Knowledge / Room acoustics fundamentals
Why the bass is wrong in one seat and right in the next
Because low-frequency sound in a room this size behaves as pressure, not as a beam, and pressure is not the same everywhere. A 40 Hz wave is over eight metres long. It fills the room, reflects off the boundaries, and adds to or cancels itself depending on where you are standing.
Because low-frequency sound in a room this size behaves as pressure, not as a beam, and pressure is not the same everywhere. A 40 Hz wave is over eight metres long. It does not travel across the room and arrive; it fills the room, reflects off the boundaries, and adds to or cancels itself depending on where you are standing. So one chair sits where the pressure is high and booms, and the chair beside it sits where it cancels and sounds thin. Both seats are hearing the same loudspeaker doing the same thing.
This is why turning it down does not fix it, and neither does EQ. Level and equalisation change what the loudspeaker sends. They do not change where the room puts the pressure. Cut the boom for the middle seat and you take the little bass the outside seat had; boost for the outside seat and the middle becomes unlistenable. A room problem cannot be fixed at the source, which is the single most useful thing to know about bass in a small room.
What does change it is where the energy is absorbed, and that means corners. Pressure is highest where surfaces meet: a corner is two boundaries at once, and the energy has nowhere to spread. A device placed there is sitting in the strongest part of the field it is trying to work on, which is why the Resonance Control Panel is 43 mm and still does work that would otherwise take far greater depth.
How much difference the placement makes is measured, not asserted. The same three panels were tested away from the walls, against one wall, and in the corners they are designed for. At 125 Hz, the corner placement absorbed around two and a half times what the free-standing placement did. Same panels, same room, same test: only the position changed.
What this is not
It is not reverberation and it is not reflection. Decay running too long across the mid band is reverberation; early arrivals blurring the image are reflection. Bass that changes as you move between seats is resonance, and a panel that answers one of the three does not answer the others.
What to read next
How many you need and where they go, a design question rather than a rule of thumb. Or the three problems and the one panel each.