Music Timing Formulas Needed

[stefancrs]

Uhm.
To me, logic would dictate the following.
At 60bpm a beat is 1 second.
At 4/2, a bar is indeed four seconds.
At 4/4, a bar is indeed four seconds.

So I'm with you McLilith. But on the other hand, I don't really care

[shamann]

Hey McLilith,

There's online BPM calculator here that lets you input both the BPM and time signature. Perhaps what you were after?

[McLilith]

Thanks stefancrs... I think.

I probably wouldn't care too much either, if I hadn't started creating a utility for calculating various parameters related to tempo and time signature. I really don't want to release a calculator that gives incorrect results.

I find it very difficult to follow the herd, if the herd is headed off a cliff. From all that I've read, that seems to be the case with much of the current software which makes tempo-related calculations.

I even sent an email to one of the fellows who had an online calculator which gives you the length of various notes, based on a tempo that you enter into the form. I asked him if he was assuming 4/4 time, and he said "yes". He admitted that back when he wrote the calculator, he didn't want to get into the extra complexity of making it work in all time signatures. That's fine with me, if he wants to make that assumption, but it should have been mentioned on the web site.

I also found another calculator on a different site, which seemed to be a direct imitation of his, except that it wouldn't even give answers for half the note values. It would seem that someone didn't do enough debugging...

I don't hold small, free, online javascript utilities to the same quality standards that I would expect from Sonar, Tracktion, etc. I can overlook the online applets to a certain extent.

On the other hand, the professional apps should certainly get things correct. However, I really don't see how they could possibly be correct, based on my current understanding of music theory. One of us has to be wrong somewhere.

If it's me that's wrong, then I want to know where I went wrong, and what is truly correct.

I absolutely do not want to create dysfunctional software.


take care,
McLilith

[McLilith]

Hey McLilith,

There's online BPM calculator here that lets you input both the BPM and time signature. Perhaps what you were after?

Thanks shamann,

This is just like a calculator that someone else gave me link for earlier. It's interesting, and it might be matching the results I'm getting...

However, they don't label a lot of their numbers with actual units, so I can't say for certain.

For example, the results directly under the "PARTIAL DELAYS - LFO" heading have fractional headings. Are these to represent quater notes, half notes, etc? -- or -- are these to represent quarter measures, half measures, etc?

If they represent measures (bars), then those results agree totally with mine. However, I have an odd feeling that these numbers were supposed to represent note vales and not measures.

I'll try sending an email to the author of the page. Maybe he/she can clarify things.


thanks,
McLilith

[AJay]

Here are what I've always understood to be the facts:

Tempo = the number of Beats per MINUTE
Time Sig. Upper Number = Number of Beats per MEASURE
Time Sig. Lower Number = Specifies which note is equal to one beat.

By changing the type of note which equals one beat your are either halving or doubling the length of the note, therefore your are either halving or doubling the length of a bar.

Bottom Number Value
1/1 - Whole note - Semi-Breve
1/2 - Half note - Minim
1/4 - Quarter note - Crotchet
1/8 - Eighth note - Quaver
1/16 - Sixteenth Note - Semi-Quaver


At 4/4 running at 120bpm .........
4/4 is 4 quarter notes - crotchet - per measure.

60/120 = 0.5 = length of one quarter note or a crotchet
a bar would equal 0.5*2 = 2 secs

At 4/8 running at 120bpm ......... halve the 4/4 bar length answer or double the tempo

4/8 is 4 eighth notes - quaver - per measure.

((60/120) /2) = 0.25 = length of one eighth note or a quaver
a bar would equal 0.25*4 = 1 sec.
((60/240) *4) = 1 sec.


At 4/2 running at 120bpm ......... either double the 4/4 bar length answer or halve the tempo

4/2 is 4 half notes - minim - per measure

((60/120)*2) = 1 = length of one half note or a minim
a bar would equal 1*4 = 4 secs.
((60/60)*4) = 4

Also remember that when using compound timing (3/4,6/8,9/8,etc), further ammendments to the formulae are required as the beats are dotted.

Where can I find an authoritative text that explains why these formulas are incorrect?

http://www.cyberflotsam.com/Music_NoteValues1.htm

http://datadragon.com/education/reading/timesig.shtml

http://www.musicarrangers.com/star-theo ... =time&p=15

[stefancrs]

At 4/8 I thought the 8ths where the beats...

[glurgle]

* replied about 4 hours too late *

[TechNoiZ]