I read this
Myth #1 "When driving a perfect loudspeaker a 1000W amp is only twice as loud as a 100W amp. When driving a real loudspeaker that suffers from thermal and mechanical power compression a 1000W amp will be less than twice as loud as a 100W amp, probably only about twice as loud as a 50W amp at best."
On the website
Barefaced Bass - Mythbusters #1 - amplifiers
I think this is incorrect as 1000w will sound twice as loud as 500w.
Reason Double to power and you get almost 3db gain
Are they incorrect ?
Or they conclusions are wrong
about the Myth 3 also i am unsure
Myth #3 - If your amp isn't powerful enough you risk blowing your speakers through underpowering.
Truth #3 - You will never blow woofers or mid-bass drivers, i.e. the 8"/10"/12"/15"/18" speakers found in a bass cab, because your amp isn't powerful enough.
My version of truth- you dont risk blowing but burning it with clipping
Myth #1 "When driving a perfect loudspeaker a 1000W amp is only twice as loud as a 100W amp. When driving a real loudspeaker that suffers from thermal and mechanical power compression a 1000W amp will be less than twice as loud as a 100W amp, probably only about twice as loud as a 50W amp at best."
On the website
Barefaced Bass - Mythbusters #1 - amplifiers
I think this is incorrect as 1000w will sound twice as loud as 500w.
Reason Double to power and you get almost 3db gain
Are they incorrect ?
Or they conclusions are wrong
about the Myth 3 also i am unsure
Myth #3 - If your amp isn't powerful enough you risk blowing your speakers through underpowering.
Truth #3 - You will never blow woofers or mid-bass drivers, i.e. the 8"/10"/12"/15"/18" speakers found in a bass cab, because your amp isn't powerful enough.
My version of truth- you dont risk blowing but burning it with clipping
Hi,
Doubling the power certainly does not sound twice as loud.
The Bel (10dB) is known in telephone systems to sound
approximately twice as loud for any given level change.
However the bass end of hifi and the F&M curves of
the bass end means a 100W amplifier sounds more
than twice "as loud" as a 10W amplifier, probably
about 3 times, certainly not 10 times as loud.
rgds, sreten.
People are poor judges of relative sound levels, why the
F&M curves are equal loudness only, normalised to 10dB
steps at 1KHz. There is very little information on peoples
perception of relative absolute levels with frequency.
Doubling the power certainly does not sound twice as loud.
The Bel (10dB) is known in telephone systems to sound
approximately twice as loud for any given level change.
However the bass end of hifi and the F&M curves of
the bass end means a 100W amplifier sounds more
than twice "as loud" as a 10W amplifier, probably
about 3 times, certainly not 10 times as loud.
rgds, sreten.
People are poor judges of relative sound levels, why the
F&M curves are equal loudness only, normalised to 10dB
steps at 1KHz. There is very little information on peoples
perception of relative absolute levels with frequency.
Last edited:
Twice the power is 3dB, 50 watts to 100 watts = 3db which is what you need to notice a change. you need 10db to sound twice as loud.
so 100 to 200 watts = 3db,
200 to 400 = another 3db or 6db from 100 watts
400 to 800 = another 3db or 9db from 100 watts
so just about 1000 watts = twice as loud as 100 watts.
Yes power compression reduces a drivers output requiring more input power to = the same acoustic output power. so 10 times the power is a rough figure. not exactly literal.
so 100 to 200 watts = 3db,
200 to 400 = another 3db or 6db from 100 watts
400 to 800 = another 3db or 9db from 100 watts
so just about 1000 watts = twice as loud as 100 watts.
Yes power compression reduces a drivers output requiring more input power to = the same acoustic output power. so 10 times the power is a rough figure. not exactly literal.
If i am putting double the power in a sub then i would expect it to sound twice as loud.
How can that sub cheat and eat up all the extra double and give me only little more loudness
10db= 10 times the power, it should be 10 times loud
dB: What is a decibel?
Play, broadnoise decreasing by 3db steps
Update: Aprox
Doubling of the volume (loudness) 10 dB
Doubling the sound pressure (voltage) 6 dB.
Doubling of acoustic power (sound intensity) 3 dB.
Is a three dB difference in sound twice as loud
Loudness volume doubling sound level change factor of perceived loudness formula calculate power level noise levels volume logarithm dependence three four fold loudness sound - by what factor does level decrease dependence comparison decibel levels 3
How loud is twice as loud - Page 3 - TalkBass Forums
if i have 2 volts reading on multimeter
then i double the amplitude i see 4 volts
but it seems loudness is different from power and amplitude
How can that sub cheat and eat up all the extra double and give me only little more loudness
10db= 10 times the power, it should be 10 times loud
dB: What is a decibel?
Play, broadnoise decreasing by 3db steps
Update: Aprox
Doubling of the volume (loudness) 10 dB
Doubling the sound pressure (voltage) 6 dB.
Doubling of acoustic power (sound intensity) 3 dB.
Is a three dB difference in sound twice as loud
Loudness volume doubling sound level change factor of perceived loudness formula calculate power level noise levels volume logarithm dependence three four fold loudness sound - by what factor does level decrease dependence comparison decibel levels 3
How loud is twice as loud - Page 3 - TalkBass Forums
if i have 2 volts reading on multimeter
then i double the amplitude i see 4 volts
but it seems loudness is different from power and amplitude
Last edited:
Hi,
Except it depends, on the spectrum the music has.
rgds, sreten.
Make a recording with various level jumps, say 3, 6, and 10dB
and decide for yourself. Try a bass heavy recording versus
say just guitar and vocals to see its not very clearcut.
It is a very rough approximation, which depends on frequency and level in non intuitive ways, but remember that loudness (The unit is the Phon) is a perceptual measure where power is a physical one, so the two bearing a non linear (and approximately logrithmic) relationship should not be a surprise.
100W -> 1000W is 10 times the power (+10dB), but perceptually only roughly twice as loud (Highy level and frequency dependent), the power has increased by 10 dB as has the SPL (Ignoring power compression), but the perceived level has only roughly doubled.
This is why PA systems become so very large so very quickly.
Regards, Dan.
100W -> 1000W is 10 times the power (+10dB), but perceptually only roughly twice as loud (Highy level and frequency dependent), the power has increased by 10 dB as has the SPL (Ignoring power compression), but the perceived level has only roughly doubled.
This is why PA systems become so very large so very quickly.
Regards, Dan.
I actually own a 1000W PA theatre amp and an 10W SET amp. It's true the 1000W amp is about 4 times louder than the 10W amp.
It's also true that the 10W amp can still get pretty damn loud. At full blast you want to stand at least 10 feet away from the speakers. In real world use, you rarely use the full output of an amplifier so perception of loudness is simply however high the gain of the amp is set to. Set a 10W amp to high gain, sell it as a 100W amp, and people will never tell the difference unless someone does an actual comparison to a true 100W amp.
It's also true that the 10W amp can still get pretty damn loud. At full blast you want to stand at least 10 feet away from the speakers. In real world use, you rarely use the full output of an amplifier so perception of loudness is simply however high the gain of the amp is set to. Set a 10W amp to high gain, sell it as a 100W amp, and people will never tell the difference unless someone does an actual comparison to a true 100W amp.
The contours of equal loudness are only 3dB~4dB apart below 40hz in the 80dB~90dB range.
3dB more down low will sound much louder.
However, as the levels go over 100dB the contours become farther apart at most frequencies and it takes over 10dB to sound twice as loud.
Power compression only makes things worse.
3dB more down low will sound much louder.
However, as the levels go over 100dB the contours become farther apart at most frequencies and it takes over 10dB to sound twice as loud.
Power compression only makes things worse.
Plenty of things willl handle 1000W for a sufficiently short time, there are only really two things that kill speakers, voice coil overheating and exceeding the mechanical limits, and the voice coil has a thermal time constant, so it can make a lot of sense to use an amplifier that can put a huge amount of power into a box short term as long as thermal limits and Xmax are respected. The PA trade has this to a fine art as power is cheap compared to having to truck extra boxes....
Also, the better end of the PA kit sometimes has sense connections to the processing so that speaker protection electronics can model things like voice coil temperature and displacement from amplifier output voltage, means you can use a really big amp with a relatively small driver safely.
Think Camco Vortex 6 pushing a Nexo Alpha E 10 inch horn loaded mid/high pack to well over a KW peak, the driver cannot handle anything like that continiously, but it does not matter, because it can use all that power short term, and the protection electronics takes care of the matter.
I have used MA5000 (2.5KW/Channel) to drive 10 inch speakers before, it sounded good and worked fine, again, sense connections and a processor with thermal and displacement modelling.
The tendency of the hifi world to use amplifiers having only notional headroom (Maybe 3dB on a good day) above speaker continious ratings has always puzzled me, as it implies that either hifi speaker continious ratings are far higher then they need to be, or that people are relying on dynamics crushed in mastering to reduce the need for ability to handle transients.
D&B audiotechnik (One of the premier makers of PA speakers in the European market) have an interesting approach, they supply the matching amplifiers for their boxes that have a very much higher short term rating then their continious power rating, this being quite deliberate as it allows the box to actually work somewhat close to its continious rating without clipping the amps on transients.
If your SPL requirement is such that you need to run a box close to its continious rating, then the amplifier MUST be capable of significantly more power at least in the short term (Thermal limit can of course be sized for the continious power rating of the speaker), otherwise you cannot get close because there will be no headroom for the crest factor.
The saving grace of the hifi scene is that even with the pathetic efficiency levels achieved by most hifi speakers, most listening is done at a tiny fraction of rated power so the speakers and aps are seldom really pushed to the limit, that "double the volume is ten times the power thing works the other way as well", and most hifis play most of the time at very much less volume then pa rigs do.
Also, the better end of the PA kit sometimes has sense connections to the processing so that speaker protection electronics can model things like voice coil temperature and displacement from amplifier output voltage, means you can use a really big amp with a relatively small driver safely.
Think Camco Vortex 6 pushing a Nexo Alpha E 10 inch horn loaded mid/high pack to well over a KW peak, the driver cannot handle anything like that continiously, but it does not matter, because it can use all that power short term, and the protection electronics takes care of the matter.
I have used MA5000 (2.5KW/Channel) to drive 10 inch speakers before, it sounded good and worked fine, again, sense connections and a processor with thermal and displacement modelling.
The tendency of the hifi world to use amplifiers having only notional headroom (Maybe 3dB on a good day) above speaker continious ratings has always puzzled me, as it implies that either hifi speaker continious ratings are far higher then they need to be, or that people are relying on dynamics crushed in mastering to reduce the need for ability to handle transients.
D&B audiotechnik (One of the premier makers of PA speakers in the European market) have an interesting approach, they supply the matching amplifiers for their boxes that have a very much higher short term rating then their continious power rating, this being quite deliberate as it allows the box to actually work somewhat close to its continious rating without clipping the amps on transients.
If your SPL requirement is such that you need to run a box close to its continious rating, then the amplifier MUST be capable of significantly more power at least in the short term (Thermal limit can of course be sized for the continious power rating of the speaker), otherwise you cannot get close because there will be no headroom for the crest factor.
The saving grace of the hifi scene is that even with the pathetic efficiency levels achieved by most hifi speakers, most listening is done at a tiny fraction of rated power so the speakers and aps are seldom really pushed to the limit, that "double the volume is ten times the power thing works the other way as well", and most hifis play most of the time at very much less volume then pa rigs do.
PA systems often have to play live music, where you get much higher dynamics, maybe +35dB transients over average levels.
Recorded music only has +12dB transients over average level, and often less. Clipping is already built into the recording. There is simply no need for big headroom in hifi. If your average listening level is 0.5W, then just build amps 10W and over. All this talk of 1000W amps belong in the PA scene.
Recorded music only has +12dB transients over average level, and often less. Clipping is already built into the recording. There is simply no need for big headroom in hifi. If your average listening level is 0.5W, then just build amps 10W and over. All this talk of 1000W amps belong in the PA scene.
Depends on what recorded music surely, +12 over average might fit quite a lot of pop and rock, but you are going to want rather more then that if orchestral of the purist sort is your thing (And if you have the listening room to take advantage of all that dynamic range).
Besides, power is cheap, doubly so if you don't have to do high average power (No thermal issues), think class H with the high voltage rail quite a long way above the low voltage one.....
Regards, Dan.
Besides, power is cheap, doubly so if you don't have to do high average power (No thermal issues), think class H with the high voltage rail quite a long way above the low voltage one.....
Regards, Dan.
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