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Tilt filter, "blue-ing" filter (cough cough martin?)
Re: Tilt filter, "blue-ing" filter (cough cough martin?)
btw that schematic is currently only 
and not 
and not -
martinvicanek
- Posts: 1334
- Joined: Sat Jun 22, 2013 8:28 pm
Re: Tilt filter, "blue-ing" filter (cough cough martin?)
I uploaded version 2 in the original post above.
@Adam, this was actually my first thought: I nailed the transfer function at 1 kHz. However, I realized that if you tilt whichever direction, you'll overflow the next stage. I found it annoying to have to adjust the volume each time I changed the slope. HTat's why I chose the other normalization, with pink noise resembling (very roughly) a musical source.
@guyman, not quite sure what exactly you want to achieve?
@Adam, this was actually my first thought: I nailed the transfer function at 1 kHz. However, I realized that if you tilt whichever direction, you'll overflow the next stage. I found it annoying to have to adjust the volume each time I changed the slope. HTat's why I chose the other normalization, with pink noise resembling (very roughly) a musical source.
@guyman, not quite sure what exactly you want to achieve?
Re: Tilt filter, "blue-ing" filter (cough cough martin?)
I want to create a smile/frown (low/high boost cut) filter consistent with both the db/octave law of power, and normalization technique you are implementing in these filters. Let's say 0/db per octave is x, or our input signal, unaltered across the spectrum. in one instance we tilt it y db resulting in both + and - gain changes, and in another instance we tilt it -y db resulting in both + and - gain changes. Again like you emphasized before this is not relevant to a changeable "center frequency" but to your approach to normalization (not sure I fully understand - which may be the root of me missing this whole thing.)
In my smile, or low/high boost filter, you tilt the filter both +-y db from x, but only keep the corresponding +gain changes from both tilts, and vice versa with the frown/ low/high cut filter. you keep the -y gain changes from x from -+y tilt.
like let's say you have purple noise (+6db/oct) and brown noise (-6db/oct), on the smile filter you would have the positive high frequency gain changes from the +6db/purple tilt, and the positive low frequency gain changes from the -6db/brown noise tilt, resulting in a boosting filter that is consistent to the spectrum.
perhaps I lack the language to articulate it, or my imagination has run far too rampant.
I'm going to fiddle with your updated schematics and see what's going on.
In my smile, or low/high boost filter, you tilt the filter both +-y db from x, but only keep the corresponding +gain changes from both tilts, and vice versa with the frown/ low/high cut filter. you keep the -y gain changes from x from -+y tilt.
like let's say you have purple noise (+6db/oct) and brown noise (-6db/oct), on the smile filter you would have the positive high frequency gain changes from the +6db/purple tilt, and the positive low frequency gain changes from the -6db/brown noise tilt, resulting in a boosting filter that is consistent to the spectrum.
perhaps I lack the language to articulate it, or my imagination has run far too rampant.
I'm going to fiddle with your updated schematics and see what's going on.
Last edited by guyman on Sun Sep 30, 2018 6:48 pm, edited 1 time in total.
Re: Tilt filter, "blue-ing" filter (cough cough martin?)
Actually my imagination is not failing me. This is a hyper-relevant tone nob, consistent with the laws of power and our hearing.
Re: Tilt filter, "blue-ing" filter (cough cough martin?)
Is something like LU normalization possible?
Re: Tilt filter, "blue-ing" filter (cough cough martin?)
Do you have a copy of the one that's nailed to 1k? I am assuming it doesn't have normalization.