One of the most common audio problems in YouTube and social media content is the voice-over-music balance: either the music drowns out the voice, or the music is turned down so far it might as well not be there. The professional solution isn't just about volume levels; it's about frequency separation.
Why volume alone doesn't fix it
Voice and music fight for the same frequency space, roughly 200Hz to 4kHz, where most of the intelligibility and presence of both the human voice and most musical instruments live. When you play them simultaneously at similar volumes, they compete in that range and both sound worse. Simply turning the music down reduces the problem but doesn't solve it. You end up with quiet music that feels like an afterthought.
The professional approach is to make space for the voice in the music's frequency response using a technique called sidechain EQ or, more practically, high-pass filtering the music.
Step 1: High-pass filter the music
Select your music track on the FCP timeline and open the Audio Inspector. Add the Channel EQ effect (Audio Effects → EQ → Channel EQ). In the Channel EQ interface, enable the high-pass filter and set the cutoff frequency to around 200 to 300Hz. This removes the low-frequency rumble from the music that the voice doesn't compete with anyway, cleaning up the overall mix.
More importantly, create a notch in the music's midrange: use a parametric EQ band and reduce the music by about 3 to 6dB around 1 to 3kHz, the exact range where voice clarity lives. This "carves out" space in the music for the voice to sit without the voice needing to be louder to compete.
Step 2: Compress the voice
Compression evens out the level variation in a voice recording so the quieter moments are brought up and the louder moments are pulled back. This makes the voice more consistently audible against the music across all the level changes in natural speech.
In FCP, add the Compressor effect to your voice track (Audio Effects → Levels → Compressor). A ratio of 3:1 to 4:1 with a fast attack (~5ms) and medium release (~100ms) and a threshold set to engage on the louder moments of speech is a good starting point. Reduce the output gain (make-up gain) by as much as the compression adds to keep the overall level appropriate.
Step 3: Set the level balance
After EQ and compression, set your levels: dialogue typically sits at −6 to −10 dBFS peak, and background music at −20 to −25 dBFS while dialogue is playing. The music should be heard but never demand attention when someone is speaking. Check the overall mix on headphones and on a phone speaker. The phone speaker test is particularly revealing because poor voice-music balance is most obvious on small speakers.
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