Hey y’all,

Im sure this topic has been talked about many times, but I’m more than a little confused.

I have the Yamaha Stagepas 300’s which sound great BTW. The 300’s specs are 150w per speaker (combined 300w) and a max output of 112d. 

So I unplugged one of the speakers and it didn’t loose any “volume/loudness” but did I loose 150 watts?? Am I correct, what’s the difference?  So, in terms of loudness, is it safe to say I need to focus on decibels, not wattage?  With that in mind, are the Yamaha Stagapas 500’s with the specs of 250w per speaker and combined 500 watts with a max of 116d not much louder than the 300’s that have 112d’s?

Is there an explanation available without getting too scientific?

Thx as always

Is there an explanation available without getting too scientific?

Probably not. (lol)
One deals with how we, as humans perceive sound, and the other is a measurement of energy.
Words like “logarithmic” and “linear” sneak into the conversation - so no, probably not. :-)

DeciBels (named after Alexander G. Bell) is an attempt to represent a human perception of sound, and much like trying to measure pitch perception is rather technical (and involves logarithmic mathematics). dB is always expressed as a ‘ratio’ or a comparison: what that means is, if you assign the very softest sound perceptible by a human being a value of 1, then the loudest sound is about 1,000,000,000,000 - yes that is one trillion (with a “T") times louder. (Okay our ears are pretty good and compress a huge range of sonic energy).

dB can be used to measure the sound and even to measure amplitudes of voltage or current (although the logarithmic formula differs)… oops! too scientific. The dB’s you see when then are spec’ing speakers is typical called the SPL (or Sound Pressure Level) - (that is a scientist trying to put a number on how IN YOUR FACE the sound is). On the SPL scale the rusting of leaves is about 10dB, someone whispering is 20dB, busy street traffic 70dB, outboard motor 90dB, Full Orchestra 100dB, Chainsaw 110dB, 120dB is a ridiculous rock concert, 130dB your ears start to hurt and at 140dB your career as a musician is over, dude!!!

Watts (named after James Watt) are a measurement of energy and is easy because it is a linear measurement (much easier to understand).

Okay now for some fun facts about all this: In order to increase the output of an audio system by +3dB you basically have to double its available power. Double the power and it gets you about +3dB more level.

+3dB is perceivable by everyone as an increase in volume. And it is significant because as a human your perception of sound is not linear. If you wanted an amp that increased the sound output of the StagePas300 for example, by 10dB, you’d need to get the (yet to designed) StagePas3000 - which would be about 1500Watts per side…

If you need this type of power in a convenient powered cabinet you can get close with the new Yamaha DSR-series (which deliver a mind boggling 1300Watts per powered cabinet!!!) SPL in excess of 138dB

If you get a chance to hear the DSR’s little brothers, the DXR-series, you’ll want to listen to the DXR8’s, especially, since they have the same size speaker components as your StagePas300, but the DXR8’s have an 1100Watt amp built-in to each cabinet (plus a lot of fancy processing and a revolutionary crossover and other cutting edge stuff). SPL 133dB

(I should mention that the beauty in having all that power is that you don’t have to use it, the cabinets are designed to sound good at all volumes. Power in reserve is always the situation you want with your sound system. When a sound system is struggling it does not sound good - a good sounding system is loud without sounding like it is struggling to be there !!!)

Thanks so much Mr. Phil, this may take me more than a few to digest!  Quick glance at the DXR’s, man.. As songwriter of my favorite group Chicago’s Robert Lamm said “I’d Rather Be Rich”