It could make a difference with cheaper devices also...
I own 12 chinese 10 bucks one, some others few bucks more, around my room....It cost me many times less than ONE Acoustic Revive device...
This S.G. grid add an atmosphere around each instruments and a more encompassing " listener envelopment" impression ... I use also ionizers with great success... This ionizers are way less well known for their audible effect, more subtle than S.G. but anyway it is audible and impossible to disconnect them when you are used to them with S.G.
If temperature change affect room acoustic ionizer too...
BUT in a bad room untreated and un controlled or /and with a system wrongfully matched few people will hear NOTHING and will claim that this is snake oil for sure....All around audio threads...
😁😊