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Old March 12th 15, 12:53 PM posted to uk.rec.audio
Don Pearce[_3_]
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Posts: 1,358
Default Help with understanding pink noise results

On Thu, 12 Mar 2015 13:35:47 +0000, Sumatriptan
wrote:

On 11/03/2015 11:05, Don Pearce wrote:


Those last curves have been "corrected" to look flat. Essentially what
they are showing is the difference between the perfect pink noise and
that recovered from the record.

Yours is showing signs of being a bit saggy at the top and bottom of
the band. Could do particularly with a touch of bass lift.


OK, I've put up a revised curve that I 'corrected' with an eq with slope
opposite the the 10 dB/Decade slope of 1/f pink noise.

He
http://www.nu-ware.com/Misc/Screensh...0Flattened.png

As well as the 'correction' I added 330 pF of capacitive loading since
the only other capacitance was the 100 pF of the preamp input and Shure
cartridges work best with 400-500 pF, says the spec. Recall, I have
removed the phono leads and installed the preamp in the turntable near
the tonearm.

I know that this result assumes that the pink noise from the record is
perfect, which is most likely not so.

Whatever, the output sounds excellent to me and my first tests with
LP--CD transfer went very well.


The bottom end looks pretty good.The 4dB drop from 2kHz 9kHz would be
the sort of adjustment a mixing engineer would make to remove some
"air" from a recording. Equalise that back up to flat, and suddenly
sounds played from this cartridge will gain a lot of sparkle.

d