WHAT DOES LED ZEPPELIN GOLD RECORDS MEAN?

Now that you choose to mention it, the very first 2 tracks manage to absence very low bass, (in addition to a bass drum strike just ahead of the fade out of Custard Pie). But then “In My Time of Dying” seems to have some additional bass… undecided what was happening here, probably recorded in drips & drabs in several places, although the mid-