From 759b0a994d88fe9292b535269b37744d1eb8d381 Mon Sep 17 00:00:00 2001
From: ed <s@ocv.me>
Date: Thu, 9 Sep 2021 00:27:18 +0200
Subject: [PATCH] alternative equalizer tuning

---
 copyparty/web/browser.js | 33 +++++++++++++++++++++++++++++----
 docs/biquad.html         | 26 ++++++++++++++++++++++----
 2 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/copyparty/web/browser.js b/copyparty/web/browser.js
index eb3b4674..a3e101c9 100644
--- a/copyparty/web/browser.js
+++ b/copyparty/web/browser.js
@@ -1063,6 +1063,31 @@ var audio_eq = (function () {
 		"last_au": null
 	};
 
+	// some browsers have insane high-frequency boost
+	// (or rather the actual problem is Q but close enough)
+	var cali = (function () {
+		try {
+			var ac = new AudioContext(),
+				fi = ac.createBiquadFilter(),
+				freqs = new Float32Array(1),
+				mag = new Float32Array(1),
+				phase = new Float32Array(1);
+
+			freqs[0] = 14000;
+			fi.type = 'peaking';
+			fi.frequency.value = 18000;
+			fi.Q.value = 0.8;
+			fi.gain.value = 1;
+			fi.getFrequencyResponse(freqs, mag, phase);
+
+			return mag[0];  // 1.0407 good, 1.0563 bad
+		}
+		catch (ex) {
+			return 0;
+		}
+	})(),
+		mp = cali < 1.05;
+
 	var cfg = [ // hz, q, g
 		[31.25 * 0.88, 0, 1.4],  // shelf
 		[31.25 * 1.04, 0.7, 0.96],  // peak
@@ -1073,10 +1098,10 @@ var audio_eq = (function () {
 		[1000, 0.9, 1.1],
 		[2000, 0.9, 1.105],
 		[4000, 0.88, 1.05],
-		[8000 * 1.006, 0.73, 1.24],
-		[16000 * 0.89, 0.7, 1.26],  // peak
-		[16000 * 1.13, 0.82, 1.09],  // peak
-		[16000 * 1.205, 0, 1.9]  // shelf
+		[8000 * 1.006, 0.73, mp ? 1.24 : 1.2],
+		[16000 * 0.89, 0.7, mp ? 1.26 : 1.2],  // peak
+		[16000 * 1.13, 0.82, mp ? 1.09 : 0.75],  // peak
+		[16000 * 1.205, 0, mp ? 1.9 : 1.85]  // shelf
 	];
 
 	try {
diff --git a/docs/biquad.html b/docs/biquad.html
index 52322154..6e0bbe77 100644
--- a/docs/biquad.html
+++ b/docs/biquad.html
@@ -3,6 +3,24 @@
 setTimeout(location.reload.bind(location), 700);
 document.documentElement.scrollLeft = 0;
 
+var cali = (function() {
+    var ac = new AudioContext(),
+        fi = ac.createBiquadFilter(),
+        freqs = new Float32Array(1),
+        mag = new Float32Array(1),
+        phase = new Float32Array(1);
+
+    freqs[0] = 14000;
+    fi.type = 'peaking';
+    fi.frequency.value = 18000;
+    fi.Q.value = 0.8;
+    fi.gain.value = 1;
+    fi.getFrequencyResponse(freqs, mag, phase);
+
+    return mag[0];  // 1.0407 good, 1.0563 bad
+})(),
+    mp = cali < 1.05;
+
 var can = document.createElement('canvas'),
     cc = can.getContext('2d'),
     w = 2048,
@@ -28,12 +46,12 @@ var cfg = [ // hz, q, g
     [1000, 0.9, 1.1],
     [2000, 0.9, 1.105],
     [4000, 0.88, 1.05],
-    [8000 * 1.006, 0.73, 1.24],
+    [8000 * 1.006, 0.73, mp ? 1.24 : 1.2],
     //[16000 * 1.00, 0.5, 1.75],  // peak.v1
     //[16000 * 1.19, 0, 1.8]  // shelf.v1
-    [16000 * 0.89, 0.7, 1.26],  // peak
-    [16000 * 1.13, 0.82, 1.09],  // peak
-    [16000 * 1.205, 0, 1.9]  // shelf
+    [16000 * 0.89, 0.7, mp ? 1.26 : 1.2],  // peak
+    [16000 * 1.13, 0.82, mp ? 1.09 : 0.75],  // peak
+    [16000 * 1.205, 0, mp ? 1.9 : 1.85]  // shelf
 ];
 
 var freqs = new Float32Array(22000),