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For sure - dipoles behave different in coupling/exciting the room modes as monopole speakers (boxed speakers) do - move them away from the back wall - this will increase LF output due to better exitation of the lower room modes. I respectfully submit that bending wave transducers are not dipoles, they are bipoles.The whole cancellation effect of dipole operation at lower frequencies is out the window, so to speak with dipoles. On the other hand with bending wave bipoles, Bending waves on the rear surface will be in phase with the front surface. It's just a matter of careful dampening at the the edges of the board to retard reflections back to the epicenter without impeding edge motion too much. The edge is where the most travel of board takes place, thus providing the highest amplitude of lower frequencies. Mounting a bending wave transducer can be a tricky situation. Thats why many of us have reported that lifting the board from the floor has a dramatic effect on bass. The "Q" can be very high and narrow, in some cases undetectable by a spectrum analyzer, but quite noticeable by ear.
Electrostatics are dipoles, very fast and accurate, but they need to be large to get bass. NXT type panals need to be large too, but mostly to move anough air.
Quote from: captainjack115 on 5 Nov 2009, 04:01 pmElectrostatics are dipoles, very fast and accurate, but they need to be large to get bass. NXT type panels need to be large too, but mostly to move anough air. Why are NXT type panels called distributed mode speakers? Because they are neither pure dipole neither pure bipole. They have opposite phases 'distributed' on every side of the panel. They don't pressurize a room like monopoles and bipoles would do at very low frequencies. But they don't have a clear dipole separation either. And their ability to produce bass is very well defined by their size in the first place. A small DMS will NOT produce bass, regardless how much air you are able to move with it.
Electrostatics are dipoles, very fast and accurate, but they need to be large to get bass. NXT type panels need to be large too, but mostly to move anough air.
It would seem that at some point this technique changes from true bending waves to something more along the lines of pistonic behavior. We may need to think about something Bob Carver did with his woofer system on the original Amazing Loudspeaker by having a high "Q" at low frequencies to make up for cancellation due to baffle width. It's hard to say at this point, we're not dealing with true bipole or dipole operation, but a chaotic transition.
They do sound omnidirectional, compared to Stig Carlsson's designs, familiar here in Sweden, I think that the panel's response are very much more omnidirectional than Stig Carlsson ever accuired with his dynamic speaker designs. But even those old designs did show remarkable 'no shows'.
I thought i read that these are just speakers with no cone? Why couldnt you take another driver and just cut the basket off and remove the cone then attach it the same way we do these?