Embedded rumble... on LP's that is...

Nice system! White is a lovely color for audio gear, isn't it?

There were many records in the old days with a very low frequency rumble that was due to (uneven cooling I think in) the pressing process. Many preamps/receivers of the day came with what were euphemistically called "rumble filters" ;--)

But "high frequency reverb"? Do you mean "feedback"? I ask because high frequencies don't reverberate (either naturally in space, or through artificial electronic means), so I'm trying to figure out just what it is you're hearing.

If I had to guess, and since it only occurs in that one inter-band space, I'd guess it was electronic feedback that somehow got into the final master tape or the cutting process itself.

I've never heard what you describe -- what you often hear on older records is the faint sound of tape print-through just before the next band actually starts.
.

Low frequency rumble can come from lots of things. Some of the old RCA Living Stereos made in London have rumble from the underground (subway). Air conditioners can cause it, so can truck traffic outside the recording venue. This is 'audible rumble' that is easily heard if you have speakers which do deep bass. Not a clue what the high pitched sound might have been - not something I have experienced.

Nsgarch, FWIW a rumble filter principal purpose was to reduce the amount of low frequency resonance (in the inaduble regions) caused by mis-matched mass and compliance issues involving cartridges and tone-arms. The most obvious evidence of such rumble was watching the woofer cone flutter away even there was little apparent bass in the music. The driver is trying to reproduce those 7hz+/- frequencies and soaking up a lot of amp power doing so to the detriment of the audible frequencies. The rumble filter could help, but not solve, the mis-match. Don't know why manufacturers dropped them - maybe its because since most vinyl systems are now used by very knowlegable set up folks its not the issue it used to be for the plug and play croud.

Newbee, I thought that was subsonic filtering, taming the woofer's untimely excursions.