Yhyjyk

I'm trying to find a way to measure the speed of a song from the perspective of singing/rapping. So far all I can find is BPM (beats per minute), however there are at least 2 issues with that:

• The BPM number depends on which beats are counted, quite often a website will report twice the BPM that I measure by myself.


• The BPM is not always related to the vocal speed. For example, "Thoughts Of A Dying Atheist" by Muse has 179 BPM but the singing part is quite slow, while "Break Ya Neck" by Busta Rhymes has only 83 BPM, but a... neck-breaking rapping speed.

Is there a more accurate measurement for the vocal speed? I'm thinking something along the lines of (continuous) syllables per minute, excluding the instrumental parts.

There is the concept (not specific to music) of Speech Tempo. As you will see from the article, there is some degree of discussion about how this should be measured - for example, words per minute, syllables per second, or sounds per second. One could imagine even deeper levels of granularity - such as the inclusion of changes in pitch or timbre as sound 'features'.

Within rap music, it's common to measure rap performances in terms of syllables per second - such performances have been noted in the Guinness book of Records.

I humbly propose "maximum notes/second": Take the fastest part of the song and calculate the number of notes in that amount of time. If you have a passage that is super-fast in one part but really slow in another, it's way more important to know that you need to be able to rap/sing/play at that fastest part's speed to play the whole song. Compare the intro of Eminem's "Rap God" to the fast part. Obviously, to tackle that song, one needs to be able to rap as fast as the fastest part, not just the average of the whole song.

Disclaimer: No one uses this, because I made it up. I think it's way more useful than average notes/second.

I don't think there's a useful single value that you can use to summarise a song like this. Instead, it's probably most useful to consider a combination of the BPM, the length of rhythmic subdivisions, and distribution of rhythms. For example, Break Ya Neck has a BPM of 166*, and semiquaver/quaver (16th note/8th note) rhythms sustained over the period of several bars. In comparison Thoughts Of A Dying Atheist is 179 BPM but the rhythms are mainly a mixture of crotchets (quarter notes) and longer notes, with no consecutive passages of 8th notes.

*I know you said 83 in your question but I think 166 is more accurate. When/why BPM values can vary by a factor of two would be a good topic for another question!