This has been determined to not be a fault of the software, but is an open
issue nonetheless as it still directly affects the experiment.
On iMac computers running 10.9.3 or higher, the volume begins to rise in
amplitude over the course of a trial. This occurs on trials using an IOI of
roughly 500 and higher.
This is not at fault of the software because internal recordings of the audio
being produced reveals no crescendo in the waveform. Furthermore playing back
the recording on other Apple computers and PC's also reveal no crescendo, while
the same recording played back on the newer iMacs again reveal the crescendo.
As far as we can test, this phenomena only affects iMacs built on or after
2013. We ran the audio file with few Macbook Airs running 10.9.4 and heard no
crescendo. Most likely this is a hardware issue, but there is not enough
evidence to confidently rule out the operating system.
Attached is a word document outlining the issue with embedded pictures of the
waveforms of internal and external recordings of IOI 800, an internally
recorded audio file for IOI 800, and two audio recordings of the same trial;
the internal recording of IOI 600, and the external recording heard on the iMac
of IOI 600.
Original issue reported on code.google.com by kgau...@gmail.com on 14 Aug 2014 at 10:32
Original issue reported on code.google.com by
kgau...@gmail.comon 14 Aug 2014 at 10:32Attachments: