I've read about damping factor, and how it relates to the control of drivers, and the corresponding changes that it can make to a frequency response based on the impedance curves of the amp and drivers.
However, I've always noticed that amplifiers which have a high output impedance and corresponding low damping factor were never able to deliver much power/current to low impedance speakers/headphones. Is this at all related to damping factor, or is there other variables involved here? What causes this to happen? I feel like this is a really simple question but I haven't really found a simple answer to it yet.
Also, beyond this, I've found examples such as the SPL Phonitor X, which despite having an output impedance less than 0.4ohm (measured by Amir) was still unable to provide enough power/current to low impedances. This especially made me question things, this to me looked similar to the characteristics I've commonly found high output impedance amplifiers to have. Is this to do with a lack of current able to be supplied by the power supply?
For headphones the video below should provide a satisfactory explanation (which BTW is common for Julian Krauses's videos):