Free · no sign-up · runs in your browser
Learn to hear frequencies
One EQ band is boosted. Switch between EQ and flat, then name the band. Start here with level 1, or open the full EQ ear trainer for cuts, third-octave bands and your per-band scores.
Turn your volume down before you press Start.
Level 1 · +12 dB · 4 octave bands
- Score
- 0
- Streak
- 0
- Best
- 0
Space switches
Which band is boosted by 12 dB?
Turn your device volume down, press Start, then switch between EQ on and Flat and pick the band that changed.
Levels 2 to 4, cuts, third-octave bands and your per-band scores are on the full trainer.
The tools
9 tools · no account- 01 EQ ear trainer Hear one EQ band boosted or cut on pink noise or a drum loop, switch between EQ and flat, and name the frequency. Four levels and free practice.
- 02 Online tone generator Sine, square, sawtooth and triangle tones from 20 Hz to 20 kHz, with a level in dBFS and an exponential sweep.
- 03 Online metronome A steady metronome with accented downbeats, compound and odd time signatures, and subdivisions.
- 04 Tap tempo BPM counter Tap along to a song and read its tempo, from a line fitted through every tap rather than just the first and last.
- 05 BPM to delay and reverb time calculator Milliseconds for every note value at a tempo, straight, dotted and triplet, plus tempo-synced reverb pre-delay and decay.
- 06 Note frequency calculator and chart Every note from C0 to B8 in hertz for any A4 tuning, and any frequency turned into the nearest note plus cents.
- 07 Decibel calculator Add sound levels properly, subtract background noise, convert power and voltage ratios, and scale level with distance.
- 08 Audio file size and bitrate calculator Exact sizes for WAV and AIFF at any sample rate, bit depth and channel count, and for constant-bitrate MP3 and AAC.
- 09 Room mode calculator Axial, tangential and oblique modes from a room’s dimensions, with coincident modes flagged and the Schroeder frequency.
Delay times at common tempos
Any tempo →Milliseconds per note at a glance. For any other tempo, and for triplets and reverb times, use the delay time calculator.
| BPM | Quarter | Eighth | Dotted eighth | Sixteenth |
|---|---|---|---|---|
| 70 | 857.1 ms | 428.6 ms | 642.9 ms | 214.3 ms |
| 90 | 666.7 ms | 333.3 ms | 500.0 ms | 166.7 ms |
| 100 | 600.0 ms | 300.0 ms | 450.0 ms | 150.0 ms |
| 110 | 545.5 ms | 272.7 ms | 409.1 ms | 136.4 ms |
| 120 | 500.0 ms | 250.0 ms | 375.0 ms | 125.0 ms |
| 128 | 468.8 ms | 234.4 ms | 351.6 ms | 117.2 ms |
| 140 | 428.6 ms | 214.3 ms | 321.4 ms | 107.1 ms |
| 174 | 344.8 ms | 172.4 ms | 258.6 ms | 86.2 ms |
Who this is for
Producers and engineers who want to name a frequency by ear instead of sweeping for it; players who want a metronome that keeps time and handles 7/8 properly; home-studio and live engineers who need a delay time, a test tone or a quick decibel sum mid-session; and anyone setting up a room who wants to know why one bass note booms. Each tool does one job and loads fast on a phone.
What is different here
Every tool is free, needs no account and runs entirely in your browser. Nothing you type is sent anywhere, and none of the tools uses your microphone. The audio tools generate sound with the Web Audio API built into your browser, including the EQ trainer’s pink noise and drum loops; the calculators do their arithmetic on your device.
Each page names the formula it uses, works through an example with real numbers, and says where the answer stops being trustworthy: why a laptop speaker cannot teach you 63 Hz, why a room never quite behaves like the room mode equation, why two speakers do not always add 6 dB. The about page collects the methods and their limits in one place.