What is your take on high efficient speakers vs. low efficient speakers?

In my experience, each pair of speakers that isn't driven easily by 30 Watt amplifier - sounds too compressed to me.

And it easy to explain. When you put dozens watts on speakers voice coil - it overheats that leads to very sever and clearly listened compression.

@alexberger wrote:

In my experience, each pair of speakers that isn’t driven easily by 30 Watt amplifier - sounds too compressed to me.

That outcome is also very much dependent on the specific amplifier used. I’ve heard a very good 30W pure class amplifier drive a pair of notoriously heavy load S.P. Technology Revelation’s rather effortlessly, whereas coupling them to a pair of 200W NuForce monoblocks felt like those amps struggled by comparison - even though, on paper, they’d have a +6dB headroom advantage.

Which is also to say that the sensitivity rating is only a partial signifier; a complex passive cross-over can bring many a wattage proficient (but apparently PSU weak) amp to its knees, with the same amp performing closer to its full potential and rated specs presented to an easier load. A more load benign amp requires a sturdy, powerful PSU, and those things come at a cost.

On principle though we fully agree. A difficult to drive pair of speakers, likely due to the "load severe-ness" as caused by its XO, presents a significant problem to me that only highlights why I’d rather have it configured actively sans passive XO, but that’s another discussion. High eff. passively configured, heavy load speakers would likely prove less of a hassle to the amp given that it has more headroom to deal with a complex XO.

And it easy to explain. When you put dozens watts on speakers voice coil - it overheats that leads to very sever and clearly listened compression.

In practicality I’m inclined to believe thermal modulation (as term also used by poster @audiokinesis) is the more general problem, as this comes into effect with peak heat build-ups in voice coils (and XO?) with short term transients, that dulls the perceived transients somewhat. It seems this phenomenon is less a studied field, but it could explain with why transient snap sounds more convincing with high eff. speakers.

Not to say thermal compression isn’t an issue with low eff. speakers. Dynamic prowess and their fuller swings certainly takes a hit here.

Both can be great dude!!

@kennyc wrote:

Some members seem to advocate whether high efficiency speakers are better or not. Sonics is my priority not speaker efficiency. I only address speaker efficiency if it is required/driven by a sonic goal- wanting to hear flea watt 300b tube amp magic which would necessitate a very efficient speaker.

High efficiency speakers aren’t necessarily better, but high eff. in itself can have a significant advantage going for it that impacts (or is brought to realization by) a range of factors like size, driver types, acoustic transformation and dispersion characteristics, and this in turn has sonic implications that’s also about ’different’ rather than just better/worse. It’s not like we have two pair of speakers that look exactly alike with the same drivers and all and a similar frequency response with the one pair being low eff. and the other high eff. Comparing high eff. speakers with low eff. dittos comes with several factors "interfering" that are linked to high eff., but extracting high eff. from that "equation" would seem to shortchange the bigger picture of what’s involved and that has significance sonically.

A very high eff. speaker system over its entire spectrum with a wide frequency range (say, down to 20Hz) will by necessity be large to indeed very large and horn-loaded (its total size depending on the specific implementation of the upper bass to midrange horn in particular). If well implemented and given proper horn size and acoustic surroundings (i.e.: mostly about size also), such an all-horn system to my ears potentially is in a very different league compared to smaller, low eff. speakers, with a sound that’s much more akin to a live event presentation, be that acoustic or amplified. To some this quality mayn’t be of vital importance, nor may they be able to or don’t want to accommodate such a system in their surroundings (cost may also be a factor), but nevertheless these qualities are undeniable and on full display.

As with many things as well as high efficiency and its significance though, it depends.

inna wrote:  "Bass gives a foundation. This is a very big disadvantage of high efficiency design. "

I respectfully beg to differ.  My fully horn loaded DIY speakers have a measured output at 25 Hz that is identical to the 1kHz reference.  There is an 18sdB/octave roll off below 25 Hz.  This is accomplished with Bill Fitzmaurice designed HT Tuba folded corner horns which have a sensitivity of about 103 or 104 dB/2.83v/meter.