Both of my OHMs (100S3 and F5) are older refurbed cabinets with no plinth underneath.
Floor interactions are not unqiue to bottom ported OHMS butsomething to take into account.
I use Auralex Subdude isolation platforms under my 100s to manage floor interactions with a floor similar to yours.
FWIW floor interactions proved to be a similar problem for me with other conventional monitor speakers on even heavy quality spiked stands in other rooms on that floor as well, so an issue to get a handle on but not necessarily unique to OHMs. I use isoacoustics pro monitor stands under my small Triangles in that other room and those turned out to be the only stands that worked well enough in there.
Nothing needed under my large F5s in teh basement on carpeted concerete foundation, which served as my reference for getting things on teh upper level under control.
In the end I learned that managing floor interactions is a big key to getting the best sound.
Of course there are many factors that affect room acoustics, floors being only one of them, so each case will be unique and may call for a different approach or in some cases even nothing special at all.
New OHm Walsh cabinets have a plinth built in underneath whereas neither of my OHM Walshes do so that should make for some difference. Others might be able to comment further on those.
Floor interactions are not unqiue to bottom ported OHMS butsomething to take into account.
I use Auralex Subdude isolation platforms under my 100s to manage floor interactions with a floor similar to yours.
FWIW floor interactions proved to be a similar problem for me with other conventional monitor speakers on even heavy quality spiked stands in other rooms on that floor as well, so an issue to get a handle on but not necessarily unique to OHMs. I use isoacoustics pro monitor stands under my small Triangles in that other room and those turned out to be the only stands that worked well enough in there.
Nothing needed under my large F5s in teh basement on carpeted concerete foundation, which served as my reference for getting things on teh upper level under control.
In the end I learned that managing floor interactions is a big key to getting the best sound.
Of course there are many factors that affect room acoustics, floors being only one of them, so each case will be unique and may call for a different approach or in some cases even nothing special at all.
New OHm Walsh cabinets have a plinth built in underneath whereas neither of my OHM Walshes do so that should make for some difference. Others might be able to comment further on those.