The under appreciated impedance curve


One thing that a lot of audiophiles don't look at or don't know how to interpret is the impedance curve. I call it the honesty curve too.

Of course, most audiophiles know to look for high imepedance speakers for tubes, and that low impedance speakers are going to be more amplifier demanding.

I also look for:


  • A drop in impedance at 100 Hz at or below 3 Ohms - Indicates "amplifier sensitive"
  • A ragged magnitude instead of simple, clearly defined humps. If the impedance is ragged it indicates highly equalized components.


One speaker which breaks both of these rules was just reviewed at Stereophile, the Wilson Yvette.


https://www.stereophile.com/content/wilson-audio-specialties-yvette-loudspeaker-measurements



Like all things, there are no absolutes but these are the things I look for in a speaker. What do you look for in the impedance curve?
erik_squires

Showing 1 response by atmasphere

Anytime I get asked about the suitability of a speaker with our gear I always look for the impedance curve. All amplifiers make more distortion into lower impedances so I look for that sort of thing- it can be pretty detrimental in the bass where a lot of energy can be needed. The reason its so detrimental is distortion components can extend to some very high frequencies- and we might be talking about some very high orders- not just 7th but well above the 20th and the like. The ear finds this irritating!

You can reduce the amplitude of the harmonics by simply presenting the amp with an easier load. This has the effect of smoother sound with greater detail, regardless of the amp.

Tubes in general like to drive higher impedances solely due to a higher output impedance. Our smaller amps are the most popular, so I impedance curves are very helpful. I'm not a fan of Stereophile but their measurements of speakers have been very helpful in the past.