March 29, 2011

10 Qs For Peter Thomas, PMC Loudspeaker Owner/Designer.

Peter Thomas was here recently to present AV Designs an Award Of Excellence for their new flagship AV showroom, featuring the PMC MB2-XBD active speaker system. Since I already spoken to Andy many times already, I'd focus on Peter now, when I had the chance to pick Peter's thoughts on speaker design philosophy, hifi and music in general. As promised, here's my 10 Qs! Pete Thomas is very focused, when it came to his forte topic, loudspeaker design.

Big E: Peter, welcome to Malaysia! Your first time here, I presumed?

PT: Yes, it's my first time here and my god, what a beautiful country to be in! It's so..... green here, compared to the mucky grey we get in the UK.

Big E: You're the last of the surviving member of the BBC speaker design division?

PT: I am not sure if I am the surviving member of that club, but certainly the only one still actively managing my business. There are other speaker brands that continue the BBC speaker design philosophy, like Spendor or Harbeth naturally comes to mind.

Big E: What are your thoughts exactly on the famous lower mid range(100Hz) bump on the LS3/5a, as an ex-BBC guy and as a loudspeaker designer today?

PT: I think Dudley Harwood(who later went on to start up Harbeth) is a genius in the way he maximise the design of the LS3/5a model, given the technical limitations of the time. He had used the "famous" bump in frequency response to give the impression of more bass quality than the actual speaker is capable of physically. I think it made the speaker more enduring to the music lovers.

Big E: Are you an analog or digital music guy?

PT: I am mostly analog, given the material of my musical preference are mostly available on that medium. Having said that, I think digital can sound very good too, if the people in the recording studio did all the right things, and there are just as many bad sounding records too, due to the poor quality pressing process control.

Big E: As we enter the era of hi-rez downloads format in digital music, do you think the latest format places more stress on hifi equipment, speakers in particular?

PT: I don't think so. Given that 16/44.1kHz already achieves a very good standard of specification based purely on audio parameters, 24/96 or 24 192kHz merely allows more sampling rates over the same frequency bandwidth. On top of that, almost all new commercial recordings today are done in digital at 24/192kHz or higher. This allows the recording and mastering engineers room to "dumb down" the recordings, as a safe guard, so that our domestic hifi equipment doesn't break during replay. All commercial recordings available today are "dumb down", even the so called hi-rez format.

Big E: But still, hi-rez does sound a lot better than CD, right?

PT: I agree, Hi-rez gives so much more density, depth, and acoustic space to the musical content. These are things that our measurements doesn't tell us. So we must listen with our ears, and not only rely on measurements. I had asked Pete which is his favourite PMC loudspeaker design? And he kept us guessing!

Big E: Now we come to the exciting part, which is speaker design, your area of expertise! Tell me why doesn't PMC use exotic materials, or "audiophile boutique" parts in it's speakers, even the high end models?

PT: That's a good question, but to me the best approach to speaker design success is synergy. I feel that expensive materials alone does not guarantee good sound! I know many hi-end designs today uses aluminium or carbon treated boxes and "audiophile boutique" parts to enhance showroom appeal. I personally prefer to put the money in the parts that really matter, and that's the drivers. I can tell you that industrial grade passive components like resistors and capacitors have tolerances of less than 10%. Speaker boxes made from exotic materials can contribute to the final sound, but at what cost? And did you know that even the best speaker drivers available today can still distort by as much as 30% or more, when pushed beyond their designed operating limits? I believe there's still a lot of work to be done in this area, which is most important. Speaker design is as much acoustic science as it is art, and it's up to the individual designer to set his priorities. Mine is design synergy, where every single part is made to work as one, so that the results in sound that is greater than the sum of it's parts, now that for me, is a successful design.

Big E: What about the hi-end market's preference for 1st order/6db passive x-over designs?

PT: I think that 1st order/6db passive x-over design superiority is a myth, very much mis understood by the hi-end market. The reason everyone else does 1st order passive x-over designs is because it's easy and cost less to implement. I personally feel that 1st order passive x-over design places too much stress on driver's operating beyond their comfort zone, resulting in more distortion from the over driven drivers. I personally prefer 4th order, or 24db passive x-over networks, because they keep the drivers operating within their comfort zone, resulting in less distortion, less distortion also means more music. However, the mathematics involved for 24db x-overs are much more complicated and much more challenging to implement successfully. In the end, I suppose both gradual or steep x-over network designs have their pros and cons, and it's up to the speaker designer to work around the drivers integration with which ever order of passive network he feels suits the purpose.

Big E: The latest PMC Fact series loudspeakers sounds rather different from the classic i series, why is it so?

PT: That was intentional! I wanted to Fact series to sound closer to what you'd get with these babies(pointing towards the MB2-XBD active speaker system). I voiced the Fact to sound like the PMC active speaker designs, but with the traditional passive x-over network. The result is a speaker with wider bandwidth, dynamic range, and superior resolution with a slightly forward mid range, to give an illusion of better sound staging and imaging properties.

Big E: How did you come up with the speaker product names like BB5, OB1 or TB2? It's like an alphabet hot soup!

PT: Now, you saw in my presentation earlier, showing me carrying the BB1 out of my garage for testing. So how we started BB1 was actually a joke, between my and my partner then Adrian(who is no longer with us). You can see the big box, right? That's how it all started, BB1 means Big Box 1, MB2 means Medium Box 2, TB2 means Tiny Box 2, LB1 means Little Box 1, and OB1 means Other Box 1(nothing to do with Star Wars as Dick Tan had originally taught).

But that's the official, sanitised version of the story. All of us present that day were made to sworn secrecy over the real story, so we are not allowed to share, sorry. Ha! Ha!

After the Q&A session, we moved to the "Happy Meal" session covered by Odiosleuth earlier, accompanied by more impolite and secret jokes, that only those present that night can cherish in memory.

No comments: