Cabinet insulation

[EFK]

I've seen a number of pictures of old cabs - all closed back, I think - that have ratty looking fiberglass insulation taped or glued around the inside. I think this is supposed to eliminate "standing waves" or other undesirable effects. However, no new cabs seem to do this, at least I haven't seen anything like that from Mojo, Stagecraft, Lopo, Avatar etc. I'm sure there is probably better insulation available with less bulk nowadays, too. So, anyone feel like commenting on insulating vs. not insulating a cab? Also, any point to insulating an open back cab?

[BrianH]

I tried sheets of batting in a closed back 4x12 once. It did add some low end oomph but also made the highs a bit muffled.

[Maverick]

With the advent of particle board backs, the insulation disappeared.

I know that convoluted foam inside the back panel will give more punch to the tone.

[908ssp]

On Marshalls the insulation disappeared a long time before the particle board back. Only the first couple years 64-65 had insulation, 66-71 did not and particle board didn't appear till 71 and later. The earliest cabs had it because they didn't know better.