Double down, good or bad?


I came across this article on Atma Sphere's website:

http://www.atma-sphere.com/papers/myth.html

In short, Atma Sphere believes having a power amp that is capable of doubling its power when impedance is half is not necessarily a good thing because speakers in general do not have a flat impedance across all freq range.

On paper, it does make sense. Though I am sure speaker designers take that into consideration and reduce/increase output where necessary to achieve the flatest freq response, that explains why most of the speakers measured by Stereophile or other magazines have near flat responses.

But what if designer use tube amps to design his speakers, mating them with solid state should yield higher bass output in general? Vice versa, tube amps yield less bass output at home?

I have always been a tube guy and learned to live with less bass weight/impact in exchange of better midrange/top end. Will one be better off buying the same exact amp the speakers were "voiced" with, not that it will guarantee good sound, at least not to everyone's ear.
semi
The Power paradigm term for this is 'power amplifier' since such amplifiers attempt to make constant power into all loads rather than constant voltage.
Er, no, unless you're inventing your own terminology here.

A voltage amplifier amplifies voltage, as in a small-signal transconductance stage. A current amplifier amplifies current, as in a cathode- or emitter-follower. So . . . a "power amplifier" amplifies both, as in the output stage of a typical transformer-coupled tube amp.

As a complete device, an audio "power amplifier" of course must amplify both in order to be of much use, hence its name.
Kirkus, you are right in most of your posts and apparently either did not read something somewhere in mine or misinterpreted it. First, I'm not talking about clipping here- at all. I am well aware of the significance of the woofer in the box! The very point of a woofer in the box is that there is a resonance. Voltage paradigm amplifiers ('voltage source' amps) will throttle back their power as they encounter the resonant peak of the box, and so not exacerbate that resonance. That is the basis of the theory of the idea of making an amp that is a 'voltage source'.

Maybe you missed the link, so here it is again:
http://www.atma-sphere.com/papers/paradigm_paper2.html

Before the Voltage paradigm was proposed (MacIntosh and EV were two proponents in the 50s and 60s) the Power paradigm was the only game in town. I have had to create the terms 'Voltage Paradigm' and 'Power Paradigm' simply because the industry is mum on this subject in general- its inconvenient.

Yet the web audio forums are full of people that are constantly harping about aspects the the conflict between these two paradigms- tubes vs transistors is one of those debates that seems to arise from this conflict. But if you think my posts are *about* tubes vs transistors you have missed the point entirely!

The Voltage Paradigm uses a sort of short hand nomenclature that leads to confusion and I think this is happening for you in this case. Of course all amplifiers are power amplifiers, what the Voltage Paradigm seeks to do is call an amplifier a 'voltage source' when it refers to an amplifier that makes constant voltage into any load (i.e. doubles its power as the load impedance is cut in half). Amplifiers that have a high output impedance and make (or attempt to make) constant power are termed 'current source' amplifiers.

What is important to note here is the word paradigm. If you are operating solely within a paradigm, anything outside that paradigm can be construed as blasphemy.

The Power Paradigm amplifier is a 'power source', i.e. it will make constant power into any load. That is the voltage and current will both vary. I don't know of an amp that does this but that is the ideal, just as there are no true 'constant voltage' amplifiers out there either- that is the ideal. Does this clarify things?
What the Voltage Paradigm seeks to do is call an amplifier a 'voltage source' when it refers to an amplifier that makes constant voltage into any load (i.e. doubles its power as the load impedance is cut in half).
For the benefit of others who may read this, and along the lines of my earlier post in this thread, I think it is important to clarify here that "doubles its power as the load impedance is cut in half" in this context does NOT necessarily mean that the power RATING doubles as the load impedance is cut in half.

It means simply that a voltage paradigm amplifier, as a consequence of its very low output impedance, WILL deliver twice as much power into a 4 ohm load as into an 8 ohm load, provided that it is not called upon to deliver more power than it is capable of delivering (e.g., it reaches the clipping point). And that maximum power capability will in some cases correspond to significantly less than twice the number of watts at 4 ohms as at 8 ohms.

Regards,
-- Al
First, I'm not talking about clipping here- at all. I am well aware of the significance of the woofer in the box!
Atmasphere, clipping power is precisely what this thread, and "doubling-down" is all about. What I'm confused about is why you seem to be discussing clipping-power specifications and output-impedance specifications as if they're interchangable . . . or at least a common debate. They're not.
What is important to note here is the word paradigm. If you are operating solely within a paradigm, anything outside that paradigm can be construed as blasphemy.

The Power Paradigm amplifier is a 'power source', i.e. it will make constant power into any load. That is the voltage and current will both vary. I don't know of an amp that does this but that is the ideal, just as there are no true 'constant voltage' amplifiers out there either- that is the ideal. Does this clarify things?
Blasphemy is for the dogmatic, and I think it's best not to look at audio this way :). A typical high-quality conventional solid-state amplifier is pretty damn close to a pure voltage source. There's no reason why one couldn't build one that was almost a perfect constant-current source as well (except that it would severely alter the frequency response of the attached loudspeaker). But if it's a perfect "power source" you want, then you simply need to build a passive network that inversely approximates the impedance of the speaker, and use it in series with an amplifier that has a low output impedance.
Before the Voltage paradigm was proposed (MacIntosh and EV were two proponents in the 50s and 60s) the Power paradigm was the only game in town. I have had to create the terms 'Voltage Paradigm' and 'Power Paradigm' simply because the industry is mum on this subject in general- its inconvenient.
I think the industry is mum because these Paradigms only really exist on the Atmasphere website. Exactly who proposed this 'Voltage Paradigm'? Can you cite it as a bibliographical source, like one should in a proper scholarly paper?

I know we've been down this road before . . . but if you actually measure the output impedance of most hi-fi amplifiers from the 1950s and 1960s (McIntosh, Marantz, Scott, Dyna, Fisher, Quad, Leek, Citation, Eico, etc. etc.), they have a reasonably low output impedance . . . low enough to keep the impedance-related response variation of even a modern loudspeaker within +/- a dB or so. Did these manufacturers jump the gun on the Voltage Paradigm, not realizing it shouldn't be in effect until . . er . . Thiele and Small had ratified it? Of course not.

Atmasphere, I understand and respect that you design your products (and analyze their measured performance) in a way that meets your specific technical goals and personal preferences. But as for these "white papers" that you present on your website and promote on these forums . . . they simply don't pass muster in terms of technical or historical accuracy, or good scholarly form . . . the Grand Conspiracy overtones being particularly tiresome.
Kirkus, does this description help?:
http://www.stereophile.com/solidpoweramps/16threshold/index.html