Very low speaker impedance

Engineering anything (whether a speaker or a car) is a series of complex compromises and choices and the answers chosen will vary with the intended use.

For example, which is faster for a 200 mile trip - a Greyhound bus or a Porsche? You can't really answer that question until you know more about the trip. If 40 people need to make it, the Greyhound bus is going to be a lot faster no matter how fast the top speed of the Porsche.

Take just a single factor in voice coil design. The impedance will vary with the length of the wire (among other factors.) A longer wire raises the impedance and gives a more concentrated magnetic field, but also increases the mass of the coil. So we have a balance that needs to be struck - you can't have both any more than you can put 40 seats into a Porsche.

For most consumers, it is best not to worry about the engineering issues the speaker designer faced. You're better off listening to lots of different speakers and you'll eventually find one where the design goals (with the inherent compromises) closely align with the strengths you find important in a speaker. Keep in mind the others will have those priorities in a different order. That helps explain why there are probably 1000 different makes and models of speakers on the market today.

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.

Chris, you seem to have an impedance obsession!

The only way to really answer your question is to poll every speaker manufacturer out there and ask if they made some type of compromise in their design regarding impedance. Some may have, many probably have not. Many won't tell you one way or the other as they regard their design efforts as proprietary work.

The error in your proposition is your statement:

...even if they know a low impedance design would be better instead sonically

Impedance is only one part of a complex set of issues. It may have nothing to do with a particular design's sonic goals. Or, it could even hinder achieving an important goal in a particular design. For example, low impedance draws lots of current. Current generates heat in a voice coil and that heat can damage or destroy a driver. So, in some designs, a low impedance could reduce the effective dynamic range. Many people regard improved dynamic range as sonically better than impaired dynamic range. In this "for example" the speaker may well perform better if the impedance is not low!

You need to get this one-note samba out of your head. Impedance is only one fact of many, many technical issues in a speaker design. You get a good speaker only when ALL of them are well coordinated toward the design goal.

Impedance is still the same variable these days it always has been. So are all the other variables.

Switch gears to fighter aircraft for a moment. During WWII the Mitsubishi Zero was one of the most maneuverable fighters around. One of the reasons was the manufacturer left off most of the armor plating that protected the pilot. The reduced weight help make the plane more maneuverable. (That's an interesting choice if you happen to be the pilot.)

Fast forward and we now have materials that provide pilot protection but weigh less. But they still weigh something and still take up room. The plane's performance would improve if you left off those materials, whether the old armor or the modern version.

So, sure. Modern materials and techniques may lessen the burden of a design compromise compared to older techniques, but that doesn't get rid of the issue.

You're still on your one-note samba. Even today, impedance alone does not determine the quality of a speaker. It is just one of dozens upon dozens of factors a speaker designer gets to juggle.

(Written as I am enjoying a gorgeous rendering of the 4th movement of Beethoven's String Quartet in G on my very 8 ohmish Spendor SP1/2Es.)