playback volume low

I am using Audacity to record some individual audio files as they play on my computer. I am using the same settings for all files, both on my computer and in Audacity. As I listen and record, all these files seem to be at the same volume.
Almost all the finished recordings have excellent playback volume, but a few have low volume.
I will have to re-record the low volume files (that’s OK…they are short). Is there a setting beforehand, or an edit afterward that will create finished files with higher volume?
Thanks in advance.

I will have to re-record the low volume files (that’s OK…they are short).

Assuming you don’t have some kind of “serious problem” that’s also causing sound quality problems… No! Just run the Amplify effect to amplify after recording.

It’s better to record a little low to leave some “headroom” to avoid clipping (distortion), and then boost the volume later.

You can also enter an negative dB number into the Amplify effect to reduce the volume. (So, you are attenuation instead of amplifying.)

Is there a setting beforehand, or an edit afterward that will create finished files with higher volume?

There is a [u]Recording Volume Control[/u] and a [u]Recording Meter[/u] but depending on what you’re recording from, sometimes you can’t adjust the recording volume.

Perceived loudness is “complicated” and you can’t always go-by the the meters.

…If you’re still having trouble, give us more details about what you’re recording and how you are recording.

Obviously I am new to Audacity…I am slowly understanding more.
What is the difference between Amplify, Normalize, and Loudness Normalization?
Assuming all of these would be applied to the recording afterward…is Amplify what I need?
Looks like there might be some trial and error to get the volume right.
I should have listened to the recording before I exported it.

This is a very good question. Here are links to the three for easy reference:
Amplify
Normalize
Loudness Normalization

They all do pretty much the same thing. Amplify by default will amplify to maximum permissible without distortion, but it assumes there is no DC offset introduced by the recording equipment (you can’t hear DC offset). See also: Amplify and Normalize

However, one extremely loud noise or clap or gun shot in a recording can force the remainder to an unacceptable low value. More commonly, the absence of dynamics could force a recording to be unacceptably loud (think commercial). “The perception of loudness is related to sound pressure level (SPL), frequency content and duration of a sound.” - See Loudness

Amplify worked for me. I found that I needed to add the suggested amount, to bring it up to 0.0.
Audacity is an amazing program!
Thanks for your help!