Clearthinker, good questions, great thread!You brought up all the eternal questions in audio - high power vs low power and high vs low efficiency, and of course, cost issues. Looking at the average audio product, 1 in 10 sounds very good, while the rest is mediocre to bad. (Due to flaws, or more frequently, due to equipment mismatching. Even for low efficiency speakers, you have to hear about 20 to find one great sounding. The same is true for high efficiency speakers, and given that it's rare to hear even a single one of those, and you need to hear 20 systems with them to have a comparable basis to low efficiency speakers. Most people do not get to that point, and as there's a minuscule chance that one trips onto a great sounding one right at the first try, the automatic assumption is that H.eff speakers are inferior.
The true difference between low and H.eff speakers is that H.eff speakers couple cone movement to the air much better, hence they translate much more of the audio signal to sound. As a result, you hear much more dynamic resolution, and you also hear much more of any defects the system has. It's not just the speakers issues are magnified with high sensitivity, but also the rest of the audio chain is forced to come out of hiding, and their flaws are exposed. That's why slid state amps sound generally quite bad or at least disappointing with them. Indeed, most tube amps have issues as well, but a good tube amp can be built in a reasonable budget that will sound good, while I have yet to hear a solid state amp that sounds even remotely acceptable once efficiency goes beyond 100dB/Wm.
The issues with H.eff were not just affordability but availability as well. The retailer can stock half a dozen to a dozen plus speakers in the same space that a single pair of H.eff speakers require. When a store owner can stock 5 pairs of speakers total, he's not going to stay in business. Also, while nowdays the price range for H.eff drivers went down, in the 50s-60s when the low efficiency speakers changed the scene the driver costs for H.eff drivers were much much higher than low eff drivers, and the relative cost of even a simple audio system rivaled that of a motor bike or a car, so the only choice really was the low efficiency version. Plus, who wants to give up half the living room space to a stereo system when you can get one that can be shoved onto the shelves? Also, you cannot sell the weak amps and sources with H.eff speakers as any deficiency will be glaring at you, so that's another key factor that limits H.eff and favors low eff speakers.
Class D for the low end is a very enticing solution, and is a fantastic compromise if you want H.eff midrange and top end. Yet, the stark difference in sensitivity between the two parts of the spectrum will come and bite our donkeys (or, asses). Your ears will come to realize after a while that there is a huge disconnect, and you will loose interest in the sound. To me, one of the biggest advantages of high efficiency is the efficient bass. It sounds first as if there was lower bass extension, because you are not getting that "pressurized" feeling that your head is about to explode with the sound pressure. However, you will notice that the sound is not a porcelain muppet freakshow anymore with angry goblins kicking your seat, but you are hearing much more natural presentation - base will sound breathing and alive, and when you turn the volume down the soundstage does not collapse.Amplifier power: for 100dB/Wm efficiency you need 60 milliwatts for a VERY LOUD volume, and you still have tremendous headroom even when using a 500milliW (half a W) amplifier. The quiet passages will play at microwatt levels - that is a few millionth of a watt! So, if you have an amp that excels at 6000W that;s not necessarily going to be a virtue here, as does it also excel at a millionth of a watt?
I have a youtube channel dedicated to audiophile education, (Real World Audio), and most of my videos are about these subjects, distilling my 20+ years of experience building & designing speakers and amplifiers.
The true difference between low and H.eff speakers is that H.eff speakers couple cone movement to the air much better, hence they translate much more of the audio signal to sound. As a result, you hear much more dynamic resolution, and you also hear much more of any defects the system has. It's not just the speakers issues are magnified with high sensitivity, but also the rest of the audio chain is forced to come out of hiding, and their flaws are exposed. That's why slid state amps sound generally quite bad or at least disappointing with them. Indeed, most tube amps have issues as well, but a good tube amp can be built in a reasonable budget that will sound good, while I have yet to hear a solid state amp that sounds even remotely acceptable once efficiency goes beyond 100dB/Wm.
The issues with H.eff were not just affordability but availability as well. The retailer can stock half a dozen to a dozen plus speakers in the same space that a single pair of H.eff speakers require. When a store owner can stock 5 pairs of speakers total, he's not going to stay in business. Also, while nowdays the price range for H.eff drivers went down, in the 50s-60s when the low efficiency speakers changed the scene the driver costs for H.eff drivers were much much higher than low eff drivers, and the relative cost of even a simple audio system rivaled that of a motor bike or a car, so the only choice really was the low efficiency version. Plus, who wants to give up half the living room space to a stereo system when you can get one that can be shoved onto the shelves? Also, you cannot sell the weak amps and sources with H.eff speakers as any deficiency will be glaring at you, so that's another key factor that limits H.eff and favors low eff speakers.
Class D for the low end is a very enticing solution, and is a fantastic compromise if you want H.eff midrange and top end. Yet, the stark difference in sensitivity between the two parts of the spectrum will come and bite our donkeys (or, asses). Your ears will come to realize after a while that there is a huge disconnect, and you will loose interest in the sound. To me, one of the biggest advantages of high efficiency is the efficient bass. It sounds first as if there was lower bass extension, because you are not getting that "pressurized" feeling that your head is about to explode with the sound pressure. However, you will notice that the sound is not a porcelain muppet freakshow anymore with angry goblins kicking your seat, but you are hearing much more natural presentation - base will sound breathing and alive, and when you turn the volume down the soundstage does not collapse.Amplifier power: for 100dB/Wm efficiency you need 60 milliwatts for a VERY LOUD volume, and you still have tremendous headroom even when using a 500milliW (half a W) amplifier. The quiet passages will play at microwatt levels - that is a few millionth of a watt! So, if you have an amp that excels at 6000W that;s not necessarily going to be a virtue here, as does it also excel at a millionth of a watt?
I have a youtube channel dedicated to audiophile education, (Real World Audio), and most of my videos are about these subjects, distilling my 20+ years of experience building & designing speakers and amplifiers.