How important is the efficiency of a speaker to you?

Well, D.Wilson ( paw, unfortunatelly. ) was not so stupid and " deaf " as his national manager and he used only Krell/Spectral amplifiers with the Watt/WAMM speakers to monitoring all his great Wilson Audio recordings.

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The manual suggests that direct-coupled Futterman and similar tubed amplifiers are inappropriate, but gives the OK for other tube models when used on their 4 ohm tap. I have to disagree. A 1 ohm load severely limits the output power from a tube amplifier. For example, a 100W output (17dBW, 8 ohm) into a 4 ohm load will typically fall to 7dBW, or 10W in level terms, when faced with 1 ohm. Simply, this means that the amplifier will clip 10dB earlier if a strong musical signal appears at 2kHz, which is not unlikely, since this frequency is well in the main music power band.

Let us also assume a typical case where the tube output impedance and cable loop are limited to 0.4 ohms. Overall there is a loss of 0.8dB over the whole range, but at the 2kHz minimum impedance the loss increases to nearly 3dB, this inducing a dip in acoustic frequency response of 2.2dB which may well alter the sound of the speaker.........................................................Last and by no means least, there is the matter of that awkward load impedance, and the corresponding, almost unforgivable dip to 0.33 ohms noted on the review pair.......................................................Depending on the amplifier used, there was also a touch of hardness on, or edge in, the upper midrange which was ameliorated by using the Goldmund Mimesis 3 power amplifier and one or two of the other high-current amplifier types such as the Krell. This mid-treble problem was rather amplifier-dependent (due to the impedance characteristic...."

Btw, we have to remember that that 1 0hm and 0.32 ohm at those frequencies is not a discrete impedance value but part of the speaker impedance curve and  the adjacent frequencies and developed harmonics are " touched " too.

Stupid people are all over the world and just fine with me.

R.

@phusis

My argument is that this efficiency as it relates to speaker performance is a complex issue, much more than a simple number. You forget I am engaged with dealers and end users who ask these questions (and similar ones) quite often. The desire to reduce a complex issue down to a simple one is very attractive when the subject is complex. THAT is my point, not that there aren’t times when facts are facts.

Since you own DH1A, I can use a historical reference: I bet you remember many people arguing the advantage of 1.3 inch throat driver/horns (EV) vs 2 inch driver/horns (JBL) and vice versa. That discussion was often reduced to focus on one attribute (throat diameter) when really it was a far more complex issue than that, depending on what you were trying to accomplish.

Brad

Dear @phusis  : " Indeed sufficient headroom is a prime takeaway here (regarding both speakers and amps) - that is, it’s that it actually matters, and far more than people seem to realize. "

Normally audiophiles do not cares enough about " headroom " eve3n some of them not even know what it means in electronics and especially when we are talking of speaker/amp combinations.

As  a fact I learned through my first hand audio experiences when I owned thr Classé DR3-VHC This amp is a pure Class A design with a power of " only " 25 watts but in its times was only one of the few amps that handled with aplomb the Apogee Scintilla that gone even lower than 1 ohm impedance and with not high efficiency but around  79db at 3m. but ( if I remember the Classé came with 7db on headroom and from here its VHC denomination: very high current. ).

R.

Its very important to some so much so that they house giants. Its also of very little importance to some so much so that they house giant amplifiers. If you don't want high power it would be important to you.

Is the entire "speaker efficiency" conversation motivated by passions and opinions about the free choice of amplifiers -not speakers ? 

Brad