At first, you have to open the MP3 or other audio or video file. To do that press on the "Open" button on the toolbar or select "Open" from the "File" menu.
You can also drag and drop the audio or video file to open it.
Step 2 - Select which part to adjust
Secondly, mark which part of the MP3 file you want to adjust.
You can do this by selecting the part of the MP3 file's waveform.
Alternatively, if you know the start and end time or duration of the desired part, enter the start time, end time or duration in the appropriate text boxes.
To select the whole MP3 file, press Control-A or click on "Select All" of the "Edit"->" Select" menu.
Step 3 - Use the Equalizer Screen
Now select "Equalizer" from the "Effects" menu.
Then you can select a preset such as "Classical","Club","Dance","Rock","Pop" e.t.c. or you can set which frequencies to amplify directly.
Use the sliders to set the value of decibels by which each frequency will get amplified.
To show even more frequencies press on the "More Frequencies" button.
To save the current settings as a new preset, enter a preset name in the "Preset" button and press on the "Save Preset" button.
To delete a preset, select it first and then press the "Delete Preset" button.
You can also set the bandwidth and the method to specify the bandwidth of the filter.
Moreover, it is possible to set the maximum and minimum value by which the frequencies will get amplified.
Finally, press on the "OK" button.
Step 4 - Specify Output Format Settings
Press on the "Output Format" button to specify various output format settings or leave the default ones.
Step 5 - Get the Result
Lastly, select "Save Whole Clip" from the "Cut" menu to get the result file.
In case, you want only a part of the MP3 file, after selecting it, you can choose also "Cut Only Selection" from the "Cut" menu.