Quote Originally Posted by Smokey;368846
I mentioned before that alot of poeple associate loudness with power :D

Loudness and power are not directy related. Even 1 watt of power can make a speaker pretty loud. The extra power is not for loudness, but rather for cleanly reproducing transient peaks. Check out this web site that explain it better. I quote the most important part:

"It is obvious from the example above that adequate amplifier power is necessary to provide an accurate portrayal of music. This is especially true when attempting to reproduce realistic levels, or when driving inefficient speakers. However, even small efficient speakers may require copious amounts of power to cleanly reproduce transient peaks. In the final analysis, it is difficult to have too much power. While a small amplifier of only a few watts output can produce surprising average loudness, the dynamic peaks will usually suffer."

[url=http://www.gcaudio.com/resources/howtos/voltageloudness.html
The Relationship of Voltage, Loudness, Power and Decibels[/url]

I understand fully and have two examples to prove your point...

A long time ago, before man roamed the Earth, a friend had speakers that had peak indicators on them (little lights that would light up when the power reached the maximum that the speakers were rated at)...(cool huh!). I'm not sure what the limits were that would trigger these lights, but I assume it was over 100 watts.

His amp also had meters (VU) on it. So one day, he was cranking it for the enjoyment of himself and his neighbors and the lights on his speakers were flashing, but when he looked at his power meters on his amp, it was only showing about 30 watts. He was confused and so I explained the difference between continuous power and peak power and that the speaker lights were indicating peak power while the amp was showing continuous power.

Thinking in round numbers, let;s assume that his amp was putting out 120 watts peak and 30 watts continuous. This is a headroom of 6db (30/60/120). According the the article that you posted, this is a 4 times increase in power and only 50% increase in loudness.

Here is a link to relative loudnesses that I will use as a reference (I assume these numbers are representative of continuous power). Sound levels (dB) and relative loudness of typical noise sources in indoor and outdoor environments.

Using the numbers for "Moderately loud - Living room music" , it shows 76db. Since my speakers are 91db efficient. This means it takes about 1/5 of a watt to drive my speakers to this volume (76db). Since my amp is about 6 watts, this makes my maximum volume about 97db at 4 watts. We'll just toss the last 2 watts out since it won't add any appreciable loudness. This gives me a headroom from 76db to 97db of 21db. Also, the peak of 97db is almost equal (according the the link I sent) to a "Bell J-2A helicopter at 100 ft . . . 100 dB"

That seems pretty respectable, don't you think? From these numbers, it seems, to me, that 6 watts is enough to create decent music. Of course, if I turn up the volume, the amount of relative headroom shrinks.

If you think it will only play a low volumes, you couldn't be more mistaken. Have you ever watched the movie "Lost in Space"? It begins with a space battle where the good guys are fighting the Genteks over a space gate they are constructing. I play that movie at a realistic volume. Even a movie theater doesn't get much louder.

Of course, listening distance and room size figure into all of this and believe me, it is minimal. Out of necessity, my stereo is in a small room. It's a funny thing, I was going to give up on this audio thing because I didn't have a suitable room to set it up in, but as it turned out, I couldn't be more pleased.

The other story (much shorter) is that in the 70's I owned a pair of Phase Linear dipole speakers and a receiver rated at 80 watts. The speakers were rated at (if I remember correctly) 350 watts. While I loved the clarity of these speakers I also loved the dynamics and loudness that my friends box speakers put out. So, one day cranked my speakers as loud as I could to see if I could get them to sound like my friends speakers. Well I couldn't (it's the nature of dipole), but in the process, I blew out one of my drivers. I was surprised since my speakers were rated to take much more power. That's when I learned that too little power was worse than too much.

However, and I'm not sure about this, at 6 watts which is way below what my present speakers can handle, I don't think I could blow a speaker even if I ran my amp into full clipping for a prolonged period of time. I'm not going to test this!

Anyway, thanks again. I really enjoy being forced to think about things.