Thank you. Well it's LS50's all along, we've been talking about them. They are the ones that time and again get this type of reviews saying that they like power to perform their best (usually in the context that they need more than average).
It is always safe to say that the more power you have for the LS50 the less chance, or zero chance ultimately for them not to perform their best. I am just trying to remind you that you could reach that ultimate point easily.
Let's take a look of the following comparison:
LS50: sens 85 dB, 2.83V/1m, Max SPL: 106 dB, Amp req: 25-100 W Imp dip: 3.2 ohm
R500: sens 88 dB, 2.83V/1m, Max SPL: 111 dB, Amp req: 25-150 W Imp dip: 3.2 ohm
Based on the specs, the LS50 is relatively more "power hungry" than the R500 and most likely than "average", if we consider average means sensitivity of around 90 dB, 2.83V/1m, Max SPL: 112-115 dB, Impedance dip: 4-6 ohm, just for example. I do want to include the max output/spl for such consideration otherwise a lot of micro HTIB type or satellite speakers would be considered power hungry due to their low impedance. Note that their electrical phase looked quite good, no issues there. If the phase angle is large when the impedance is low, it could cause the amp to heat up more.
The caveat: Okay so they are power hungry, but remember, they can only output 106 dB @1m. if you punch in the numbers into that online peak spl calculator, for a pair of LS50, at 1m, with 0 room gain, would in fact get you about 107 dB. So you could in fact reach their maximum specified output with a 100 WPC amp.
Now let's look at the NRC graphs, you will see that at average 90 dB @ 1m, THD was <1% from 250-20,000 Hz. That'a amazing, but from 200 Hz down to 50 Hz the THD jumped from about 1.75% to 35% at 50 Hz. So based on that alone, you really don't want to give those speakers much more than 100 W of "clean" average power or 200 W of peak power.
Again, I agree we can consider them power hungry relatively speaking, but it is not necessary to power them with a 200 WPC amp. It wouldn't hurt obviously if you do, but a 100 WPC amp that can output 150 WPC at the impedance dips of 3.2 ohm should also do fine. Just about any 4000 series Denon, 7000 series Marantz and RX-A1000 (and above) Yamaha AVR can do them justice based on facts and figures.
I mentioned earlier, I know about this calculator and have used it a lot. I was only worried about those impedance dips. You make it sound as it's all nonsense, which I need some time to get use to, bc reviews are almost unison about "power to the kef's".
I understand the feeling, that's why I posted the way I did and I never meant to even imply such talks were "nonsense", not at all. I simply tried to qualify such statements by others. I might have said something similar too in the past, though hopefully I would have qualified it with some conditions.
I don't really listen to my music very loud, but I remember someone here saying if you have an excellent recording that sounds perfect at low levels and starts to hurt your ears at higher volume levels, your amp is probably short of breath. The way he put it "higher" was still in the amp's comfort zone, not concert loud.
I agree with such saying, but it could also be the speakers that became
short of breath too, it depends on which device has become the bottle neck when being pushed to produce more.
Now, I am taking my time with this and won't rush into anything since my room is not treated and higher levels could just mean more sound reflections, but I was looking for a chance to talk directly with someone who experienced this slight boost in SQ with more power to see what it's all about.
Problem is, who do you believe? I have paired my LS50 with a 50 WPC NAD integrated, a 13 year old AVR, and a 300 WPC amp and found the AVR could do just as good as job as the 300 W amp that also costs 3X the cost of the AVR when new. That's just my experience, you can easily find online posts that reported night and day kind of improvements simply by adding a power amp to their AVR, let alone using a high end separate pair.
You can see that I prefer to go with facts and figures from verifiable specs/bench tests. There is no perfect way, but subjective reviews/forum talks are not as reliable.
I don't suspect they have enough for easy listening, I was only asking because of all those transients and those dips and the reviews agreeing that LS50 do improve with power. I also needed some real world numbers about how much more power is more power.
If you go back to that online calculator, use 10 ft for distance, a 100 WPC amp should get you 101 dB, so allowing for a 20 dB for the transients in the music assuming you do listen to classical music, you should be able to get >80 dB of average spl. For me, 75 dB average is about my limit.
If you listen to 75 dB average, then the KEF suggested 100 W amp or D&M mid range AVRs will get you >25 dB of peak of clean power. If you need more than that, then you should get yourself a well specified and tested 200 WPC amp. Any more than that you won't gain anything in terms of sound quality because the speakers will become the real bottleneck.
What I'm aiming at is a solid 100 that can go all the way down to 1Ohm. When I dig up something like that it will probably be here until it melts.
I posted this before, but please do me a favor, take a good look of the bench test data of the AVR-3805 linked below. It was tested in 2004 so there is no need to register, if you want to read the newer ones then you have to register.
http://www.milleraudioresearch.com/download/reports/aug04/denonavr3805.html
Please scroll down to see the dynamic output into 1 ohm test, it actually passed that test when some separate power amps (such as TLSGuy's favorite Quad 909
) failed even the 2 ohm test, so don't discount your AVR too quickly. They may or may not be able to do a good job on the LS50. Being too lazy to switch things around, and limited by room as I have the R900 side by side with them with a piano in the middle, I let the AVR permanently hooked up to the LS50, knowing for sure that they won't do better with my spare separate components.
I dare say few power amps, and no AVRs can sustain 100 W into 1 ohm without activating the protective circuitry, but the odd older mid range AVR such as my 3805 obviously could do it (160 W 0.8% THD) dynamically, i.e. for a very short duration. I suspect some of the newer 4000 series Denon, 7000 series Marantz and the RX-A20X0 and above could have decent dynamic output into 2 ohm.
