Watts accustic aint watts electrical.
An electrical watt is 1 amp times 1 volt or any combination that mathematically works out from Power = volts time amps
Acoustic watts are a strange beasty and can only be measured with an acoustic watt meter. Seems that sound waves actually move power around but not in a volts time amps fashion so a watt of acoustic power is nowhere near a watt electrical. ie the acoustic watts are always much higher than any electrical wattage you might be pushing. It is a gimmick by the stereo manufacturers to promote their products. nobody want s 10 watt stereo, that is not enough to power a decent light bulb...... or so the thinking goes.
My stereo is wired through the ammeter and it does not even move the needle even with full power. It is a 100 watt "acoustic" watt stereo. A needle width on my ammeter is about 0.125 amp
Bill-
This is so far off topic...
Still you bring it up...
There really is such a thing as an acoustic Watt. Go here to learn about it.
http://en.wikipedia.org/wiki/Sound_power There is however no conspiracy by the electronics manufacturers to use acoustic Watts. When you see the graph you will understand why. No radio or amplifier manufacturer would want to advertise their item as being capable of producing 1/1000th of a Watt out of any speaker.... As a side note, if they chose to, it would be completely wrong, as the acoustic Wattage output would be transducer /speaker dependent.
As an industry we state output from electronic devices as electrical Watts. We state and measure speaker output in decibels. To use acoustic watts would be foolish and provide a highly unreliable amd meaninglessly small number to use.
There are lesser-known and basically unknown manufacturers out there who use trickery in advertising their goods. One can have a model 5000W amplifer, where "5000W' is simply the alpha-numeric expression of the model number, but has nothing to do with any real measurable output.
I have seen little electronic devices with big steel slugs mounted inside for weight, that had power connections to operate the LED lights, and had not much more than a transformer inside... The "heat sink" had the phrase 100W + 100W = 200W screen printed on it. While this is a mathematically accurate statement where "W" is smply a variable, it too had nothing to do with any power output from the device....
I have also seen devices that were advertised as 100-Watt devices. Super... That statement of power
consumption did a completely accurate job of telling the consumer how much power the item USED, but spoke nothing to how much it put out....
Now since we are so far off topic, know there are lots of analogs between acoustic devices and some electrical counterparts. A horn like found on a PA enclousre is quite similar in analogy to an electrical transformer where voltage and current can be manipulated inversely. The horn takes very high pressure and very high velocity air and trades velocity for amplitude. A woofer in a sealed enclosure can be seen to be analogous to a first-order circuit where a capacitor is in series with a load to block low frequencies. Similarly a woofer in a vented enclosure, (Helmholtz Resonator) can be seen to be analogous to a circuit that contains a series capacitor and a parallel inductor tied to a load.
Ironically, there has even been work on an acoustic amplifier! In the years preceeding the Apollo Space Program, the Ling Corporation, (historically tied to Altec Lansing, Lansing corp, James B. Lansing, JBL) developed a "relatively" high-speed variable valve that was used to modulate a high-pressure column of air. By "relatively" high speed, the valve would not go above some very low frequency, maybe 200 Hz as I recall from reading about it... The pressurized air was contained in a big tank, basically a giant compressor tank. The valve was connected to a very large horn. The tank,valve, and horn were the acoustic analog to a single-ended triode tube audio amplifier. The tank and valve were push-push only, not push pull like a class A/B amp, but the valve was directly coupled to a giant horn (again, think transformer).... They simply skipped the loudspeaker, since they were modulating air-pressure and sound directly. They used these devices to simulate rockets at take off, to determine probable damage by acoustic energy at differeng distances to determine safe distances for people, structures etc...
Anyway, I have taken this thread about as far out on a tangent away from the OP's intent as anyone ever has. So sorry, but hopefully my input is amusing, if possiblly enlightening!
