The blog post explores the physics behind the distinctive "whoosh" sound created by passing objects like airplanes. It explains how this sound isn't simply the object's engine noise, but rather the Doppler-shifted frequencies of ambient noise—like wind, traffic, or conversations—being compressed as the object approaches and stretched as it recedes. This effect, similar to how a siren's pitch changes as it passes by, is most noticeable with fast-moving objects in relatively quiet environments. The post further delves into how our brains perceive these shifting frequencies, potentially misinterpreting them as the sound of the object itself and sometimes even creating phantom whooshing sensations when no physical source exists.
Tapping a wheel of cheese is a traditional method used to assess its quality and maturity, particularly for hard cheeses like Parmesan. The process involves using a small hammer or tool to strike the wheel at various points, listening to the resulting sounds and vibrations. A trained ear can interpret these sounds to determine the presence of cracks, voids, or inconsistencies within the cheese, as well as gauge its texture and overall ripeness. While not a foolproof method, tapping provides valuable insights into the internal structure of the cheese without cutting into it, helping cheesemakers and affineurs ensure quality and select the best wheels.
Hacker News users discussed the practicality and cultural significance of cheese wheel tapping. Some commenters debated the efficacy of tapping for assessing quality, suggesting other methods like drilling and plugging might be more reliable for determining internal defects. Others highlighted the performative aspect, arguing it's primarily for show or tradition, particularly for hard cheeses where tapping yields limited information. The rhythmic and visual appeal of the process was also noted, along with its potential to engage customers. A few users shared anecdotes about witnessing cheese tapping firsthand, and others wondered about regional variations in the practice. There was also brief discussion about the tools used, such as hammers and mallets, and the specific sounds produced.
OpenAI has introduced two new audio models: Whisper, a highly accurate automatic speech recognition (ASR) system, and Jukebox, a neural net that generates novel music with vocals. Whisper is open-sourced and approaches human-level robustness and accuracy on English speech, while also offering multilingual and translation capabilities. Jukebox, while not real-time, allows users to generate music in various genres and artist styles, though it acknowledges limitations in consistency and coherence. Both models represent advances in AI's understanding and generation of audio, with Whisper positioned for practical applications and Jukebox offering a creative exploration of musical possibility.
HN commenters discuss OpenAI's audio models, expressing both excitement and concern. Several highlight the potential for misuse, such as creating realistic fake audio for scams or propaganda. Others point out positive applications, including generating music, improving accessibility for visually impaired users, and creating personalized audio experiences. Some discuss the technical aspects, questioning the dataset size and comparing it to existing models. The ethical implications of realistic audio generation are a recurring theme, with users debating potential safeguards and the need for responsible development. A few commenters also express skepticism, questioning the actual capabilities of the models and anticipating potential limitations.
This blog post details how to create a simple WAV file audio player using a Raspberry Pi Pico and a VS1053B audio decoder chip. The author outlines the hardware connections, provides the necessary MicroPython code, and explains the process of converting WAV files to a suitable format for the VS1053B using a provided Python script. The code initializes the SPI bus, sets up communication with the VS1053B, and then reads and sends the WAV file data to the decoder for playback. The project offers a straightforward method for adding audio capabilities to Pico projects.
Hacker News users discussed the practicality and limitations of the Raspberry Pi Pico as an audio player. Several commenters pointed out the Pico's limited storage, suggesting SD card solutions or alternative microcontrollers like the ESP32 with built-in flash. Others questioned the need for code to handle WAV file parsing, advocating for simpler PCM data streaming. Some users expressed interest in using the project for specific applications like playing short notification sounds or chiptune music. The discussion also touched upon the Pico's suitability for audio synthesis and the potential of the RP2040 chip.
Summary of Comments ( 32 )
https://news.ycombinator.com/item?id=43713524
Hacker News users discuss various aspects of the "whoosh" sound phenomenon. Several commenters offer additional examples of sounds exhibiting similar characteristics, such as the Doppler shift observed with passing cars or the sound of a large truck passing a house. Some discuss the physics behind the phenomenon, including the role of air pressure changes and the shape of the object creating the sound. Others delve into the subjective experience of these sounds, noting how perception can be influenced by factors like background noise and individual sensitivity. One compelling comment highlights the prevalence of this effect in movies and its potential exaggeration for dramatic effect. Another interesting observation is the comparison to the "sonic boom" of a supersonic aircraft, contrasting the continuous whoosh with the sharp crack of the boom. Finally, a few commenters mention the psychological impact of these sounds, including their potential to be unsettling or even anxiety-inducing.
The Hacker News post titled "Passing planes and other whoosh sounds," linking to an article on windytan.com about the physics of whooshing sounds, has generated a modest discussion with several interesting comments.
One commenter shares a personal anecdote about experiencing the Doppler effect with the sound of a passing plane, noting the distinct drop in pitch as the plane moves away. They also connect this experience to the sound of cars passing by, highlighting the commonality of the phenomenon in everyday life.
Another commenter delves into the specifics of the Doppler effect, explaining how the frequency shift is dependent on the relative velocity between the source and the observer. They then raise the question of why the sound of a passing plane seems to "whoosh" down rather than up, even though both rising and falling frequencies are involved. They hypothesize that this perceived downward shift is due to the greater change in frequency occurring as the plane moves away, alongside the general decrease in loudness as the source recedes.
A subsequent comment builds on this hypothesis, suggesting that the human ear is more sensitive to downward frequency changes and that the decreasing volume of the receding sound source might contribute to the perception of a downward whoosh.
Another commenter links to a Wikipedia page about the sonic boom, a different phenomenon associated with supersonic aircraft, distinguishing it from the Doppler effect discussed in the original article. This comment helps clarify the different types of sounds generated by moving aircraft and their underlying physical principles.
One user mentions their experience with sailplanes, explaining how the quiet nature of these aircraft allows for a clearer perception of the Doppler shift and a more pronounced "whoosh." This adds another real-world example to the discussion and highlights how the surrounding environment can influence the perception of these sounds.
Finally, a commenter with a background in audio engineering provides a more technical explanation, mentioning how the perceived pitch of complex sounds like those produced by aircraft engines is not solely determined by the fundamental frequency but also influenced by overtones and harmonics. They suggest that the Doppler effect's influence on these different frequency components might contribute to the complex nature of the perceived "whoosh."
In summary, the comments on the Hacker News post provide a range of perspectives on the physics and perception of whooshing sounds, from personal anecdotes to detailed explanations and related phenomena, demonstrating a shared curiosity about the acoustic world around us.