This is Relative Waves, a log of CD waveform comparisons.
The purpose of this blog is to identify and illustrate differences between different pressings of a CD. In my personal collection, I try to find the earliest pressing of a CD. There are times I will buy a replacement CD without being certain as to whether it is better or worse than the one I already have. To assist in that determination, I wrote a software utility that will create images of waveforms that can be overlaid to see the differences. This utility is CDWaveform and is open-source and free.
As I was testing my utility, I did comparisons using a moderate collection of duplicate CDs. These provided good examples of different masterings used by different CD manufacturing plants. As I continue to create these waveforms, I will post up comparison images and give links to download the waveform data files so you can use CDWaveform to compare them to your CDs.
Since the waveforms only illustrate amplitude variances, they can’t definitively identify when an album has been remastered poorly, except in cases where the result is brickwalled. Equalization differences can make one version sound boomy or too sibilant. In cases like that, you get into subjective “better” or “worse”. Some people like it boomy, some don’t.
Beginning in April 2018, CDWaveform was improved to give a graphic of summed frequencies on the album. It’s not spectral or anything fancy. It just has the basic function of illustrating when the EQ is different between pressings. Of course louder pressings will be greater along the entire spectrum, but you’ll get the right impression from looking at the results. It’s not meant to be overly analytical.