impedance swings will change the spectral response using tubes.
More important (maybe) would be how complicated the crossover is and how the phase angles measure. Large phase angles and an impedance dip at the same frequency would be a non-starter for tubes. For me, at least. The lower the frequency the greater the offense, in general.
Getting phase data from a manufacturer is nearly impossible. Check some Stereophile speaker reviews to see what I'm getting at.
More important (maybe) would be how complicated the crossover is and how the phase angles measure. Large phase angles and an impedance dip at the same frequency would be a non-starter for tubes. For me, at least. The lower the frequency the greater the offense, in general.
Getting phase data from a manufacturer is nearly impossible. Check some Stereophile speaker reviews to see what I'm getting at.