I run Audacity on a mac mini, OS X.10.4 YOSEMITE.

I want to select a portion of a track, and lower the volume/ amplitude of
the selected area. The Amplify Effect only increases the amplitude,
even if I slide the slider to the left. The manual contradicts this. On my mac, the
amplitude only increases, but I need to decrease selections.
Advice is required. Thank you !


You can’t slide the Amplify slider to the left like the attachment? Can you type negative numbers into the number windows?

Which Audacity? We need all three correct numbers. That screen shot is from Audacity 2.1.0.

Screen Shot 2015-08-31 at 13.10.10.png

An alternative to using amplify with a negative value, is to use Audacity’s envelope tool to lower the volume of parts


Thanks for replying.
I have Audacity 2.1.0,
YES I can push slider to the left, and the numbers in the
box change, accordingly,normally.
However, when I apply the effect,
the modification occurs POSITIVELY, even though the
numbers appear -23 in the negative.
I reinstalled this version of Audacity, same response.
So, it is quite mysterious.
I am not familiar with ENVELOPE TOOL.
Perhaps that will be helpful. Also, a friend of mine installed Audacity on his mac YOSEMITE.
He also finds AMPLIFY will not alter tracks into the nefgative. Exactly what I experience.
So, I am stumped by this !

envelope tool !

Trebor provides an interesting window with a video of actions
taken by cursor via ENVELOPE TOOL !
Where can I find this demo video?
I have not found any demo videos via the manual.
In fact, I could not find any reference to ENVELOPE TOOL.

I am a total novice. I realize that I have to go slowly,and first
understand how to use the manual, and how to learn one step
at a time.

For example, the envelope demo shows something that does not match what my
window sees when I click eNVELOPE TOOL.
I know it will be a slow learnig curve, and I don’t want to abuse the forum consultation
by asking too many basic things. It could become tedious and ridiculous.

I don’t want to abuse the forum consultation by asking too many basic things.

We’re not bashful. We’ll tell you when you’re being tedious and ridiculous.

Select the whole track by clicking just above MUTE.
The envelope tool is the two white arrows and bent blue line. That puts blue activity lines above and below your track. Those click and drag (attach) and the sound follows you. Or should follow you.

Screen Shot 2015-09-01 at 12.24.02.png

Back to regular editing with the “I-Beam” tool.

THANKS FOR THE DIRECTIONS. I will play with this and see if I can get a sense of it.


I made that GIF animation myself , a screen-capture from my Windows, (not Mac) computer , ( no sound with GIF ).

No animation/video in Audacity manual. There are unauthorised Audacity video tutorials on YouTube,

The envelope tool section in the Audacity manual is here … Audacity Manual

You have to click on this icon

to use the envelope tool.

Are you using Audacity supplied by us: Audacity ® | Download for Mac OS?

If you apply a negative amplification amount in Amplify, the blue waves get less tall (they are less close to the top and bottom of the track).