|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
declare(strict_types = 1); |
|
4
|
|
|
|
|
5
|
|
|
namespace ExtendedStrings\Strings; |
|
6
|
|
|
|
|
7
|
|
|
use ExtendedStrings\Strings\Instrument\InstrumentInterface; |
|
8
|
|
|
|
|
9
|
|
|
class HarmonicCalculator |
|
10
|
|
|
{ |
|
11
|
|
|
/** |
|
12
|
|
|
* @param \ExtendedStrings\Strings\Note $soundingNote |
|
13
|
|
|
* @param \ExtendedStrings\Strings\Instrument\InstrumentInterface $instrument |
|
14
|
|
|
* @param float $tolerance |
|
15
|
|
|
* |
|
16
|
|
|
* @return Harmonic[] |
|
17
|
|
|
*/ |
|
18
|
|
|
public function getHarmonicsForSoundingNote(Note $soundingNote, InstrumentInterface $instrument, float $tolerance = 50.0): array |
|
19
|
|
|
{ |
|
20
|
|
|
$harmonics = []; |
|
21
|
|
|
foreach ($instrument->getStringFrequencies() as $stringFrequency) { |
|
22
|
|
|
$string = new VibratingString($stringFrequency); |
|
23
|
|
|
$harmonics += $this->findNaturalHarmonics($soundingNote, $string, $tolerance) |
|
24
|
|
|
+ $this->findArtificialHarmonics($soundingNote, $string); |
|
25
|
|
|
} |
|
26
|
|
|
|
|
27
|
|
|
return $harmonics; |
|
28
|
|
|
} |
|
29
|
|
|
|
|
30
|
|
|
private function findArtificialHarmonics(Note $soundingNote, VibratingString $string): array |
|
31
|
|
|
{ |
|
32
|
|
|
$harmonics = []; |
|
33
|
|
|
$soundingNoteFrequency = $soundingNote->getFrequency(); |
|
34
|
|
|
$stringFrequency = $string->getStoppedFrequency(); |
|
35
|
|
|
foreach (range(6, 2) as $number) { |
|
36
|
|
|
$fundamental = $soundingNoteFrequency / $number; |
|
37
|
|
|
if ($fundamental > $stringFrequency) { |
|
38
|
|
|
$baseStop = $string->getStringLength($fundamental); |
|
39
|
|
|
$halfStop = (($number - 1) / $number) * $baseStop; |
|
40
|
|
|
|
|
41
|
|
|
$harmonics[] = new Harmonic($halfStop, $baseStop, $string); |
|
42
|
|
|
} |
|
43
|
|
|
} |
|
44
|
|
|
|
|
45
|
|
|
return $harmonics; |
|
46
|
|
|
} |
|
47
|
|
|
|
|
48
|
|
|
private function findNaturalHarmonics(Note $soundingNote, VibratingString $string, float $tolerance = 50.0): array |
|
49
|
|
|
{ |
|
50
|
|
|
$harmonics = []; |
|
51
|
|
|
$soundingCents = $soundingNote->getCents(); |
|
52
|
|
|
foreach (range(1, 8) as $number) { |
|
53
|
|
|
// Convert harmonic number to (possible sounding) frequency. |
|
54
|
|
|
$candidateFrequency = $string->getHarmonicSoundingFrequency(1 / $number); |
|
55
|
|
|
|
|
56
|
|
|
// Convert (possible sounding) frequency to cents above C4, for comparison. |
|
57
|
|
|
$candidate = Note::fromFrequency($candidateFrequency, 440.0, [$soundingNote->getAccidental()]); |
|
58
|
|
|
$difference = abs($candidate->getCents() - $soundingCents); |
|
59
|
|
|
|
|
60
|
|
|
if ($difference < $tolerance) { |
|
61
|
|
|
$stringLengths = Harmonic::getStringLengthsFromNumber($number, true); |
|
62
|
|
|
foreach ($stringLengths as $stringLength) { |
|
63
|
|
|
$harmonics[] = new Harmonic($stringLength, 1.0, $string); |
|
64
|
|
|
} |
|
65
|
|
|
} |
|
66
|
|
|
} |
|
67
|
|
|
|
|
68
|
|
|
return $harmonics; |
|
69
|
|
|
} |
|
70
|
|
|
} |
|
71
|
|
|
|
extended-strings /
strings
