make loud noises quieter


First, my apologies, my question has probably been asked before, but I can’t find a thread - probably because I don’t know the correct terminology to search for.

I have an audio import from a blu-ray movie that import to several mono tracks. I mixed and rendered to one track, and have exported to mp3, so I can listen to the audio on my iPhone (it’s a foreign film, and I’m learning the language).

My problem.
When I am in the car, I can just barely hear the audio at full volume. But then BAM - a dog barks or someone in the film slams a door and the noise pops my eardrums because it’s so loud! The waveform looks like the snapshot here:

What can I do to (most importantly) get the extra loud sounds to be be softer, quieter, so they don’t kill my ears, and (less important) make the normal volume of the speech a little louder?

I’m an extreme noob, but I tried “compression”, and “normalize”, and ended up with an MP3 that is even harder to hear, when in the car - though the sudden, extreme noises are bearable.

Thanks in advance! (and thanks for the great software, audacity team!)


I have an audio import from a blu-ray movie that import to several mono tracks.

What did the original audio tracks sound like and how did you rip them? Based on DVD technology, one of those tracks should have been the Center track with all the dialog on it. DVDs have another interesting technology that everybody glosses over. Movies have an effects technology that punches things like explosions (and car doors slamming and dogs barking) to make the home experience as much like the theater experience as possible.

Final Cut and DVD Studio Pro have the technology to use those effects, but nobody ever does in home movies, so the prevailing wisdom is adjust it so it’s out of the way and forget about it. You can’t forget about it in commercial DVDs because the studios use it and it’s baked in.

There is another problem that’s working against you. As the technology progresses, the studios make it harder and harder to rip shows.

We have a BluRay player at work that has “normal” stereo outputs for inclusion into non-advanced households and I know it works with “normal” DVDs, but I don’t know what happens when you play a BluRay disk. That may be one escape. Record from the player rather than trying to rip the data.

Or you could have a broken disk. I’ve seen DVDs with highly messed up sound tracks.


If it’s multi channel surround-sound there will be a low frequency bassy channel, including that channel in your mix at the same level as the other channels may explain why bassy sounds are extremely loud in your mix. You can use the level slider (I’ve marked it green on your image below) to adjust the level of each track in the mix. Cut back the level of the dog-bark door-slam channel before saving the mix as MP3.

You’ve cut off the time scale, so we can’t judge the attack from the image.
However the amplitude scale is shown and parts of the waveform are beyond +/- 1.0 (it shouldn’t do that).

If you use Audacity’s “Amplify” (in “Effect” menu) on default settings, it will reduce (sic) the amplitude of the waveform so none of it is beyond +/- 1.0 , (the red lines I’ve drawn on your image). .

Then you could apply dynamic range compression to make the loud bits quieter and quiet bits louder.
Chris’s dynamic range compressor is better then the compressor which is shipped with Audacity.