Impedance - The most ignored and useful measurement tool

Not long ago I went down that rabbit hole.  Replaced a set of Focal 807Ws as I wanted to downsize.  It's impedance curve if I remeber correctly show two humps in the bass regions and a rising impedance in the mids to relatively high ohms although it's sensitivity was measured an avg of 88.2 or thereabouts.

What I replaced them with were Audel Magika II as a smaller option that has worked well for me.  It also shares a similar impedance curve.

Some notable brands/reviewers have stated (without assessing phase) that these kinds of impedance were an old design designed to be more tube friendly and modern designs should be more level after bass and closer to 4 ohms to maximize the power output and ability to play the speakers louder.  Wont mention who but many should know. Probably right for some, not for all.

Whether it's better SQ, specs, whatever is the question I suppose. 

My Dali Opticon 1s have a relatively flatter impedance, also decent measured sensitivity at around 88 dB.  My main amp plays both well although my smaller amp  could not bring the Audel to perform as well while it did with all others so current might be a factor also. 

If I went tubes, then impedance may be more critical. 

Also, the Audels hit a low of 7 ohms in the mids whereas many speakers can dip below 4.   In the higherst frequencies it dips to 5 ohms but there it is inconsequential regarding power output of the amp.  essentially it acts like a 9 ohm or higher speaker which relies on current output. Perhaps the high ohms prevent my 40 watt amp form delivering enough current?  

My CA-1 performs great and the combo is very transparent but just avoids being too much in being described as analytical as well as being overbearing in the upper mids like many speakers can be. 

Ideally I suppose tolerances and curves would be tighter but those are how things measure versus sounds to an individual. 

Learned alot from Erin's Corner but never bought based soley on his recommendations.  I live with what I buy and like.  Not perfect but good.  If it works well, I'm good.  Getting a better something here typically meant giving up something there all too often.  If a speaker, amp, dac, etc. performs well enough, then enjoy.

I haven’t read this entire thread, but so far, I’m finding it to be a very smart conversation, just the kind of thing that I wish was posted more often on platforms like Audiogon.

The only thing I want to add is that anybody seriously interested in this topic should try to search out a copy of Joe D’Appolito’s long-out-of-print book "Testing Loudspeakers," published in a 1988 small-print run by Audio Amateur Press (which at the time was publishing Audio Amateur and Speaker Builder magazines).  Yes, this book was writtten by THAT D'Appolito.

It’s an outstanding reference, a bit technical for some, but written from an audiophile / speaker-designer’s perspective.

It took me several years to find a copy in the early 90s, and it cost me over $150 from a rare-book seller.  But it was worth the cost & effort to me b/c at the time, I was testing speakers for mainstream magazines. Today, though, even Amazon has copies of a 2018 reprint in the $40-50 range and I believe it's also on Google Books.

Highly recommended.

I wonder if Joe is still alive.  Last I heard, he was at Snell, but that was 15 or 20 years ago...

Honestly, if anyone is interested, head over to DIYaudio were a lot over talented and helpful builders hang out.

I didn't mean to start a whole conversation on impedance, just on how having basic diagnostic tools like this one can be really helpful..

@erik_squires +1 "You’d be surprised how many speakers have a woofer or tweeter that has stopped working but the listeners don’t even realize it. “ I will be not!

speakers impedance is good start, but it will not tell us whole story!

whole amp+cable+speakers system need to be characterized on frequency and time domain, incl. distortions etc., using precise measurement microphone in listening room, using fuzzmeasure software or audio analyzer. I wouldn’t be surprised to see large number of setups will show >5% distortions, +/-10dB amplitude deviation in freq. response, and bad resonances! Tests should be done at different power level, starting 50mW. 

speakers impedance is good start, but it will not tell us whole story!

Nor do I ever claim it is.

whole amp+cable+speakers system need to be characterized on frequency and time domain, incl. distortions etc.,

Why? I was only posting this to show how an important tool can help audiophiles diagnose their problems faster, fix broken systems and mod safely.

I never claimed it was a replacement for full speaker analysis, which in the use cases I spoke about is not needed.  When you say need I think you are thinking far beyond the limited situations I was discussing.