"Power hungry" speakers


Hi folks, can you please explain to me why certain speakers so demanding with regard to amplifier power? I'm not talking about some notoriously-difficult-to-drive Apogees or some old Thiel models, but about speakers like the Sonus Faber Extrema's. These speakers do not belong to the realm of the less-than-1-Ohm-impedance-drop speakers, but need high powered amplifiers if you want to make them sing. Even 300 Watts wouldn't be enough! What is this for some ridiculous statement (or is this a fact?). What is the explanation for this phenomenon? I do not know much about physics, but I wonder what is happening with those Watts inside the speakers: will they be converted into warmth or something?
dazzdax
Both of you (Sean and Bemopti) mentioned the use of complex crossovers that are consuming the Watts. As far as I'm informed, the crossover in the Sonus Faber Extrema is very simple. It is in fact a design without capacitors in the signalpath. How do you explain the fact that these speakers (the Extrema's) in particular are very power hungry?
I'm not familiar with Sonus designs at all. The only thing that i can think of is tonal balance. A speaker with a very laid back or semi-sunken response will never sound as "loud" as a speaker with a more forward ( or even "flatter" ) response. From what i've read, the Sonus speakers have a rather laid back / soft presentation. Sean
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I believe the motor magnet affects efficiency.
The stronger the magnet, the louder the speaker will play with x amount of power.
The size of the drivers is also a factor. Tiny drivers cannot move enough air (to go loud) with average power.
Dazzdax, maybe I have an explanation about the crossover of the Sonus being simple, and yet, why of their consuming such a large amounts of current? Last year, I was experimenting with an old Pioneer receiver from the 70s I have picked up from the garbage as well as a small midi JVC system (2002 model) that I had imported from Asia. I was trying to make them run with a pair of EPOS ES11, 87 db efficiency, no crossover, just one cap between the wires and the doomed metal tweeter. This load was supposed to be very benign...and yet, the sound was very distant, muddied, with both...I was running them with a pair of old radioshack wires I had both for non essensial duties...had chopped some and had decided to "solder" them together again.

Later, I ran the same set of wires to my powered sub and guess what, the same muted sound. I swapped cables and there the sub was, reproducing loud, clear volumes and programs.

The point is this, even with copper wire and simple solder, there can be a major hampering in the power and delivery of the signal to some drivers. Eventhough Sonus might have what it seem to the naked eyes as a "few" components, they still might be robbing the drivers of the "original" watts that were intended for them.

Do not get me wrong, people swear by Sonus Faber and other of these rather power hungry speaker manufacturers, but maybe it was the intention of the company to make somehow demanding speakers in order to get clientele who are moneyed, AKA: can afford to have monster amps, rather than some tube loving, hi efficiency owners of SET amps.

To make my speculation into conclusion, you will simply need to have the same pair of speakers, Sonus with one tweeter and one 6-7 inch midwoofer and another of the same type of set up, one tweeter and midwoofer, play the same source or selections for about 2 hours at medium volume. Then, touch the crossovers of the X brand of speaker and the Sonus. If the Sonus crossover components are warmer than the other speakers, then you will be able to determine that the Sonus Fabers soak up the watts and current converting them into heat rather than sound waves. Inefficient, even with a group of smaller crossover components!
JM Labs originated as a speaker manufacturer (JM= Jacques Mahul, the designer of said speakers). Allegedly, Focal acquired the speaker manufacturer who now operates as the finished (consumer) products division of Focal. So it wasn't quite a matter of fitting the drivers into a speaker enclosure -- at least, not in the beginning...
As a general rule, efficiency in drive units is a function of moving parts mass vs. magnet strength. High strength magnets are expensive.
Efficiency in the speaker system, as has been noted, is also a matter of how much energy is used by the filters (x-over, notches, zobels, etc, you name it).
Hence, average magnets with heavy filters, do not a dynamic speaker make! Ultimately, small level info is lost to our perception as Sean notes -- and the result can be pleasant, flat across the critical range, etc, and "laid back".

Re, Sonus Faber & others: don't forget that, while the x-overs may be capacitor-less, it doesn't mean they are simple (1st order, etc) all over (I don't know if they are...). Also, the drivers used, like the expensive Scanspeak woofs on some models, are not that sensitive to begin with... some are ref'd at 86-87db...