Rapicorn Audio’s free music tools cover the basics of daily practice on one page: a guitar, bass and ukulele tuner, a virtual piano, a metronome with tap tempo, a BPM tapper and an MP4 to MP3 converter. Everything runs in your browser, so your audio and video files are processed on your own device and never uploaded to a server. There is no account, no install and no cost.
How to use it
- Choose the tool you need from the hub.
- For the tuner, allow microphone access when your browser asks. Play one string at a time, let it ring, and adjust the tuning peg until the reading settles on the target note.
- For the virtual piano, play notes to check a pitch, work out a melody or find a reference note before singing.
- For the metronome, set a tempo, or tap along to a song to set it by feel. Then practise against the click.
- For the BPM tapper, tap steadily in time with the music for several beats. The reading becomes more reliable the more taps you give it.
- For the MP4 to MP3 converter, select an MP4 file from your device. The audio is extracted and converted locally, and you save the MP3 when it is done.
How the tools work
Tuning reference. The tuner compares the pitch it hears against standard concert pitch, where A4 = 440 Hz (the reference set in ISO 16). It estimates the fundamental frequency of the note you play and shows how far you are from the nearest target. Western instruments use twelve-tone equal temperament, so each semitone is a frequency ratio of 2^(1/12), about 1.0595. Small deviations are measured in cents, with 100 cents to a semitone, calculated as 1200 × log2(played frequency ÷ target frequency).
Standard tuning frequencies, rounded to two decimals:
| Instrument | Strings (low to high) | Frequencies (Hz) |
|---|---|---|
| Guitar | E2, A2, D3, G3, B3, E4 | 82.41, 110.00, 146.83, 196.00, 246.94, 329.63 |
| 4-string bass | E1, A1, D2, G2 | 41.20, 55.00, 73.42, 98.00 |
| Ukulele (GCEA) | G4, C4, E4, A4 | 392.00, 261.63, 329.63, 440.00 |
Standard ukulele tuning is re-entrant. The G string sits higher than the C string, which gives the instrument its bright sound. Bass notes are harder for any microphone-based tuner because they are so low, so play them firmly and in a quiet room.
Tempo. BPM means beats per minute. A tap tempo or BPM tapper measures the time between your taps and converts it with BPM = 60 ÷ average interval in seconds. Taps half a second apart give 120 BPM. Averaging over several taps smooths out the small timing errors every human makes.
Audio extraction. An MP4 is a container that usually holds a video stream and an audio stream, very often encoded as AAC. Converting to MP3 decodes that audio and re-encodes it as MP3. Both formats are lossy, so the MP3 cannot sound better than the original audio track. Because the work happens in your browser, speed and the largest file you can handle depend on your device’s processor and memory.
What these tools do not do. The tuner does not record or store your playing. The converter does not download from YouTube or other streaming sites, cannot handle DRM-protected files, and does not restore quality lost in the original. Browsers also slow down timers in background tabs, so keep the metronome tab in front while you practise.
FAQ
Are my files really not uploaded?
Yes. The converter processes the MP4 inside your browser on your own device, and the tuner analyses microphone input locally. Nothing is sent to Rapicorn Audio’s servers, which also means there is no upload wait for large files.
Why is the tuner jumping around or not picking up my note?
Background noise, other strings ringing, and very low notes all make pitch detection harder. Mute the strings you are not tuning, pluck cleanly, and move closer to your device’s microphone. Check that your browser has microphone permission for the page.
How accurate is the BPM tapper?
It is only as steady as your tapping, and it averages your taps to reduce error. Tap for at least eight beats on a clear pulse, such as the kick drum. Songs with tempo changes or a loose, live feel will give a less stable number.
Will the MP3 sound the same as the video’s audio?
It will be close. It will not be identical, because MP3 is a lossy format and the MP4’s audio is usually already lossy AAC. Converting from one lossy format to another cannot add back detail, so the MP3 will never exceed the quality of the source.