Hi-fi? caught up with Thomas to discover all about his hi-fi journey.
What first made you interested in hi-fi?
It started when my grandfather gave me his wind-up gramophone. I was fascinated by how it worked – it seemed almost magical. Then I began collecting 78rpm records, which started my lifelong passion for sound and music. By the early 1970s, I was an avid hi-fi enthusiast, constructing my own speakers and amplifiers before going on to study electronics at Canterbury.
I was introduced to IMF transmission lines by Tom Barron (now PMC’S UK sales manager) at the Audio Olympia show in London. “You’ve got to hear these, there’s something very special about their sound,” he said. That was another lightbulb moment.
Your first hi-fi system?
Garrard SP25 MKIII, Shure M75EJ MM cartridge, Armstrong 625 Tuner/amp and Wharfedale Dovedale III (3-Way) sealed boxes, Sony TC377 reel to reel. My bank manager couldn’t understand why I needed to borrow such a lot. I convinced him it was worth spending money on things you are passionate about.
Your first job in audio?
In 1977, I had an engineering position in BBC Radio, based in Broadcasting House, servicing both valve and semiconductor amplifiers, tape machines, turntables, mixing desks and monitor speakers. I moved into project work and designed a bespoke turntable to transfer 78rpm discs and another to play a wide variety of cylinders from the BBC library.
I became manager of BBC Outside Studios, with responsibility for Maida Vale studios and looked after the technical facilities for Radio 1, 2 and 3 for rock and classical sessions. It gave me a huge insight into the world of music, across all genres, and fuelled my passion for great sounding audio equipment.
What was the BBC like then?
When I joined it was very ‘public school’ and extremely formal. Many employees were former officers approaching
“Adrian and I founded PMC because there were no speakers transparent enough to convey music realistically – we knew we could remedy this”
retirement, having been recruited straight after the war. As TV accounted for most of the licence fee, Radio had been set in aspic since the 1930s – when we had to change valves in a mixing console, its stamp was usually pre-war. But with the colour licence in the 1970s, there was a larger budget for recording facilities, so all the old valve kit was scrapped and replaced with solid state, using the latest integrated circuits. The BBC had over 200 studios, it was a huge network to upgrade and manage.
How did PMC come about?
My work at the BBC’S music studios centred on the need for cutting edge monitoring speakers that could be used at high volumes. I worked with many speaker companies to achieve this.
At the same time, EX-BBC engineer Adrian Loader and I were looking to replace our hi-fi speakers. We auditioned all the top ‘reference’ models available, but decided instead to design a speaker for our own use. Several years’ work resulted in a prototype loudspeaker design, the BB5, which BBC Radio chose for their music studio at Maida Vale. And after 27 years, they are still in daily use.
The majority of speaker designers used ported or sealed cabinets, but we wanted a more sophisticated approach that would benefit both the studio and home user. After extensive tests, we found that a transmission line system for bass loading gave a performance that significantly exceeded the conventional bass loading principles. This is when the Advanced Transmission Line was born.
I left BBC Radio in 1991 and formed the Professional Monitor Company (PMC) with Adrian. We began production of the BB5 active speaker system, supplying professional studios around the world, including the BBC, Metropolis Studios and Capitol Studios. Customers included Prince, Stevie Wonder and Robbie Williams, to name just a few.
Why is a transmission line design better than others?
We felt that speaker design could be improved and one way was to evolve transmission line design, which can give enormous benefits over conventional loudspeakers, but is difficult to get right.
One advantage is that the bass driver is controlled over a wide frequency range, which in turn reduces distortion. A spin-off from the lack of distortion is that the upper bass and midrange detail is not masked by harmonic distortion in the low frequencies.
The result is a transparent midrange and fast attacking bass, with real clarity. Another advantage is a cabinet that produces a higher volume and greater bass extension than a ported or sealed design of a similar size.
Why don’t more companies use transmission lines?
It is difficult to get right and takes a lot of time, effort and resources. For many, it isn’t financially viable to manufacture transmission line cabinets and bespoke drivers to match. We take the approach that the result is far more important than making a product to a set price point.
Original TLS weren’t ideal; it took a huge amount of work to reinvent them creating our own acoustic modelling techniques, damping materials and driver design to develop the original transmission line theory to ATL.
What makes PMC different?
We believe the music is what matters; it’s what gives us the passion for what we do. We founded the company because there were no loudspeakers transparent enough to convey music realistically – Adrian and I knew we could remedy this using advanced engineering and a holistic design approach.
Sonic neutrality and transparency has always been our obsession, all in the interests of reproducing music as vividly and faithfully as possible, just as the artist wanted you to hear it. Put simply, it’s easy to produce a loudspeaker that is either neutral but boring or lively and extremely coloured… neither is good to reproduce all genres of music. The goal is to combine neutrality and dynamism.
Were you tempted to follow BBC engineering principles – thin wall cabinets etc?
We follow the BBC’S design procedure by initially using speech to develop a speaker, as the human ear is most sensitive to that, then we move on to music. The template we follow is to neither trust measurement or subjective listening exclusively… but taking a balanced view to create a world-class design. The BBC’S thin wall mass damping technique was cutting edge for its time, but to reduce and eliminate all that is not music takes more inert materials and techniques.
What’s your favourite speaker you’ve worked on?
It could be the BB5 – that was the first speaker we produced commercially, and it set us on the road of what was to become PMC. Without that, we wouldn’t be where we are today.
But we’ve spent the last 26 years perfecting our engineering art and have just released Fenestria, the pinnacle of what we can produce. I am particularly proud of the fact that my son, Oliver, was the head engineer on the project.
Measurement or listening… which takes priority?
We take measurement as seriously as listening. We use a huge amount of cutting edge measurement when designing our speakers, including sophisticated laser measurement techniques to ‘see’ the sound emanating from the speakers. This enables us to design all the elements to work together and create the best speaker we can.
Every speaker we build is subject to a critical listening test, which is the ultimate determiner before it is packaged and sold. The music it reproduces is, after all, the most important thing. However, we can’t create such good speakers without the measurement, so both have an equally valid place.
Your three favourite classic hi-fi products?
The ultra-rare Gale record player, Lecson AP1 & AC3 Pre Power and the chrome capped Gale 401s. I’m lucky to have them all. They are part of our historic archive of significant audio designs.
What do you think speakers will be like in 20 years?
Active, wireless, voice operated, smaller with greater performance… hopefully.