# Sensitivity, impedance or recommended minimum amp power?



## alecsus27 (Nov 21, 2010)

Hi,

I just changed my Yamaha RX-473 for RX-673 and want to buy 5.0 speakers to listen to in a 13 square meters (11x11 feet) room, 50/50 musiv/movies (gonna buy a subwoofer too next month).


I will not listen loud (live in an appartment) so please tell me, which characteristics listed in the thread title are more important to look after in choosing the speakers? That is, in order to get the best/good enough sound quality at a low/medium listening in that room. So, I don't want speakers which need to be put out loud in order to get the music sound good enough (by good I mean getting to clearly hear all instruments, all frequencies being put out).


I am aware that the higher the sensitivity/efficiency in a speaker - the better (the speaker/music will sound louder at given volume knob position, as compared to a lower sensitivity speaker). I also know that an 8 ohms speaker will need to draw less power from the receiver - as compared to a 6 ohm speaker - in order to put out the same level in sound.


My question is: given the low musical possibilities of this receiver, should I first look for speakers with lower wattage recommended amp. power? Or more important is to get higher impedance/efficiency speakers? 

Of course, it would be preferably to get a mixture of these characteristics - unfortunatelly, the speakers I need to choose between (Tannoy Mercury V1 and Q Acoustics 2020i) have them parted (Tannoy are 8 ohms and 10 W recommended amp power, but are only 86 db; Q Acoustics, are 88-89 db, but only 6 ohms and have 25 recommended min. amp. power)


As for the speaker frequency - it's another matter, I will leave that aside.


Thank you.


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## chrapladm (Jun 17, 2009)

Do you have the RX-V673?

If so 150 watts is plenty for most speakers you will be looking at for dynamics and headroom. And I am confused on which speakers you are trying to decide between?

And are you saying the speakers are only needing an amp that is rated for very low wattage? 10-25watts?


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## alecsus27 (Nov 21, 2010)

Yes I have the RX-673 and I just changed my mind, instead of Tannoy or Q Acoustics've I've ordered a 5.0 pack of Monitor Audio BX2/BXFX/BX Centre - due to arrive tomorrow.

The minimum recommended amplifier power for the MA's is 30 W, that is, I should probably need a minimum of 30 w per channel in order to get a good enough quality in sound?

The room is small (13 square meters, or 11x10 feet) and unfortunatelly the speakers will be placed very close to the corners. the surrounds will be wall hanged, right in the back corners, on the side walls. Listening position on a couch, against the back wall.Oh, and no chance for me to listen to them prior to buying.

The American/Canadian version of RX-673 draws 400 W, while for some reason the European one only 330W. If we consider the loss through heat dissipation, video upscaling etc, the probable real power output would be about 200-220. If we divide this by 7 channels, we remain with some 30 W per channel. This would be the limit accepted for a reasonable drive for the MA's, am I correct?

Or am I wrong and that minimum recommended power is for the whole capacity of the receiver (not only for what it is capable to push through one channel - if all 7 channels driven)?


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## mpompey (Jan 5, 2007)

From what you described the RX-673 should be able to drive your speakers fine. I doubt you would be driving speakers to near clipping levels as you mentioned you didn't want to disturb your neighbors. Your receiver will never have to drive all channels at max power, so the 673 should be fine for the task.

Receiver/Amplifier specs can be confusing because some manufacturers aren't consistent on how they measure max, for how long, which channels. Checking Yamaha's specs I don't see a listing for all channels driven at max. I see specs for 1 and for 2 channels driven.


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