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Speaker impedance patterns - how to read them?

I know this has probably been discussed ad nauseam, but here's my question. I'm grateful for any sensible opinion.

Premise.
A speaker system may have a complex impedance pattern that can vary from 3-ohms to 30-ohms depending on frequency. Some speaker systems with similar impedance patterns may be stated as being 8-ohm loads because the speaker is 8 ohm in an important part of its frequency response, but only there.
A tube amp, as a voltage amplifier, likes a regular impedance pattern. Almost no speaker system has a constant, regular impedance pattern. I am aware that solid state, powerful amps are built to compensate for modern speakers' complex impedance patterns, but there are tube amps around and people who love them. It's difficult to understand what average load a given speaker system will present to the amp.

Question.
When looking for suitable speakers for a tube amp - mine is a PrimaLuna EVO 100, 40w x 2 from EL34s - what must be looked at? How to best interpret the impedance pattern, whenever available? Assuming that one listens at normal levels in a medium-sized room, what are the criteria for matching speaker and amp?

Thanks for your views. M.
martinguitars

Showing 2 responses by tablejockey

tablejockey
4,032 posts
 
Learning more about technical specs is always helpful, but since what matters is they sound good to your ears. I'd put emphasis on simply trying different speakers and not get caught up in tech talk. Graphs won't guarantee them pleasing your ears. That amp is small enough to take to a dealer for  demo.

I've used a PL Prlogue, which is the forerunner to your EVO 100. Most of the popular brands are 87-89 db, and will work fine-for "normal listening."  As the manual suggests, try both 4/8 ohm taps.

I used a sealed cabinet, 89 db speaker with good results. 

 

tablejockey
4,032 posts
 
Nice choice. Placement/room for optimizing.

Avoid the cable forums.
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