Myth Busters: 1000W amp is only twice as loud as a 100W amp

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I agree Vostro,Twice as loud is very loud
Serten and other Friends, you are right 10db is 2ce loud but it is highly dependent on frequency too.
Dmills is right on the money, The unit of apparent loudness Lapp is the Phon
nkolisnyk, i always thought log antilog, integration was man made math hell for students. Didnt know nature runs a lot of things on log, antilog, integration

I came across this amazing 32 page research about human ears
http://courses.physics.illinois.edu/phys406/Lecture_Notes/P406POM_Lecture_Notes/P406POM_Lect5.pdf

Here are some facts for those who don't wanna read whole research paper or want to avoid the graphic ear images
Here is the human ear loudness equation nature decided to use:confused:


Human ear loudness curve


Page 18 and 30 ear sensitivity changes with age. As you grow old you need more tweeters(high freq.) not subs. Very different situation for women.


Page 19 The Range of Human Hearing: Sound Intensity, Sound Intensity Level vs. Frequency:

Page 22 Relationship between Apparent/Perceived Loudness Level

Page 23 The Just Noticeable Difference (JND, in dB) in our human hearing is JND ΔLp ∼0.5 dB. Changes with age again n freq

Lastly i think all ours ears are different and i think everyone hears the same music a little differently.
After reading this paper I wont be surprised if Dogs hear mozart as white noise. lol
Will read that article some other day. Its way too much info
 
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Surely how many decibels (or phons) it takes to make something "twice as loud" depends very much on how loud it is to begin with?

So 20dB SPL might reasonably be described as "twice as loud" as 10dB SPL, whereas 100dB isn't nearly as convincingly twice as loud as 90dB....a logarithmic scale upon a logarithmic scale....

But spl meters are cheap as chips nowadays, so you could always get one and try it out, see how many dBs sounds like twice as loud to you for various volumes, frequencies, program materials etc. If you do, let us know your findings, I'd be interested to hear them.

Prof Steven Errede, one of whose papers is mentioned earlier, has the notes for his course in "Acoustical Physics of Music" available online, there's an index at:

UIUC Physics 406 Lecture Notes
 
I see that people need some treble boost as older, especially males!

People age 65 lose at least 6dB hearing at all frequencies, 40dB (!) hearing at higher frequencies! This means older people need an amp with 4x the wattage.

Not necessarily...if we use our hifi system to reproduce what we hear at the concert hall the loss is built into our perception of the live event and would not need to be compensated for by the reproduction chain.
 
Not necessarily...if we use our hifi system to reproduce what we hear at the concert hall the loss is built into our perception of the live event and would not need to be compensated for by the reproduction chain.

And what if you listened to the concert when you were 20 years old, fell in love with the music, and now you are 65 years old, and you listen to the reproduction of said music? The reproduction would sound vastly different from the music you fell in love with when you were young.
 
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Joined 2007
And what if you listened to the concert when you were 20 years old, fell in love with the music, and now you are 65 years old, and you listen to the reproduction of said music? The reproduction would sound vastly different from the music you fell in love with when you were young.

Except the brain seems to be very good at filling in the missing bits so long as the beat and rhythm are still able to be heard well.

But getting old and going deaf sucks, and I can't wait for Bionic ears; which still seem to be at least a decade away even with all the money being paid into research. As far as power goes when you get to Bi and Tri-amping you seem to be able to get away with slightly less over-all power Why is that??
 
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Joined 2001
Amit:

Why not just decide for yourself about decibels and "twice as loud"? It's easy to do.


First, download freeware SweepGen-I've been using it for years.

Then go to the following site:
Audio Tools - from David Taylor, Edinburgh

Then, in the middle of the page, (you might have to scroll down), click on
"Download SweepGen V3.5.6".

This freeware allows you to select any frequency between 20-20K Hz, and gives you decibel slider so you can tell how many decibels you are going up and down.

Just be sure the "L+R" box is checked. Then select any mid or high frequency you like, and move the volume up and down 3 db or 10 db at your choosing.

This way, you can hear first-hand how many decibels it takes to sound "twice as loud".
 
With regards to 2. and 3. under powered amps will blow tweeters in no time flat. An old saying: underpowered amps blow tweeters overpowered ones rattle woofers. Usually one plays underpowered amplifiers full bore to get decent sound volume which results in clipping and this blows the tweeter (how many people blow their car's tweeters?). With overpowered amps your speaker will distort long before it blows the voice coil and unless you are an idiot and play your speakers continuously while distorting (or don't know the difference) then they will fry.
 
With regards to 2. and 3. under powered amps will blow tweeters in no time flat. An old saying: underpowered amps blow tweeters overpowered ones rattle woofers. Usually one plays underpowered amplifiers full bore to get decent sound volume which results in clipping and this blows the tweeter (how many people blow their car's tweeters?). With overpowered amps your speaker will distort long before it blows the voice coil and unless you are an idiot and play your speakers continuously while distorting (or don't know the difference) then they will fry.

In the PA world, they use amps with twice the power handling of the speaker to avoid this. In the hifi world, whose ears are going to take heavy clipping continuously long enough to blow a tweeter? Today's tweeters could also handle more power than in the past.
 
Let me add that in the PA world they use very good and properly set limiters , same with crossovers, and they avoid clipping like the plague.
They have the tools , of course.
Anybody who does not care, soon has a series of very expensive "lessons" teaching him.
 
In the PA world, they use amps with twice the power handling of the speaker to avoid this. In the hifi world, whose ears are going to take heavy clipping continuously long enough to blow a tweeter? Today's tweeters could also handle more power than in the past.

Only with the correct crossover, tweeters can only handle about 5w.
 
Agree, and forgot one extra detail: *standard* practice in mid price PA cabinets, such as those bought and operated by Musicians themselves (vs. hiring a Pro Sound Company) is to add a power limiting car type lamp in series with the tweeters, just in case the operator is careless.
So much so, that typical 12V 15W car lamps are called "Tweeter Lamps" in speaker accessories catalogs.
For those interested in the Math, such lamps dynamically limit current to slightly over 1A, so 8/10W *max* into the tweeter.
Any extended abuse and the lamp blows like a fuse.
 
"under powered amps will blow tweeters in no time flat. "

It's not the clipping of the underpowered amp that causes the tweeter to blow.

It is either the increase in long-term average-power of the undistorted portion of the program material, or mechanical damage to the tweeter that causes it to fail (single-strand lead-out wire).

The increase in HF from the bass line clipping the amplifier is of short duration and trivial compared to the increase in average power during the much longer time the amplifier is not clipping.

From examining thousands of tweeters that failed over a 30+ year period of time, and deliberately trying to blow tweeters on the bench, I can recognize the failure mode from an autopsy.
 
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And what if you listened to the concert when you were 20 years old, fell in love with the music, and now you are 65 years old, and you listen to the reproduction of said music? The reproduction would sound vastly different from the music you fell in love with when you were young.

Only if you have a superhuman ability to precisely remember sound details from years ago...but our brains don't work that way. That is why anecdotal reports of "this (cable/capacitor/Shakti stone/etc.) sounds better than that one" are unreliable without closely controlled listening tests in close sequence. Hearing is a very accommodative sense and the gradual shelving down of high frequencies over decades is more subtle than you would think. Only when the losses reach down into the mid-frequencies that are critical for speech comprehension do we notice, and even then many geezers will insist that they are hearing fine and the problem is that everyone around them mumbles. As a 60 year old who now wears hearing aids, you may be assured that I speak from experience.
 
While it is reconized that 10db is the difference to sound twice as loud this does not compensate for percussive energy. Easy to understand , listen to 6.5 fullrange driver playing at 93 db and then a big fullrange system playing at that same 93 db..

The loudness perception will be different for both ....

I see that people need some treble boost as older, especially males!

People age 65 lose at least 6dB hearing at all frequencies, 40dB (!) hearing at higher frequencies! This means older people need an amp with 4x the wattage.

Funny , i use less now than at 25, listen to music now at a lower level and can still hear 16k last hearing test ...

I'm almost as old as Pano and dirt ...:)

"Any extended abuse and the lamp blows like a fuse. "

Use the #211-2 (about 1A) to protect an 8Ω 1" voice-coil.

Use the #1156 (about 2A) to protect an 8Ω 1-3/4" voice coil.


I usually use a 10 amp speaker fuse to protect my amplfiers ...:)
 
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"under powered amps will blow tweeters in no time flat. "

It's not the clipping of the underpowered amp that causes the tweeter to blow.

It is either the increase in long-term average-power of the undistorted portion of the program material, or mechanical damage to the tweeter that causes it to fail (single-strand lead-out wire).

What do you think clipping is, it's the increase in average power when the top of the sine wave is cut off almost approximating a square wave.
 
Hmmm... I have very good and well trained hearing. Can reproduce frequency by memory. Can hear distortions, imagine waveform, and guess schematic that can produce such distortions. But how can I tell if the sound is louder TWICE, but not say 1.8 times, nor 3 times? I have no scale to measure. Who really does? I am curious.

Only if you have a superhuman ability to precisely remember sound details from years ago...but our brains don't work that way.

Mine does. I remember mom's, dad's voices, voices of my friends, sounds of gramophone, sounds of different radio receivers, guitar amps, studio reproduction of our ensemble when we were recorded, and so on. I am 55 now, and remember at least 50 years' old sounds.

...but I don't hear differences in cables. :)
 
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