Lossless WAV speed listening, hearing science and gear.
🧑🏫 Stories
A trading-company CEO in his 60s, stuck for a decade through every method, doubled his listening in a month. The record of measure, train, re-measure — and how this experience became the app Sound Power.
📱 Apps
From the niece incident to a 12-person experiment, and through the failure of a ₩70 million outsourcing attempt to April 2026 — ten years of lectures became an app. A record of what the Daechung English app does and why it was built.
📱 Apps
A side effect of English class gave birth to an app — one that self-measures hearing age and audible frequency range and trains with high-frequency speed-listening. And the story of holding the line on its wording through five Google rejections.
📱 Apps
An app built after watching one user who listened to the Bible on MP3 every day reached English-speaking users first — under the name Speed Bible. The story of 200 users in two weeks, now expanding to seven languages.
📱 Apps
Speed English in April, Sound Power in May, Speed Bible in June — one a month. The trick was not speed but structure: a single engine that keeps consonants intact at raised playback rates, with different material poured through it.
🔬 Sound science
It is not that you are bad at remembering. The ear settles into its first language inside the first year and stops splitting sounds that language never uses — which is why a word you know on the page can go straight past you when somebody says it.
🔬 Sound science
A chart that hands each language its own frequency band — Korean around 500–2,000 Hz, English around 1,000–5,000 Hz — is used everywhere to explain why listening fails. Run the same chart on Japanese and its prediction falls apart.
🔬 Sound science
English meaning can turn on a consonant that lasts about 0.04 seconds. Missing that flicker — rather than missing the word — is what makes English sound blurred.
🧑🏫 Stories
Have 12 people do only Korean speed-listening for a month and all 12 opened their English ears. A fifth-grader, a CEO in his 60s, a labor attorney and a tax accountant, and a neurologist — a record of the cases.
📚 Method
50% of US-show lines is the repetition of just 50 words; 80% is 350 words. The problem is that those easy words “aren’t heard” — why the ear has to get used to liaison and contraction.
📚 Method
Hangul speed-listening is training in listening to Korean at 2×–6×. You came to learn English — so why start with Korean? The principle, the method, and why “only Korean, yet English comes through,” in one article.
📚 Method
Speed-listening → variable-speed shadowing → variable-speed reading → audio composition → 1-minute speech. The 5-step method that gets English into ear and mouth without memorizing, plus the “50% rule.”
📚 Method
Months of shadowing and your listening has not moved — the problem may be your eyes rather than the method. The brain takes what it can see before what it hears, so the moment the transcript is open the ear has stopped working.
📚 Method
Nobody sits down to memorise the words of a favourite song; you play it enough times and the words move in on their own. These are the four steps that do the same thing to sentences in the language you are learning.
📚 Method
“So what do I actually do, and how?” The exact 30-day routine we give students: Day 0 measure → Week 1 Korean speed-listening → Week 2 4× → Week 3 the branch point → Week 4 the 5 steps. 30 minutes a day, every day.
📚 Method
An hour of travelling a day is thirty hours in a month, and none of it has to be found — it is already being spent. Here is what to do with your ears on a train, behind the wheel, on foot, on a bike, and on the days you do not go anywhere at all.
📚 Method
That the will to study English doesn’t last three days is not weak will but a boring method. Hear it and it’s fun; fun and you do more — the virtuous cycle of Dopamine English.
📚 Method
Too embarrassed by grammar mistakes to speak? In Silicon Valley, broken English is the global standard. The real reason India, China and Europe are good at English.
📚 Method
Why give a method such a careless(?) name? To smash Koreans’ biggest disease — the perfect-English disease. “Daechung” (roughly) is not laziness but the courage to set down the unnecessary.
📚 Method
The whole run of a sitcom uses around 15,000 different words, yet about 80% of what is actually said comes from roughly 350 of them. A beginner does not need a native accent or native idiom — only the standard the rest of the world can follow.
📚 Method
Drama is the hardest listening there is — slang, private jokes, an accent invented for one character. News is read in standard pronunciation with a shape you can follow, so moving it earlier in the order costs nothing and saves years of frustration.
🔬 Sound science
You start a listening course for a new language and find you read faster in your own. These are the five changes learners keep reporting to us — and the line we do not cross in describing them.
🔬 Sound science
There is a circuit that comes on when you are doing nothing at all. In one experiment, how the ten minutes after learning were spent still showed up in recall seven days later — which is why a listening session stops at ten minutes.
🧑🏫 Stories
Students at a royal school founded in Seoul in 1886 were interpreting within six to ten months, and a British consul reported home that Koreans were the finest linguists in the East. What they were given first was not grammar but sound.
🧑🏫 Stories
A Korean primer of the 1900s wrote child as 촤일드 (chwa-il-deu) and rice as 으라이쓰 (eu-ra-i-sseu) — closer to the sound an English speaker actually makes than the standard Korean spellings in use today. It is what happens when people write down what they hear.
📚 Method
A method claiming “English comes through in a month” once swept Japan. The secret wasn’t English but high-speed listening to the mother tongue — the very principle Ossam replicated in Korean, confirming success in all 12.
📚 Method
Move to the country and the language will follow — it is the most expensive assumption in language learning. Exposure only turns into learning once the ear can take the sound in, and that part can be done before you fly.
📚 Method
Over 40% of Seoul National University students said they fear the English interview — what a top college-entrance grade didn’t solve is hearing and perfectionism. The order of training when 30 days remain to the interview.
📚 Method
An academy that won’t send a child home until they memorize 100 words a day — the shortcut to making English a hated subject. The opposite order, by which a Yeouido fifth-grader came to catch 70–80% of Zootopia in a month.
📚 Method
The hard part of listening training is never the difficulty, it is finding the half hour. The easiest ten minutes to keep are the ones between brushing your teeth and turning the light off — not because sleep does something magic, but because nothing else wants that slot.
📚 Method
“4× sounds like noise”, “am I supposed to catch all of it?”, “my ears ache afterwards”, “can I leave the subtitles on?” — the questions we have been asked more than any others, answered short. Most of them resolve into the same sentence.
📚 Method
A baby born anywhere ends up speaking the language around it, because for the first months the ear can still tell apart the sounds of every language. What ear training loosens is not one language’s filter — there is only one filter.
🔬 Sound science
We filter the water we drink and the air we breathe, and nobody checks the quality of the sound we take in all day long. Here is what the broadcast experiments, the people who make sound for a living, and the market’s own price list have to say about that.
🎛 Gear
Choosing a lossless file is only the first link in the chain. If anything between that file and your ears compresses it again, the file stops mattering — and four questions will tell you whether that is happening.
🧑🏫 Stories
A ₩70 million outsourcing bill in 2021. That app died when the dev team broke up. How an English teacher who could not write a line of code went, with AI, from Python to a web app to mobile apps — and on to a patent-pending technology.
📱 Apps
English tales read aloud over Korean court music, sent as uncompressed 44.1kHz WAV — which is why one episode runs past 100MB. This article says what is in the sound, and stops there.
🤝 B2B
The 2024 Lancet report named hearing loss the top modifiable risk factor for dementia. A guide to the measure → train → re-measure hearing program that senior centers, welfare centers and senior communities can adopt.
🤝 B2B
People pay extra for a lossless music tier, yet the English audio a child hears every day is MP3. A new story an academy can offer parents — the quality of the sound — and the forms of adoption.
🤝 B2B
Good content is being shaved to MP3 at the last gate before it reaches the reader’s ear. Lossless conversion of language-course audio, a hearing-measurement bootcamp, and engine-API partnership — what publishers and edtech can take.
📚 Method
Shadowing means following a voice the way a shadow follows a body. The name is everywhere, yet what you are actually meant to do is rarely explained — so here is the definition, and how it differs from reading aloud and dictation.
🔬 Sound science
The same sentence read with your eyes and read with your voice is not the same job for the brain. And yet “reading aloud is good for you” and “shadowing with the transcript open is fake” are both true — here is how the two fit together.
📚 Method
Four conversation lessons a week and a two-hour class on top, kept up for years, and the language sits exactly where it started. It is not laziness — it is arithmetic, and arithmetic has only two ways out.
📚 Method
Trying to be somewhat better at the thing you already do is the hardest move available. A line from a business talk turns out to describe language study exactly.
🧑🏫 Stories
A 66-year-old student, retired as a middle-school principal. Being of the grammar generation, English had been a lifelong handicap. Yet what he did in the first month was not English but Korean.
🧑🏫 Stories
Two brothers in the 4th and 5th grade who were not good at English said one day that they could follow an American cartoon. What happened in a little over three months — and what could not be verified.
🧑🏫 Stories
When 6× became fully audible, one grade-schooler asked for something faster. Following that question led to an unexpected fact — practice the fast, and the slow becomes easy.
🧑🏫 Stories
The third class of a group that had done only Korean speed-listening for a month. We gathered to talk about English, but what came up was the cinema, memory, and table tennis.
🔬 Sound science
ETS, which runs the TOEFL, publishes country average scores each year. In the 2019 data Korea’s reading was above the world average and speaking below. What we have trained shows plainly.
🧑🏫 Stories
A grade-schooler came to a Yeouido talk with her mother. In the consultation I heard that her academy makes her memorize 100 words a day and will not send her home if she fails.
🧑🏫 Stories
Say you’ll play Korean at a place that teaches English, and pushback comes from inside too. It did. The story of how the company split, for and against, over the weight of Korean speed-listening.
📚 Method
Most language courses begin with letters, words and grammar and reach listening last — the exact reverse of how every one of us learned a first language. Here is what changes when the order is put back.
📚 Method
There is an idea: sell the why, not the what. It carries straight over to studying English — name the cause wrong and even the best method gets aimed at the wrong place.
🧑🏫 Stories
In 2025 total private-education spending for grades 1–12 was ₩27.5 trillion, and a large share went to English. Spend this much and still not hear it as an adult, and what is short is neither money nor time.
📚 Method
A reader wrote in: months of shadowing Friends, long lines leaving nothing behind but rhythm, two weeks to finish one episode with a dictionary open. Going back to grammar was not the answer, and neither was switching to cartoons.
🔬 Sound science
Ten books read while working out speed listening and ear training. Rather than a bare list, this also records what we took from each one and what we left where we found it.
🔬 Sound science
A Korean science documentary measured what 10 minutes of MP3 does to the body. Reaction time, muscle response, plant growth — and a fetus that winced in one second.
🔬 Sound science
Degraded audio costs you even when comprehension is perfect. Pupil dilation, dual-task accuracy and reaction time put numbers on it.
🔬 Sound science
Pupils widen, memory drops, answers come later — all measured on listeners who felt they had understood every word. Three studies, three numbers.
🔬 Sound science
Speech compressed to 2–5× hands the brain a harder-than-normal task. Start with Korean you already understand, and the processing speed you build transfers to English.
🔬 Sound science
The Lancet: around 40% of dementia is preventable, and hearing loss is the single largest modifiable risk factor. Here is the evidence, cited.
🔬 Sound science
Hearing fades from the top down, so the highest tone you can still hear is a rough gauge of your hearing age. What the number means, how it is measured, and why training moves it.
🔬 Sound science
Studio masters are uncompressed WAV without exception. What reaches your ears is FLAC, ALAC — or usually MP3. Here is what happens in between.
🎛 Gear
A file of ones and zeros is not sound. A DAC turns it into the analog vibration your ears feel — and that little stick you plug into your phone is exactly that.
🎛 Gear
Listen over Bluetooth and most of what makes BrainHz different — lossless WAV and restored high frequencies — is gone. Here is why wired is the rule.
🎛 Gear
Feed in 48 kHz lossless and it still fails if the receiver smears the signal — the brain goes back to reconstruction work. Why the receiver matters, plus four picks by situation.
🔬 Sound science
Vinyl is analog, CD is digital. Here is the whole landscape sorted into three simple buckets: analog, digital-lossless and digital-lossy.
🎛 Gear
Over Bluetooth the Charge 6 is lossy, but connected by USB-C it plays up to 24-bit/96 kHz lossless. Here is how to switch it on.
🔬 Sound science
Lossless files like WAV and FLAC keep everything the recording captured. Here is what MP3 throws away, whether the difference is audible, and what you need to hear it.