Watts and power

EPDR is not a measure of impedance, nor does it represent what the maximum current will be for a given voltage. EPDR is used as a measure for amplifier dissipation loading (not delivered power either).


EPDR is a measure of the maximum loading point of the output devices of a linear power amplifier. It is the point where the (current * voltage drop, rail to output) in the amplifier is at a maximum, hence where the dissipation is at a maximum within the amplifier. That is all it means.  It is not a direct relationship to what the maximum current draw is of an amplifier. EPDR does not occur at the impedance minimum in a reactive load, which means it also does not occur where the maximum current is delivered for a practical speaker.


Note my statement below. I specifically used 2 ohms as a minimum as that is the impedance minimum, and hence represents where the current peak would occur for any given voltage.

You did not indicate what you used for the a current probe.

P = I*I*R. Alexia's lowest impedance is 2 ohms. That means 80*80*2 = 12,800 watts (minimum) during that peak.

From Stereophile,

https://www.stereophile.com/reference/707heavy/index.html

EPDR is simply the resistive load that would give rise to the same peak device dissipation as the speaker itself.

Can somebody break it down in layman's terms for me?

Among the many wonderful quotes attributed to the late Nobel Laureate extraordinaire Richard Feynman is this one: "If you can't explain it to a six year old that means you don't really understand it."

Probably not an exact quote. Another variant goes, "I couldn't reduce it to the freshman level. That means we really don't understand it."

The common thread being the idea that when you really do understand something you are able to explain it in very clear and simple language and even to people with no special knowledge of the subject. 

Can somebody break it down in layman's terms for me?

Apparently not. Draw your own conclusions.

Layman’s terms:

It all comes down to "rated" power of your amplifier across the impedance of your speakers, with high emphasis over the bottom KHz or so.

Note I said across impedance, and not just at the lowest impedance as is often brought up. While a 4 ohm speaker may drop to 2 ohms (or less), it may also go up to 10 or 12 ohms (or higher) and do that over a relatively narrow frequency range. At a given volume level, not being able to deliver the required voltage at the impedance peaks or the current at impedance minimums will both cause issues in sound.

We next get into continuous ratings and peaks ratings. There are US and international standards for peak ratings. Are they good enough? Questionable, but nothing is stopping anyone from over designing beyond the standards with oversized transformers and/or large capacitor banks (or an architecture that allow more power supply droop). Of course you need high enough power supply voltages and beefy enough power supply to support the music peaks at the impedance peaks (which can be where heavy bass occurs), and a beefy enough output stage (and power supply) to support the current peaks and the minimum impedance, which are pretty much always bass.

From above .... beefy supply is the first need independent of the speaker requirements, and if your speaker dips low in impedance, you need a beefy output stage too, .... and there are many architectures that have been created to allow higher short term power bursts as is required for real music, but does not improve continuous power ratings.

So can you tell the "power" from the specs .... maybe. Depend on whether the amplifier vendor provides you enough details and you know enough about your speakers. That is about as easy as one can make it.

millercarbon
Can somebody break it down in layman's terms for me?

In a layman analogy for you.

These speakers, one of the worst load a speaker has ever measured. .9ohm EPDR
https://paragonsns2.imgix.net/wp-content/uploads/2017/05/Alexia-S2-Cove-Mariposa-Silver-5.jpg?w=1024...

Which amp will drive them the best?

This 175w Gryphon Antillion that almost doubles to 1ohm?
https://gryphon-audio.dk/wp-content/uploads/2018/10/ANTILEON_1.jpg

Or this 17 x times more powerful into 4ohms 3000w!!! Behringer Class-D that seriously get current starved and goes backwards into 2ohms
  https://www.storedj.com.au/behringer-nx3000-ultra-lightweight-3000w-class-d-power-amplifier?gclid=EAIaIQobChMIuJ-N8_fe5gIVjDgrCh1W0gqmEAQYAiABEgJjnfD_BwE

The choice is your
Cheers George