Lowering audio's "highs"

I am listening to an instructional audio and every 10-15 seconds, the speaker’s volume, very briefly, rises above a level I find comfortable listening to. How can I lower the “highs”? Related to that, how can I know how much to lower the highs? I am a novice using Audacity.

Also, the audio is an MP3. If I want save my changes, should I export it as MP3? If so, what export settings should I use?

Thanks,
Howard

Try using the Limiter effect http://manual.audacityteam.org/man/limiter.html

Reducing the peak level by 6 dB is equivalent to reducing the level by half. So, if you first Normalize (http://manual.audacityteam.org/man/normalize.html) to 0 dB and then set the Limiter to:
Type: Soft Limit (default)
Input Gain: both 0 (default)
Limit to (dB): -6
Hold: 10 (default)

and that will reduce peaks that are over -6 dB down to -6 dB.

Steve,

The audio is an MP3. If I want save my changes, should I export it as MP3? If so, what export settings should I use?

Howard

MP3 is a lossy format : there is accumulative damage by repeatedly using MP3.

If you must make an MP3 of an MP3 use the highest quality settings to minimize the loss.

Loss-less formats like WAV & FLAC are the best quality, but their file size is ~10x larger than MP3.