Playing multiple sounds at once

Introduction

This tutorial will explain different methods attempted in getting multiple sounds to play concurrently using python.

Steps

• Pick wav files desired to be played.
• Load wav files in code and save it to a variable that can be called later.
• Find a line of code that will play the sound.
• Find a line of code that will allow the sound to be played while different notes are being played at the same time.

Libraries tested

• pydub
• multiprocessing
• multithreading
• swmixer
• pygame

Pydub and Pygame

These two libraries were used in finding the best way to play a sound by itself.

Using pydub:

from pydub import AudioSegment
from pydub.playback import play
sound = AudioSegment.from_wav('/home/pi/laserharp-sounds/samples/harpSound1.wav')
play(sound)

Using pygame:

import pygame
pygame.init()
pygame.mixer.init()
firstSound = pygame.mixer.music('/home/pi/laserharp-sounds/samples/ambi_dark.wav')
secondSound = pygame.mixer.music('/home/pi/laserharp-sounds/samples/ambi_choir.wav')
firstSound.play()
secondSound.play()

Multiprocessing and Multithreading

Using Multiprocessing:

from multiprocessing import Process
def play1():
 if(lightlevell > 800):
    s = pygame.mixer.sound.load('/home/pi/laserharp-sounds/1.wav')
    pygame.mixer.sound.play(-1)
def play2():
 if(lightlevel2 > 800):
    s = pygame.mixer.sound.load('/home/pi/laserharp-sounds/2.wav')
    pygame.mixer.sound.play(-1)
processes = []
if __name__=='__main__':
  processes.append(Process(target = play1))
  processes.append(Process(target = play2))
for process in processes:
  process.start()
for process in processes:
  process.join()

Using Multithreading:

from threading import Thread
def play1():
 if(lightlevell > 800):
    s = pygame.mixer.sound.load('/home/pi/laserharp-sounds/1.wav')
    pygame.mixer.sound.play(-1)
def play2():
 if(lightlevel2 > 800):
    s = pygame.mixer.sound.load('/home/pi/laserharp-sounds/2.wav')
    pygame.mixer.sound.play(-1)
threads = []
if __name__=='__main__':
  threads.append(Thread(target = play1))
  threads.append(Thread(target = play2))
for thread in threads:
  thread.start()
for thread in threads:
  thread.join()

Multithreading with Swmixer

from threading import Thread
import swmixer
import os 
swmixer.init(samplerate=44100, chunksize=1024, stereo=False)
swmixer.start()
def play1():
 if(lightlevell > 800):
    a = swmixer.Sound('/home/pi/laserharp-sounds/1.wav')
    swmixer.play(-1)
def play2():
 if(lightlevel2 > 800):
    a = swmixer.Sound('/home/pi/laserharp-sounds/1.wav')
    swmixer.play(-1)
threads = []
if __name__=='__main__':
  threads.append(Thread(target = play1))
  threads.append(Thread(target = play2))
for thread in threads:
  thread.start()
for thread in threads:
  thread.join()

If you choose to use Java, this might be a useful link. It shows how to use Threads to play multiple sounds at once. - Java link

Pygame with Channels

#this is code from the final version of code used to program the Laser Harp. This is saying that if lasers 1 and/or 2 are broken, the wav file associated with that file will be played. 
import pygame
pygame.mixer.pre_init()
pygame.mixer.init()
pygame.init()
if(light_level > 800):  # state 1
  pygame.mixer.Channel(0).play(pygame.mixer.Sound('/home/pi/laserharp-sounds/1.wav'))
if (light_level2 > 800):  # state 2
  pygame.mixer.Channel(1).play(pygame.mixer.Sound('/home/pi/laserharp-sounds/2.wav'))

Final version of code

Link to project

Laser Harp