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audio: remove dc bias

This commit is contained in:
Steven Hugg 2019-08-24 10:46:32 -04:00
parent dd070f71fc
commit d4873545b2
2 changed files with 5 additions and 4 deletions

View File

@ -395,10 +395,11 @@ export var SampleAudio = function(clockfreq) {
self.sr=self.context.sampleRate; self.sr=self.context.sampleRate;
self.bufferlen=2048; self.bufferlen=2048;
// Amiga 500 fixed filter at 6kHz. WebAudio lowpass is 12dB/oct, whereas // remove DC bias
// older Amigas had a 6dB/oct filter at 4900Hz.
self.filterNode=self.context.createBiquadFilter(); self.filterNode=self.context.createBiquadFilter();
self.filterNode.frequency.value=6000; self.filterNode.type='lowshelf';
self.filterNode.frequency.value=100;
self.filterNode.gain.value=-6;
// mixer // mixer
if ( typeof self.context.createScriptProcessor === 'function') { if ( typeof self.context.createScriptProcessor === 'function') {

View File

@ -27,7 +27,7 @@ const vsyncFrequency = hsyncFrequency / 0x148;
const cpuCyclesPerLine = cpuFrequency / hsyncFrequency; const cpuCyclesPerLine = cpuFrequency / hsyncFrequency;
const timerFrequency = 500; // input 2 bit 0x8 const timerFrequency = 500; // input 2 bit 0x8
const cyclesPerTimerTick = cpuFrequency / (2 * timerFrequency); const cyclesPerTimerTick = cpuFrequency / (2 * timerFrequency);
const audioOversample = 4; const audioOversample = 2;
const audioSampleRate = 60 * scanlinesPerFrame; // why not hsync? const audioSampleRate = 60 * scanlinesPerFrame; // why not hsync?
export class VicDual extends BasicScanlineMachine { export class VicDual extends BasicScanlineMachine {