"Power hungry" speakers

You mentioned an spl rating of 76 dB's. At 70 dB's, this would allow you 6 dB's of headroom before you reached 1 watt of input. As mentioned though, i didn't know if you were measuring at 1 meter ( which is useless except for sake of comparisons to reviews ) or at the seated listening position. Given that most rock music only offers appr 5 - 6 dB's of dynamic range, you would be using 1 watt of power to produce the full dynamic range of such a recording based on the above information. This isn't to say that i was recommending such an installation or that it would work as well as theory dictates, i was just spouting off figures based on the math that "acoustic theoriticians" would tell us was sufficient. We all know better than that.

I was also wondering by what you meant by the statement that very few amps would drive them beyond 70 dB's??? Obviously, most any amp could generate 1 watt of electrical output relatively easily, so what's the fuss? As mentioned, the only thing i can see coming into play here is the low impedance / protection circuitry kicking in.

As to why the Class D amps work better, that has to do with the reduced duty cycle that the amp sees, the lack of sag in the power supply and lower levels of reflected EMF generated by the speaker. As you reduce the duty cycle of the amplifier, you also reduce the amount of drive applied to the speaker. Less drive equates to lower levels of reactance, which gives us less reflected power to deal with. This in turn allows the amp to load up more efficiently, which is just more icing on the cake. If the switching frequency is high enough, the power is delivered in very short and fast pulses, giving the power supply ample time to recover from the small amount of power drawn from during those bursts. If the switching frequency is too low, you can hear the "pulsing" of signal and it sounds fuzzy, choppy and lacks cohesiveness. A higher switching frequency limits the duration between pulses and the energy in the gaps is somewhat "filled in" by what is called "the flywheel effect". In English, the overshoot of energy initially applied keeps the forward or reverse momentum going until the next pulse is delivered. The potential for distortion with such a design is quite high, but with newer technology and MUCH higher switching rates, they are finding ways to get around this. Sean
>

Thank you, Sean. Perhaps the 76db rating of the Scintilla is not the limiting factor in it's compatability with amps. I should add that the Scintilla is rated .8 ohm, or neary a dead short, which is what nearly all amps choke on.

Yes, class D modules engineers are having success getting around the switching speed devil. I use amps utilizing B&O's ICE module. I can't say I understand the white papers, but I can attest to it's amazing delivery.

Sean...I find that "large scale classical" pieces often run about 76 dB most of the time, with occasional louder passages. The way I determine this is by playing a concerto (for example: violin) or a vocal piece. I ask myself "is the violin louder than a real violin can play?" or a similar question for the vocalist. I often find that it is easy to crank the volume up higher than this criteria would allow. Perhaps this is because we are used to listening to "live" performances that are "reinforced". Amplification of an instrument above its true volume is like putting your girlfriend's complexion under a microscope. You will not like the result.

Down in New Orleans last week (I have almost sobered up) I spoke with some musicians who suggested a reason for the exaggerated bass that seems to be so prevalent. They suggested that the guys who do the audio mixing have been overexposed to loud music, and have lost LF hearing. (I thought it was HF that goes first, but they said No, LF). To these guys the exaggerated bass sounds right.

Somebody started a good thread recently exposing the purposefully cranked up bass response of recent ultra expensive speakers, the explanation being, "That's what the buyer wants."

Those of us looking for the Holy Grail of true fidelity are in a decided minority.

Eldatford -- few recordings are actually made at 0db, containing "optimum" dynamic range of the (digital) medium. Mostly thiongs are compressed and, as you note, processed. So, the actual sound level can go up & down -- accordingly, don't we often play with the volume control during the same symphony?
OTOH, I read s/where that classical can have a dynamic range of ~110db (at a large auditorium). That's staggering for our rooms & equipment, let alone actually recording such ranges. BUT, a Mahler cd I have goes from ~65db (spl) to ~85 at listening position (so count in room reflections as well) in the same movement!
Cheers