[JN] "Twice as LOUD"??

Bjørn Kolbrek bkolbrek at gmail.com
Fri Feb 15 01:54:49 CST 2019


Important point in the article Hans linked to:

"it is applicable only to adding loudness for identical sounds. If a 
second sound is widely enough separated in frequency to be outside the 
critical band of the first, then this rule does not apply at all."

But back to JC's original point: that an extra watt will probably not 
make much difference:

 > And that is the extra watts one gets from fixed bias, compared with 
self bias does NOT mean all that much in terms of loudness in a system.

(unless, of course, the amp was 1/2W to begin with.) And how the amp 
clips may be more important than when.

We should be using dBW (dB relative to 1W). Might help us making better 
decisions when it comes to power output.

We have the same issue in the loudspeaker industry, the power rating 
numbers game. But with the additional complication that increasing the 
power handling quite often reduces the efficiency. So even if you can 
increase the power handling by 1dB (say 500 to 625W), you may lose 
1.5-2dB in efficiency (heavier cone, greater gap clearances etc), and 
get a net loss of 0.5-1dB of max SPL. Not a great deal, but it means 
that the effort to increase power handling was completely pointless.

-Bjørn

On 14/02/2019 23:19, Hans Hedal via Sound wrote:
>
> bear wrote:
>
>> Twice as loud is a subjective perception.
>
> This passage gives an objective physiological background for the 
> "TWICE AS LOUD" rule.
> See textbox "Rule of Thumb" for Loudness:
>
> http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/loud.html#c2
>
>
> Hans
>
>
> _______________________________________________
> Sound mailing list
> Sound at soundlist.org
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