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Impedance - The most ignored and useful measurement tool

I’m constantly reading about audiophiles diagnosing their speakers or attempting to mod their crossovers with expensive new parts. The one tool I wish they’d all get and rarely do is an impedance graphing tool. These are either nearly free or affordable.

They let you produce impedance charts like Stereophile does, as well as measure capacitors and inductors with ESR/DCR respectively.

In the nearly free variety you can build one and use Room EQ Wizard. In the affordable is the Dayton Audio V3. Either one does an excellent job of measuring a driver, crossover parts and the entire speaker as well. Completely irreplaceable tools.

Diagnosing your speakers with the help of others on the internet is made so much easier when you have one of these. Even if your speakers are fine, measure them and keep the charts handy for when they do go bad, it will make it much easier to understand what is and is not working. Replacing a cap/coil? Measure them and the speaker before and after when you are done to make sure everything came back together properly.

You’d be surprised how many speakers have a woofer or tweeter that has stopped working but the listeners don’t even realize it.  These are immediately visible problems in the impedance plot.

Of course, it's just a tool, but when a driver goes bad, or a solder joint fails the impedance charts will go wildly off track.  It's up to you to dig in and diagnose further.

erik_squires

Showing 1 response by cundare2

cundare2
286 posts
 

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...

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