Daniel and Kelly's Extraordinary Universe
Hosted by Daniel Whiteson and Kelly Weinersmith
Written by a model from the transcript; not yet reviewed.
This episode explores the physics and biology of sound alongside audio engineer and producer Mat Kesselman, who reveals how he cleans up unedited podcast recordings. The host and the guest explain acoustic phenomena such as frequency, amplitude, harmonics, timbre, interference, and psychoacoustic masking. They demonstrate raw audio clips containing false starts, background noises, and grocery store beeps, illustrating the extensive editing required to produce a seamless listening experience. Kesselman also shares how he accidentally predicted a California earthquake using a microphone as a seismometer while working with Smokey Robinson.
The episode opens with the hosts introducing themselves, joking about their voices, and explaining the challenges of recording a polished podcast.
The hosts explain why they invited audio engineer Matt Kesselman to discuss sound and how he improves their recordings.
Daniel gives a detailed explanation of how sound waves travel, the role of frequency and amplitude, and how speakers and microphones work.
The hosts recap the key takeaways about sound engineering, AI, and personal voice perception before closing the episode.
The hosts take a short commercial break, then tease the upcoming interview with Matt and other guest segments.
The hosts play a raw clip of their conversation and then the edited version to illustrate the difference Matt makes.
Matt joins the show to talk about his workflow, the time it takes to edit, and the use of AI in audio production.
The hosts explore why people hear their own voice differently when recorded, discussing inner ear conduction and self-perception.
Explains how human hearing differs from sight and the role of psychoacoustics in audio editing.
Discusses the 1–5 kHz band where humans are most sensitive and its applications like sirens.
Describes how masking lets us discard inaudible frequencies, enabling efficient MP3 encoding.
Shares anecdotes from recording sessions, including an accidental earthquake prediction and a celebrity interview.
Speakers and Microphones as Inversesinsight
The host explains that speakers and microphones are the inverse of each other. A speaker shakes a cone at a specific frequency to create pressure waves, while a microphone converts pressure waves back into physical vibrations.
Speed of Sound in Materialsdata
Sound travels at different speeds depending on the stiffness and density of a medium, moving at 340 meters per second in air, 1,500 meters per second in water, and several kilometers per second in steel.
The Role of Audio Engineeringinsight
The guest explains that educational lecture-style podcasts require significant editing because speakers naturally start over, pause, and refine their explanations on the fly to communicate complex ideas clearly.
Spectral Analysis of Background Noisestrategy
The guest demonstrates how unexpected noises like animal sounds or door slams appear as visible splotches on a spectral graph, allowing an audio engineer to draw them out visually.
Best Heard Sound Frequenciesdata
Humans hear frequencies between one and five kilohertz best. This specific range corresponds to the sounds of leaves rustling, twigs breaking, and babies crying.
Psychoacoustic Masking and MP3sinsight
Psychoacoustic masking creates predictable blind spots in human hearing where certain present frequencies make people temporarily deaf to others, which is the principle behind MP3 compression.
Predicting an Earthquake with a Microphonestory
While recording an interview with Smokey Robinson in Santa Monica, the guest noticed unusual low-frequency spikes on a spectrum analyzer, realizing his suspended microphone had accidentally acted as a seismometer before an earthquake.
“sound is not a thing.”
“I think of biophysics means biology is modifying physics.”
“I might just change how it sounds, but the ideas are purely yours.”
“I think you have a great voice, Kelly. I love hearing it.”
“What we hear and see and feel is not reality, but our useful version of reality.”
“The frequency range we hear best is between one and five kilohertz. And that is the range of leaves rustling and twigs breaking.”
“If there are certain frequencies present, we are deaf to certain other frequencies. In those moments, it's just like a blind spot in the car.”
“The MP3 file format was born. It does throw away a lot of things, but it throws away only things you would not perceive anyway.”
Daniel and Kelly chat with DKEU's audio engineer, Mat Keselman, about the physics of sound and give a behind the scenes look at how Mat works his magic. See omnystudio.com/listener https://omnystudio.com/listener for privacy information.
12,466 words · 8 speakers
Speaker names marked are inferred from speaking time and the show’s known hosts — they are not voice-verified.
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