Concentric drivers

As for concentric drivers, they are actually separate drivers with a crossover so the movement of the woofer will not affect the tweeter only the other frequencies it carries. 

I have a pair of Thiel CS6 speakers which have first order crossovers plus a concentric mid/tweeter. This crossover design makes each driver cover a much broader frequency range. Theoretically this would worsen any doppler effect. Other Thiel models have the same characteristic - they use first order crossovers and several models have concentric drivers. Vandersteen is another example of using first order crossovers.

I’ve read dozens of Thiel speaker reviews over the years and I’ve never seen a reviewer mention anything about the doppler effect altering the sound. In fact I’ve probably read over a thousand speaker reviews in my life and I don’t recall anyone ever mentioning doppler. You would think that golden eared reviewers would race to tell you about how their exceptional hearing detected that they were hearing the doppler effects of a particular speaker.

I’m going to stick my neck out and say that the doppler effect for speakers isn’t a thing. I wouldn’t be surprised if some company cited this as a reason why their speakers are better but I suspect that not all marketing hype is real. Except when it comes to cables where you should believe everything the manufacturer says.

I mean if you setup a big speaker on a trampoline and crank up the volume real high, maybe there could be some measurable doppler effect. But there's really not much specifically about a concentric driver to be concerned about.

The woofer does act as a horn extension for a Tannoy's tweeter, but it's never been a topic of discussion or concern, to my knowledge. 

I agree with Mulveling, (whose system I would love to hear), Tannoys have been recognized as one of the best-sounding speaker systems on the planet for almost all the years I've been alive.

I don't care if there is some Doppler effect happening, I love their sound, and that's what matters to me.

Regards,

Dan

The Ohm  acoustics speakers should not have doppler affect since all frequencies from the driver are coherent from one source and align in parallel as they leave the driver due to the driver alignment and method of transmission from back of the speaker