lambdaway :: musical

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_img data/8BCDB20E-D0D4-4FD7-A3F0-35BB74535D03.jpeg 
 
_h1 musical scales

_p See also [[dodecaphony|http://lambdaway.free.fr/workshop/index.php?view=dodecaphony]] and [[fantasia|https://imslp.org/wiki/Fantasia_in_D_minor,_K.397/385g_(Mozart,_Wolfgang_Amadeus)]].

_p Using the {b musicalScale()} javascript function found in [[rosettacode.org|https://rosettacode.org/wiki/Musical_scale#JavaScript]], we build a lambdatalk interface to output the 8 notes of the C major diatonic scale, and more.

_h2 functions

{pre
'{def note
 {lambda {:i}
  {floor {* 262 {pow 2 {/ :i 12}}}}}}   // do = 262Hz, la = 440Hz 
-> {def note
 {lambda {:i}
  {floor {* 262 {pow 2 {/ :i 12}}}}}}

'{S.map note {S.serie 0 12}}
-> {S.map note {S.serie 0 12}}

'{def scale
 {lambda {:notes}
  [{S.map {lambda {:i} {note :i},} :notes}]}} 
-> {def scale
 {lambda {:notes}
  [{S.map {lambda {:i} {note :i},} :notes}]}}

'{def play
 {lambda {:n}
  {input {@ type="button" 
            value="Play :n" 
            onclick="musicalScale({scale :n})"}}}}
-> {def play
 {lambda {:n}
  {input
 {@ type="button" 
    value="Play" 
    onclick="musicalScale({scale :n})"}}}}

'{def display 
 {lambda {:n} 
  {span {@ style="vertical-align:{* 5 :n}px; 
                  letter-spacing:0.05em;"}:n}}}
-> {def display 
 {lambda {:n} 
  {span {@ style="vertical-align:{* 5 :n}px; 
                  letter-spacing:0.05em;
               ;;   border:1px solid #444; border-radius:10px;
                 "}:n}}}

'{def foo
 {lambda {:n}
  {div {@ style="background:#ddd; padding:5px;"}
  {S.map display :n}}
  {play :n}}}
-> {def foo
 {lambda {:n}
  {div {@ style="background-color:#ddd; padding:5px;"}  
  {S.map display :n}} 
  {play :n}}}
}

;; {div {@ class="solf"}}

_h2 playing

{pre

1) diatonic up
'{foo 0 2 4 5 7 9 11 12}    // do ré mi fa sol la si do
-> {foo 0 2 4 5 7 9 11 12 12 12}

2) diatonic down
'{foo 12 11 9 7 5 4 2 0}    // do si la sol fa mi ré do
-> {foo 12 11 9 7 5 4 2 0 0 0}

3) twelve intervals of the octave
'{foo {S.serie 0 12}}
-> {foo {S.serie 0 12}}

4) starting xxx
'{foo 0 2 3 5 7 3 7 7 6 2 6 6 7 3 7 7 0 2 3 5 7 3 7 12 10 7 3 7 10 10 10 10}
-> {foo 0 2 3 5 7 3 7 7 6 2 6 6 7 3 7 7 0 2 3 5 7 3 7 12 10 7 3 7 10 10 10 10}

5) the same reversed
'{foo 10 7 3 7 10 12 7 3 7 5 3 2 0 7 7 3 7 6 6 2 6 7 7 3 7 5 3 2 0 0 0}
-> {foo 10 7 3 7 10 12 7 3 7 5 3 2 0 7 7 3 7 6 6 2 6 7 7 3 7 5 3 2 0 0 0}

6) random walk
'{foo {S.map {lambda {} {round {* 20 {random}}}} {S.serie 0 30}}}
-> {foo {S.map {lambda {} {round {* 20 {random}}}} {S.serie 0 30}}}

7) en route vers "A la claire fontaine..."
'{foo 0 0 0 4 4 2 4 0 0 0 4 4 2 4 4 4 4 4 4 2 0 4 7 4 7 7 7 4 0 4 2 2 2}
-> {foo 0 0 0 4 4 2 4 0 0 0 4 4 2 4 4 4 4 4 4 2 0 4 7 4 7 7 7 4 0 4 2 2 2}
     il  y   a   long temps que je t'ai me  ja    mais   je ne t'ou blie rai.
'{foo 0 0 0 0 0 0 4 4  4 4   2   0  4 4  0 0 4 4 4 4 4    2  0  4 4  2 2  0 0} 
-> {foo 0 0 0 0 0 0 4 4 4 4   2   0  4 4  0 0 4 4 4 4 4 4 2  0  4 4  2 2  0 0}
}

_img https://musescore.com/static/musescore/scoredata/gen/4/7/8/5057874/bd9f25e2845bff6d17bb5a610d46334244658fb8/score_0.png

{script 
function musicalScale(freqArr){
    var AudioContext = window.AudioContext || window.webkitAudioContext;
    var audioCtx = new AudioContext();

var oscillator = audioCtx.createOscillator();
    var gainNode = audioCtx.createGain();

oscillator.connect(gainNode);
    gainNode.connect(audioCtx.destination);

duration = 0.25   // seconds
    freqArr.forEach(function (freq, i){
        oscillator.frequency.setValueAtTime(
                   freq, audioCtx.currentTime + i * duration);
    });

oscillator.start();
    oscillator.stop(audioCtx.currentTime + freqArr.length * duration);
}
}

{style 
.solf { 
  background-image: url("https://www.tabs4acoustic.com/images/uploads/images/Exemples_introduction_au_solfege_0015-600x70.png") 50% 50% ;
  background-color: #888;  
  box-shadow:0 0 8px #000;  
}
}