On the markets, the output power on the spec sheet is quite confused. From 1x w to 16xx w, when I learned electronics, my lecturer told me that the power output in cinema is about 1xx w only. How come does a power amplifier for normal consumers deliver thousands watts? Too big power for the house of normal customers and too costly. In the past, FTC and EN standard govern to quote the RMS output power in spec sheet. Do those rules become invalid? Any new standards to replace the previous ones? 
It’s fairly straightforward. The mains power (240V at up to 10A, or 2400W max hereabouts) is fed through a transformer with around 85% efficiency, giving us say 2100W max, then rectified and filtered, then fed through a class A-B power amp with maybe 60% efficiency, giving us say 1200W max from an Australian plug. Finally they feed the power through a complex marketing bullish!t network, and put 4kW out to the speaker. Funny enough, the whole mess only weighs a couple of kilos, so it must be terribly clever.
It's apparently reared its ugly head again - the wattage misinformation statistics.
This has been growing since the beginnings of the Digital Age.
And yes, to do nothing more than confuse or dazzle the dumbed-down hoardes of newer consumers that don't have a clue what wattage really is.
To pick up a 15 pound amplifier in one hand, and its front panel clearly labeled with "2000 Watts" - is laughable.
Yes indeedy.... it's a bunch of BS for sure.
This has been growing since the beginnings of the Digital Age.
And yes, to do nothing more than confuse or dazzle the dumbed-down hoardes of newer consumers that don't have a clue what wattage really is.
To pick up a 15 pound amplifier in one hand, and its front panel clearly labeled with "2000 Watts" - is laughable.
Yes indeedy.... it's a bunch of BS for sure.
That's largely the difference between hifi speaker sensitivity and PA speaker sensitivity in, for example, old school type cinemas, auditoriums and arrays for outdoor events. Tubes and transformers of any quality in former times were expensive and required regular parts replacement and maintenance - sensitive speakers were not particularly expensive so the choice was obvious then.
Some loudspeakers and arrays show a staggering 20dB SPL difference for the same size drivers but used in different applications. That translates to an enormous difference in power requirements and for tubes, several small amplifiers (with some out of service for maintenance) was the most economical way to provide the sound for movies and PA.
Modern cinemas are a different story. First they are smaller with fewer seats that in Dad's day but amplifier watts are now quite cheap. Sensitive, high linearity speakers that go loud are no longer cheap, so you can see where this is going - more power with more linearity and lower cost works better and cheaper for high SPL, high sound quality, extended bass and more dynamic sound.
Home theatre amplifiers are really a number, 5 or more, very efficient and cheap class D amplifiers. but the specifications of bona fide products are generally correct and an 8 channel home theatre system with big subwoofers, front, centre, rear and side speakers in a big den under your house can really chew up the power - maybe not a full 1kW continuously, but certainly approaching that with some dramatic, bass heavy sound effects.
I don't pretend to know much about FTC standards which in Australia are about fair trading and EN standards apply to European Economic Community technical standards - very broad areas of government, lots of talk and paperwork, perhaps more fit for a lounge or "everything else" forum discussion.
Yes, there is a load of nonsense ratings from nonsense sellers out there - you can pick the charlatans out, can't you? Hint: they don't originate from local sources, do they...
Some loudspeakers and arrays show a staggering 20dB SPL difference for the same size drivers but used in different applications. That translates to an enormous difference in power requirements and for tubes, several small amplifiers (with some out of service for maintenance) was the most economical way to provide the sound for movies and PA.
Modern cinemas are a different story. First they are smaller with fewer seats that in Dad's day but amplifier watts are now quite cheap. Sensitive, high linearity speakers that go loud are no longer cheap, so you can see where this is going - more power with more linearity and lower cost works better and cheaper for high SPL, high sound quality, extended bass and more dynamic sound.
Home theatre amplifiers are really a number, 5 or more, very efficient and cheap class D amplifiers. but the specifications of bona fide products are generally correct and an 8 channel home theatre system with big subwoofers, front, centre, rear and side speakers in a big den under your house can really chew up the power - maybe not a full 1kW continuously, but certainly approaching that with some dramatic, bass heavy sound effects.
I don't pretend to know much about FTC standards which in Australia are about fair trading and EN standards apply to European Economic Community technical standards - very broad areas of government, lots of talk and paperwork, perhaps more fit for a lounge or "everything else" forum discussion.
Yes, there is a load of nonsense ratings from nonsense sellers out there - you can pick the charlatans out, can't you? Hint: they don't originate from local sources, do they...
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RayLi--was your lecturer working for "Big Media " ( you know who )?
Movie theater Noise .....
This is a major issue in America and now the UK.
Its so bad now US audiologists are having to supply American kids with hearing aids ( no complaints from the hearing aid companies) --check out share prices .
Dr.John Bedolla -emergency room doctor-- Seaton Health care ( just one of many ) -quote " Human beings did not experience sound louder than 90-100 decibels for much of human history until the invention of gunpowder and machinery .
So for the vast majority of human existence our ears NEVER adapted to loud noises "---
He goes on-- Quote--"certain types of high spectacle movies , such as Transformers ,have decibel levels of 90db for almost the entire movie and have decibel levels of 120db for significant periods and some points getting to 130db .
Now 130db is a jet engine at about 10--TEN meters " end quote .
Why have US authorities not stopped this and yes I can quote many US citizens with ears bleeding at the end of the movie as well as REAL stats --if required ?
Because they get round the law by the old fashioned use of Compression techniques --very sly .
I have a wealth of data if anybody want to criticize this--mainly American as they have been doing it the longest so casualty figures are available --no Big Media shareholders please.
Real life- once the hairs at the end of your auditory nerve system die --they do NOT regenerate -has anybody seen somebody totally deaf with a hole drilled in their skull and a miniature amplifier connected direct to their brain ---I have.
Movie theater Noise .....
This is a major issue in America and now the UK.
Its so bad now US audiologists are having to supply American kids with hearing aids ( no complaints from the hearing aid companies) --check out share prices .
Dr.John Bedolla -emergency room doctor-- Seaton Health care ( just one of many ) -quote " Human beings did not experience sound louder than 90-100 decibels for much of human history until the invention of gunpowder and machinery .
So for the vast majority of human existence our ears NEVER adapted to loud noises "---
He goes on-- Quote--"certain types of high spectacle movies , such as Transformers ,have decibel levels of 90db for almost the entire movie and have decibel levels of 120db for significant periods and some points getting to 130db .
Now 130db is a jet engine at about 10--TEN meters " end quote .
Why have US authorities not stopped this and yes I can quote many US citizens with ears bleeding at the end of the movie as well as REAL stats --if required ?
Because they get round the law by the old fashioned use of Compression techniques --very sly .
I have a wealth of data if anybody want to criticize this--mainly American as they have been doing it the longest so casualty figures are available --no Big Media shareholders please.
Real life- once the hairs at the end of your auditory nerve system die --they do NOT regenerate -has anybody seen somebody totally deaf with a hole drilled in their skull and a miniature amplifier connected direct to their brain ---I have.
It all has to do with the peak to average ratio of music. If you want to convince yourself,try a little experiment. Get ahold of an old-school iron horse amplifier rated at 100 watts per channel, 8 ohms. And a big PA speaker that can take abuse, a 28 volt (at least 100 VA) transformer, a 100 watt incandescent light bulb, and an oscilloscope. Connect the speaker to one channel, and the transformer and light bulb to the other, and play music from a mono source. Monitor both channels with an oscilloscope. Slowly turn the music up until you start to see clipping. Then take note of how bright (dim) the light bulb is, and how much peak voltage you see on the scope. Then turn the music UP until you see the light bulb at full brightness and tell me how distorted the music sounds - and how LOUD. The result is very enlightening (pun intended). Don’t do this with a home hi-fi speaker or you will be at least buying a tweeter, and perhaps a woofer and midrange.
One cannot squeeze more power out of a machine then what is put in. #2 is perfectly clear, and the rest is marketing (fairy tales). I agree with #6, #8 and #9 - psychology can supply many answers here...
Keep in mind that in the recent past perception or experience were rooted in 'tubes', handwriting and personal introductions: proof was needed whatsoever. In our current times however, expectation, promise and 'mediasation' has changed this perception. One rule keeps afloat: PROOF. No obedience, no belief.
Oh, I can tell you a fantastic story...
Keep in mind that in the recent past perception or experience were rooted in 'tubes', handwriting and personal introductions: proof was needed whatsoever. In our current times however, expectation, promise and 'mediasation' has changed this perception. One rule keeps afloat: PROOF. No obedience, no belief.
Oh, I can tell you a fantastic story...
And that is why I insist on using ear plugs in the cinemas. The sustained barrage on our ears is just insane. I walked out of a cinema last year (took my son to see one of the newer animated films) and in no uncertain tones told the manager that they had better turn the volume down - the majority of the viewers were children under the age of ten. Man was I pissed off. He did get the volume turned down to an acceptable level.
W are W .
W RMS is a misnommer for W.
Applying the RMS calculation to power is a nonsense.
Note that the power of an amplifier always emanates from the measure of voltage in V in a load in Ω.
The specifications of amplifiers using voltage in V across load in Ω would clear up the constant confusion about their power.
W RMS is a misnommer for W.
Applying the RMS calculation to power is a nonsense.
Note that the power of an amplifier always emanates from the measure of voltage in V in a load in Ω.
The specifications of amplifiers using voltage in V across load in Ω would clear up the constant confusion about their power.
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There are two issues:
1. Speaker efficiency. Professional speakers are roughly 10x the efficiency of consumer entertainment systems. It's about size, precision and engineering vs marketing. Professional bass and mid range speakers are at least 15 inches. Bose, for example is a marketing company and their classic product require huge amounts of electrical power to produce reasonable sound levels. Speakers have an efficiency rating based on the acoustic level in dBA at a distance of one meter.
2. Amplifier power exaggeration. Marketing has found a long list of excuses to exaggerate the power output of amplifiers, such that the specification is as much as 8x the actual continuous RMS power. You will see phases like "music power", "peak power" etc. This kind of marketing fraud was ramped when "solid state" amplifiers were new and transistors were expensive.
1. Speaker efficiency. Professional speakers are roughly 10x the efficiency of consumer entertainment systems. It's about size, precision and engineering vs marketing. Professional bass and mid range speakers are at least 15 inches. Bose, for example is a marketing company and their classic product require huge amounts of electrical power to produce reasonable sound levels. Speakers have an efficiency rating based on the acoustic level in dBA at a distance of one meter.
2. Amplifier power exaggeration. Marketing has found a long list of excuses to exaggerate the power output of amplifiers, such that the specification is as much as 8x the actual continuous RMS power. You will see phases like "music power", "peak power" etc. This kind of marketing fraud was ramped when "solid state" amplifiers were new and transistors were expensive.
Pre-compression audio has quite a bit higher crest factor so that surely has to be factored in. Perhaps not as high in broadcast rooms as it used to be in analog era recording studios, but still.
It sounds big power has not much effect to the customers. It has lost the direct comparison between models and not in breach with any legislation. If the suppliers prefer to quote PMPO, it does not matter but the measurement method must be standardized for direct comparison of the results. Currently every supplier applies to their own method. It is no way to do a fair comparison before decide to purchase.
Current draw ratings these days are only for what the amp “typically” draws from the wall, not the maximum that it could draw. If it were the latter, you wouldn’t legally be allowed to plug it into anything short of an electric range outlet. The amp in this example is “rated” to draw 13.9 amps on the back panel. I’ve had it getting the speakers starting to smell, and never had the breakers trip. Sine wave testing into a water heater element will trip it in about 10 seconds.
How long an amp can put out full power is all over themap, and generally you get what you pay for, and no more. The amp in question will put it out long enough for most practical purpose. You can buy better, for $3-5000. You can do much worse.
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Forr's post #14 is actually an accurate description of audio amplifier "wattage" rating.
People have been led to believe in the "RMS" value for decades, and with audio frequencies, there isn't any accurate form of dealing with anything RMS.
Perhaps a more sensible and accurate way to rate any given amplifier is its ability to supply a particular decibel level (cleanly) as a result for a particular speaker.
Wattage isn't everything, I find it interesting that many people seem to go after amplifiers/receivers in the 20-40 "watt" range.
For instance....
Why is something like a 1970 Harman Kardon 330A/B draws so much attention in audio circles?
People have been led to believe in the "RMS" value for decades, and with audio frequencies, there isn't any accurate form of dealing with anything RMS.
Perhaps a more sensible and accurate way to rate any given amplifier is its ability to supply a particular decibel level (cleanly) as a result for a particular speaker.
Wattage isn't everything, I find it interesting that many people seem to go after amplifiers/receivers in the 20-40 "watt" range.
For instance....
Why is something like a 1970 Harman Kardon 330A/B draws so much attention in audio circles?
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