16 ohm speakers: Pros & cons

Audiokinesis.... Transformer taps are another issue. How about experimenting with a driver that has a split (dual) voice coil, that you can hook up in series or in parallel. This would take just about everything out of the comparison except the voice coil impedance.

Gregm...A third advantage of 16 (or 32) ohm speakers is that lower gauge speaker wire can be used. This is a big factor if you are running 100 feet or more for some kind of a public performance, but would also apply to shorter audiophile cables.

Compared with and 8 ohm speaker, a 16 ohm speaker requires that the amplifier put out twice the VOLTS for a given power, because it draws half the amps. Solid state amps are limited by the volts they can output...within reason (and until a fuse pops) they can hold up this voltage regardless of the current drawn. Thus their wattage rating increases for lower impedance speakers. Tubes have high voltage capability, but can output little current, therefore tubes are usually interfaced using a step-down transformer which trades off voltage for current. This transformer has different taps (connection points) on its secondary winding so as to match different speaker impedances, so that the amp will work equally well with any impedance.

In the non-audiophile world, where solid state amps reign, 16 ohm speakers have the advantage that you can hook four of them up in parallel, and still have only a 4 ohm load.

Audiokinesis...You made a bunch of changes to your speaker system, so it's not definite that the improvement was due to the amp performing better with higher impedance. My review of amp specs shows that 4 ohm and 8 ohm distortion specs are the same, but 2 ohm specs (where the amp can do this) are usually degraded.