Vogone's Hi Adjust filter does modify the high frequencies if they are present. If Vogone runs at all, it is working and all parts are working... otherwise it would crash.
If you have tried various discs with female voice for the singer, then the only other variable I can think of is your speakers are not reproducing the high frequencies.
Can you play a CD through Media Player and hear higher frequencies than you hear from Vogone while playing using the High Play button? If not, your speakers and amp may be reducing the bandwidth you can hear. This is a normal problem we run into and may be the reason.