Re: [LAD] Floating point processing and high dynamic range audio

On Thu, Jul 22, 2010 at 01:05:01AM +0200, Philipp Überbacher wrote:

> I think the word loudness is a problem here. Afaik it usually refers to
> how it is perceived, and twice the amplitude doesn't mean twice the
> perceived loudness. It may mean twice the sound pressure level, energy,
> or intensity (if we ignore analogue anomalies, as you wrote in some other
> answer).

Subjective loudness is a very complex thing, depending on the
spectrum, duration, and other aspects of the sound, and also
on circumstances not related to the sound itself.

For mid frequencies and a duraion of one second, the average
subjective impression of 'twice as loud' seems to correspond
to an SPL difference of around +10 dB.

I often wondered what criterion we use to determine which
objective SPL difference sounds as 'twice as loud'. We don't
have any conscious numerical value (there may be unconscious
ones such as the amount of auditory nerve pulses, or the amount
of neural activity), so what it this impression based on ?

The only thing I could imagine is some link with the subjective
impression of a variable number of identical sources. For example
two people talking could be considered to be 'twice as loud' as
one. But that is not the case, the results don't fit at all (it
would mean 3 dB instead of 10).

> It may be nitpicking, but I found it important to differentiate
> between the physical phenomenon and the perception.

Not nitpicking at all...

Ciao,

-- 
FA
There are three of them, and Alleline.
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