Wrong octave system-wide

[aik099]

When I press Middle C, then noteon event reports it as C3 while it should be C4.

I'm using event listening code from README.md:

 // Listen for a 'note on' message on all channels
  input.addListener('noteon', "all",
    function (e) {
      console.log("Received 'noteon' message (" + e.note.name + e.note.octave + ").");
    }
  );

Same happens, the other way around: attempt to play C3 actually plays C4:

output.playNote('C3', 'all', {duration: 2000, velocity: 0.25});

Here are octaves shown by Synthesia and it clearly shows that when C3 is reported by noteon event, then Synthesia (and other programs) display it as C4:

I'm suspecting an issue when in math, when decoding/encoding midi messages.

When I press 1st key on the keyboard (A0) it's reported as A-1, which according to README.md is a special code for stop playing note on all channels (see output.stopNote("C-1"); in there).

[aik099]

Removing last - 1 from WebMidi.prototype.getOctave method should fix octave reporting in events:

old: return Math.floor(parseInt(number) / 12 - 1) - 1;
new: return Math.floor(parseInt(number) / 12 - 1);

Examples:

• MIDI Code: 60 (Middle C); Result: Floor(60 / 12 - 1) = 4
• MIDI Code: 21 (A0): Result: Floor(21 / 12 - 1) = 0

[aik099]

Changing octave + 2 into octave + 1 in the WebMidi.prototype.noteNameToNumber method should fix the playNote method:

old: var result = ((octave + 2) * 12) + semitones;
new: var result = ((octave + 1) * 12) + semitones;

Examples:

• Note: C4 (note "C", octave: 4); MIDI Code: ((4 + 1) * 12) + 0 = 60
• Note: A0 (note "A", octave: 0): MIDI Code: ((0 + 1) * 12) + 9 = 21

[aik099]

I can send a PR with above described changes as well.

[aik099]

I've also found https://www.midi.org/forum/830-midi-octave-and-note-numbering-standard article where a lot confusion happens between fact what octave Middle C is coming from: C3, C4, C5 or something else.

We can make octave numbering offset configurable, in WebMidi.enable method (3rd parameter) but I'm afraid, that it will only make things worse, because it would allow for negative octave numbers as a result and no standard at the end.

[djipco]

We can make octave numbering offset configurable, in WebMidi.enable method (3rd parameter) but I'm afraid, that it will only make things worse, because it would allow for negative octave numbers as a result and no standard at the end.

As far as I'm concerned, having negative octave numbers is not an issue and should not be considered a criteria. I actually think it would be a good idea to allow for on-the-fly system-wide octave offsetting. However, I'd like to make an informed decision here. Here's what we know:

• The scientific pitch notation considers middle C to always be C4.

• The MIDI standard does not define a pitch for middle C but it does consider middle C to be note number 60. Different manufacturers have assigned middle C to various octaves/pitches (usually C3, C4 or C5).

• This article and this other one say that General MIDI requires note number 69 to be pitched at A440. I could not find official confirmation for this. This would make middle C to be C4.

• The MIDI Tuning Standard states that note number 69 should be tuned at 440Hz by default, which would also make middle C (60) to be C4.

Given that, I would tend to agree to go with C4. However, this is a breaking change. What are people's views on this?

[francoisgeorgy]

Hi,

I always thought that middle C = C4 was a standard or at least a "de facto" standard. I'm quite surprised this is not really the case.

But, it seems that there is kind of a consensus toward that C4 value. So, for me this is the best candidate. I vote for it :-)

Sorry not to be able to bring more to the discussion.

[aik099]

@francoisgeorgy , maybe you can tweet about it. My twitter followers are developers mostly, so I'm not even trying 😉 to tweet about it.

[djipco]

I always thought that middle C = C4 was a standard or at least a "de facto" standard. I'm quite surprised this is not really the case.

You would find many people to disagree with that statement. For example, various pieces of hardware and software treat MIDI note 60 (middle C) as C3. Some notable examples that come to mind are Yamaha's hardware, Apple's Logic, Steinberg's Cubase, etc. Also, many people were taught middle C = C3 in music school.

Given the variations in practices and opinions on this matter, I think the best course of action is to align with some sort of standard. In this case, the most obvious one seems to be scientific pitch notation.

So, I'm going to change WebMidi.js to define middle C as C4. However, this change is going to be accompanied by a way to globally modify this behaviour.

[djipco]

As discussed, middle C has been configured to be C4 in the latest /src version. A new setting called WebMidi.octaveOffset is also available to globally offset octave numbering. This means you can use WebMidi.octaveOffset = -1 to maintain compatibility with existing projects.

Please test it out using /src/webmidi.js and report back here. I'll publish it to NPM once I have confirmation that it works properly.

[aik099]

I'll added a note about code in 5a0e0ae commit directly, because you're not using a PR.

Will test shortly.

[aik099]

Tested, that behavior explained in code above WebMidi.octaveOffset setting works as described:

• the C4 becomes C5 if I use +1 offset
• the C4 becomes C3 if I use -1 offset

[djipco]

Fixed in release 2.1.