Originally Posted by Driftrs
Hi guys, I'm rather confused right now... So I just purchased a set of cm10s plus centre, and obviously want to upgrade my denon x1200w. An entry level receiver, apparently outputs 112.8w with two channels driven at 8ohm with 0.1% distortion.
Now, marantz flagship 7010. Again according to sound and vision, 128w under the same scenario. Now in terms of actual volume, that's a barley perceptible difference. In terms of cost, we're looking at about $600 to $4000 (aud)
I realise there's more to a receiver than wattage. However when people tell you you need to have at least a Denon 4xxx or marantz 6xxx to avoid under powering the speakers... The actual numbers seem a bit arbitrary?
Can anyone help explain this to a newby?
Firstly, one should never pay any attention to the large wattage numbers emblazoned in three colors on the box...or any other marketing for that matter. Consumer AVR manufacturers IMO grossly mislead the public as to how much real wattage the unit is capable of. However, this is quite a rabbit hole since speaker loads are reactive, real world listening seldom has more than two or three channels "peaking" simultaneously, etc.
The better way to compare is to look at the maximum current draw (wattage) spec for the unit. Take out maybe 10% for processing duties, and then divide the rest by the number of amplified channels. So for instance, because you mentioned the 7010 (which is a great unit BTW), it's specs call for 125wpc for each of its 9 channels at 8 ohms with reasonable distortion at full bandwidth. Digging a bit deeper into the specs shows that the rated wattage for the unit (current draw) is 710 watts. So theoretically, if ALL channels were firing equally at the same time (very unlikely), the most you would be able to muster would be 78.8wpc, less any processing power required. Of course there are a HUGE amount of variables (content, speaker resistance, channel levels etc) that will affect this, but 125wpc in the real world...you'll never see it. Its going to be closer to the 70wpc.
Now, whether you will notice any difference between the ability of different receivers to power your CM10's to loud levels is debatable. The CM10 is a very efficient speaker, so in reality you don't need a whole lot of power to get it loud. If you are crossing the bottom end over to a sub(s), you'll need even less. If you really want them to crank though, buy an external amp. There IS a big difference in power and grip with outboard amps that receivers just cant match, but most of these gains will only be seen at quite loud levels.