Pygame Sounds manually building buffers.

sounds.py

import pygame
from itertools import cycle
import math

RESOLUTION = (800, 800)
BITS = 16
MAX_SAMPLE = 2**(BITS - 1) - 1

LEFT_FREQUENCY = 0
RIGHT_FREQUENCY = 450


def left_sample(time):
    result = int(MAX_SAMPLE * math.sin(2 * math.pi * LEFT_FREQUENCY * time))
    print(result)
    return result


def right_sample(time):
    return int(MAX_SAMPLE * .5 * math.sin(2 * math.pi * RIGHT_FREQUENCY * time))


pygame.mixer.pre_init(44100, -BITS, 2)
pygame.init()
display = pygame.display.set_mode(RESOLUTION)

duration = 1.0

sample_rate = 44100
n_samples = int(duration*sample_rate)

buffer = bytes()
for s, f in zip(range(n_samples), cycle([left_sample, right_sample])):
    for b in abs(f(s/sample_rate)).to_bytes(2, byteorder="little"):
        buffer += b.to_bytes(1, byteorder="little")
print(buffer)
sound = pygame.mixer.Sound(buffer=buffer)

sound.play(loops=-1)

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

pygame.quit()