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What Heyser did

Posted by tomservo (M) on February 5, 2023 at 09:09:46

In Reply to: Dick Heyser posted by tomservo on January 26, 2023 at 14:29:09:

Or at least a couple things important to Audio.

In his day, there were ways to measure Frequency response but time blind, there was no "phase response" AND if you set up a cost no object HP network analyzer, you could get phase if close enough but the speaker was buried in time delay related phase shift and reflected sound.

His TEF machine first captured "how far away is the speaker" at the highest frequencies (most precise) with the Energy vs Time Curve and then measured the magnitude with actual loudspeaker phase. Not just that but many measurements could be taken indoors now because of the Frequency windowing (much better noise immunity than time windowing)

With that, many things could be seen like the first waterfall displays, impulse response, step response, predictions of intelligibility and many other useful acoustic tools. It did not become the dominant technique because it was patented and narrowly licensed (like Beta tape was).
I even dragged an early TEF into the great Pyramid to measure the sound in the Kings chamber.

I can attest first hand to one way his discoveries went on to effect audio.

In the video "How we hear" i was asked about "hearing" and how we sense direction and distance.
https://www.facebook.com/watch/126113687424773/423500813293005

In the part describing the notches in your hearing, Doug Jones (in the original video i linked and was a friend of Dick's) was one of those people, he used the TEF machine to take those "in ear" measurements that discovered the last bits of "how we hear" direction and height. The LEDR recording Doug and co made used those notches to make objects move in the stereo image.

Those things i described about developing the speaker were actually following along an imaginary speaker Dick described late in life in one of the papers Doug had, a broad band single point in time and space.

With his TEF machine i was able to make one as he described theoretically in that video and has been the primary type of speaker we made.
The way i found was also one that had horn loading and the directivity of a large constant directivty horn.

How was also a question the video guy asked. See the "Expansion rate" video for a dry marker scribble.
Tom

• How we hear   (Open in New Window)

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