18 Chapter 1
To put all this in perspective (I worked at Altec at the
time) I knew of no manufacturer in audio capable of
making any of these measurements. We all had Bruel
and Kjaer or General Radio frequency analyzers and
good Tektronics oscilloscopes, but zero true acoustic
phase measurement capabilities. I do not mean to imply
that the technology didn’t exist because Wente calcu-
lated the phase response of 555A in the 1920s, but rather
that commercial instruments available in audio did not
exist until Richard Heyser demonstrated the usefulness
of the measurements and Gerald Stanley of Crown Inter-
national actually built a commercially available device.
Heyser’s remarkable work became the Time, Envelope,
Frequency (TEF) system, first in the hands of Crown
International, and later as a Gold Line instrument.
The early giants of audio computed theoretical phase
responses for minimum phase devices. A few pure sci-
entists actually measured phase—Weiner, Ewask, Mari-
vardi and Stroh, but their results had failed to go beyond
their laboratories.
From 1966 until today, 42
years later, such analysis can
now be embodied in software
in fast, large memory comput-
ers. Dennis Gabor’s (1900–
1979) analytic signal theory
appeared in Heyser’s work as
amplitude response, phase
response, and Envelope Time
Curves (ETC). One glance at
the Heyser Spiral for imped-
ance reveals Gabor’s analytic
signal and the complex num-
bers as real, imaginary, and
Nyquist plot. The correlation of what seems first to be
separate components into one component is a revela-
tion to the first time viewer of this display. The unwind-
ing of the Nyquist plot along the frequency axis
provides a defining perspective.
Heyser’s work led to loudspeakers with vastly
improved spatial response, something totally unrecog-
nized in the amplitude-only days. Arrays became pre-
dictable and coherent. Signal alignment entered the
thought of designers. The ETC technology resulted in
the chance to meaningfully study loudspeaker–room
interactions.
Because the most widely taught mathematical tools
proceed from impulse responses, Heyser’s transform is
perceived “through a glass darkly.” It is left in the hands
of practitioners to further the research into the transient
behavior of loudspeakers. The decades-long lag of aca-
demia will eventually apply the lessons of the Heyser
transform to transducer signal delay and signal delay
interaction.
I have always held Harry Olson of RCA in high
regard because, as editor of the Audio Engineering
Society Journal in 1969, he found Richard C. Heyser’s
original paper in the waste basket—it had been rejected
by means of the idiot system of non-peer review used
by the AES Journal.Calculators and ComputersIn the late 1960s, I was invited to Hewlett Packard to
view a new calculator they were planning to market. I
was working at this time with Arthur C. Davis (not a rel-
ative) at Altec, and Art was a friend of William Hewlett.
Art had purchased one of the very first RC oscillators
made in the fabled HP garage. He had used them for the
audio gear that he had designed for the movie—Fantasia.
The 9100
calculator–
computer was
the first brain-
child that Tom
Osborne took
to HP, after
having been
turned down
by SCM, IBM,
Friden and
Monroe. (I
purchased one;
it cost me $5100. I used it to program the first acoustic
design programs.) In 1966, a friend introduced Osborne
to Barney Oliver at HP. After reviewing the design he
asked Osborne to come back the next day to meet Dave
and Bill, to which Osborne said, “Who?” After one
meeting with “Dave & Bill,” Osborne knew he had
found a home for his 9100. Soon Bill Hewlett turned to
Tom Osborne, Dave Cochran, and Tom Whitney, who
worked under the direction of Barney Oliver, and said, “I
want one in a tenth the volume (the 9100 was IBM type-
writer size), ten times as fast, and at a tenth of the price.”
Later he added that he “wanted it to be a shirt pocket
machine.”
The first HP 35 cost $395, was 3.2 × 5.8 × 1.3 inches
and weighed 9 oz with batteries. It also fit into Bill
Hewlett’s shirt pocket. (Bill Hewlett named the calcula-
tor the HP 35 because it had 35 keys.) Art Davis took
me to lunch one day with Mr. Hewlett. Because I had
been an ardent user of the HP 9100 units, I was selected
to preview the HP 35 during its initial tests in Palo Alto.