Difference between high and low frequencies usually have to do with the interpolation.
The difference between high and low bitrates is always prominent… differences between various bit-rate images tell you exactly what.
To show you difference between dithering and none-dithering, i think Bantai’s post will help you out the better understanding: http://www.renoise.com/board/index.php?sho…mp;#entry149611
Regarding differences in bitrate and frequency quality in any host regarding plugins is something you should be cautious with if plugins do not support e.g. 96Khz but are forced to play that rate, the audio coming out goes twice as slow…