Is the 1”/2.5cm air gap between subs and bottom of sofa an absolute requirement or can the sub work if perhaps the bottom material of the sofa is completely covering the sub??

The material has some give upwards, ie it’s not a hard fixed base of the sofa that is pressing onto the sub. 
 

Whilst it may not be ideal I’m trying to work out how much it will impact the sound having no airflow around the sub

thanks for your advice and thoughts - oh and “put it out in the open cos it’s beautiful” isn’t really going to help me. Wife wants it hidden and trying to keep everyone happy. 
 

thanks