Impulse per quarter note
Pulses per quarter note (Engl. Pulses per quarter note ), also known as pulses per quarter (PPQ) and ticks per quarter note (TPQN), is the smallest unit of time for the quantization of note and sound events in both step sequencers and is used in the MIDI standard.
If the resolution is too low (too few PPQN), the music recorded in the sequencer may sound artificial (because it is quantized by the clock frequency ), thereby losing all the subtle variations in timing that give the music a "human" feel. Deliberately quantized music can have resolutions as low as 24 (the standard for Sync24 for MIDI) or even 4 PPQN (which has only one measure per sixteenth note). On the other hand, modern computerized MIDI sequencers designed to capture more nuances are usually designed for 960 PPQN and beyond. Quantization-free recording and post-quantization is also possible.
This resolution is a measure of the time in relation to the tempo, since the tempo defines the length of a quarter note and thus the duration of each impulse. The resulting PPQN per MIDI beat therefore relates to the time base in miroseconds, defined as 60,000,000 × MicroTempo = beats per minute ( bpm ).
literature
- Meinard Müller: Information Retrieval for Music and Motion . Springer, New York 2007, ISBN 978-3-540-74048-3 ( limited preview in Google book search).
Individual evidence
- ↑ MIDI File Format: Tempo and Timebase. Retrieved July 26, 2020 .