Bob's Intro
My Audio webpages are intended to be fun and informing
for the analog audio engineering hobbyist.
Some Background:
I grew up marveling over the 1950's Hi-Fi system my
Dad built. The speaker cabinet was a folded corner horn design. Pretty fancy
for the times. As a young boy, most of my toys were electronic stuff pulled
out of peoples trash. At some point I figured out how to turn an old junked
radio into a usable amplifier, by feeding signals into the top of the volume
control. When I was about 7 years old, my Dad removed the magnet from his University
"Diffusacone" 12 inch speaker driver, and repaired the burnt open
voice coil, on our dining room table. It was a success. I watched the whole
thing. In about 3rd grade my Dad gave me a small battery operated taperecorder,
which I eventually disected carefully, so I could reuse every part. When I was
10 years old (1965) a friend found a stereo amp in someone's trash and gave
it to me. He knew I loved tampering with electronics, especially audio stuff.
My dad hooked it up and showed me what true stereo was all about. I had thought
it was just mono with two speakers. He put on a stereo demo record and I was
blown away. I think my destiny was largely formed that day.
My mom played piano and violin, so I had a lot of musical
influence from her, besides the music on the radio in Detroit Michigan (Motown).
When I was 11 (1966), a friend let me take apart his parents Magnavox stereo
console enough so I could see what a crossover network consisted of (just a
4 uF capacitor in series with a 3 inch tweeter - "Ah HA!!!" I could
do that"). Now I was off and running, building multi-way speaker systems.
I got into transistor amplifier building, mostly from kits in highschool. In
10th grade I started playing guitar and eventually built 3 Fender Dual Showman
guitar amps, and sold two of them in order to afford one for myself. A few years
later I moved to Oregon.
In 1978, I got my Associate of Science Degree as an
Electronic Engineering Technician from LCC in Eugene, and got hired by Tektronix
in Beaverton, Oregon. Now I got to pick the brains of the big boys (top class
EE's), and have access to tons of very good parts. Plus, they offered free classes
taught by the top-notch pioneering Engineers. My career was really taking off
big time.
I've had the good fortune of working as an Engineering
Assistant with some amazingly good engineers both in Video Engineering at Tektronix
(Bruce Penney MSEE), and in various engineering groups at Dolby Labs in San
Francisco (SR noise reduction, Cinema Products Engineering and custom projects
for the Listening Rooms under the direction of Senior Engineer Ken Gundry),
and a few AV companies.
During my time at Tektronix I troubleshot and calibrated
250mHZ Oscilloscopes (all variations of the 475 and 465's), professional Video
Demodulators and very high end Spectrum Analyzers in a production environment.
As an Engineering Assistent, I helped develop the worlds best (According to
ABC in 1983) Digital Video Frame Syncronizer (The 110S), which included state-of-the-art
A to D and D to A video converters. We also produced a few NBS (National Bureau
of Standards) traceable video calibration fixtures, and a baseband digital video
test signal generator for TV stations.
I've worked at two "Pro-AV" (Audio and Video)
companies fixing electronics on the bench and in the field. I've done some high
quality digital recordings of various musicians, non-professionally. I've done
extensive research and experimentation on how the ear-brain mechanism psycho-acoustically
determines image location. I've played with head mic techniques, holographic
generator variations, effects of listening room acoustics. I've attended the
Don Davis 3 day long Sound System Engineering seminar (in 1984).
In the last 10 years (2006 - 2016), I've researched,
designed and built most of the projects you see on this website.
Although I believe the information on these pages is
accurate, I'm a student like the rest of us. I encourage corrections, and feedback
in general.
I hope these projects and the detailed design information
is helpful and inspiring.
May the ozmosis of the cosmosis be with you.
Bob Richards
Portland Oregon, USA