What are these blocks?

[electricblue]

We’ve just bought a 1930’s semi which is double glazed, but by the looks of things some older aluminium secondary glazing remains. We’re going to take that out, but what are these blocks with holes in between the double and secondary glazing? I assume some sort of thermal bridging? Thanks in advance to anyone who can solve this mystery!

 

[Deleted member 174758]

Cribbage boards?

 

[KenGMac]

electricblue, good evening.

Suggest a google for " Helmholtz resonator sound absorption"

Seen in various locations, such as shooting ranges to dampen the noise.

Ken

 

[JamieB3009]

I would get them checked to make sure they are not asbestos insulation boards before ripping out as they look similar. Given the age of the house it is entirely possible.