Hi efficient speaker, bass problems

"Because all high efficiency speakers have an uneven bandwidth when being driven..."

This depends of the thermal and mechanical power handling capacities of the drivers used. For instance a 4" fullrange driver with 1/2 mm of linear excursion and 30 watts power handling is going to go non-linear long before a 12" prosound woofer with 9 mm of linear excursion and 900 watts power handling. The latter will probably remain linear to a far higher SPL than most similar-sized low-efficiency home audio woofers.

Duke
dealer/manufacturer

The latter will probably remain linear to a far higher SPL than most similar-sized low-efficiency home audio woofers.
-Audiokinesis

Please define Low efficiency,

Have to disagree here, most domestic homes speakers ( good ones) will not have any issues with power induced linearities at domestic listening levels.

regards,

Sorry , should have said High sensitivity speakers . One of the above posters mentioned amps , and yes now that I think about it the high sensitivity speakers that friends use are being powered by low powered amps .

In that case it is prolly a function of amp output impedance and not
power. Tube amps, especially set amps are of high out put
impedance. When this reacts with a speakers impedance which can be low in the bass and higher in the treble (without a zobel network which
wil lower efficency) the result is a less controlled and responsive
bass.

In my opinion a fairly high output impedance (low damping factor) amplifier actually works extremely well with proper loudspeaker matching. In the bass region, a high output impedance has the effect of raising the woofer's electrical Q, which reduces electromagnetic damping. But if we start out with a woofer + box that would "normally" be overdamped, the net result with the low-damping-factor amplifier is a properly damped system... but in addition, you get a "free lunch": You end up with deeper bass extension than you would have gotten with a high-damping-factor solid state amp! If done right, you can get as much as 1/3 octave deeper extension. To put this in perspective, this is more than you'd normally get from doubling the box size while maintaining the same efficiency. I exploit this "free lunch" routinely.

Duke