Very low speaker impedance

Other than your needing an amplifier that will behave itself at very low impedance loads, it is not possible to give a simple answer.

The impedance versus wire mass (length) is just one of =many= factors that affects impedance. Crossover design affects impedance. Cabinet design affects it. The other parameters of driver design (magnet strength, gap distance, other voice coil materials, suspension, cone material/mass... etc., etc., etc. also affect it. It is a juggling act for a designer to gain the attributes they want without losing too much ground elsewhere.

And with that, we haven't even gotten to the more exotic driver designs such as planar, electrostatic and so on.

I think it is a mistake for an end user to get wrapped up with technical issues that can be difficult even for professionals. To declare a speaker will be "fast and dynamic" based on a single spec is a simplistic mistake.

I'll be up front and state that I have no idea why Kinoshita speakers exhibit a low impedance. As noted, the voice coil wire length was simply an example of one of many factors. Their impedance spec may well be due to something else. I've not heard them and would find it impossible categorize their sound based on the fact they are low impedance.

I'll restate it this way. Technical issues are very important considerations in helping the designer reach his goal. But without knowing the design goal, specs by themselves can be quite misleading.

I believe it's mainly because they want the box a certain shape (narrow). If the speaker box can be made whatever size the deisgner wants (wide but not aesthetically pleasing) then a lot of trade-offs can be eliminated.

My guess is that, in the case of the big Konishita speakers, the designers perceive a worthwhile advantage in wiring many voice coils in parallel instead of using some other configuration. For one thing, the amplifiers will deliver a lot of wattage into this configuration - or die trying!

When confronted with having to choose between wiring for a 4-ohm load vs a 16-ohm load, I chose the 16-ohm configuration. My priority was compatibility with specialty tube amps, and I think that even solid state amps sound better into a high impedance load as long as the result isn't premature clipping. Apparently I'm very much in the minority here.

Seldom is the impedance curve one of the primary driving factors in a loudspeaker design; usually other things are higher priority and the impedance falls where it falls. In unusual cases (Apogee, Konishita, InnerSound/Sanders Sound panels), the speaker's impedance curve falls outside the comfort zone of most amplifiers, but in that case there are usually still specialty amplifiers that will work well, though the number of choices will of course be more limited.

Rating amplifiers by their 2.83 volt sensitivity rather than their 1-watt efficiency gives an advantage to lower-impedance speakers, at least on paper. Wired for 16 ohms my speakers are 89 dB/2.83 volts, but wired for 4 ohms they'd be 95 dB/2.83 volts. In either case, they're 92 dB/1 watt.

Duke

Believe it or not, not every designer builds a speaker so that their potential customer's favorite tube amp will be able to drive it.

Also, there are now quite a few audiophile quality amplifiers on the market that can drive loads less than one ohm without breaking a sweat. Most well-designed digital amplifiers will do that with ease.

I recall that back in the day, the Strathearn ribbon drivers were very popular and they presented a load of around 1 ohm unless they were padded with performance-robbing resistors. Some amp designers actually designed amplifiers that would drive that harsh load to take advantage of the ribbon's sweetness and transparency. So this is really nothing new. One of my friends used to modify tube amplifiers to drive such low-impedance loads.

Plato, funny you should mention the Strathearns. I used them in several different homebrew systems. The impedance of a single Strathern sans transformer was .55 (that's point five five) ohms! I used to drive one (or two in series) directly with an Electron Kinetics Eagle 2 amplifier. In fact, that little monster had so much power supply capacitance that you could unplug it and it would still play for 45 seconds.

Duke