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tone.js - 为什么 60 bpm 在 1 秒内有 192 个滴答声 (ppq)？

[英]tone.js - why are there 192 ticks (ppq) in 1 second at 60 bpm?

原文 2020-09-19 12:25:13 3 1 javascript/ web-audio-api/ tone.js

" Tone.js is a Web Audio framework for creating interactive music in the browser. " “ Tone.js是一个 Web Audio 框架，用于在浏览器中创建交互式音乐。”

In tone's transport object, the default number of ticks (subdivisions, or ppq) is 192 when the bpm value is at 60. It is proportional to bpm, so at 120 bpm, number of ticks (subdivisions, ppq) is 384.在tone的传输对象中，当bpm值为60时，默认的tick数（subdivisions，或ppq）为192。它与bpm成正比，所以在120 bpm时，tick数（subdivisions，ppq）为384。

Why was this number (192, or 384) chosen, instead of something like 200 (and 400 for 120 bpm)?为什么选择这个数字（192 或 384），而不是 200（120 bpm 为 400）？ Does it have any particular properties, that make it more suitable to be the default number of ticks for the default bpm?它是否具有任何特定属性，使其更适合作为默认 bpm 的默认滴答数？

1 个解决方案

PPQ (Pulses Per Quarter-node) is often in values which are divisible by both 2 and 3 which allows it to accurately represent both triplet rhythms (divisions of 3) and duplet rhythms (divisions of 2) which are pretty common rhythmic subdivisions. PPQ（每四分之一节点的脉冲数）的值通常可以被 2 和 3 整除，这使其能够准确地表示三连音节律（3 分频）和双连音节律（2 分频），这是非常常见的节奏细分。

For example, with a PPQ of 6, the quarter note could be divided in three ways: by 2, 3 and 6. Those divisions would yield an 8th note (dividing the quarter in 2), a triplet 8th note (dividing by 3) and a triplet 16th note (dividing in 6 equal parts).例如，PPQ 为 6，四分音符可以用三种方式划分：除以 2、3 和 6。这些划分将产生 8 分音符（将四分音符一分为二）、三连音 8 分音符（除以 3）和一个三连音 16 分音符（分成 6 个相等的部分）。

The higher the PPQ number, the more divisors (and therefore the more rhythms that it can represent with whole number ticks). PPQ 数越高，除数越多（因此它可以用整数刻度表示更多的节奏）。 A PPQ of 200 or 400 would be good at representing quintuplets (divisions of 5) and duplets since it's divisible by 5 and 2 many times, but wouldn't be able to be evenly divided by 3. 200 或 400 的 PPQ 可以很好地表示五胞胎（5 的除法）和双胞胎，因为它可以被 5 和 2 整除很多次，但不能被 3 整除。