Tempo

Hi all,

I think we need to get on the same page as regards "tempo".
This is a thorny topic, but I think we should grasp this beast by the horns.

For me, tempo is a term used (by humans) to say that a set of sequential 
durations are perceived to be the same, or nearly the same.

Its well known that human perception uses chunking to simplify the data 
management. We use the term "green" to describe a particular bandwidth 
of frequencies. According to Wikipedia, the complete visible spectrum 
ranges from 4*(10^14)Hz (red) to 8*(10^14)Hz (violet). The colours are 
classically chunked into 7 categories: red, orange, yellow, green, blue, 
indigo.

Similary, we have a limited spectrum of perceptible tempi.
My metronome is calibrated from 40bpm to 208bpm (i.e.  0.66Hz to 
3.47Hz). Interestingly, it divides the range into 8 categories:
1. Largo (40-60 bpm)
2. Larghetto (60-66 bpm)
3. Adagio (66-76 bpm)
4. Andante (76-108 bpm)
5. Moderato (108-120 bpm)
6. Allegro (120-168 bpm)
7. Presto (168-200 bpm)
8. Prestissimo (200-208 bpm)

Tempi outside this range simply don't exist. If one wants to maintain a 
"tempo" outside this range, one typically changes tempo to a value 
inside the perceptible range. For example, to maintain a "tempo" of 
4bpm, one could count at a perceived tempo of 60bpm and note each 15th 
beat. That's cheating. Some humans perform pretty accurately like that, 
but nobody will completely agree with a machine after a long enough time.
In real music making, performance practice (the forming of local time) 
is infinitely more important than agreeing with a machine about global, 
absolute time.
(Theoretically, all machines ought to agree on the duration of absolute 
time, but even there things are more complicated. Its necessary to have 
a central clock that periodically tells the machines what time it is.)

The bottom line is that tempo is a mental phenomenon. We don't, like 
machines, relate time to the vibration of some unchanging crystal (A 
physical second is defined as 9 billion oscillations of a caesium atom).
The guys who standardized MIDI in the 1980s didn't distinguish clearly 
enough between mental (performance practice) and physical time, and the 
Web MIDI API (latest version Dec. 2016) was right to eliminate tempi 
(MIDI ticks) from the standard.

By the way: The inability of 20th century composers to encapsulate 
performance practice in their (paper) notation meant that they needed 
specialist ensembles and/or inordinate amounts of rehearsal time. That's 
very expensive, and the result is that the performance practice for New 
Music has ceased to develop. Everything has got rather boring. There 
have been no significant advances in the performance practice of New 
Music for several decades...

Human and machine time are very different. We should talk to machines in 
their own language, but humans should be enabled to develop performance 
practice. Embedding both graphics and recordings in score files opens up 
that possibility. The development of performance practices for Jazz or 
Ancient Music has depended crucially on the availability of accurate 
recordings...

Enough!

Best,
James

Received on Wednesday, 29 March 2017 10:09:23 UTC