No open top plant pot (made from ceramic, plastic, or anything else you can dream up can be a Helmholtz resonator @ddude003. But a ceramic, glass, steel, etc.
bottle where the bottle volume and small port opening are tuned to the desired resonant frequency can be. Of course sticking a few real or fake plant stems in the small port mouth of your Helmholtz jar would ruin its tuning and function as a resonant trap. And even if we just stuck to the tuned bottles themselves we'd need a bookshelf full of them on each of the problematic walls in order to achieve a useful degree of absorption of that offending frequency associated with the SBIR suck-out.
As for those cable elevators- For the portion of the low level interconnect cable runs to my active loudspeakers which runs in parallel with the power cords to each speaker, the signal cables are strung across $.50ea 6" tall plastic stands (used to neatly space out steel rebar in poured concrete construction)...
This ensures that the low level signal cable doesn't end up with 60Hz induced hum from the high current AC power cable running in parallel beneath it.
