Re: [LAU] octaver (plugin) for bass

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To: hermann meyer <brummer-@...>
Cc: <linux-audio-user@...>
Date: Sunday, June 8, 2014 - 11:34 am

On Sun, Jun 08, 2014 at 12:36:17PM +0200, hermann meyer wrote:

> Without downsampling it use (well, 4xtimes more then now) 8% dsp

because that removes most of the broadband junk that would be generated
otherwise...

> and for guitar/bass 3kHz are

True for bass and guitar.

Still this algorithm is far from what it could be. I don't blame
for you that, it's Bernsee who is missing the consequences of his
own analysis (which is valid as far as it goes).

Take alook at his table labeled 'pass #5'. The input signal is
halfway between two bins. Assume we want one octave up. The expected
output signal corresponds exactly to bin 225. For that signal, the
output of the analysis FFT would be (similar to 'pass #1):

bin amplitude
------------------
223 0.000
224 0.500
225 1.000
226 0.500
227 0.000

And that is of course also what the correct input to the synthesis
IFFT should be. Which is quite different from what the algorithm
produces (by scaling each bin individually):

bin amplitude
-------------------
222 0.170
223 0.000
224 0.849
225 0.000
226 0.849
227 0.000
228 0.170

The result of this after the IFFT is the correct frequency, but
with two periods of the window applied (it will be zero at the
center).

The frequency values that are calculated provide exactly the
information required to avoid this and to do the correct
calculation. But it's just thrown away.

Ciao,

--
FA

A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)

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Messages in current thread:
[LAU] octaver (plugin) for bass, rosea grammostola, (Sun Jun 1, 5:22 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Sun Jun 1, 5:37 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Sun Jun 1, 6:09 pm)
Re: [LAU] octaver (plugin) for bass, rosea grammostola, (Sun Jun 1, 6:14 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Sun Jun 1, 6:31 pm)
Re: [LAU] octaver (plugin) for bass, rosea grammostola, (Mon Jun 2, 2:04 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Fri Jun 6, 10:44 am)
Re: [LAU] octaver (plugin) for bass, rosea grammostola, (Fri Jun 6, 6:36 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Sat Jun 7, 8:18 am)
Re: [LAU] octaver (plugin) for bass, Fons Adriaensen, (Sat Jun 7, 4:08 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Sat Jun 7, 5:10 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Sat Jun 7, 5:44 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Sun Jun 8, 4:39 am)
Re: [LAU] octaver (plugin) for bass, Fons Adriaensen, (Sun Jun 8, 9:49 am)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Sun Jun 8, 10:36 am)
Re: [LAU] octaver (plugin) for bass, Fons Adriaensen, (Sun Jun 8, 11:34 am)
Re: [LAU] octaver (plugin) for bass, rosea grammostola, (Tue Jun 10, 3:27 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Wed Jun 11, 5:55 pm)
Re: [LAU] octaver (plugin) for bass, Fons Adriaensen, (Thu Jun 12, 8:42 am)
Re: [LAU] octaver (plugin) for bass, Chris Cannam, (Thu Jun 12, 9:41 am)
Re: [LAU] octaver (plugin) for bass, Fons Adriaensen, (Thu Jun 12, 10:16 pm)
Re: [LAU] octaver (plugin) for bass, hermann meyer, (Fri Jun 13, 7:05 am)
Re: [LAU] octaver (plugin) for bass, Gianfranco Ceccolini, (Tue Jun 10, 3:56 pm)
Re: [LAU] octaver (plugin) for bass, rosea grammostola, (Tue Jun 10, 4:15 pm)
Re: [LAU] octaver (plugin) for bass, Gianfranco Ceccolini, (Wed Jun 11, 2:54 pm)
Re: [LAU] octaver (plugin) for bass, rosea grammostola, (Wed Jun 11, 5:52 pm)
Re: [LAU] octaver (plugin) for bass, Gianfranco Ceccolini, (Fri Jun 13, 12:56 pm)
Re: [LAU] octaver (plugin) for bass, rob, (Tue Jun 3, 9:13 pm)