Quite often, one piece of technology while solving one problem, creates another unforeseen one. More specifically, while I love listening to MP3’s in the car, I often have problems with the volume. This issue is hardly new, as CD’s were quite often not all produced at the same volume. However, when I listen to an entire CD (which is a rare event lately), once I set the volume knob, it gets to stay there for a while. Most of my MP3’s were made from the actual discs. As I keep my MP3 player in the random shuffle mode, I notice that the volume changes between each track. In some cases, it’s quite substantial as one track is way too low, the next one is too loud, and the next too low again. It can be a jolting experience when using headphones, and downright annoying in the car. Who wants to fiddle with the volume knob for every track? Well, I recently stumbled upon a software utility that promises to fix this issue.

Technically speaking, the process of equalizing the volume of digital music tracks is known as normalizing. The idea is to digitally reprocess the track so that the volume gets set to a specific level. There are many programs that can do this, but I am always concerned that it is altering the original sound file, and could introduce another layer for error and distortion that I’d rather avoid. I recently figured out a way around this concern.

I tried a freeware program known a MP3Gain. Firstly, the program states from their website:

MP3Gain does not just do peak normalization, as many normalizers do. Instead, it does some statistical analysis to determine how loud the file actually sounds to the human ear.

Also, the changes MP3Gain makes are completely lossless. There is no quality lost in the change because the program adjusts the mp3 file directly, without decoding and re-encoding.

OK, this is off to a good start, and sounds like it should get the normalizing job done right. However, I wasn’t ready to send it any original tracks, in case the theoretics didn’t translate into the practical. Rather, what I decided to do was feed it a file, like the one that was on my music player. Having an MP3 player that loads tracks as a mass storage device is a definite advantage here. By designating the files on my flash music player, only those files were adjusted, leaving the originals on the hard drive alone in case things didn’t work out as planned. Good insurance, huh?

The normalizing is done in two steps. First a track analysis is done. Roughly 80% of the files needed adjusting, leaving the other 20% alone. This took about 15 minutes for 400 tracks. Of the 80%, all of them needed a little “volume trimming” to varying amounts; none needed an increase (I’m not sure if the program can accomplish that feat). After the analysis, I hit the track gain button. It is adjustable, but I used the default setting of 89 dB. This took around 10 minutes to complete for the same 400 tracks. I think that the time was based more on the speed of the USB 2.0 connection, than my Athlon 64 3800+ processor.

With all my tracks on the player normalized, I was curios to see if it made any difference. In the end, it’s a lot better, but not quite perfect. Some tracks, like those by The Who, are simply louder in the end. Still, I can go 5 or 6 tracks now with the volume where it needs to be without an adjustment. Also, the volume adjustments are within a narrower range than before and don’t vary by nearly as much. While it is not perfect, I think this task is well worth doing. Also, I detected no errors being introduced, or loss of fidelity in my tracks. For less than a half hour of work, the tracks on my audio player are much improved, and my volume problem is considerably better. I would definitely recommend that this freeware solution be in any audio enthusiast’s bag of audio tricks.
–Jonas

Download here.