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Current optimized or voltage optimized speakers?

Just read a recent post from an old thread, and an old question, that has kicked around the Forum for some time. Back in "09," a member wrote:

"Read Atmasphere's posts and white paper. Amp choice [is] highly dependent on whether your speakers are current optimized or voltage optimized. Which strongly suggest[s] that at least a part of 'system synergy' can be predicted."

The question for the Forum is how can one know whether speakers are "current optimized or voltage optimized"?

My layman's understanding of Ralph's whitepaper is that most solid state amps are based on the "voltage paradigm" (voltage is constant and watts change with load) and that most tube amps are based on the "power paradigm" (voltage changes with load, but watts don't change very much) [or is it the other way around?? LOL]

The old post quoted above suggests that some speakers will work better with solid state amps and others with tube amps -- let's leave electrostats and maggies out of the discussion. I'm thinking about the vast array of dynamic speakers out there.

So . . . restating the question, how do we know whether dynamic Speaker X will work best with a tube amp or a solid state amp?
bifwynne
swampwalker's avatar
swampwalker
5,138 posts
 
Others w more technical knowledge than me will have more/better answers, but I think that one way to "know" (besides listening) is to look at the impedance characteristics of the speaker. Higher overall impedance and a relatively constant impedance over the audible bandwidth is a good clue that the speaker will match well w tubes. OTOH, a significant reduction in impedance, esp. in the bass, indicates that the speaker will require more wattage at those frequencies, which a tube amp is not designed to/is not able to deliver, resulting in a bass-weak presentation. An amp that "doubles down" ( delivers twice the output wattage) with a halving of the load impedance) will be better able to drive that speaker in the lower frequencies and will have a more robust bass presentation.

Considering the issue further, constant voltage sources (SS amps) deliver less power into a higher impedance load, so speakers with a high impedance SHOULD mate better with tube amps. Conversely, a tube amp will not be able to deliver steady wattage to a speaker with wide swings in impedance; hence the generalization that speakers w a flat impedance curve mate well w tube amps.
almarg's avatar
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almarg
9,670 posts
 
Couldn't have said it better than Michael (Swampwalker) did, except that in the last sentence change "wattage" to "voltage."

Also, although it doesn't directly relate to the question, it's worth mentioning that Ralph (Atmasphere) has also stated that solid state amps, as well as tube amps, will generally perform better into high impedances than low impedances. This assumes, of course, that they are not asked to approach the limits of their power capability when doing so.

One final point, although it is a fairly obvious one. Researching what amplifiers others use with a given speaker can often be helpful in determining whether to go tube or solid state.

Best regards,
-- Al
unsound
7,329 posts
 
Then there is the issue of phase angle:.............
almarg's avatar
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almarg
9,670 posts
 
Impedance phase angles which are severely negative (i.e., capacitive), especially at frequencies where the magnitude of the impedance is low, will make life difficult for the amplifier in terms of how much current it has to supply. Also, the efficiency of the speaker will most likely be less than it would be if the phase angles were more benign, everything else being equal. That will further increase the power demands on the amplifier.

I don't think, though, that highly capacitive phase angles in themselves are necessarily an indication that a suitably high powered tube amp would not be sonically compatible. Although, of course, high quality high powered tube amplification does not come cheaply.

Best regards,
-- Al
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