Now you point out it, the 1st two tracks manage to absence lower bass, (other than a bass drum strike just before the fade away from Custard Pie). But then “In My Time of Dying” appears to have some additional bass… not sure what was going on below, likely https://emiliokaqfu.boyblogguide.com/26405313/a-simple-key-for-led-zeppelin-gold-records-unveiled