Very low speaker impedance

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

Duke, that sounds like a neat setup you had with the Eagle 2 and the Strathearns. Yes, if a single ribbon was 0.55-ohm it's no wonder I always saw them being used in a line source in conjunction with one or two other ribbons.

At that time, some of my friends were using the Strathearns with dynamic woofer systems and others were using the Acoustats with highly modified Acoustat servo-charge amps. I, myself had a set of 2+2's and a set of Monitor III's with the modified servo-charge amps. You just couldn't blow those things up (the speakers). Those were the days!

Many ways to design a loudspeaker focusing in on any one spec and proclaiming it to be the only way to design for best performance is just wrong thinking. 1 ohm doesnt offer any benifits its just a design choice and I feel a wrong one at that....But see Mlsstl responce hes got it right. Loudspeaker designers all make such choices. So many variables to loudspeaker design why it interests me so. To me loudspeaker and audio design is one of the few places a bit of arts left in electronic design.