<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"><channel><title>OttoAnna</title><link>https://ottoanna.com/</link><description>OttoAnna is a free sound atlas: listen to animals, instruments and field recordings from around the world, and explore frequencies, decibels and the science of sound.</description><language>en</language><item><title>On the Sensations of Tone (Hermann von Helmholtz, 1863)</title><link>https://ottoanna.com/library/helmholtz-on-the-sensations-of-tone/</link><guid>https://ottoanna.com/library/helmholtz-on-the-sensations-of-tone/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>The Theory of Sound (Lord Rayleigh, 1877)</title><link>https://ottoanna.com/library/rayleigh-the-theory-of-sound/</link><guid>https://ottoanna.com/library/rayleigh-the-theory-of-sound/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Sound (John Tyndall, 1867)</title><link>https://ottoanna.com/library/tyndall-sound/</link><guid>https://ottoanna.com/library/tyndall-sound/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Sound and Music (Sedley Taylor, 1873)</title><link>https://ottoanna.com/library/sedley-taylor-sound-and-music/</link><guid>https://ottoanna.com/library/sedley-taylor-sound-and-music/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>The Science of Musical Sounds (Dayton Clarence Miller, 1916)</title><link>https://ottoanna.com/library/miller-the-science-of-musical-sounds/</link><guid>https://ottoanna.com/library/miller-the-science-of-musical-sounds/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Collected Papers on Acoustics (Wallace Clement Sabine, 1922)</title><link>https://ottoanna.com/library/sabine-collected-papers-on-acoustics/</link><guid>https://ottoanna.com/library/sabine-collected-papers-on-acoustics/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>The Dynamical Theory of Sound (Horace Lamb, 1910)</title><link>https://ottoanna.com/library/lamb-the-dynamical-theory-of-sound/</link><guid>https://ottoanna.com/library/lamb-the-dynamical-theory-of-sound/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>A Text-Book on Sound (Edwin H. Barton, 1908)</title><link>https://ottoanna.com/library/barton-a-text-book-on-sound/</link><guid>https://ottoanna.com/library/barton-a-text-book-on-sound/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Sound and Music (John Augustine Zahm, 1892)</title><link>https://ottoanna.com/library/zahm-sound-and-music/</link><guid>https://ottoanna.com/library/zahm-sound-and-music/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Entdeckungen über die Theorie des Klanges (Ernst Florens Friedrich Chladni, 1787)</title><link>https://ottoanna.com/library/chladni-discoveries-in-the-theory-of-sound/</link><guid>https://ottoanna.com/library/chladni-discoveries-in-the-theory-of-sound/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>The Philosophy of Music (William Pole, 1879)</title><link>https://ottoanna.com/library/pole-the-philosophy-of-music/</link><guid>https://ottoanna.com/library/pole-the-philosophy-of-music/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>A Text-Book of Physics: Sound (J. H. Poynting and J. J. Thomson, 1899)</title><link>https://ottoanna.com/library/poynting-thomson-sound/</link><guid>https://ottoanna.com/library/poynting-thomson-sound/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Classic Books on Sound &amp; Acoustics (Free, Public Domain)</title><link>https://ottoanna.com/library/</link><guid>https://ottoanna.com/library/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Decibels Explained: How Sound Level Is Measured</title><link>https://ottoanna.com/learn/decibels-explained/</link><guid>https://ottoanna.com/learn/decibels-explained/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Frequency, Pitch and the Range of Human Hearing</title><link>https://ottoanna.com/learn/frequency-pitch-and-hearing/</link><guid>https://ottoanna.com/learn/frequency-pitch-and-hearing/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>How Loud Is Too Loud? Noise and Your Hearing</title><link>https://ottoanna.com/learn/how-loud-is-too-loud/</link><guid>https://ottoanna.com/learn/how-loud-is-too-loud/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>How to Read a Spectrogram</title><link>https://ottoanna.com/learn/how-to-read-a-spectrogram/</link><guid>https://ottoanna.com/learn/how-to-read-a-spectrogram/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>How to Record Birdsong</title><link>https://ottoanna.com/learn/how-to-record-birdsong/</link><guid>https://ottoanna.com/learn/how-to-record-birdsong/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>How to Start Field Recording: Gear, Settings and Technique</title><link>https://ottoanna.com/learn/how-to-start-field-recording/</link><guid>https://ottoanna.com/learn/how-to-start-field-recording/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Room Acoustics Basics: Reverb, Echo and Absorption</title><link>https://ottoanna.com/learn/room-acoustics-basics/</link><guid>https://ottoanna.com/learn/room-acoustics-basics/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Soundscape Ecology: Biophony, Geophony and Anthrophony</title><link>https://ottoanna.com/learn/soundscape-ecology/</link><guid>https://ottoanna.com/learn/soundscape-ecology/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Musique Concrète, Sound Art and the Art of Listening</title><link>https://ottoanna.com/learn/the-art-of-listening/</link><guid>https://ottoanna.com/learn/the-art-of-listening/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>What Is Field Recording? A Beginner&#x27;s Guide</title><link>https://ottoanna.com/learn/what-is-field-recording/</link><guid>https://ottoanna.com/learn/what-is-field-recording/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Learn About Sound: Guides to Listening, Recording &amp; Acoustics</title><link>https://ottoanna.com/learn/</link><guid>https://ottoanna.com/learn/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Online Tone Generator</title><link>https://ottoanna.com/tools/tone-generator/</link><guid>https://ottoanna.com/tools/tone-generator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Online Decibel Meter (Sound Level Meter)</title><link>https://ottoanna.com/tools/decibel-meter/</link><guid>https://ottoanna.com/tools/decibel-meter/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Online Hearing Test: What Frequencies Can You Hear?</title><link>https://ottoanna.com/tools/hearing-test/</link><guid>https://ottoanna.com/tools/hearing-test/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Live Spectrogram &amp; Spectrum Analyzer</title><link>https://ottoanna.com/tools/spectrogram/</link><guid>https://ottoanna.com/tools/spectrogram/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Sound Wavelength Calculator</title><link>https://ottoanna.com/tools/wavelength-calculator/</link><guid>https://ottoanna.com/tools/wavelength-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Frequency to Note Converter (and Note to Hz)</title><link>https://ottoanna.com/tools/frequency-to-note/</link><guid>https://ottoanna.com/tools/frequency-to-note/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>RT60 Reverberation Time Calculator</title><link>https://ottoanna.com/tools/rt60-calculator/</link><guid>https://ottoanna.com/tools/rt60-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Decibel Calculator: Add dB Levels &amp; Convert Ratios</title><link>https://ottoanna.com/tools/decibel-calculator/</link><guid>https://ottoanna.com/tools/decibel-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Sound Level vs Distance Calculator (Inverse Square Law)</title><link>https://ottoanna.com/tools/sound-distance-calculator/</link><guid>https://ottoanna.com/tools/sound-distance-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Noise Exposure Calculator (NIOSH &amp; OSHA)</title><link>https://ottoanna.com/tools/noise-exposure-calculator/</link><guid>https://ottoanna.com/tools/noise-exposure-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Speed of Sound Calculator (Air Temperature)</title><link>https://ottoanna.com/tools/speed-of-sound-calculator/</link><guid>https://ottoanna.com/tools/speed-of-sound-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>BPM to Milliseconds Delay Calculator</title><link>https://ottoanna.com/tools/bpm-delay-calculator/</link><guid>https://ottoanna.com/tools/bpm-delay-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Audio File Size Calculator (WAV &amp; MP3)</title><link>https://ottoanna.com/tools/audio-file-size-calculator/</link><guid>https://ottoanna.com/tools/audio-file-size-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Lightning Distance Calculator (Flash-to-Bang)</title><link>https://ottoanna.com/tools/lightning-distance-calculator/</link><guid>https://ottoanna.com/tools/lightning-distance-calculator/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item><item><title>Free Online Sound Tools: Tone Generator, dB Meter &amp; More</title><link>https://ottoanna.com/tools/</link><guid>https://ottoanna.com/tools/</guid><pubDate>Sun, 11 Oct 2026 09:25:28 +0000</pubDate></item></channel></rss>