Finding (calculating?) speaker and amp impedance

reviewers give far too much positive press to a speaker that shows you the difference between an integrated and million dollar monoblock

+1

Every budding audiophile should endeavor to hear a time aligned [studio monitor] system with electronic XO and beaucoup watts per driver. They'd then know they were being had.

Regarding reviewers:  "and the triangle in 3rd chorus is delineated like never before" is laughable.

How to stop worrying about speaker impedance The Audiophiliac and ELAC’s speaker designer Andrew Jones set out to demystify speaker impedance.

Thank God for John Atkinson.  From my long experience in reading Stereophile technical reports it's very rare that some part of a speaker's impedance curve isn't below 4 ohms.  And vanishingly rare at 6 ohms.  Accordingly most valve amps should almost always be set to their 4 ohm tap.  If they have one.  Atkinson nearly always recommends this.  Flea power examples should really only be run into 'full' range horns with sensitivity in the high 90s and above.

@hleeid 

Surprisingly (to me) was finding out that my old 80 db sensitive little monitors are known to be great with tube amps. These are Rogers LS3/5a from the early 70s

This represents the significance of the speaker impedance load and curve characteristics. Yes, these were very low sensitivity speakers, however they were 15 ohm impedance, so very easy to drive.

The sensitivity measurement of a speaker has more to do with limits of volume/SPL for a given amount of amplifier power. How easy a speaker is to drive has more relationship and effect due to the impedance load/characteristics.People could drive the Rogers monitor speakers (82 db sensitivity) easily with low power tube amplifiers due to the very friendly 15 ohm impedance it has.

Charles

Good timing for this topic. Using a pair of Focal Aria 936’s with a PL HP Integrated and all is good. But…I just had my 45 year old Sansui AU-717 fully restored and it’s in transit as I type this. Per Stereophile’s review, these speakers drop to about 2.7 ohms in the mid/bass region, yet publish as 8 ohms nominal. The PL tube amp handles it just fine in either mode (70 wpc in ultralinear, about 40 wpc in triode).

Im eager to try the vintage Sansui in this system upon its arrival. Bad idea?