Been working on audio

[Kyle Gagner]

I wrote some code to help me generate wave files. Down at the bottom is an example which will run if you run the script. It takes a while... Reasonably good bass sound for my first attempt?

import wave
import struct
import math
twopi=2*math.pi #2*pi

class Writer: #Writes .wav files
   def __init__(self,name,channels=1,bytespersample=4,framerate=44100):
       self.file=wave.open(name,'wb')
       if bytespersample==4:
           self.convert=struct.Struct('<i')
       elif bytespersample==2:
           self.convert=struct.Struct('<h')
       elif bytespersample==1:
           self.convert=struct.Struct('<b')
       self.multiply,=self.convert.unpack(((bytespersample-1)*b'\xFF')+b'\x7F')
       self.file.setparams((channels,bytespersample,framerate,0,'NONE','noncompressed'))
       self.buffer=b''
   def Write(self,value):
       self.buffer+=self.convert.pack(int(value*self.multiply))
       if len(self.buffer)==4096:
           self.file.writeframes(self.buffer)
           buffer=b''
   def Close(self):
       self.file.writeframes(self.buffer)
       self.file.close()
class Oscillator: #Base class for wave generators
   def __init__(self,framerate):
       self.framerate=framerate
       self.accumulator=0
   def Sample(self,frequency):
       self.accumulator+=frequency/self.framerate
       if self.accumulator>0:
           self.accumulator-=1
       return self.Wave(self.accumulator)
class SineGenerator(Oscillator): #Sine wave
   def Wave(self,at):
       return math.sin(twopi*at)
class RampGenerator(Oscillator): #Ramp wave
   def Wave(self,at):
       return 2*(math.fmod(at,1)+.5)
class SawGenerator(Oscillator): #Sawtooth wave
   def Wave(self,at):
       return 2*(-math.fmod(at,1)-.5)
class SquareGenerator(Oscillator): #Square wave
   def Wave(self,at):
       if math.fmod(at,1)>-.5:
           return 1
       else:
           return -1
class TriangleGenerator(Oscillator): #Triangle wave
   def Wave(self,at):
       if math.fmod(at,1)>-.5:
           return (at+.25)*4
       else:
           return (math.fmod(at,1)+.75)*(-4)
class LowPassFilter: #Cuts out high frequencies from a signal
   def __init__(self,framerate):
       self.framerate=framerate
       self.value=0
   def Sample(self,frequency,value):
       rc=1.0/(twopi*frequency)
       a=1.0/(self.framerate*(rc+(1.0/self.framerate)))
       self.value=self.value+(a*(value-self.value))
       if self.value>1:
           self.value=1
       elif self.value<-1:
           self.value=-1
       return self.value
class HighPassFilter: #Cuts out low frequencies from a signal
   def __init__(self,framerate):
       self.framerate=framerate
       self.value=0
       self.old=0
   def Sample(self,frequency,value):
       rc=1.0/(twopi*frequency)
       a=rc/(rc+(1.0/self.framerate))#1.0/(self.framerate*(rc+(1.0/self.framerate)))
       self.value=a*(self.value+value-self.old)
       if self.value>1:
           self.value=1
       elif self.value<-1:
           self.value=-1
       self.old=value
       return self.value
class BandPassFilter: #Cuts out frequencies outside of a certain range
   def __init__(self,framerate):
       self.highpass=HighPassFilter(framerate)
       self.lowpass=LowPassFilter(framerate)
   def Sample(self,lowfreq,highfreq,value):
       return self.lowpass.Sample(highfreq,self.highpass.Sample(lowfreq,value))
class BandRejectFilter: #Cuts out frequencies inside a certain range
   def __init__(self,framerate):
       self.highpass=HighPassFilter(framerate)
       self.lowpass=LowPassFilter(framerate)
   def Sample(self,lowfreq,highfreq,value):
       return (self.lowpass.Sample(lowfreq,value)+self.highpass.Sample(highfreq,value))/2
class Misc: #Miscellaneous
   toneclasses = {'A':0,'B':2,'C':3,'D':5,'E':7,'F':8,'G':10}
   def Note(notation): #Turn a musical note (A4 Bb3 D#2 etc...) into a frequency
       if (notation[1] == '#'):
           marker = 1
           octave = int(notation[2:])
       elif (notation[1] == 'b'):
           marker = -1
           octave = int(notation[2:])
       else:
           marker = 0
           octave = int(notation[1:])
       return 440*(2**((Misc.toneclasses[notation[0]]+marker+(12*(octave-4)))/float(12)))
fr=44100 #framerate
write=Writer("Testwave.wav",framerate=fr) #file
#waves and filters
main=TriangleGenerator(fr)
mod=SineGenerator(fr)
filt=LowPassFilter(fr)
wub=SineGenerator(fr)
low=SineGenerator(fr)
saw=SawGenerator(fr)
wow=TriangleGenerator(fr)

for n in range(44100*6): #write 6 seconds of sound
   t=math.fmod(n/44100,3)
   if n%44100==0:
       print(n/44100)
   if t<3/4:
       freq=Misc.Note('A2')
   elif t<6/4:
       freq=Misc.Note('G1')
   elif t<9/4:
       freq=Misc.Note('A2')
   elif t<11/4:
       freq=Misc.Note('B2')
   else:
       freq=Misc.Note('C2')
   fpass=((wub.Sample(4)*2.5)+3)*freq
   a=main.Sample(freq+(freq*.2*mod.Sample(freq*4.7)))*4
   if a>1:
       a=1
   elif a<-1:
       a=-1
   b=saw.Sample(freq+(freq*.8*wow.Sample(freq*2.4)))
   write.Write(filt.Sample(fpass,(a+b)/2)) #add sample to the file
write.Close() #close the file

Edit: I see it murdered my indentation, E-mail me if you want the code.
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