Audio Systems: speaker wattage, watts rms, amplifier power

Question
I was wondering how many watts RMS my speakers are. I have some kinda old Magnavox MX8000-HK01, I'm not sure if it'll make a difference but they're running through a Yamaha R-7 reciever.

Answer
Speaker wattage ratings are primarily fictitious numbers anyway.  There are no universally accepted measurement standards on speaker power rating and even if there were it is too easy to fudge the measurements or the rating nomenclature.  Most advertising and marketing departments play games with these figures thus making them even more meaningless.

The speakers you are referring to are designed around a 10" woofer, 4" mid and a tweeter of some kind.  I could not find any technical specifications for this system.

The best way to determine the "usable power rating" is to do this:   With the amplifier controls set at your normal listening conditions and a music selection which contains some strong bass notes representative of the most "bassy" you would want to listen to turn  up the volume gradually until you hear the speakers "bottom out" with those strong bass notes.  By "bottom out" we mean when the power into the woofer is strong enough that the excursion of the cone goes to its maximum and begins to distort badly.  Don't push it too hard or you can destroy the voice coil.  Also, don't leave it on a bass note at these levels for a long period of time or you can overheat the voice coil and burn it out.  This is one way of getting a "practical" power maximum.  Now, all that being said, if your amp does not have enough power to drive the woofer to its limits then the rating of the speaker is higher than the amplifier power.  Do not try this with the tweeter using high frequency music as mids and tweeters burn out much more easily than do woofers.

The Yamaha R-7 receiver - according to the owners manual - is about 65 to 75 watts/channel.  It would be a good guess that this receiver is a very suitable drive for those speakers.  If you put on more power it may improve its overall sound some small, barely perceptive amount under normal listening conditions.  There are some who like to have much more power capability from the amp than the speaker can use so that under short dynamic peaks in the music the amp does not "clip" or go into overload.  Doing so can be just fine so long as the temptation to push the speakers to hard they "burn out" during some big organ passage!

Hope this helps.

PS:  Magnavox speakers have never been big "winners" in the sound quality column of preferred speakers to my knowledge.  They are generally thought of as "low fidelity" vs "high fidelity".  The models you have are from a packaged system in which the original amplifier was design to best compliment the speakers  (what ever that means)....