Perfect audio balance can be achieved. The question is: Are you leaving it up to YouTube to balance your audio track or do you put the matter into your hand?
Bass Treble Booster is a simple tool for modifying the audio spectrum settings of... you guessed it: audio files. The interface shows a standard equalizer which sets the desired levels and a working list to which you can add multiple files to be modified. That's right, you can modify files in batch.
Bass Treble Booster saves in MP3, FLAC and WAVE formats. So it can also be essentially used for simple format conversion.
FLAC and WAVE formats
The demo version will only work for 10 days. But that's okay since it also only records 2 minutes of audio per operation. The full version is a bit pricey, but if you often see yourself doing conversions and slight audio adjustments, it might just be worth it.