loudness Normanization

Don’t let the name of this topic fool you. I’ve been running into issue while making purchase of music from the artist own websites, sites like achive.org, iTune & Amazon. What’s been happening (which I just discovered) is that some sites offer .MP3 downloads while other sites offer .M4A tracks. (M4A tracks sound better than the MP3 tracks) What’s been happening is that the MP3’s would play but sound weak and low. While the M4A files would be very loud. I thought I would test something on Audacity by importing all the music files all at one time to check to “gain” levels on each track as a comparison. But I ended up getting a message saying the M4A file couldn’t be read, Unless I updated the FFmpg file, Which I did. The tracks show the veering level of sound/gain. Some off the charts while others you can barely hear.

In order to correct this, one would need to highlight/.Select the full track using the Ctrl key and your mouse. Then select “Effects” > “Loudness Normalization”. I was able to check the scale/value to -23.0 on the louder tracks and adjust the lower tracks to -13.0. What ended up happening is that both tracks ended up sounding more normal or level with the same gain without any distortion.

Just my tip for the day and I’m happy to have found this option which now allows me to listen to all my music at the same volume level.

There are other solutions -

Some player software supports [u]ReplayGain[/u]. You scan the files in advance and they are “tagged” with a volume adjustment so they play back at approximately the same volume. The actual audio isn’t changed. The volume is adjusted at playback time.

There are also MP3Gain and WaveGain which use the same algorithm to but make “permanent” changes so they work with any player, MP3Gain works directly on the MP3 data without decompressing and then going-through another generation of lossy compression. (But this does limit the adjustment to 1.5dB steps.)

These all have an optional feature of avoiding clipping. If some “quiet sounding” tracks can’t hit the target volume without clipping it will just be boosted as much as possible without clipping.

Apple has something similar called [u]Sound Check[/u]. Turn on Sound Check, and all of your files will play back at (approximately) the same volume.

I was able to check the scale/value to -23.0 on the louder tracks and adjust the lower tracks to -13.0.

. That’s not how it’s supposed to work. The setting is a target volume so if you set it to -23dB all of the tracks should be adjusted up or down to -23dB and they should be the same. (If you adjust to -13dB, some songs will clip.)

M4A tracks sound better than the MP3 tracks

That’s not ALWAYS true. M4A (aka MP4 or AAC) was intended as an improvement to MP3 but a highly compressed (low bitrate) M4A can sound worse than a less-compressed (high bitrate) MP3. Or at high quality settings, both formats can sound identical to the uncompressed original, or it can be very difficult to hear the difference (in a proper scientific, blind, listening test).

But, M4A is immune to multiple generations of compression whereas with MP3 some damage accumulates every time it’s re-compressed. When you open a compressed file in Audacity (or any regular audio editor) it gets decompressed, if you re-save in a lossy format you are going through another generation of compression and, if possible, you should avoid that with MP3s. (Sometimes you don’t have a choice.)

@DVDdoug I’ve tested or tried to test the ReplayGain & MP3Gain and none of those worked for me. I noticed one of your short videos about pod casting and thats how I learn about using the Loudness Normalization tool. It took me about 1 hour to adjust 30 sounds. But in order to test my theroy, I uploaded 5 tracks onto a USB flash drive and took the drive out to our car which is set up to play from the Flash.

When compared to a unaltered flash drive, the newly adjust tracks sounded 10x better without any distortion. But I will admit that more of the tracs that needed adjustment were the MP3’s. As you said all of these tracks started out at -23 so I had to reach an adjustment range of between -5 & -8 in order to get the MP3 tracks to soud respectable.

What ever I did while using the loudness normalization… I can now hear those tracks where as I could bearly hear them before. Today, we’ll be on the road with my newly and better sounding tracks and I’ll report back later with my findings.

just got back from our short trip. I made two USB flash drives one with the unaltered tracks & the other with the altered tracks using Audacity “loudness Normalization” option. what a differance. Using this option allows me to lower the M4a files and raise the MP3 files so that both balance out at the same gain level without distortion.
Again i’m not expert at this and took a chance just to see if this would work. If you’ve never experance what we went through… try to locate soem tracks from Amazon etc and tracks from the artist home page or sites like archive.org or even bandcamp. 9 out of 10 the MP3 tracks are low and weak sounding as compared to the M4A tracks.
I’m glad I was able to correct this.

However another issue not related to the Audacity software. I was sent a CD from one of my Ambient Artist friends… for months the cd would play until windows 10 updated soemthing. Now any player I use, be it window media or VLC etc the CD will not play. This same thing happen to my wife’s endless country music CDs. I fear that soem coding on the CD has change isn’t recegived anymore with the win10 update. The CD actually turns and the counter ticks down etc… but there’s no music.