naturerecordists
[Top] [All Lists]

Re: inverse loudness eq

Subject: Re: inverse loudness eq
From: "Paul Jacobson" thebrunswicktwitcher
Date: Sun Mar 30, 2008 3:34 am ((PDT))
Hi Lou,

Sorry F-M it is... and yes the second section is the one that's eq'd.

Using a graph which showed F-M curves of boost required for flat
response at 10dB intervals I've tried to calculate the differences
between the curves at 30dB and 80dB. I've taken 30dB as a background
level and 80dB as 50dB gain applied to the background level. Not
really correct, but a starting point.  I've then inverted the
resulting curve to try to cut the frequencies that are boosted by
applying gain to the 30dB sound field.

What I'm trying to do is use the F-M curve to apply something close
to the ears frequency sensitivity at the recorded ambient level to
the +50dB recording. It is imperfect but I thought it was worth
exploring as a way of taming the LF (over)emphasis of high gain
recordings. This is perhaps just a matter of taste, but I feel the LF
boost is a misrepresentation of what is audible to the unaided ears
of a listener standing in the same environment. Rather than simply
chopping every thing below 100hz this method will hopefully give a
better balanced result.

hope this is better explained than my first attempt!

cheers
Paul



On 30/03/2008, at 5:57 PM, Louis Judson wrote:
> Interesting sounds, Paul! I gather the EQ is on the second half - I
> have only laptop speakers at the moment... It's actually a cut if so.
>
> 2 thoughts: I think you mean "F-M" for Fletcher-Munsen, rather than
> Frequency Modulation's "FM" (we are engineeres here, if it is a
> quibble).
>
> and, how this would be an inverse of the "loudness" curve on old
> hifi amps, which is +10 @ 100Hz 6dB/Octave and +4 @ 10k 3 or 6 dB /
> Oct. (arbirary as the figures might be, relating the what volume
> level, etc.) perhaps?
>
> Third thing - I think we are aware of more bass in recordings
> because we are amplifying it over the natural level...
>
> 2c,
> Lou




<Prev in Thread] Current Thread [Next in Thread>
Admin

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU