Amp Power and Speaker set up

[k40air]

I recently purchased the RB-81 bookshelf speakers, which are rated at (150W RMS / 600W Peak)

After installing them I have been told that i am not sending them ample power. I matched them with the Yamaha HTR-6090 that does (120W x 7).

Is this true that my speakers RMS power should be less than my recievers output?

I am considering going to a smaller speaker if this is the fact.

The problem is I don't want to invest more in a larger amplifier. And the matching pair for the RB-61 center channel the RC-52 has a rating of (125W RMS / 500W Peak).

Am I getting two involved with the wattage from the reciever to the RMS power of the speaker.

I don't want to hurt the reciever.

Thanks

[Guest " "]

No, don't apply these types of metric's to your system.

There are senerio's where the amp may be too small, but it has more to do with the sensitivity rating of the speaker, which is provided in DB.  If the speaker has low sensitivity rating, more power is required to provide adequate listening levels.

See the below link which equates sound presure in DB and familuar noises.

http://www.myhometheater.homestead.com/splcalculator.html

So for example, assume a speaker sensitivity of 99 db 1watt, and assume a 5 watt amplifier, assume listening position of 15 ft, assume 2 speakers, given this info, the max expected sound pressure level would be 95.8 db, equiv to a desiel truck passing by 10 meters away.

If you substitute 120 watts for the 5 watts, you would basiclly have the sound of a train or jet running you over.

[k40air]

thanks for the reply first of all what is DB?

secondly the RB-81 will 120 Watts from the reciver be enough, is there need for a pre amp

[wuzzzer]

Its a rare instance that an amplifier is damaged by a speaker hooked up to it. I'd say 99 times out of 100 its the speaker that's going to be damaged. Probably the thing that would most commonly damage a receiver is positive and negative wires touching each other either at the receiver's speaker output terminals or at the speaker's input terminals.

Yes, you are getting too involved. []

Your RB-81 speakers are incredibly efficient compared to most bookhelf speakers. As long as you're feeding them quality watts (of which Yamaha is well-received by many on here) you'll be fine.

If you had a 5 watt or a 5000 watt amp it would be a different story.

[Guest " "]

thanks for the reply first of all what is DB?

secondly the RB-81 will 120 Watts from the reciver be enough, is there need for a pre amp

http://en.wikipedia.org/wiki/Decibel

120 watts is plenty

97dB @ 2.83V / 1m

Using the calculator, a 97 db speaker provided with 120 watts would generate 107db of sound.  Equiv to a low flying jet.