/// <summary>
/// Bandpass EQ curve, recommended for stage subwoofers.
/// </summary>
/// <param name="lowFreq">Low frequency (highpass) cutoff knee</param>
/// <param name="highFreq">High frequency (lowpass) cutoff knee</param>
/// <param name="sampleRate">Sample rate of the system to be EQ'd</param>
/// <param name="resolution">Sample resolution for <see cref="this[double]"/>, must be a power of 2</param>
/// <param name="q">Q-factor of the filter</param>
/// <param name="order">Each order increases the slope with 6 dB/octave</param>
/// <param name="gain">Filter gain</param>
public Bandpass(double lowFreq, double highFreq, int sampleRate, int resolution, double q = QFactor.reference, int order = 1,
double gain = 6)
{
positioner = resolution * 2.0 / sampleRate;
float[] reference = SweepGenerator.Exponential(20, sampleRate * .5f, resolution * 2, sampleRate),
response = reference.FastClone();
BandpassFlat filter = new BandpassFlat(lowFreq, highFreq, sampleRate, q, order);
filter.Process(response);
spectrum = Measurements.GetSpectrum(Measurements.GetFrequencyResponse(reference, response));
GraphUtils.ConvertToDecibels(spectrum);
this.gain = gain;
}
static ISoundObj GetSignalGenerator(double dBfs, out string desc)
{
double gain = MathUtil.gain(dBfs);
ISoundObj signalGenerator = null;
Sequencer seq;
string description = "Unknown";
switch (_siggen)
{
case "IDENT":
// Left-right identification: embedded resource
Assembly ass = Assembly.GetExecutingAssembly();
foreach (string s in ass.GetManifestResourceNames())
{
if (s.Contains("LeftRight"))
{
Stream res = ass.GetManifestResourceStream(s);
WaveReader rdr = new WaveReader(res);
// The stream is stereo, but we want to alternate
seq = new Sequencer();
for (int j = 0; j < 10; j++)
{
seq.Add(rdr, new List<double>(new double[] { gain, 0 }));
seq.Add(new NoiseGenerator(NoiseType.SILENCE, 2, 1.0, _inputSampleRate, 0.0, false));
seq.Add(rdr, new List<double>(new double[] { 0, gain }));
seq.Add(new NoiseGenerator(NoiseType.SILENCE, 2, 1.0, _inputSampleRate, 0.0, false));
}
signalGenerator = seq;
break;
}
}
/*
// Left-right identification signal: morse code
MorseCode envL = new MorseCode(" " + _sigparamA, 10, true);
ISoundObj sigL = new SweepGenerator(1, envL.LengthSeconds * 5, 220, 7040, _inputSampleRate, 0, false, gain, true);
envL.Input = sigL;
MorseCode envR = new MorseCode(" " + _sigparamB, 10, true);
ISoundObj sigR = new SweepGenerator(1, envR.LengthSeconds * 5, 7040, 220, _inputSampleRate, 0, false, gain, true);
envR.Input = sigR;
signalGenerator = new ChannelSplicer();
(signalGenerator as ChannelSplicer).Add(envL);
(signalGenerator as ChannelSplicer).Add(envR);
*/
description = String.Format("Left/Right channel identification");
break;
case "SWEEP":
seq = new Sequencer();
if (_sigparam1 == 0)
{
_sigparam1 = 45;
}
int lengthSamples = (int)(_sigparam1 * _inputSampleRate);
if (lengthSamples < 8388608)
{
// High-accuracy logarithmic sweep starting at 10Hz
int fade = (int)(_inputSampleRate / 20);
FFTSweepGenerator sg = new FFTSweepGenerator(2, lengthSamples, 10, _inputSampleRate / 2, _inputSampleRate, gain, false);
seq.Add(sg);
description = String.Format("Logarithmic sine sweep 10Hz to {0}Hz in {1} seconds", _inputSampleRate / 2, _sigparam1);
}
else
{
// Simple logarithmic sweep starting at 10Hz, windowed (uses much less memory!)
int fade = (int)(_inputSampleRate / 20);
BlackmanHarris bhwf = new BlackmanHarris(lengthSamples / 2, fade, (int)((lengthSamples / 2) - fade));
SweepGenerator sg = new SweepGenerator(2, lengthSamples, 10, _inputSampleRate / 2, _inputSampleRate, gain, false);
bhwf.Input = sg;
seq.Add(bhwf);
description = String.Format("Log sine sweep 10Hz to {0}Hz in {1} seconds", _inputSampleRate / 2, _sigparam1);
}
// Follow by 3 seconds of silence
seq.Add(new NoiseGenerator(NoiseType.SILENCE, 2, 3.0, _inputSampleRate, 0.0, false));
signalGenerator = seq;
break;
case "SINE":
signalGenerator = new SineGenerator(2, _inputSampleRate, _sigparam1, gain);
description = String.Format("{0}Hz sine", _sigparam1);
break;
case "QUAD":
signalGenerator = new SineQuadGenerator(2, _inputSampleRate, _sigparam1, gain);
description = String.Format("{0}Hz quadrature", _sigparam1);
break;
case "SQUARE":
signalGenerator = new SquareGenerator(2, _inputSampleRate, _sigparam1, gain);
description = String.Format("{0}Hz non-bandlimited square", _sigparam1);
break;
case "BLSQUARE":
signalGenerator = new BandLimitedSquareGenerator(2, _inputSampleRate, _sigparam1, gain);
description = String.Format("{0}Hz bandlimited square", _sigparam1);
break;
case "TRIANGLE":
signalGenerator = new TriangleGenerator(2, _inputSampleRate, _sigparam1, gain);
description = String.Format("{0}Hz non-bandlimited triangle", _sigparam1);
break;
case "BLTRIANGLE":
signalGenerator = new BandLimitedTriangleGenerator(2, _inputSampleRate, _sigparam1, gain);
description = String.Format("{0}Hz bandlimited triangle", _sigparam1);
break;
case "SAWTOOTH":
signalGenerator = new SawtoothGenerator(2, _inputSampleRate, _sigparam1, gain);
description = String.Format("{0}Hz non-bandlimited sawtooth", _sigparam1);
break;
case "BLSAWTOOTH":
signalGenerator = new BandLimitedSawtoothGenerator(2, _inputSampleRate, _sigparam1, gain);
description = String.Format("{0}Hz bandlimited sawtooth", _sigparam1);
break;
case "WHITE":
signalGenerator = new NoiseGenerator(NoiseType.WHITE, 2, int.MaxValue, _inputSampleRate, gain, true);
description = String.Format("White noise");
break;
case "PINK":
bool mono = (_sigparam1 != 0 ? true : false);
signalGenerator = new NoiseGenerator(NoiseType.PINK, 2, int.MaxValue, _inputSampleRate, gain, mono);
description = String.Format("Pink noise {0}", mono ? "(mono)" : "(stereo)" );
break;
case "INTERMODULATION":
double n = 1;
description = String.Format("Intermodulation test {0}Hz", _sigparam1);
if (_sigparam2 != 0) { n++; description = description + " + " + _sigparam2 + "Hz"; }
if (_sigparam3 != 0) { n++; description = description + " + " + _sigparam3 + "Hz"; }
signalGenerator = new Mixer();
(signalGenerator as Mixer).Add(new SineGenerator(2, _inputSampleRate, _sigparam1, gain), 1/n);
if (_sigparam2 != 0) (signalGenerator as Mixer).Add(new SineGenerator(2, _inputSampleRate, _sigparam2, gain), 1 / n);
if (_sigparam3 != 0) (signalGenerator as Mixer).Add(new SineGenerator(2, _inputSampleRate, _sigparam3, gain), 1 / n);
break;
case "SHAPEDBURST":
description = String.Format("{0}Hz windowed (Blackman) over {1} cycles", _sigparam1, _sigparam2);
throw new NotImplementedException();
//break;
default:
_siggen = null;
break;
}
if (IsSigGenEQ())
{
if (IsSigGenEQBoth())
{
description = description + ", with EQ processing";
}
else if (IsSigGenEQL())
{
description = description + ", with EQ processing in left channel";
}
else if (IsSigGenEQR())
{
description = description + ", with EQ processing in right channel";
}
else
{
description = description + ", with EQ processing";
}
}
desc = description;
return signalGenerator;
}
