Press Start microphone and allow access. No microphone? Try the test tone.
Challenges
🎵 Whistle a line
Whistle one steady note. Then slide it up and down. What can you draw?
What to notice
A whistle is almost a single pitch, so it makes one bright line.🐍 Find the snake
Say “sssss”, then “shhhhh”. Which one sits higher?
What to notice
S is higher than SH. Both look like static because there is no voice buzz, only rushing air.🌈 Vowel rainbow
Slowly say “eeee”, “ooooo”, then “ahhh”. Watch the bright bands move.
What to notice
Your tongue and lips reshape your mouth, which moves the loud bands. Recognizers use these bands to tell vowels apart.🤫 Whisper vs. talk
Say “hello” normally, then whisper it. What disappears?
What to notice
The stacked lines vanish because whispering switches off your voice’s buzz. That is why whispered words were harder in Be the Recognizer.🎹 Staircase
Sing do-re-mi up a scale. Can you make steps?
What to notice
Each note is a new pitch, so the stacked lines jump up like stairs.👏 One clap
Clap once. Why is a clap a tall, thin line?
What to notice
A clap is very short and has low and high sounds at once, just like the burst in p, t or k.🚢 Ship or chip?
Say “ship”, then “chip”. Spot the difference at the start.
What to notice
“Chip” starts with a tiny silence and a pop before the static; “ship” starts smoothly.🗣 Name game
Say your name, press Pause, then Save picture. Can a partner guess whose name it is?
What to notice
This is Spectrogram Detective with your own voices. Different people make different pictures of the same word.For teachers
Privacy
The activity does not record, store or upload audio, and it has no ads. Basic page analytics records visits but never receives microphone audio. “Save picture” downloads an image to this device, and the activity turns off the browser’s noise suppression so students see the real sound.
Setup and troubleshooting
- Works in current Chrome, Edge, Firefox and Safari on Chromebooks, Windows, Mac and iPad, over https or from a saved copy.
- If the microphone is blocked, select the lock or microphone icon in the address bar, allow the microphone, then reload. School devices may need IT to allow it.
- No microphone? The test tone draws a gliding line so you can still explain the picture.
- Too dark or too bright? Move the Sensitivity slider.
The science
The top strip is the raw “wiggle”: air pressure measured thousands of times per second. The picture below splits it into pitches. This live view uses a longer analysis window than the printed Spectrogram Detective cards, so it shows a voice as stacked horizontal lines (the harmonics of your pitch) instead of thin vertical buzz stripes. Both are real ways to picture sound.