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Old 23rd June 2011, 13:45   #46
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Re: How to calculate the efficiency of the Amplifier

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Originally Posted by navin View Post
Vina I dont for one second suspect that you cannot modify the response curve of a speaker or system with DSP to get exactly what suits your taste. However I also believe you can do this without DSP and it ain't that diffcult.

Sadly most recordings (especially the vintage ones) are terrible and hence are often more listenable on loudspeakers that are less "transparent".

We have digressed enough so let's get back to the topic on hand.

we have hijacked @jinu's thread.

But what we are discussing is very much related to what he wanted to know in the first place.



I'm a technical guy, subjective appreciation is not exactly my thing (unless you are doing blind studies - then I am the statistician).

One question for you - in "Sadly most recordings (especially the vintage ones) are terrible and hence are often more listenable on loudspeakers that are less "transparent"." why do you say the vintage recordings were terrible?

Also what do you mean by loudspeakers that are less "transparent"?
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Old 23rd June 2011, 14:04   #47
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Re: How to calculate the efficiency of the Amplifier

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Originally Posted by vina View Post
why do you say the vintage recordings were terrible?

Also what do you mean by loudspeakers that are less "transparent"?
Older (1960-1980) recordings were often not done by sober sound engineers. My reference however is not Indian/Hidustani music but the stuff that was recorded in the US in the 60s and 70s oftne by some engineer who was sharing the same cocktail of chemicals as the artists themselves.

Speakers will rolled of highs and maybe even a bit coloured midbass (the Maggie MMG/SMGs or the Klipsch Forte/Chorus/Heresey come to mind) often make such music very listenable. Take the same recording and say a WAMM or Grand Utopia etc.. and you will cover your ears.
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Old 24th June 2011, 22:52   #48
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Re: How to calculate the efficiency of the Amplifier

@jinu_ I am into reading your post #10 with thanks and with interest.

If 85dB be the desirable sound level, then would it not be the total of sound energy? I mean, you are adding powers for different speakers, which got me confused. My guess is that the required electrical energy should be much less than what you calculated. I mean your calculation of 24W seems bit high to me.

So if we consider just one representative speaker then only a few watts of electrical energy are sufficient to give you the desired sound level. This would mean not more than an ampere of current is required by the amplifier. This sounds incredible, but we could insert a current meter in the supply lead to read out the actual current being consumed. That is a simple experiment; simply replace the particular fuse with a digital ammeter and run only the ICE, keeping everything else off. Then you can measure the current drain at different volumes of sound.
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Old 25th June 2011, 21:03   #49
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Re: How to calculate the efficiency of the Amplifier

Navin, Vina, Der Alte, Cranky.. I am enjoying the discussion very much.. though i cant contribute much at this point in time and some of it :-) is going way over my head.. but still..let it roll

Gostel there was another thing i realised after a lot of reading.. refer to post 22, that the sensitivity refferred to in the ratings given by manufacturers is usally a calculated value and not practically applicable for that particular speaker.. There is different way to calculate the practical sensitivity, but that again I agree with you, with 2-4 speakers (not considering the SUB) placed in the car cabin the indvidual SPL level that should be reached should be lower in order to keep the over SPL level within reasonable limits.

My quest continues.. to find out the power required (This is a theoretical exercise, which i will validate using measurements, but first let me try and understand atleast some of the theory involved.)

Refer to this link to see how easy and how little time it takes to have permanent hearing damage
Peak SPL Calculator
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