I was re-reading a detailed technical review with detailed bench measurements of the older Walsh 200 mkII Here.
The impedance measured mostly between 8 and 25 ohms for most of the frequency range, down to 40 hz or so where the port kicks in, at which point it dropped to below 4 OHMs. That with all the rest there seems to indicate the OHMs are not as tube amp unfriendly as many conventional designs, except in the very low end bass, where tube amp unfriendly low impedences are often common as designs attempt to become more full range without achieving mammoth sized proportions. This is consistent with those here who have observed that tube amp + OHMs + subwoofer is a very good combo. If you can take the port out of play, then the OHMs become quite tube amp friendly it would seem. At least in the case of 200 MkIIs. I have not seen similar charts for newer models, but I would be very surprised if much changed for the worse in this particular department over time.
The impedance measured mostly between 8 and 25 ohms for most of the frequency range, down to 40 hz or so where the port kicks in, at which point it dropped to below 4 OHMs. That with all the rest there seems to indicate the OHMs are not as tube amp unfriendly as many conventional designs, except in the very low end bass, where tube amp unfriendly low impedences are often common as designs attempt to become more full range without achieving mammoth sized proportions. This is consistent with those here who have observed that tube amp + OHMs + subwoofer is a very good combo. If you can take the port out of play, then the OHMs become quite tube amp friendly it would seem. At least in the case of 200 MkIIs. I have not seen similar charts for newer models, but I would be very surprised if much changed for the worse in this particular department over time.