Online Spectrogram Viewer - Audio Frequency Visualizer
Load an audio file and see its spectrogram with frequency over time. Adjust resolution and color map. Discover hidden sounds.
UD5 Toolkit
Explore all seven bands of the electromagnetic spectrum — from radio waves to gamma rays. Click any segment to learn about wavelength, frequency, energy, and real-world applications.
The only part of the EM spectrum visible to the human eye
Enter a value to convert between wavelength and frequency. c = λ × f (c ≈ 299,792,458 m/s)
Load an audio file and see its spectrogram with frequency over time. Adjust resolution and color map. Discover hidden sounds.
Connect an audio source to an Analyzer Node and display frequency and time‑domain data. Learn Web Audio visualization.
Play a sweep from 20Hz to 20kHz. Test your speakers and your hearing. Simple and effective. Web Audio API.
Paste text to see a live letter frequency bar chart. Helps break substitution ciphers. All local analysis.
Select functional groups to see an approximate IR absorption spectrum. Learn spectroscopy visually. All local.
Mix white noise, pink noise, rain, thunder, wind, and cafe sounds. Individual volume, save presets. Relax or focus. All client‑side.
Choose a base color and see its complementary, split‑complementary, triadic, and tetradic harmonies. Copy palettes. Local.
Use the Magnetometer API to build a digital compass. See magnetic field strength and heading in real time.
Register a periodic background sync to fetch fresh data even when the tab is closed. Understand the API and limits.
Mix multiple ambient sounds (rain, fireplace, cafe, forest) at different volumes. Create your perfect background noise. Local loops.
Select color bands to decode a resistor's value, tolerance, and temperature coefficient. Essential for anyone working with electronics hardware.
Change the viewport meta tag and see how a page would render at different device widths. Understand responsive basics.
Register a periodic background sync with a minimum interval. See the registration state and tags. Keep content fresh.
Drop an audio file and instantly see its duration in seconds and formatted time. Read metadata without full playback.
Enter text and generate the corresponding Morse code audio beeps. Adjust speed and tone. Great for learning and practicing CW. No download.
Trigger different vibration patterns on mobile devices. Test if your phone supports haptic feedback. Simple demo.
Apply lowpass, highpass, and reverb to an audio source. See frequency response. Create your own guitar pedal. All local.
Pomodoro timer with built‑in lo‑fi music playlist (synthetic). Focus and rest cycles. No copyright music; generated tones.
Play a simple monophonic synthesizer with your keyboard. Choose waveform, attack, decay, and filter. For music fun.
Read the ambient atmospheric pressure in hPa using the Pressure Sensor API (if available). Real‑time graph.
Play a selection of local lo‑fi tracks (embedded). Simple UI with play/pause. No copyright issues. Stay focused.
Register a periodic background sync and see the status. Schedule content updates for your PWA. API demo.
Process audio faster than real‑time with OfflineAudioContext. Apply filters and export the result. Dev tool.
Pick a method, URL, headers, and body, then send an HTTP request directly from your browser. Debug APIs easily.
Hear a common bird song and choose the correct species from multiple choices. Ear training for birders.
Complete a series of visual pattern puzzles and get a fun estimated score. Purely for entertainment. No data collected.
Interactive piano showing typical vocal ranges from Bass to Soprano. Highlight your range. For choir members.
Create experimental glitch noises by toggling virtual circuit bend points. No real electronics harmed. Fun noise toy.
Play a collection of retro 8‑bit synth pads and leads using your keyboard. Record sequences and export as WAV. Pure Web Audio API.
Write a pattern and test it against URLs instantly. See which groups match. Learn the modern alternative to regex for routing. Works entirely in the browser.