Originally Posted by sofast1
I'm trying to find out what position on the volume knob is approximately full power (with tone & loudness flat/off,I know it varies slightly with input). In the old days it was around 11 o'clock, is that still true? I asked Yamaha customer support and they said "full power is when the volume control is turned all the way to the right". Yeah.....right. Any help???
The question isn't - whether you realize it or not - what is full power, but rather - what is reasonable volume?
There is a point where peaks exceed full power, and that happens much lower than you might think, though it will depend on the type and dynamics of the music. In short, ...peaks exceed full power...
is where clipping beings but it may not be noticeable. The higher you go above that, the more clipping there will be.
At about 11 o'clock you will exceed full power in the sense that clipping on peaks will begin. For a completely secondary reason, I measure the output of my speaker at different positions of the volume control using a Yamaha RX-797 100w/ch Stereo Receiver -
9 o'clock = 75dB
10 o'clock = 85db
11 o'clock = 90db
12 o'clock = 94db
1 o'clock = 98db
This is with some fairly large and efficient speakers. And this was with music, not broadband Pink Noise. Also, though it should be obvious, the reading are average not peak.
You could generalize and say that 1 o'clock is 100db, and that is LOUD! Do you really need to be playing that loud? I think, for loud play, I am typically in the 11 o'clock to 12 o'clock range, on drunken smoke filled nights on rare occasion I might run up to 1 o'clock, but that is really pushing it. At 2 o'clock and above is nothing but danger and distortion, you should never go over this amount assuming normal source equipment and normal speakers. At 1 o'clock up to 2 o'clock you have pretty significant Clipping on the peaks. There is absolutely not point in going above that.
Also keep mind that there is a Square factor
as you turn the volume up. Up +3db on the high end of the dial is a huge cascade in the power, whereas +3db on the low end of the dial is a small change in actual power. Every time the sound increased +3db, the power doubles.
Keep that is mind, when you are already loud and try to squeeze that last little bit out of the speaker, the power jumps by a huge amount.
Let's take a fairly common 87dB rated Sensitivity speaker, and start ramping the volume control up -
87db = 1w
90db = 2w
93db = 4w
96db = 8w
99db = 16w
102db = 32w
105dB = 64w (this is in the range of the physical limit of most speakers)
108db = 128w
111db = 256w
You can see the massive cascade of power in those last few nudges of the Volume Control upwards.
At higher volumes the clipping will increase. When you exceed the Power Supply Voltage, the Peak Signal is literally chopped off at the the top and bottom. The higher you go, the more that is chopped off, and the longer the output stays at full Power Supply Voltage. That build up a lot of heat in the Voice Coil.
Then there is the matter of the Excursion
of the many drivers. They are physically suspended, they can only move just so far. If you try to push them father than they can physically go, there is a chance you will push the Voice Coil out of the Voice Coil slot, and there is no guarantee that at those high volume will will accurately fall back into the slot. Even if the Voice Coil does not come out of the slot, you can push the speaker so hard the Voice Coil shape distorts causing it to rub, and that can cause a short, and that can melt the Voice Coil destroying the Driver.
The next factor is TIME,
you might be able to over-voltage a given driver for a few seconds, but if you sustain those high levels for a significant period of time, heat can build up in the Voice Coil to the point where the insulating lacquer melts again shorting the Voice Coil and damaging the Driver. I can think of one example that I personally experienced, where a person had bought a new driver for a guitar amp. We tested it out, it worked good, but then we decided to leave, and out of laziness we left the amp on. We went and came back later, and the Guitar/Amp had developed a low level feedback loop, it wasn't very loud but it sustained at the level for over an hour. When we got back the speaker was buzzing and the Voice Coil was damaged. Again, even a low level steady tone sustained over time can cause enough heat to build up to destroy a drive. Now, realistically, more dynamic music that ebbs and flows has time to dissipate some of that heat. But the potential is still there to destroy speaker with TIME.
The real secret to using your equipment safely is to have an understanding of the reasonable limits of the equipment, especially the speakers, and to have the discipline to not exceed those limits.
It is never over-powered or under-powered amps that blow speakers, it is always the guy running the Volume Control. Don't be that guy, and don't let your drunken ham-fisted friends be that guy.
In my opinion, given the Volume Level I have experienced and measured, there is absolutely not need to every go over about 1 o'clock on a standard Analog Volume Control. If you do, then you do so at your peril.
Again, the way to maintain the safety of your speakers it to have a common sense understanding of the reasonable limits of those speakers. In several decades of playing music, and even through my hard core party days, I have NEVER blown a speaker ... because I understood the reasonable limits of my speakers. On one of my systems, I am using 60w speakers on a 100w/ch amp, and still don't have a problem, because I stay within the bounds of reason.
.... don't be that guy....
For what it is worth.