Adjust output level in multiple recordings

Is there any software that will process a number of sound files and adjust their output level so that they are somewhat similar? Processing each one separately is very time consuming.

Thanks in advance.

You can try mp3gain. Here is an old article on it:

I would definately back-up your music first.

You could also use the batch processing facility of Audacity…

I have always used normalize:

Many thanks to all of you. I will try all three suggestions and report the outcome.

I found this method the simplest and most effective. I do prefer working in a console. Invoking

mp3gain -r -k *mp3

made the adjustment swiftly and to my satisfaction.

Thanks again.