On Thu, 04 Oct 2007 08:48:33 GMT, (Don Pearce)
wrote:

On Thu, 4 Oct 2007 11:38:01 +0300, "Iain Churches"
wrote:


"Iain Churches" wrote in message
ahti.fi...

Which explains why many still stubbornly use the long
superceded "A" curve.


Don. I forgot to mention, I was looking at a British valve amp
yesterday built 1990s. The difference between the noise
floor measured "audio band" and "A" weighted was 20dB !!

A magical improvement at the press of a button.

Iain


Just done something similar on my DAW. I've also created an A curve.
Made a chunk of white noise and compared the average noise levels.

Flat -19.44dB
A wt -21.7dB
468 -12.59dB

So that is a 19dB difference. I only eyeballed the filters, so I could
be a bit out. This is all a bit odd. I can see there being differences
between two subjective curves purporting to be of the same thing, but
19dB? Something smells nasty.

d

Bugger, that is 9dB, not 19.

d

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Pearce Consulting
http://www.pearce.uk.com