How important is the efficiency of a speaker to you?

@mazian   Class D amps are certainly a lower priced option, but most folks still are not that impressed with the SQ. 

When discussing speakers that are hard to drive, I'm not really talking about speakers that cannot be driven by just a few watts. The video above, with the Decware amp is interesting, because while this amp probably sounds good within its envelope, at just 2.3 watts/ch, it clearly is extremely limited as to what speakers it will work with. This is basically the other end of the scale, the speakers in my OP need a minimum of 100 watts/ch and an amp that can push current into a very low load. The opposite is the case with a tube amp that puts out flea power...this amp can only be matched with a very small number of speakers. ( Relatively). 

So, while I would agree that the cost to put together a system with a flea watt amp is probably less than one that needs a brute of a ss amp upstream, neither is great IMO. 

@kennyc  Well if you think that, there is no further need for you to post on this thread.

@quincy  There is another factor, a high powered good sounding ss amp, particularly one that can push current into very low impedances, is also going to cost a lot more ( on average) than a good sounding medium ( maybe even high powered) powered tube amp.

@ghdprentice   I agree with this. Not only do you restrict yourself to a subset of speakers, but in the worst case examples, you also restrict yourself to a subset of amps. Like many of us, i know of a few a'philes who bought their dream speaker, only to find that the amp(s) required were a deal breaker, not only from a budget perspective, but also in many cases, from a placement/heat/aesthetics/weight perspective as well.

The speakers I was referring to were not Wilson's. Nonetheless, it is interesting what you posted about Alexia 1's. They are known to be extremely difficult to drive. Is it possible that the ARC Ref 75SE has a more capable transformer, and as such can drive the Alexia's? 

@rauliruegas Funny you bring up the Parasound amps. A fellow a'phile whom I know well, decided to buy a pair of very expensive and very difficult to drive speakers, reasoning like you, that the Parasounds would be the answer. His budget was limited a little, so he spent the $$ on the speakers and left himself with only one option for the amps...based on his budget. Let's just say that the speakers went onto the used market within a few months, and he was forced to sell them at a considerable loss. I believe what @atmasphere noted above is the whole reason.

PS. He no longer owns the Parasounds either.

@atmasphere   Thank you. If you would have told the dealer exactly what you posted, he would have belittled you just the same. Some folk have agendas, and in this case, the guy was only interested in selling this speaker....not in discussing in any way the potential downfalls that this design elicits. OTOH, that was his job that day.

@lonemountain I couldn't agree with you more, it is absolutely important that one match their desired speaker to the space/room that it is going to be listened to in. However, the efficiency and the very nasty load that the speaker in question presents to the amp is a factor that IMO should not be overlooked, regardless of the room size. Personally, i am not that concerned about speakers that present a moderate efficiency, only those ( like the design in question, and others) that present basically a short to the upstream amp! 

@rauliruegas I cannot comment too much on the sound of the Parasounds and the speaker at this fellow’s room. I heard the combo briefly, but do remember thinking that the synergy was not there between the components.

Keeping in mind that the speakers in question drop down to around 1ohm in the bass, resulting in a speaker that very few amps can drive to anything that can bring about their best. Nonetheless, the Parasounds were not an amp that resulted in this fellow being impressed with the combo.

@rauliruegas   Presumably by now you have replaced the caps in those ML 20.6's?? Yes?

@deep_333 LOL, there are a number of well respected speakers that drop down to 1ohm. I won’t consider them for purchase; but I suspect that most folks will not label their designers...’lazy low IQ individuals’! The speakers I was listening to in my OP come from a well known designer who has had several ’amp busting’ speakers on the market in the past.

@rauliruegas While the speakers in my OP were indeed not the same as the ones in my example with the Parasounds, the speakers in the OP were in the same category ( and actually the same maker) as the ones in my example. I suspect that the Parasounds ( like most amps, and as Atmasphere pointed out above) would not be working at their best with such a load.

@rauliruegas   I suggest since you are such a big fan of the Parasound JC1+'s sound that you go out and immediately buy a pair, if you haven't already...That's what I am talking about...;0)

@atmasphere   :0)

@rauliruegas  If you are happy with owning an arc welding machine, more power. Personally, I prefer to listen to music, and as such I generally prefer the lower powered amps, most particularly of the tube variety. I am in 100% agreement with what @atmasphere stated above. 

If a speaker requires an amp/ arc welder up front to drive it, then IMO, there is a problem with the speaker design. YMMV.

@rauliruegas Which other gentleman are you referring to? I don’t think anyone on this thread is totally wrong…except maybe you, lol😁.

just kidding..😎

@lonemountain   While I would agree that sensitivity alone is not a indicator of quality or sonic virtue in loudspeakers, it certainly is an indicator as to what one can expect as to choosing an amp that will work well with said speakers. As such, the number and type of amps that will work is now significantly diminished, and as pointed out above by atmasphere, said amp will almost certainly NOT be working at its best. It also pretty much removes certain types of amp designs...mostly in the tubed genre.

@rauliruegas I think we need to be more clear as to what we are discussing when it comes to lower sensitivity. There is little question that a lot of great speakers are in the less efficient camp, meaning that they are not in the 100db/w mode, but closer to 85db/w etc., These very same speakers may drop down into the 3-4 ohm load in the bass, which might present a more challenging load to some amp designs, but like pointed out, with a sufficiently beefy power supply, will still work fine. These are not really the speakers that I am talking about here ( not sure about others), instead the designs that are on the market ( or have been on the market) that drop down to 1 ohm or less, and as such, are now presenting a very difficult load to the upstream amp. There are not too many speakers that this applies to, but you might be surprised by how many it does. Plus, many of these designs are from well known ( and respected) manufacturer’s, like the ones in my OP.

Gents, I think we can summon up the above posts with this: It is extremely important to acquire a speaker that has a good synergy with the amp that powers it.

@invalid   You bring up a great point. The signal to noise ratio is a factor with most gear. Tube gear is likely to be noisier than ss gear. The question is how important is the tube noise through the more efficient speaker to the listener. I'm not so sure that it off-sets the overall performance to such an extent as to rule out certain speakers?

@kennyc The only thing that I think also needs to be added, or considered, when one goes and just buys a speaker that is requiring a monster amp upstream, is this…. That particular amp will most likely ( I can think of maybe one tube amp that might work, and it too is very expensive) be a very expensive ss high powered amp.The problem is that many of these very inefficient speaker designs, which can sound excellent, are also typically very pricey by themselves. So, not only is one now digging deep to just buy the speaker, but also one has to consider the potential for in many cases doubling the cost to acquire the amp,unless of course we are talking about Parasound’s…@rauliruegas

@lonemountain Brad, I think one of my points is that the free choice of speakers and amplifiers are connected. IOW, a highly inefficient speaker is going to severely limit your amp choice, and conversely a very low powered amp ( or an amp with minimal current drive capability) will also be a non-starter with a speaker that cannot be properly driven by said amp. Therefore, picking out either one of these designs invariably leads one down a path, that may or may not be where one wants to go.

@lonemountain Brad, you make an interesting point. While most folk would consider your example as efficient, the other variable, which could effect how an amp interacts with this speaker is how the load the speaker presents varies across it’s frequency spectrum. For example, I know of a very good metal box speaker that has specs similar to what you post ( not quite as good, about 89db vs.90db), but this speaker drops down to less than 1 ohm in the bass regions between 35hz and 55hz. Therefore, I’m not so sure I personally would consider this speaker as an efficient speaker, or easy to drive.