With IQbuds, you can adjust the overall volume of both the left and right bud. These adjustments are made in the Person Profile section of the App.
Below 1KHz, there is one setting (setting 2) that provides some low-frequency boost.
Above 1KHz, there are three settings (3, 4 and 5) that provide a boost in the high frequencies.
It is not possible to adjust the amplification at specific frequencies.