LOUDSPEAKER SELECTION

Maybe  this page should really be called "loudspeaker and amplifier selection", because there is no one solution that meets all requirements.  Firstly I will talk about loudspeakers, or at least what I see/hear and what I require personally in a loudspeaker.  I believe that the important parameters in any loudspeaker are EFFICIENCY and LINEARITY.  I assume that all high quality loudspeakers will have adequate frequency response, so do not cover that here. Of  these two parameters, one should in theory put linearity as the first priority (by linearity I mean a level response right across the audio frequency range with no adverse peaks or troughs), but I will try to explain why I personally consider efficiency to be also of  paramount importance. So far it doesn't make sense, so I will explain what I mean by way of  analogy:

A. Suppose a Sumo wrestler sits on a garden swing (one that can take his weight of  course).  You are the lucky person who has to push him, so you do, and to your chagrin the swing hardly moves. You push him harder and it swings a bit, and when it comes back for you to push the next time, rather than you pushing him, he knocks you over.

B. Now you have a 10 year old child sitting in the swing and you push him and he goes a long way. you soon find that you can push him so that the swing goes nearly horizontal, but you are in control and it is great fun for all !

C.  Now you strap a baby into the swing and with gusto  give the poor little fellow the ride of  his life, after a few mighty shoves, the swing does a loop and waps you in the back of  the head. Just joking of  course, but this is the analogy.

Situation A I compare to an audio system with inefficient speakers, say below about 89dbA sensitivity. The lower the figure the more heavily 'damped' the sound.  The plus side of  such speakers is that they can deliver a tremendous amount of  oomph from really powerful amplifiers.   The downside is that the dynamic feel and response is not  so good. One tends to get a fairly flat sound stage with little real depth.

Situation B I compare to an audio system with an efficiency in the range 89 to 99 dBA.  It is AMAZING how much easier the music is projected into the room. It seems to be brought out, giving also greater width and height as well as depth, to the less efficient speakers.  One gets a real "3-D" presentation of  the music, and this is where one can really believe that the music is so realistic that it could be live.  In particular the dynamic response is hugely enhanced, so that the difference between a soft 'ding' on a triangle and a massive chord on an electric guitar REALLY  is as much as one would experience in reality. 

Situation C I compare to high efficiency systems with over 100dBA sensitivity and this is the province of  the horn systems, which nowadays tend to combine one or two horns with a sub-woofer with its own amp.  I have not heard too many of  these. The sound is extremely exotic, but there is a but, and that is that the soundstage can be brought out so much that one is immersed within it.  Thus one can lose the idea of  a group performing INFRONT of you.  Furthermore, the phasing of  the sub system may not be as good as a conventional loudspeaker system, and the horns may not handle everything thrown at them without misbehaving at times. 

No prizes for guessing which efficiency range I like, but I do firmly believe that for ME,  the mid 90s is the right sort of  effieiency.

Now I have to couple this discussion with amplifier types, because I believe that there are two or possibly three different combinations of   amplifier and speaker which each offer a  'best' solution:

1.  For those who like to listen to LIVE music, especially acoustic material, vocals, etc, then IMO the ideal solution is  a mid 90s efficiency system coupled with a SET amp.  It may be that the high efficiency systems with associated sub-woofers can give equal or in certain cases even greater pleasure, depending on the type of music.

2.  For those who love rock music almost exclusively, then it may be that a low efficiency system is better, and for rock music a SET amp is definitely NOT the best solution.  Some of  the best rock amps in the world are push-pull amps with banks of  pentode valves in parallel, providing awesome power all the way up from deep bass to the highest notes on a guitar, or  therabouts  (at least to several KHz), without bothering about ultra low distortion, and DEFINITELY without extended treble response.  

There is an incompatibility between the above, so the question is "Can a Gainclone amp solve the problem and combine the two".   In theory the answer should be "yes", but the loudspeakers cannot be too efficient and have massive treble response if  one wants the best sound for rock music.  A possible solution could be to limit the treble (and maybe the dynamic response also) at the pre-amp stage of  a system, so that one could 'limit' a high efficiency system to give a rock music characteristic. I think that could work, and I know that there are many car and home audio systems where one can select different types of sound, eg jazz, classical, speech, etc.

3. The third type of system is  the Home Theatre system, and increasingly we all have to have such systems for our DVDs, with usually a 5.1 surround sound comprising Left Front, Centre, Right Front,  Left Rear, Right Rear, and sub-woofer, and there are 6.1 and even 7.1 systems on the market.  It should be noted that such