neingeist
/
arduinisten
Archived
1
0
Fork 0
You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
This repo is archived. You can view files and clone it, but cannot push or open issues/pull-requests.

67 lines
1.5 KiB
Python

############################################################
#
# karplus.py
#
# Author: MV (http://electro-nut.blogspot.com/)
#
# Generates a plucked string sound WAV file using the
# Karplus-Strong algorithm.
#
############################################################
from math import sin, pi
from array import array
from random import random
import wave
# KS params
SR = 44100
f = 220
# WAV params
NCHANNELS = 1
SWIDTH = 2
FRAME_RATE = 44100
NFRAMES = 44100
NSAMPLES = 44100*2
# max - 128 for 8-bit, 32767 for 16-bit
MAX_VAL= 32767
class String:
def __init__(self, freq, SR):
self.freq = freq
self.N = SR/freq
# 'pluck' string
def pluck(self):
self.buf = [random() - 0.5 for i in range(self.N)]
# return current sample, increment step
def sample(self):
val = self.buf[0]
avg = 0.996*0.5*(self.buf[0] + self.buf[1])
self.buf.append(avg)
self.buf.pop(0)
return val
str1, str2 = String(196, SR), String(440, SR)
str1.pluck()
str2.pluck()
samples = []
for i in range(NSAMPLES):
sample = str1.sample()
if(i > NSAMPLES/8):
sample += str2.sample()
samples.append(sample)
# samples to 16-bit to string
tmpBuf = [int(x*MAX_VAL) for x in samples]
data = array('h', tmpBuf).tostring()
# write out WAV file
file = wave.open('karplus.wav', 'wb')
file.setparams((NCHANNELS, SWIDTH, FRAME_RATE, NFRAMES,
'NONE', 'noncompressed'))
file.writeframes(data)
file.close()