Ear Test using MATLAB
First of all - don't use 80kHz (I don't know why you came up with this number as a limit for MATLAB, whereas it is 1e6 in fact) but something that is more reasonable and standardized, i.e. 96kHz (or 88.2kHz if you wish...). Another thing is that your sound card might not be able to serve such high sampling frequency. You should check that in playback options --> Advanced tab and set it correctly. Last thing - you should drop using obsolete sound and use audioplayer - unless you use some ooold MATLAB.