From 99b4ad5f982c98116a9b8d15778b0bb98ef104fe Mon Sep 17 00:00:00 2001
From: Chuf <42591821+gapeman@users.noreply.github.com>
Date: Thu, 14 Mar 2019 20:32:54 +0100
Subject: [PATCH] Fixes issue #717

GainNode now attenuates or boosts the signal correctly, according to the logarithmic dB scale
---
 js/media/index.ts | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/js/media/index.ts b/js/media/index.ts
index 471b1a83..cbc54819 100644
--- a/js/media/index.ts
+++ b/js/media/index.ts
@@ -188,13 +188,12 @@ export default class Media {
     this._gainNode.gain.value = volume / 100;
   }
 
-  // From 0 to 100
   // The input value here is 0-100 which is kinda wrong, since it represents -12db to 12db.
   // For now, 50 is 0db (no change).
-  // For now we map the values 0-100 to 0.25-1.75
+  // Equation used is: 10^((dB)/20) = x, where x (preamp.gain.value) is passed on to gainnode for boosting or attenuation.
   setPreamp(value: number) {
-    const percentDelta = (value - 50) * 0.02;
-    this._preamp.gain.value = 1 + percentDelta * 0.75;
+    const db = (value / 100) * 24 - 12;
+    this._preamp.gain.value = Math.pow(10,(db/20));
   }
 
   // From -100 to 100