The video shouldnât affect the audio.
Hang-on, âloudnessâ gets complicatedâŚ
Note that YouTube and all of the popular streaming services use loudness matching (1) so the loudest part of your audio should (approximately) match the loudest part of everybody else. This is a linear adjustment before playback starts so the quiet parts remain relatively quiet and loud parts remain relatively loud.
Make sure you Normalize or Amplify to âmaximizeâ the digital level. (The âdigital maximumâ is 0dB.) These are linear adjustments (like adjusting the volume control) so as long as you donât âtryâ to go over 0dB it wonât affect sound quality. This should generally be done as the last step.
But, peaks donât correlate well with loudness, so for example, if you peak-normalize all of your music (2) some songs will still be louder than others. Short-term peaks donât sound as loud as sustained loudness and our ears are less sensitive to low & high frequencies, and most sensitive to high frequencies.
Certain instruments (acoustic guitar for example) are highly dynamic. There is a wide range between loud & quiet and if you normalize/maximize it, it will sound quiet compared to most music. Saturated-distorted electric guitar is more âdenseâ and will sound loud when normalized.
Very-deep bass or strong highs can also limit the âloudnessâ. The highs usually arenât an issue unless they are artificial/synthesized.
YouTube (and the others) wonât push the peaks into clipping (distortion) and thatâs probably why you are quieter than everybody else.
YES! Dynamic compression is how you âwinâ The Loudness War! (Although you canât really win with online loudness matching.)
In general, compression lowers the loud parts and/or boosts the quiet parts, pushing everything toward the same volume.
In practice, it usually pushes-down the loud parts and then make-up gain is used bring-up the overall volume.
Limiting is a kind of fast-compression. For âloudnessâ, limiting usually works better than regular compression because there is no delay (no âattack timeâ).
Audacityâs limiter actually uses look-ahead (negative attack time) so itâs very-good and it doesnât distort the wave shape. It also has a make-up gain option.
Compression (including limiting) does, of course, reduce the musical dynamic contrast and if over-done it can make music boring. A lot of people really hate the loudness war for that reason!
Virtually ALL commercial music has SOME compression except for maybe some classical recordings.
Donât confuse dynamic compression with file compression like MP3. MP3 has no effect on the dynamics.
Again, music is pretty boring with no dynamics.
Only if itâs âtoo loudâ and clipping/distorting. And if there are multiple instruments or chords it will be louder whenever there is more than one ânoteâ combined.
(1) Sometimes this is called loudness normalization, but ânormalizationâ usually means peak-normalization which is a âsimple mathematicalâ process with no regard to perceived loudness.
(2) Most commercial music is already peak normalized but some songs are still louder than others.