WHAT DOES LED ZEPPELIN GOLD RECORDS MEAN?

Now that you simply mention it, the 1st 2 tracks manage to lack lower bass, (besides a bass drum hit just prior to the fade out of Custard Pie). But then “In My Time of Dying” seems to have some a lot more bass… not sure what was occurring listed here, in all probability recorded in drips & drabs in numerous places, however the mid-variety is