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In Reply to: Re: 21st Century Science posted by tomservo on April 7, 2007 at 09:00:02:
>>> "May, I have read a number of your posts and you are totally serious about sound.
Sadly, if you really want to know how things work, you have to start with what is known from a science perspective." <<<
Thank you for your courteousness Tom, but you really should have been more aware about our technical background before giving me a lecture on technical aspects of audio !!
Peter was a radio engineer in the RAF and after that he and I have been involved the world of audio for the past 52 years. 30 of those years involved audio equipment retailing and in manufacturing our own range of moving coil, orthodynamic and electrostatic headphones and loudspeakers !!!!!!!!
You say you have been involved with loudspeakers. I personally worked out and drew out an 8 ohm coil for an orthodynamic diaphragm, ready for etching, to fit the magnetic structure of the Strathearn orthodynamic panel speaker - whilst Strathearn were still cutting a quarter ohm coil - by hand - from aluminium foil and sticking it onto a mylar sheet - by hand !!! And, in addition, they then had to use a step up transformer to get this quarter ohm coil up to 8 ohms to match it into the amplifier !!!!
I have been involved in all aspects of audio, by Peter's side, for 52 years !! From the years of valves only (no transistors) and mono (before stereo).!!!
25 years ago our life changed. This was when Peter SUDDENLY found that he had the best sound he had ever had in his life !!!!! The rest of the story is well known.
So. Tom, in answer to your sentence "If you want to know how things work !!!"
I DO !!! But, thanks again for your courtesy.
“So. Tom, in answer to your sentence "If you want to know how things work !!!"
I DO !!! But, thanks again for your courtesy.”
Well May, I would have to say I have not reached that level where I can say I know how everything works, in fact, it usually appears that the more you know about something, the more you realize there are things you don’t know.
While I have not worked in the “hifi” market, other than working for Grommes precision in the 70’s (tube amplifiers) in engineering and repair, all of my life has been involved in solving technical / acoustic / electronic problems and I did contribute a few times to the late Audio magazine. My hobby and keenest area of interest happens to be hifi and building loudspeakers and drivers, so yes like I said I work with speakers.
I would like to think that the approach of using science and measurement as key elements to design is useful. So far as the obligatory technical penis waving in return, at Intersonics, I designed and built major sections of several experiments flown on the two space shuttle flights and sounding rockets, including the acoustic levitation transducers and power amplifier / control electronics. In addition to NASA work, I worked on projects as weird as measuring the resonance in pecan shells to the thickness of the carbon layer at the bottom of a working blast furnace (with sound) in US Steel in Gary Indiana. I also started the Servodrive speaker division with a loudspeaker I invented, one of which even eventually helped Joyce Poole at Cornell U. establish low frequency elephant communication for National Geographic.
We took on some hard jobs too, I designed a sonic boom simulator of massive proportions and several smaller ones for NASA research. This had to be waveshape accurate, not just ridiculously large.
All of this was in new ground where there was nothing you could look up, when the job is “hard” you run out of ways to do it. Ask your husband, how do you pass 300 Amps through a one turn coil, 3/8 inch id at 12 – 14 MHz, without an ensuing fire. It turns out you can electromagnetically levitate glass a “non conductor” with a 3 phase version.
For the last 9 years I have been designing commercial sound loudspeakers exclusively for a living but we did take on a Military “subwoofer” project recently we called the Matterhorn. While not a hifi speaker, the spec required low distortion, its dimensions may provide a laugh. Click on the construction video link.
This gives an idea what I have been up to in the past
And now where our speaker are used in commercial sound
And my solution to the “how to make a time coherent full range horn dilemma” or “how to make a small bass horn with nice response and group delay?”
None of this “new stuff” would be possible for me to conceive or design without using facts from the “book of science” and computer models that count on fixed relationships that “always” happen. .
It is the rare exception when something doesn’t fit when all the fine details are accounted for.
I ask, how much real innovation is there in home hifi?
How often do “new” ways of doing things really come along?
Lacking those, what else can a manufacturer, marketer or salesman do to create demand / sales?
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