2.5mm linoleum passes through bass and mid frequencies

This was listened while moving a small Roberts portable radio outdoors.


Then placing a small 7in x 10in linoleum sheet between radio and ear.


It was tried on FM music broadcasts as well as in FM broadband noise.


Linoleum at such thickness stops HF while transiting mid and low frequency content.


This is sound insulation.


Sound absorption is a different matter. It should absorb bass and mid content due to elastomer deflecting hysterisis loop heat dissipation.


So once a box of linoleum is made and a speaker drive unit is mounted on front panel (see linoleum Pleiades Auratone 5C type fullrange monitoring speaker):


Not much trapped energy should be inside as mid, low frequency content escape.


What is left inside must be prevented from reverberating a lot due to membrane (panel) elastomer absorption.


The cubic speaker box can be felt to vibrate a low frequencies and this may be a reason why bass sounds adequate possibly due to the higher vibrating surface area.