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 rudyb

Although all the technicalities and electronic measurements can be interesting, with an amp + speakers combination there's only one determining factor ... your ears. No matter what weird variations in impedance they may have, in the end it's how they sound that matters. By the way, room acoustics will probably contribute a great deal to the overall sound.
@Max Yes, doing our research, our reading, and maybe even some measurements, is big part of the fun of the hobby, as is exchanging knowledge, ideas and opinions on a forum like this. But while I might buy a new photo camera solely based on reviews ... amps, speakers and headphones are the kind of products I would never buy without having heard them myself first, no matter what raving professional- or user reviews or semi-scientific analysis may say.