Adjusting volume on several audio files

[Moti]

Hello Forum,
My OS is windows 7 pro Sp1, (home pc), Audacity version 2-1-2
Starting to make a music cd for quiet listening when going to sleep, gathered some 40 mp3 files, each one has its own volume,
some high - have to adjust the player, some low - have to adjust the player again. Is it possible with this program to bring these files to some uniform volume level, may be not all 40 at once but 5 or 10 at a time.
I hope to get some answers, so I can go on making the cd.
Answers will be appreciated.
Thanks
Moti

[DVDdoug]

Try MP3Gain.

MP3Gain will automatically match the perceived volumes using the ReplayGain Algorithm. And, it works without decompression/re-compressing the files.

may be not all 40 at once but 5 or 10 at a time.

You can drag-and-drop all 40 into MP3Gain at once. Make sure you're set-up for Track Gain (not Album Gain). Album Gain will adjust all of the songs by the same amount instead of to the same amount.

Since many songs, including many quiet sounding songs are already normalized/maximized, any method you use to match volumes will reduce the volume of the louder songs... So don't be surprised if overall, your songs sound quieter.

Starting to make a music cd for quiet listening when going to sleep, gathered some 40 mp3 files

A regular audio CD has a maximum playing time of about 80 minutes, so you can't fit 40 (typical-length) songs on an audio CD.

You can burn the compressed MP3s files directly on the disc as "data" (with 5-10 times the playing-time), and the CD will play on your computer, on some car stereos, and on most DVD or Blu-Ray players. But, a regular audio CD player won't play MP3 files.



About MP3...
As you may know, MP3 is lossy compression and audio CDs are uncompressed PCM (the same underlying format as WAV files). Most CD burning software can make an audio CD from MP3s, but if you want a regular audio CD, it's better if you can use uncompressed originals.

When you open an MP3 (or other compressed format) in Audacity (or any "normal" audio editor) it has to be decompressed. If you re-save (export) to MP3 it has to go through another generation of lossy compression. So if you want to use MP3s, it's best to start with an uncompressed file (or lossless file). Or, if you don't have an uncompressed original, try to minimize the number of times you compress it.

A good quality (high bitrate) MP3 can often sound identical to the uncompressed original. But, it's "good practice" to avoid unnecessary lossy-compression.

[Motim]

Hello,
Thanks for the detailed answer.
I'll give this MP3Gain program a test after installation.
Question: I use Audiograbber to rip some of my music cds, what wav kind to save, 16 bit or 32 bit.
Thanks for answering
Motim

[Gale Andrews]

I use Audiograbber to rip some of my music cds, what wav kind to save, 16 bit or 32 bit.

32-bit (float or integer) is twice the size of 16-bit, but 16-bit and 32-bit are lossless and should sound identical for a CD rip. Standard audio CD's are 16-bit, and you don't make them better by upconverting to 32-bit WAV.

So I suggest 16-bit, unless the rips are for editing in Audacity and Audiograbber saves as 32-bit float. In that case there may be trivial benefits in ripping as 32-bit float.

Gale

[DVDdoug]

Question: I use Audiograbber to rip some of my music cds, what wav kind to save, 16 bit or 32 bit.

If you are making an audio CD you can skip the MP3 conversion and use WaveGain.

[Motim]

Hello,
Thanks for all the answers.
I gave a try with MP3Gain, and it works good enough for me, and what's more - do not have to install it.
Thanks again.
Motim