If note detection does not work or delivers bad results
Music apps | PerfectTiming

If note detection does not work or delivers bad results

Music apps | PerfectTiming

How the note detection works

Attack

The detection is optimized for instruments like guitar, bass, drums, which show a steep audio signal raise on attack. For instruments with a “soft attack” the detection might fail.

The app looks for steep signal raises based on the setting for “min. level difference for attack” to detect a note attack.

Note detection
GOOD recording: This audio signal shows a steep raise on each attack and a line slope for the fade out note.

It’s hard to detect an attack, when the audio signal is hardly dropping after each attack. As a consequence the next attack can’t be seen clearly:

Here you see a small raise in the signal at the attack only. The detection algorithm is confused with other “saw teeth” of the signal.

Release / Note length

For the note length detection it is necessary to silence after each note. Note length detection is not available in mode “Metronome”.

The app uses the median level of the note signal for the recognition (horizontal line in the picture above at the bottom). This is because the audio signal may have a lot of “saw teeth” e.g. on low bass notes. The release point is derived from the crossing of the two lines.

The note fade-out can be seen on the right side of the signal.

The picture below shows a signal, which is not suitable for note length detection:

This note does not allow differentiating between note “sustain” and release, as a linear slope starts after the attack. Here the note length cannot be determined.

Recommended Settings

Attack

It is important to see a steep signal raise in the graph for a note attack, which you can achieve with:

  • Adjust instrument/amp volume and/or your playing volume level (play softer or harder, stop the note before next attack)
  • Play a higher string / higher music-note, as they have less sustain
  • Use a sound with no/little reverb and little compression
  • When recording with a microphone, try placing it close to the instrument or amp or play in a room with little reverb
  • Enable setting “Normalization”
  • Adjust the detection setting “Min. level difference for attack”: lower the setting, but keep it above a level of other signal “teeth”.
  • For fast metronome patterns, mute the strings while playing

Release and note-length

The audio signal need to allow the app to differentiate between the note sustain and release:

  • Stop (silence) after each note
  • Make sure that the attack is recognized properly
  • Adjust the noise level in the settings, so that the silence between the notes does not show any graph
  • Adjust the fade-out time in the settings