Determining exact power being sent to your speaker

@stuartk -- seems you've also provided a good example of "prickly defensiveness"....  😉

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@mlsstl 

Your prickly defensiveness is entirely unwarranted. 

As I made no accusations, assertions or assumptions, I find it quite puzzling that you would describe my QUESTION as "putting words in [your] mouth".

All I have to say on this topic...

@stuartk -- I have nothing against lots of power and have owned and heard lots of amps over the years, ranging from not much power to lots of watts.  So, you're putting words in my mouth with the "mutually exclusive" comment.  It's just in my case, my favorite amp is currently a 20 watt/channel class A Aegir, which replaced a VTV Hypex with many times the power. I prefer the Aegir's sound and never had a hint of running out of steam at my preferred listening levels. 

That's the nice thing about this hobby -- people can pursue what works for them. As they, YMMV for others. 

@mlsstl 

"I happen to be in the camp that is more concerned about the sound quality of an amp rather than whether it has a zillion watts"

Just curious -- are you suggesting these two factors are mutually exclusive? 

I happen to enjoy both aspects of my Hegel H390. My speakers have never sounded as good as they do with Hegel (250 watts @ 8 ohms/500 watts @ 4 ohms) and the amps "warm side of neutral" sonics work very well with my other components. 

Vrms x Irms = Pavg. This average power is equal 0.5 of peak power for sinewave.. Pavg represents dissipated heat while rms value of power curve would be 0.62 of peak power for sinewave and it does not represent anything.

The amplifier power is never continuous. It’s 0W at silence and maximum wattage at the loudest.

A speaker’s power rating is based on maximum output. If a speaker is rated for 100W maximum, you can safely use a 300W amplifier with it so long as you don’t play it too loud.

You can calculate "too loud" bu using the power to db conversion. That is, if a speaker is rated for 100W, and 90 dB sensitivity:

dB = log10(100) = 20.

That is, at 100W input the speaker will play it’s rated sensitivity + 20. So, if your speaker is 90 dB at 1 watt, it will be at 110 dB at maximum. Just don’t play your speaker more than 110 dB (at 1 meter or yard) and you’ll be fine with any size amp.

https://www.rapidtables.com/convert/electric/db-converter.html

The first thing I'd suggest you do is buy a sound level meter. Ones for home use are relatively inexpensive ($20 to $30) or you can download an app for your smartphone for even less, or free. This will give you a ballpark idea of just how loud you listen. (One's person's "loud" may be someone else's "medium", etc.) For example, my "loud" these days is around 85 dB average. 

Then, look up the sensitivity of your speakers. A lot of modern speakers have ratings in the upper 80s -- for example my Ohms are 88 dB -- it takes one watt of power to produce that sound level. Small bookshelf speakers tend to be a bit less sensitive, while many larger speakers, like horn systems, tend to be much more sensitive -- they will play much louder on that one watt of power. 

Even if one watt of power gives more volume than your average listening level, you still need more power than that from your amp. Music is dynamic with loud, short duration peaks above the average playback level-- such as a drum strike or orchestra crescendo. 

Unless you are a head-banger that likes your music at an average volume of 100 dB or more, there usually isn't much concern about having too much power, though some do get carried away on this issue. I happen to be in the camp that is more concerned about the sound quality of an amp rather than whether it has a zillion watts. 

What rrog said. I started a thread about that exact same thing with an old Realistic power meter and was so surprised I was only using a watt or two listening at a decent volume.

use 12v lamp car brake to save tweeter ,, paraleling if you want more power 

Have you ever owned an amplifier with meters? Chances are you are using a lot less power than you think.

Thanks for the responses...sounds like I am good to turn it up a bit more than in the past which is good because I was starting to think I might need to get some new speakers...(*grin)

Vineman55, average music power delivered to speakers is only few percent of peak power (unless you listen to sinewaves) It is because average loudness you listen to (half of peak loudness) requires only 1/10 of peak power. In addition music has gaps. I would be more concerned with damage to tweeter caused by clipping when amplifier is too weak. Clipping produces a lot high frequency energy (harmonics) that might burn out tweeter.

The exact power delivered to the speaker can only be measured as transient. It's power at particular moment since we're dealing with the signal and not DC. The specified power is mostly measured within the audible frequency bandwidth. The measured power is usualy done against sine wave that gradually goes from most negative to the most positive value. The gap between maximum values called Amplitude. Power measured against Amplitude is called Maximum Power. The specified power is most-likely RMS power which is product of 0.707*Maximum Power. Sound is far more complexed form of signal that less-likely can be represented by meaning of Amplitude, Maximum Power and RMS. To measure power at particular moment delivered to the load you need oscilloscope. The load is also non-linear and complex value that should also be noted. It consists of linear DC Resistance and complex Signal Reactance...

Done that somewhere in the middle of high school...

There are technical experts here who can answer your question but for now, you should rest easy knowing that it is much more likely that you would damage your speakers from driving an underpowered amp into clipping than it would be to overpower them.