How much power do I really need?

[wxn]

Hi everyone.
I've been reading a lot recently, mostly Elliot's website. One of his articles state that average music has a swing of about 10 to 20 dB, which means 100W amplifier for 10W of average power if want to eliminate clipping. In other words, for two 40W midbasses I will need at least two LM3886 in BTL mode and >100W of total power.
Am I missing something or quality music listening is a really power hungry thing.

[peranders]

Somewhere between 50-100 W will cover most needs if you play home and have normal speakers. One LM3886 with 50-70 W out and 120 peak will get you evicted from your apartment.

10 watts average power is pretty load. Normal listening level is 0.1-5 watts.

[wxn]

Let's say the drivers are 87dB/w, so doubled they'd produce 90db/W. With 10W, this would result in 100dB of sound. Unfortunateli I am not very familiar with the numbers. Could someone give me an idea just how much decibels can normal human take before his ears start to ring?

[x. onasis]

I can give you my impressions. At the numbers you're suggesting above, say an MTM using two 87dB woofers pushing them around 10W, my meter reads an average of 88-89dB about 14ft. away. Thats loud enough that you'd have to talk very loudly to communicate with someone standing right next to you.

This is loud, but some people actually like to listen to music at louder volumes. Recently I was letting a friend audition an amp and speakers at his secluded home in the woods. They immediately cranked the volume to an average of about 92dB, that produced peaks above 100, we had to shout to each other to be heard, and within a minute I was experiencing "temporary threshold shift" which is not a ringing in your ears, but more like a lessening of hearing sensitivity in the higher octaves. This is the ear's way of protecting itself temporarily, but repeated exposure to these volumes will produce permanent hearing loss.

I believe if you hear a ringing, you have done some level of permanent damage.

Everyone's preference for listening to music is different, but I've found most people listen at about low 70's to enjoy the music at full bodied presence....about 80dB when critically listening to new speakers and feel around 85dB is loud music in their home.

Here's a chart

[wxn]

Wow, thanks for such an informative reply. So all this means that if i have a pair of 90dB/W towers, I only really need no more than 10W per channel, even having in mind all the peaks and stuff (I surely don't want to lose hearing and/or upset my neighbours).
And from this, even a single LM4766 could drive both channels without overloading, right? Cool

[MarcelvdG]

According to Dutch law, when someone is subjected to sound levels above 80dB A-weighted (power average) at work, his or her employer must provide hearing protection. Above 85dBA, the employee must wear the provided protection. Of course the unweighted levels can be higher, for example when the sound consists mainly of bass.

For what it's worth, I used to use a 2 times 20W amplifier with my two ESL-63 loudspeakers (86dB at 2.83V, extrapolated to 1m). The amplifier has a clipping LED that indicates any momentary clipping. It never indicated clipping during normal use, except one time when I played a recording with excessive wind noise (made outdoors with a microphone without wind screen).

[percy]

I only really need no more than 10W per channel even having in mind all the peaks and stuff

I am no expert and please correct me if I am wrong but - from what I have read so far - isn't this incomplete information ?
Don't we need to know how much "reserve" the amp has AND how much the power supply should have ? i.e at what max power level the amp will be able to deliver a clean peak before it starts clipping ? And that the power supply should have enough capacity to provide for that peak(100W+?).

What if the amp starts clipping at 20W ? What if the power supply cant provide anything more than what is needed for 10W ?

[jackinnj]

well, you can't always get what you want, i said you can't always get what you want, but if you try sometime, you'll find, you'll get what you neeeeed.

[percy]

I beg your pardon ?

[wxn]

percy, actually it was 1W average power that I've had in mind, not 10W + 10dB swings, sorry if my crappy english makes it harder to understand what I am trying to say