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

phusis,

Thank you for an excellent description of what is most prized about the sound of high efficiency systems, particularly, horn-based systems.  

While good design of such systems will ameliorate midrange "peaky" or "nasal" colorations, such systems do tend to be a bit less smooth in frequency response than better low-efficiency direct radiating speakers.  I hesitate to say this because so many people have heard grossly uneven horn and wide range high efficiency driver systems, and do associate such systems with such coloration, but I will say that such problems can be effectively ameliorated in better designs.  Still, I can see why such systems will not be to everyone's taste.  

What do you guys consider high efficiency or low efficiency?   MY main speakers are rated at 93.5db efficient and my office speakers are rated at 88db.

@tannoy56 wrote: "What would you say are the attributes of low efficient speakers? Anyone?"

Low efficiency speakers will give you deeper bass response for a given enclosure size, often dramatically so.

The obvious implication of the above is, low-efficiency speakers tend to have much higher "spouse acceptance factors".

As was mentioned previously, low efficiency speakers tend to have wider dispersion, this because designs which result in high efficiency (such as horns) tend to have deliberately narrowed dispersion. Whether wide or narrow dispersion is better is subject to debate, and imo depends on the room itself and other other considerations.

Some horns have coloration, which imo eliminates them from serious contention. At the risk of over-generalizing, I’d be wary of horns which have sharp-edged internal "kinks" and/or sharp edges around the mouth.

In general smooth frequency response is less expensive to achieve with low-efficiency speakers than with high-efficiency speakers. This is because there are inevitable tradeoffs in driver design, and some of the characteristics which contribute to response smoothness work against high efficiency, and vice-versa.

I’m sure there are other attributes of low-efficiency speakers which I have overlooked.

Imo amplifier + speakers + room = "a system within a system". Typically the room is the most expensive component, and the most difficult to upgrade, implying that the speakers and the amp(s) should be chosen to work well in that particular room as well as with each other.

Imo, ime, ymmv.

Duke

High-efficiency speaker manufacturer

I sort of think that 95-96 is at the low end of the range.  My speakers are 99 db/w efficient, and friend calls that medium efficiency (his speakers are above 112 db/w efficient.  It also matters how smooth and high is the impedance curve of the speaker.  I recall how one of the Wilson Watt/Puppy speakers was supposedly 95 db efficient (at a nominal 4 ohms, meaning some more realistically at 93 db/w efficient) which should have made it fairly easy to drive, but it turned out to be a very demanding and difficult speaker to couple with some tube amps.  On the other hand, the original BBC monitor LS3/5A (15 ohm version) which is rated in the low 80's as far as efficiency goes, couples well with even somewhat low-powered amps because it is a very easy load.  

@larryi wrote: "I sort of think that 95-96 is at the low end of the range. My speakers are 99 db/w efficient, and friend calls that medium efficiency (his speakers are above 112 db/w efficient."

Imo this is something to be aware of:

Very often the limiting factor for high-efficiency systems is the on-axis frequency response at high frequencies. And one way to get very high efficiency numbers is to use a horn whose pattern at high frequencies is very narrow, such that all of the high frequency energy is concentrated in a narrow beam, thereby maximizing the on-axis sound pressure. If the same compression driver were used on a wide-pattern horn, the same amount of acoustic energy would come out, but because it’s spread over a wider angle the on-axis PRESSURE would be less.

By way of analogy, consider a garden hose with an adjustable nozzle. The on-axis PRESSURE is higher when the nozzle is adjusted for the narrowest possible pattern, but the same AMOUNT of water comes out regardless of the pattern width. So too with horn radiation patterns.

Implied by this is the fact that an omnidirectional speaker system is actually putting out a lot more acoustic energy than we would normally infer from its "on-axis" efficiency.  So comparing efficiency (or voltage sensitivity) specs is not necessarily making an "apples to apples" comparison.

Duke