Tech Brand Talk

Amplifiers, Impedance and Electrostatic Speakers

by Blogger on ‎05-25-2010 08:13 AM - last edited on ‎04-05-2012 11:07 AM by Administrator

In the world of speakers, there's often great mystery and misinformation when it comes to a speaker's "Ohm" value, or impedance, and how it relates to amplifiers or receivers. I'll attempt to explain some of the typical misunderstandings, especially when it comes to electrostatic speakers.

 

3763iAA253E7ECDE2DD90What's an Ohm you say?

Well, say it with me as I begin...OOooohhhhmmmm...

 

Ok, so not that Ohm (spelled Aum or Om), but this Ohm. Ohms are nothing more than the value of a speaker's electrical resistance, otherwise known as impedance. But did you know that a speaker’s impedance fluctuates at different frequencies? Most speaker manufacturers use the lowest point after resonance to determine the “nominal impedance” (or approximate designed impedance). I know, I know—who would have thought one simple number could be so complex?

 

So what’s the deal with impedance?

Complexity—that’s part of the problem with the nominal impedance rating. To simplify things, think of a speaker like a big resistor (restricting the flow of power from an amp) in an electrical circuit; the higher the impedance value, the lower the power flowing through that speaker; the lower the impedance value, the higher the power flowing through that speaker.

 

Which amp should I get, and how does speaker impedance factor into a decision?

Since most MartinLogan speakers are rated at 4 or 6 Ohms, we hear this question a lot. Most mainstream amplifiers are rated at 6 or 8 Ohms. However, this does not mean they are not capable of handling a lower impedance speaker load, it just is simply how the manufacturer decided to rate the amplifier.

 

Will amplifiers rated at 6 or 8 Ohm work with MartinLogan electrostatic speakers?

Absolutely! All MartinLogan speakers are compatible with receivers rated at 4, 6 or 8 ohms. We have tested several mainstream, high quality receivers and have found all are more than capable of driving 4 ohm speakers. The limitations of an amplifier rated at 6 or 8 Ohms only becomes obvious at extremely high sound volumes over a very extended time period. For most every other normal application an amplifier rated at 6 or 8 ohms will perform perfectly with MartinLogan speakers.

 

 

Comments
by J_BROWN Emerging Expert on ‎07-14-2010 10:43 AM

Well written.

 

It is also worth mentioning that the logan's will dip down as low as 1Ohm at 20,000 hz. These exotic frequencies are easy to drive with most descent receivers, and there are few recordings that carry these super high frequencies.

 

1Ohm at 20Hz would be a different story!

 

Can't wait for my Vantages!

by AYGREN(anon) on ‎08-10-2010 08:01 PM

I have repaired a handful of Martin Logan speakers and own a pair myself. The main cause of their failure was to due under powering. Most people fail to understand that your amp should be more powerful than the speakers. When an amp is of lower wattage, and you turn up the volume on the amp to the point where it starts to clip, the only thing you're hearing is DISTORTION. A 20 watt amp can destroy a 100 watt speaker, if the amp goes into DC (clipping).

 

Martin Logan speakers are power hungry, as are all electrostatic speakers. PLEASE pay attention. 

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