Beaten to it. bah!


Actually 80dB  is not an especially  onerous a spec,  a biscuit tin soldered shut round the seam will do that, until you start adding penetrations for services - do you need water, vacuum or gas  for example, or mains or lights?

Of course they do not make biscuits that big, as they would be hard to eat, and dashed tricky to cook as well probably, but you get the idea.


I'd suggest you chat to one of the suppliers of off the shelf solutions such as ETS Lindegren or MDL or visit someone with a chamber and just look at it.

If you have an excess of labour over budget (university dept for example) I know a few outfits have successfully built their own.

At that spec you could have up to about a foot square or so of "double glazed"  (i.e. 2 layers of mesh about an inch apart) mesh window to peer through if you like mesh


Do you need it to be absorptive of RF or is internal reverberation acceptable ?


The former requires absorbent material to be placed and tuned for the bands of interest, and for wide bandwidths you have to accept a very small quiet spot where it is properly anechoic .


A reverberation chamber however is just a metal box. Our 4m cube one is double skinned 1,2mm thick tinplate laminated on either side of 25mm plywood in sections bolted with gib strips and mesh inserts in the joins to make the walls floor and roof , as this allows them to contain a reasonable blast if something fails, absorbing energy by splintering the wood, as well as stopping photons long and short with the metal.

Door seals will indeed be meander channel and finger stock finger stock  door seals   . The force to close is considerable, if more than about 1m by 2m they will probably need gas assist to shut properly - fingers out !.

What is your peak power handling - will it need air extraction or cooling water ? (honey comb is the key for air, and consider waterpipes as dielectric loaded waveguides to set your maximum diameter If you need a lot  of water and so need large bore pipes, consider an all metal plumbing circuit and  heat exchanger so that the water going outside is fully shielded from the live water inside) .

Note that lights will need to be behind mesh, especially if you are doing EMP work - or the lights tend to blow out during testing. That is not an issue at low powers - but if you need a quiet room for listening tests then consider filament lamps powered by DC as less likely to radiate and interfere with measurements.


You may need ramps to get heavy things over the door sills and a pulley in the roof centre for setting up tall stuff.

If there are cables in and out for instrumentation and command  they should leave through a single access panel (or if there must be two they should be in the same side please ) that can be removed to have filtered bulkhead connectors or a small box fitted to either side of it for each wire to be filtered and trapped.  Do not let anyone drill right through the walls, or bring an untrapped wire in, so make it easy to do it right by making good provision.

An emergency call switch can be string pull through a meander line of metal tube in good electrical contact with the wall as it penetrates, wiring outside, string on inside.  No telephone unless in a shielded box that stays shut during tests !.


Once many experiments have had a go, and the access panel looks like a Swiss cheese  it can be replaced with a new piece of plate  for modest cost and the chamber is as good as new..



just some out of order ideas - are you able to say what is it for ?

light reading

Beaten to it. bah!


Actually 80dB  is not an especially  onerous a spec,  a biscuit tin soldered shut round the seam will do that, until you start adding penetrations for services - do you need water, vacuum or gas  for example, or mains or lights?

Of course they do not make biscuits that big, as they would be hard to eat, and dashed tricky to cook as well probably, but you get the idea.


I'd suggest you chat to one of the suppliers of off the shelf solutions such as ETS Lindegren or MDL or visit someone with a chamber and just look at it.

If you have an excess of labour over budget (university dept for example) I know a few outfits have successfully built their own.

At that spec you could have up to about a foot square or so of "double glazed"  (i.e. 2 layers of mesh about an inch apart) mesh window to peer through if you like mesh


Do you need it to be absorptive of RF or is internal reverberation acceptable ?


The former requires absorbent material to be placed and tuned for the bands of interest, and for wide bandwidths you have to accept a very small quiet spot where it is properly anechoic .


A reverberation chamber however is just a metal box. Our 4m cube one is double skinned 1,2mm thick tinplate laminated on either side of 25mm plywood in sections bolted with gib strips and mesh inserts in the joins to make the walls floor and roof , as this allows them to contain a reasonable blast if something fails, absorbing energy by splintering the wood, as well as stopping photons long and short with the metal.

Door seals will indeed be meander channel and finger stock finger stock  door seals   . The force to close is considerable, if more than about 1m by 2m they will probably need gas assist to shut properly - fingers out !.

What is your peak power handling - will it need air extraction or cooling water ? (honey comb is the key for air, and consider waterpipes as dielectric loaded waveguides to set your maximum diameter If you need a lot  of water and so need large bore pipes, consider an all metal plumbing circuit and  heat exchanger so that the water going outside is fully shielded from the live water inside) .

Note that lights will need to be behind mesh, especially if you are doing EMP work - or the lights tend to blow out during testing. That is not an issue at low powers - but if you need a quiet room for listening tests then consider filament lamps powered by DC as less likely to radiate and interfere with measurements.


You may need ramps to get heavy things over the door sills and a pulley in the roof centre for setting up tall stuff.

If there are cables in and out for instrumentation and command  they should leave through a single access panel (or if there must be two they should be in the same side please ) that can be removed to have filtered bulkhead connectors or a small box fitted to either side of it for each wire to be filtered and trapped.  Do not let anyone drill right through the walls, or bring an untrapped wire in, so make it easy to do it right by making good provision.

An emergency call switch can be string pull through a meander line of metal tube in good electrical contact with the wall as it penetrates, wiring outside, string on inside.  No telephone unless in a shielded box that stays shut during tests !.


Once many experiments have had a go, and the access panel looks like a Swiss cheese  it can be replaced with a new piece of plate  for modest cost and the chamber is as good as new..



just some out of order ideas - are you able to say what is it for ?

light reading