[pygame] Why does pygame.sndarray.make_sound seemingly quadruple the sound duration?

[Mike Lawrence]

The following code:

    import pygame, numpy
    pygame.mixer.pre_init(frequency=96000,size=-16,channels=1)
    pygame.init()
    a = numpy.random.randn(96000)
    sound = pygame.sndarray.make_sound(a)
    print sound.get_length()

yields a print-out of 4.0, suggesting that the specified duration of
96000 samples at a 96000kHz sampling rate was somehow quadrupled
somewhere along the way. Any idea what I'm missing here? Or is this a
bug?