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Add a Low Pass filter for CPS-1/2.

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sergiobenrocha2 2015-11-26 22:12:46 -02:00
parent daeb8cacaf
commit 7ef52f1da1
2 changed files with 56 additions and 2 deletions
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11
audio/audio_filters/EQ.dsp
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@ -26,9 +26,16 @@ filter0 = eq
# Due to frequency domain smearing, you will not get exactly +3 dB at 1 kHz.
# By default, this filter has a flat frequency response.
#
# Dumps the impulse response generated by the EQ as a plain-text file
# with one coefficient per line.
# eq_impulse_response_output = "eq_impulse.txt"
#
# Using GNU Octave or Matlab, you can plot the response with:
#
# f = fopen('/path/to/eq_impulse.txt');
# l = textscan(f, '%f');
# res = l{1};
# freqz(res, 1, 4096, 48000);
#
# It will give the response in Hz; 48000 is the default Output Rate of RetroArch

47
audio/audio_filters/LowPassCPS.dsp Normal file
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@ -0,0 +1,47 @@
filters = 1
filter0 = eq
eq_frequencies = "8000 10000 12500 16000 20000"
eq_gains = "0 -30 -30 -30 -30"
# Low pass filter for the QSound chip from CPS-1/2.
# Some games have aliasing due low quality samples, so you can hear some annoying noisy near 11 kHz
# Defaults
# Beta factor for Kaiser window.
# Lower values will allow better frequency resolution, but more ripple.
# eq_window_beta = 4.0
# The block size on which FFT is done.
# Too high value requires more processing as well as longer latency but
# allows finer-grained control over the spectrum.
# eq_block_size_log2 = 8
# An array of which frequencies to control.
# You can create an arbitrary amount of these sampling points.
# The EQ will try to create a frequency response which fits well to these points.
# The filter response is linearly interpolated between sampling points here.
#
# It is implied that 0 Hz (DC) and Nyquist have predefined gains of 0 dB which are interpolated against.
# If you want a "peak" in the spectrum or similar, you have to define close points to say, 0 dB.
#
# E.g.: A boost of 3 dB at 1 kHz can be expressed as.
# eq_frequencies = "500 1000 2000"
# eq_gains = "0 3 0"
# Due to frequency domain smearing, you will not get exactly +3 dB at 1 kHz.
# By default, this filter has a low pass response with cuttof frequency at ~8600 Hz.
# Dumps the impulse response generated by the EQ as a plain-text file
# with one coefficient per line.
# eq_impulse_response_output = "eq_impulse.txt"
#
# Using GNU Octave or Matlab, you can plot the response with:
#
# f = fopen('/path/to/eq_impulse.txt');
# l = textscan(f, '%f');
# res = l{1};
# freqz(res, 1, 4096, 48000);
#
# It will give the response in Hz; 48000 is the default Output Rate of RetroArch