SnowDrifter

It's fine. Shoot it with some compressed air or ignore it. Don't use any liquid

Ayyy what's up bud

Drop the drama, keep answers to the original post. Next person who tries to poke the stick is going on vacation. No, I don't care who started it. RMS = root-mean-square = average voltage under a sine wave. Remember integrals? Think about it. It'll come to you. Square waves will carry a higher RMS but will not carry a higher peak voltage, ergo there is no increase in motor force to the driver. Additionally, periodic DC contamination at the top and bottom of the wave will change the inductive behavior of your driver. Big tl;dr power from clipping / sawtooth wave =/= power from a clean sine wave. You can fudge the numbers higher by clipping but it won't translate into real world usability, and I would argue would even be a determent. Now there IS a standard of rating power established by the consumer electronics association (CEA) which theoretically means it will output rated. But you'll often find that the magic logo and claims can be falsely applied to products. Higher end equipment often won't carry it since it's a moot point - word of mouth advertising, independent tests, no point. And add to that, many cheaper amps just stick big meaningless numbers on the box to deceive consumers who don't know any better to make a sale. All that to say.... Your question regarding amplifier ratings doesn't really have any straight answer. Regarding the dd-1, it detects distortion based on an ideal sine wave as a reference point. Not all amplifiers will work with this due to either signal delivery or how they handle signal processing. Regarding your gain, it's a ratio of input voltage to output voltage. It is NOT a volume knob. Half gain is not half volume. Example: Amplifier has a maximum clean output voltage of 50v RMS or ~71v peak to peak (dictated by the power supply of the amplifier). With an input voltage of 3v, you would need that ratio to be 23.7:1. Since it's just a potentiometer with no fine labeling or detents, and there is a great degree of variability in input signal strength, trying to do any sort of math here would be an act of futility. That's where the dd-1 comes in. It helps you find the appropriate setting for your individual setup. As a point of note, you can turn up the gain past this and get higher readings on your multimeter sure. But you can't exceed the power supply constraints of your amplifier. You can't pull 100v out of a 71v power supply, so the equipment response will be to clip - to flatten out the top of the sine waves, which presents the issues I mentioned above.

It's possible sure. Though probably not in a musical / daily driver environment. You'd be playing a game of maximizing efficiency. Make panels and surfaces rigid so they don't absorb energy. Play with tuning so you can maximize resonance around a specific frequency. So, yes, you can do 160 on 3k. However it wouldn't be a musical 160. It would be purpose built and engineered for a meter.

Done

Good shit! Fix your links

I would be surprised if that fried it. It's just a DC reference signal. Same as you'd get on the 'positive' side with the volume down. Toss a new battery in, make sure your cord is plugged in all the way. Try measuring again either on the deck, or pick an arbitrary low volume setting on the deck and check at the amp.