To Doug Schneider,
I'm in the market to buy the KEF R500 speakers, and I auditioned them at a local dealer together with an Arcam FMJ A18 amplifier. I was blown away by their performance, and they made the Monitor Audio RX6 speakers sound bad; like, without a soul.
After the audition, I Googled them and came across your review of the speakers on SoundStage! Hi-Fi.
In your opinion, is the amplifier auditioned strong enough for the speakers or would you recommend spending more to get the A28 from Arcam? Are there other amps that you can recommend for the R500 speakers that are around €1000?
Kind regards,
Robert Kooiman
The R500s are fantastic speakers, so I'm not surprised you were blown away by them. Their sensitivity of 86.75dB is about average, so they don't need obscene amounts of power to play at reasonable listening levels. On the other hand, their power handling is exceptionally high and they can play extremely loud when given plenty of of juice, so they can make use of a high-powered amp if that's what you have.
But it's important to know that it takes quite a bit more power to get an appreciable increase in output level. The rule for amplifier power and loudspeaker output goes like this: for every doubling of amplifier power, the sound pressure level (SPL) increases 3dB. This means that moving from 50W to 100W will give you just 3dB more output, and to get yet another 3dB of output you need 200W! It's easy to see why some people use amps that can deliver hundreds of watts of power if they really want to play their speakers loud (and the speakers can take all that power without blowing up). On the other hand, it's also important to realize that speakers of average sensitivity only need a few watts to sing, particularly if the room they're being played in isn't that big.
It's been some time since I auditioned Arcam's electronics, so I don't have first-hand experience with their current lineup. But when I reviewed an FMJ A32 integrated amplifier and FMJ 23T CD player several years ago, I thought they were quite something for their prices. I have no reason to believe that their current line wouldn't be just as good, if not better. The A18 is rated to deliver 50Wpc (into 8 ohms), which would probably be enough power for the R500s if you listen in a small- to medium-sized room and don't want to play them loud enough to disturb the neighbors. But if your room is quite large and/or you really want to crank the R500s up, then you'll probably need to look for something rated at 100Wpc or more. If you liked the sound of the A18, you might want to look at their A38, which is rated to deliver 105Wpc (into 8 ohms). Their A28, which is rated at 75Wpc, probably wouldn't play all that much louder than the A18. If you need more than 100Wpc, look for an integrated amp or separate preamplifier/power-amplifier combination rated at about 200Wpc. Frankly, I can't imagine you needing more power than that. . . . Doug Schneider
