Initial commit

.gitignore

@@ -0,0 +1,2 @@
+/.idea/
+/vendor/

bin/app.php

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+<?php
+
+// http://enjoythemusic.com/diy/0311/crossover.htm
+
+use Scientific\Frequency;
+use Scientific\Impedance;
+
+require_once __DIR__ . '/../vendor/autoload.php';
+
+$frequency = new Frequency(unit(9000));
+$tweeter = new Driver(new Impedance(unit(8)));
+$woofer = new Driver(new Impedance(unit(4)));
+
+$crossover = new FirstOrderTwoWayCrossover($frequency);
+$capacitor = $crossover->getTweeterCapacitor($tweeter);
+$inductor = $crossover->getWooferInductor($woofer);
+
+printf(
+    'First order 2-way crossover @ %s (slope = %s):%s',
+    $crossover->getFrequency(),
+    $crossover->getSlope(),
+    PHP_EOL
+);
+printf(
+    ' - %s capacitor in series with %s tweeter%s',
+    $capacitor->getCapacitance(),
+    $tweeter->getImpedance(),
+    PHP_EOL
+);
+printf(
+    ' - %s inductor in series with %s woofer%s',
+    $inductor->getInductance()->format('milli'),
+    $woofer->getImpedance(),
+    PHP_EOL
+);

composer.json

@@ -0,0 +1,13 @@
+{
+    "name": "joopschilder/speaker-params",
+    "description": "Speaker parameter modelling program",
+    "autoload": {
+        "files": ["src/Lib/helpers.php"],
+        "psr-0": {
+            "": ["src"]
+        }
+    },
+    "require-dev": {
+        "symfony/var-dumper": "^5.2"
+    }
+}

composer.lock

@@ -0,0 +1,270 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "997f1773a8a4495e430433bfebab7f7c",
+    "packages": [],
+    "packages-dev": [
+        {
+            "name": "symfony/polyfill-mbstring",
+            "version": "v1.22.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-mbstring.git",
+                "reference": "5232de97ee3b75b0360528dae24e73db49566ab1"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/5232de97ee3b75b0360528dae24e73db49566ab1",
+                "reference": "5232de97ee3b75b0360528dae24e73db49566ab1",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.1"
+            },
+            "suggest": {
+                "ext-mbstring": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "1.22-dev"
+                },
+                "thanks": {
+                    "name": "symfony/polyfill",
+                    "url": "https://github.com/symfony/polyfill"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Mbstring\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill for the Mbstring extension",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "mbstring",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/polyfill-mbstring/tree/v1.22.1"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2021-01-22T09:19:47+00:00"
+        },
+        {
+            "name": "symfony/polyfill-php80",
+            "version": "v1.22.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-php80.git",
+                "reference": "dc3063ba22c2a1fd2f45ed856374d79114998f91"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-php80/zipball/dc3063ba22c2a1fd2f45ed856374d79114998f91",
+                "reference": "dc3063ba22c2a1fd2f45ed856374d79114998f91",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.1"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "1.22-dev"
+                },
+                "thanks": {
+                    "name": "symfony/polyfill",
+                    "url": "https://github.com/symfony/polyfill"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Php80\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ],
+                "classmap": [
+                    "Resources/stubs"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Ion Bazan",
+                    "email": "ion.bazan@gmail.com"
+                },
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill backporting some PHP 8.0+ features to lower PHP versions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/polyfill-php80/tree/v1.22.1"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2021-01-07T16:49:33+00:00"
+        },
+        {
+            "name": "symfony/var-dumper",
+            "version": "v5.2.6",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/var-dumper.git",
+                "reference": "89412a68ea2e675b4e44f260a5666729f77f668e"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/var-dumper/zipball/89412a68ea2e675b4e44f260a5666729f77f668e",
+                "reference": "89412a68ea2e675b4e44f260a5666729f77f668e",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.2.5",
+                "symfony/polyfill-mbstring": "~1.0",
+                "symfony/polyfill-php80": "^1.15"
+            },
+            "conflict": {
+                "phpunit/phpunit": "<5.4.3",
+                "symfony/console": "<4.4"
+            },
+            "require-dev": {
+                "ext-iconv": "*",
+                "symfony/console": "^4.4|^5.0",
+                "symfony/process": "^4.4|^5.0",
+                "twig/twig": "^2.13|^3.0.4"
+            },
+            "suggest": {
+                "ext-iconv": "To convert non-UTF-8 strings to UTF-8 (or symfony/polyfill-iconv in case ext-iconv cannot be used).",
+                "ext-intl": "To show region name in time zone dump",
+                "symfony/console": "To use the ServerDumpCommand and/or the bin/var-dump-server script"
+            },
+            "bin": [
+                "Resources/bin/var-dump-server"
+            ],
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "Resources/functions/dump.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Component\\VarDumper\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Provides mechanisms for walking through any arbitrary PHP variable",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "debug",
+                "dump"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/var-dumper/tree/v5.2.6"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2021-03-28T09:42:18+00:00"
+        }
+    ],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": [],
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": [],
+    "plugin-api-version": "2.0.0"
+}

src/Components/Capacitor.php

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+<?php
+
+namespace Components;
+
+use Scientific\Capacitance;
+
+class Capacitor
+{
+    public function __construct(
+        private float $capacitance
+    )
+    {
+    }
+
+    public function getCapacitance(): Capacitance
+    {
+        return Capacitance::fromValue($this->capacitance);
+    }
+}

src/Components/Inductor.php

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+<?php
+
+namespace Components;
+
+use Scientific\Inductance;
+
+class Inductor
+{
+    public function __construct(
+        private float $inductance
+    )
+    {
+    }
+
+    public function getInductance(): Inductance
+    {
+        return Inductance::fromValue($this->inductance);
+    }
+}

src/Driver.php

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+<?php
+
+use Scientific\Impedance;
+
+class Driver
+{
+    public function __construct(
+        private Impedance $impedance
+    )
+    {
+    }
+
+    public function getImpedance(): Impedance
+    {
+        return clone $this->impedance;
+    }
+}

src/FirstOrderTwoWayCrossover.php

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+<?php
+
+use Components\Capacitor;
+use Components\Inductor;
+use Scientific\CrossoverSlope;
+use Scientific\Frequency;
+
+class FirstOrderTwoWayCrossover
+{
+    private const PI = 3.1415926535;
+    private const TWO_PI = 2. * self::PI;
+
+    public function __construct(
+        private Frequency $frequency
+    )
+    {
+    }
+
+    public function getFrequency(): Frequency
+    {
+        return clone $this->frequency;
+    }
+
+    public function getSlope(): CrossoverSlope
+    {
+        return CrossoverSlope::fromDecibelPerOctave(6.);
+    }
+
+    public function getTweeterCapacitor(Driver $driver): Capacitor
+    {
+        $f = $this->getFrequency()->getValue()->unit();
+        $z = $driver->getImpedance()->getValue()->unit();
+
+        return new Capacitor(1. / (self::TWO_PI * $f * $z));
+    }
+
+    public function getWooferInductor(Driver $driver): Inductor
+    {
+        $f = $this->getFrequency()->getValue()->unit();
+        $z = $driver->getImpedance()->getValue()->unit();
+
+        return new Inductor($z / (self::TWO_PI * $f));
+    }
+}

src/Lib/helpers.php

@@ -0,0 +1,10 @@
+<?php
+
+use Scientific\Unit;
+
+if (!function_exists('unit')) {
+    function unit(float $value): Unit
+    {
+        return new Unit($value);
+    }
+}

src/Scientific/Capacitance.php

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+<?php
+
+namespace Scientific;
+
+class Capacitance extends Quantity
+{
+    protected function getSymbol(): string
+    {
+        return 'F';
+    }
+
+    protected function getName(): string
+    {
+        return 'farad';
+    }
+}

src/Scientific/CrossoverSlope.php

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+<?php
+
+namespace Scientific;
+
+class CrossoverSlope extends Quantity
+{
+    public static function fromDecibelPerOctave(float $dbPerOctave): static
+    {
+        return static::fromValue($dbPerOctave / 10.);
+    }
+
+    protected function getSymbol(): string
+    {
+        return 'B/Oct';
+    }
+
+    protected function getName(): string
+    {
+        return 'slope';
+    }
+
+    public function __toString(): string
+    {
+        return $this->format('deci');
+    }
+}

src/Scientific/Frequency.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Scientific;
+
+class Frequency extends Quantity
+{
+    protected function getSymbol(): string
+    {
+        return 'Hz';
+    }
+
+    protected function getName(): string
+    {
+        return 'hertz';
+    }
+}

src/Scientific/Impedance.php

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+<?php
+
+namespace Scientific;
+
+class Impedance extends Resistance
+{
+}

src/Scientific/Inductance.php

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+<?php
+
+namespace Scientific;
+
+class Inductance extends Quantity
+{
+    protected function getSymbol(): string
+    {
+        return 'H';
+    }
+
+    protected function getName(): string
+    {
+        return 'henry';
+    }
+}

src/Scientific/Quantity.php

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+<?php
+
+namespace Scientific;
+
+use InvalidArgumentException;
+
+abstract class Quantity
+{
+    /*
+     * https://en.wikipedia.org/wiki/Metric_prefix
+     */
+    private const METRIC_PREFIXES = [
+        'yotta' => 'Y',
+        'zetta' => 'Z',
+        'exa'   => 'E',
+        'peta'  => 'P',
+        'tera'  => 'T',
+        'giga'  => 'G',
+        'mega'  => 'M',
+        'kilo'  => 'k',
+        'hecto' => 'h',
+        'deca'  => 'da',
+        'unit'  => '',
+        'deci'  => 'd',
+        'centi' => 'c',
+        'milli' => 'm',
+        'micro' => 'μ',
+        'nano'  => 'n',
+        'pico'  => 'p',
+        'femto' => 'f',
+        'atto'  => 'a',
+        'zepto' => 'z',
+        'yocto' => 'y',
+    ];
+
+    abstract protected function getSymbol(): string;
+
+    abstract protected function getName(): string;
+
+    public function __construct(
+        private Unit $value
+    )
+    {
+    }
+
+    final public static function fromValue(float $value): static
+    {
+        return new static(new Unit($value));
+    }
+
+    final public function getValue(): Unit
+    {
+        return $this->value;
+    }
+
+    final public function format(string $prefix = 'auto'): string
+    {
+        if ($prefix === 'auto') {
+            $prefix = $this->getAppropriatePrefix();
+        } else if (!method_exists($this->value, $prefix)) {
+            throw new InvalidArgumentException('Invalid size: ' . $prefix);
+        }
+
+        $value = $this->value->{$prefix}();
+        $prefix = self::METRIC_PREFIXES[$prefix] ?? '?';
+        $symbol = $this->getSymbol();
+
+        return sprintf('%.3g %s%s', $value, $prefix, $symbol);
+    }
+
+    private function getAppropriatePrefix(): string
+    {
+        foreach (array_keys(self::METRIC_PREFIXES) as $prefix) {
+            $value = $this->value->{$prefix}();
+            if ($value >= 1. && $value < 1000.) {
+                return $prefix;
+            }
+        }
+        return 'unit';
+    }
+
+    public function __toString(): string
+    {
+        return $this->format();
+    }
+}

src/Scientific/Resistance.php

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+<?php
+
+namespace Scientific;
+
+class Resistance extends Quantity
+{
+    protected function getSymbol(): string
+    {
+        return 'Ω';
+    }
+
+    protected function getName(): string
+    {
+        return 'ohm';
+    }
+}

src/Scientific/Unit.php

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+<?php
+
+namespace Scientific;
+
+class Unit
+{
+    public function __construct(
+        private float $value
+    )
+    {
+    }
+
+    public function yotta(): float
+    {
+        return $this->zetta() / 1000.;
+    }
+
+    public function zetta(): float
+    {
+        return $this->exa() / 1000.;
+    }
+
+    public function exa(): float
+    {
+        return $this->peta() / 1000.;
+    }
+
+    public function peta(): float
+    {
+        return $this->tera() / 1000.;
+    }
+
+    public function tera(): float
+    {
+        return $this->giga() / 1000.;
+    }
+
+    public function giga(): float
+    {
+        return $this->mega() / 1000.;
+    }
+
+    public function mega(): float
+    {
+        return $this->kilo() / 1000.;
+    }
+
+    public function kilo(): float
+    {
+        return $this->unit() / 1000.;
+    }
+
+    public function hecto(): float
+    {
+        return $this->unit() / 100.;
+    }
+
+    public function deca(): float
+    {
+        return $this->unit() / 10.;
+    }
+
+    public function unit(): float
+    {
+        return $this->value;
+    }
+
+    public function deci(): float
+    {
+        return 10. * $this->unit();
+    }
+
+    public function centi(): float
+    {
+        return 100. * $this->unit();
+    }
+
+    public function milli(): float
+    {
+        return 1000. * $this->unit();
+    }
+
+    public function micro(): float
+    {
+        return 1000. * $this->milli();
+    }
+
+    public function nano(): float
+    {
+        return 1000. * $this->micro();
+    }
+
+    public function pico(): float
+    {
+        return 1000. * $this->nano();
+    }
+
+    public function femto(): float
+    {
+        return 1000. * $this->pico();
+    }
+
+    public function atto(): float
+    {
+        return 1000. * $this->femto();
+    }
+
+    public function zepto(): float
+    {
+        return 1000. * $this->atto();
+    }
+
+    public function yocto(): float
+    {
+        return 1000. * $this->yocto();
+    }
+}