About BPM (Not related to Beatmapping)

FathomAssembly

Joined February 2015

Topic Starter

FathomAssembly 2015-09-10T14:31:31+00:00

Hii ! =3

There's some things I don't understand about BPM, if you've got some free time, can you try to clear that for me please ? =3

First, why do the BPM refer to the number of beats of the main rythm(s) of the song, and not to the actual number of total Beats per Minute ?
For instance, when creating a beatmap, you measure just the BPM with the main rythm's beats, but you ignore all others beats, so the real BPM should be higher ?

Also, about the streaming speed (measured with t/160893), why do I only get 214.4 BPM when I clicked 20 times in 1.33 seconds ? (Screen in spoiler)

SPOILER

I wonder that because (let's say I clicked 20 times in 1.5s to simplify the arithmetics) :

60 (seconds) / 1.5 (seconds) = 40

40 (forty times twenty clicks) * 20 (clicks) = 800 (clicks/beats per minute)

So, why am I streaming only at 214.4BPM and not 800+ ?

Sorry if my questions are unclear/hard to understand, and thanks for any answer !

When life offers you a dream so far beyond any of your expectations, it's not reasonable to grieve when it comes to an end.

My french translation (but I much prefer the english original): « Lorsque la vie vous offre un rêve Ô combien préférable à toutes vos attentes, il n'est pas raisonnable de la pleurer lorsqu'elle arrive à sa fin. »

B1rd

2,974 posts

Joined December 2013

B1rd 2015-09-10T15:35:02+00:00

For the majority of maps the streams are in 1/4 notes and the normal circles are in 1/2 notes. If you look in the editor you will see.

Railey2

515 posts

Joined February 2015

Railey2 2015-09-10T20:45:31+00:00

BPM measures quarter notes per minute. Streaming is usually going along with sixteenth notes, which means that you hit 4 times the BPM's amount of circles, if you were to stream consistently for full 60 seconds.

For instance, if you stream 200BPM, you'll hit 800 circles per minute. You got the maths down correctly, except the divide through 4-part.

The confusing thing is, that testing this with your example will never give me 214 as a result.
It should be ((60/1.33)*20)/4 = 226

SPOILER

nice find here:

Corin wrote:
Left hand:
Well, earth is very dangerous!
Wouldn't you like to go back to Mars - where you came from?

Your 20 hits has been complete in 1.33 seconds.
Average hit speed: 15.04 per-second
Osu! 1/4 stream hits speed is at: 225.6 BPM

Right hand:
OMG, this is fast! You are too good

Your 20 hits has been complete in 1.42 seconds.
Average hit speed: 14.04 per-second
Osu! 1/4 stream hits speed is at: 210.7 BPM

Derp

t/35610/start=150

derp indeed

Your program seems to use a formula that is not know to me. I have no idea what it could possibly be calculating, but it surely isn't using sixteenth notes, eighth notes, or thirty-second notes. Maybe whoever wrote the formula thought that a minute has less than 60 seconds, or they divide through more than 4.
Or they do something else entirely. Whatever it is, its not streaming speed or BPM.

roufou

987 posts

Joined September 2011

roufou 2015-09-10T21:11:20+00:00

I see it as this, BPM is done for convenience...for instance 70 and 140 bpm are no different, but generally if the song is 140 bpm and packed with halfnotes 70 makes it easier to understand.

let me go a bit more in depth, for music it mainly consists of full notes, half notes and quarter notes, full notes are held for one full beat, half notes are held a half beat (1/2) and quarter notes a quarter of a note (1/4). now obviously there are 1/3, 1/6 and 1/8 etc. etc. but my point is that BPM does not actually affect how many beats the song has, but rather how fast you should be reading the sheet of paper that says 80 BPM, now opinions might differ, but that's how I see it.

not sure if any further explanation is required?

I guess I could explain a bit better... you see a song at 160 bpm and most of the notes are half notes? maybe half the song? well in that case you basically play the song as twice of 80 bpm, which is 160 bpm, now the song might be more convenient to read as 80 bpm as then it'll be 1/4 and 1/4 are basically the easiest to read and play, and generally the standard for most of the song unless it's in a different beat than 4/4 (which is a bit rarer). let's say it's still 160 bpm and it starts throwing a bunch of 1/4 at the end, then it might be nice to have the first half at 80 bpm and the second half at 160...
well this is basically how it works, hope my explanation was somewhat insightful...I tried.

FathomAssembly

52 posts

Joined February 2015

Topic Starter

FathomAssembly 2015-09-10T21:34:45+00:00

So, BPM does not refer to the total number of beats per minute, but only a fraction of it ? And the reason for that is that it simplifies whatever you are doing with the song ? Is that right or am I still wrong ?

I don't see the point (nor do I understand everything), but I'm sure it's like a lot of things, it may look useless at first glance, but it is here for a good reason.

Thanks for your replies =3

When life offers you a dream so far beyond any of your expectations, it's not reasonable to grieve when it comes to an end.

My french translation (but I much prefer the english original): « Lorsque la vie vous offre un rêve Ô combien préférable à toutes vos attentes, il n'est pas raisonnable de la pleurer lorsqu'elle arrive à sa fin. »

Railey2

515 posts

Joined February 2015

Railey2 2015-09-10T21:54:44+00:00

When you listen to a song, do you sometimes find yourself nod your head along with the music?
THATS what BPM measures per minute, also (not that commonly) known as quarter notes. Count headnods in a minute = BPM

Its nothing less than a measure of speed for music.

FathomAssembly

52 posts

Joined February 2015

Topic Starter

FathomAssembly 2015-09-11T14:34:51+00:00

Okay, thanks again =3

When life offers you a dream so far beyond any of your expectations, it's not reasonable to grieve when it comes to an end.

My french translation (but I much prefer the english original): « Lorsque la vie vous offre un rêve Ô combien préférable à toutes vos attentes, il n'est pas raisonnable de la pleurer lorsqu'elle arrive à sa fin. »

fat pear

264 posts

Joined July 2014

fat pear 2015-09-12T08:29:15+00:00

because 1/4 streams are 1/4 of the bpm you idiot

Railey2

515 posts

Joined February 2015

Railey2 2015-09-12T11:13:32+00:00