bipoles/dipoles for music...

I would use the terms focused versus unfocused imaging to realistically assess imaging performance.

Bipoles and dipoles are capable of a focused presentation I believe as are omnis, however the presentation is often (not always) different from say a good pair of monitors.

Ratios of direct to reflected sound is a discriminating factor. Bipoles/dipoles are different than most conventional box designs in this regard but setup including distance to walls also comes into play (except perhaps in an anechoic chamber) and might be done differently for different speaker types depending on the target results desired.

Time coherency across the audible sonic spectrum at any particular instant is a related but different sonic artifact that factors into quality imaging. Not sure bipoles/dipoles ae categorically any better or worse than other designs at this aspect either.

Prepare for an onslaught of responses from Maggie lovers. Boy, are you asking for trouble. I attend at least a dozen live performances a year. I find that Maggies do a credible job of reproducing symphonic music.

I own both . One pair are Von Schweickert VR2s which has a rear firing tweeter/midrange cone "ambience" driver. They sound good thats all I care about.
My Jm Lab Focal Electra series speakers only have front firing drivers and ports, they sound even better to my ears. I drive the VR2s with a Jadis DA-60 so they are being used with good electronics, that's not the issue.

Forgot about planars/Maggies...thinking more of conventional drivers...oh well...didnt mean to single out Mags..wasn't the intention