Higher sensitivity - more dynamic sound?

@audiokinesis —

Thanks for your informative post.

Stereophile’s attempt into debunking thermal modulation doesn’t surprise me.. 

@lonemountain —

This whole efficiency argument is twisted a bit by marketing. A designer liek Doug will tell you if you want additional low end from a driver, you can optimize t for this but the efficiency will decline.

That’s a matter of size, not that you can’t mate efficiency with extension on principle. My tapped horn subs 97dB sensitive and will do ~127dB’s at the tune, which is 22Hz. 20cf. volume per cab - that’s (one of the reasons) why.

So your 102dB 1w/1m speaker may not have such good dynamics with a 20W amp if 1W= 102dB SPL then .2W=105, 4W =108, 8W =111, 16W=114dB SPL and we are out of [low distortion] power. That’s 12dB of dynamic range! That’s not even equal to the dynamics of vinyl.

Why would you limit the power to 20W for this example? Only suits your argument. I have a 97 to 111dB sensitive subs to main speaker setup powered actively by ~2.5kW total - problem solved.

So now compare a speaker with 86dB 1w/1m:  2W = 89dB, 4W = 92dB, 8W=95dB, 16W = 98dB, 32W =101dB, 64W=104dB, 128W= 107dB, 256W = 110dB SPL!  So the 86dB 1/1m speaker on a 250W/ch amp has 24dB of dynamic range! That's a huge increase when you take into account the log level nature of dB SPL, ideas such as 10dB SPL is considered twice as loud.  12dB dynamics is never better than 24dB dynamics, under any measurement or circumstance.  

That's being creative. Not only will you have to deal with peak power compression effects here but long term power compression as well, which in effect limits the available dynamic bandwidth. May look good on paper, but..

@lonemountain --

I think your post makes my point. Efficiency alone is not the sole issue or a spec to chase. Amp power, purpose and many other factors matter a lot. In live sound, 127dB SPL is important. In home audio, its damaging to our hearing.

The 127dB info only served to prove that eff. + extension is readily possible. I wouldn’t dream of using the max. potential in my home environment, but headroom is your friend, not least in LF, and thus the max. SPL numbers should make more sense in this context. Operating the amps much below full tilt is also worthwhile headroom, I might add.

The 20W limit was only responding the post of the 25W amp mated to an efficient loudspeaker had better dynamics (earlier in this and other threads). Good amps with high power are very available.

But more wattage in low eff. speakers comes with a price eventually, as per Duke’s post just above.

Amp power, purpose and many other factors matter a lot.

Quality wattage where it matters most, and power quantity (and overall quality) ditto; I use 30W class A from ~600Hz on up, ~2kW from ~85 to 600Hz, and 500W below ~85Hz. The pro class D-based amps used below 600Hz are quality amps and more than sufficient for the respective frequency spans - that's one of the beauties of active config. that such a distribution of amp types is possible. 

@jhills --

Making this about low efficiency speakers/higher power SS amp vs. high eff. speakers/low power tube amps is not the strictly defined combo context here, but rather low vs. high eff. speakers - certainly per the OP. It makes sense using low powered tube amps with high eff. speakers (and vice versa with low eff. speakers), but you get lots of the benefits with high eff. speakers no matter the amp principle. Myself I use a combination of class A and class D solid state coupled actively to my high eff. speakers, and from my chair bypassing the passive filter is the real treat with the benefits it offers with digital filter settings to more readily accommodate horns with steeper slopes, etc.; not whether tube amps are used instead of SS.

Re: playback volume, it’s a common misconception that high SPL capabilities (with high eff. speakers) necessarily equates into the need or want for high SPL playback. To me at least it’s generally about how it sounds at average SPL’s (i.e.: ~65 to 90dB range) and how the segment of speakers I’ve chosen excel here, but with the added bonus of a greatly enhanced, effortless dynamic bandwidth, in addition to prowess into transient capabilities and overall presence and physicality of reproduction, whether at low or high SPL’s. It’s not about clearing the roof over my head with +120dB levels, but the incentive to listen at higher SPL's with speakers that can handle it cleanly with ease and powerfully is not diminished, I might add.

And let’s expand a bit on ’effortless’: headroom is your friend - can’t be re-iterated enough, it seems - and that even more so when we enter LF territory. You want 105dB clean peaks at the listening position you want headroom to spare, not just merely enough, and this goes for speakers as well as amps. So, when I say my subs can put out ~127dB’s at the LP down to almost 20Hz, that’s not to say it’s my desire to actually achieve those levels - far from it - but once you hear bass reproduced effortlessly at every desired level, headroom makes sense.

@jhills --

Last word in efficient or not, I prefer the big open and natural sound of electrostatics and planers over boxes, hands down, but that’s just my personal preference.

Absolutely fair.

Being natural representatives of the (very) high efficiency segment: do you have experience with horn speakers, be that horn hybrids or all-horns? Tall large-horn speakers can have a sound reminiscent of large panel speakers, certainly akin to a limited dispersion "big open and natural sound" you’re describing, and a sound that sets itself apart from smaller, low efficiency box speakers in general. Not trying to convert you into being a horn freak (I suspect that attempt would be futile), but just to break down more stereotypical assumptions of their characteristics as being in every case from the same piece of sonic cloth. With horns in particular, size matters, but few want to accommodate that in their homes.

If all I wanted was loud, forward and dynamic I’d buy a Jukebox.....Jim

I hope that’s not your condensed takeaway from what high efficiency is necessarily about. By contrast a jukebox is only representative of that: a jukebox.