Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique?

2016-12-14 Thread robert bristow-johnson
Original Message Subject: Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique? From: "James McCartney" Date: Wed, December 14, 2016 2:15 pm To:

Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique?

2016-12-14 Thread robert bristow-johnson
Original Message Subject: Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique? From: "Ethan Fenn" Date: Wed, December 14, 2016 12:09 pm To: music-dsp@music.columbia.edu Cc:

Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique?

2016-12-14 Thread James McCartney
On Wed, Dec 14, 2016 at 11:07 AM, James McCartney wrote: > > > On Wed, Dec 14, 2016 at 11:03 AM, James McCartney > wrote: > >> >> >> On Wed, Dec 14, 2016 at 8:47 AM, Ethan Fenn >> wrote: >> >>> >>> Another interesting family of curves

Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique?

2016-12-14 Thread James McCartney
On Wed, Dec 14, 2016 at 11:03 AM, James McCartney wrote: > > > On Wed, Dec 14, 2016 at 8:47 AM, Ethan Fenn > wrote: > >> >> Another interesting family of curves is given by f(x) = x / (1+x^N)^(1/N) >> for even N. The fractional power is kind of

Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique?

2016-12-14 Thread James McCartney
On Wed, Dec 14, 2016 at 8:47 AM, Ethan Fenn wrote: > > Another interesting family of curves is given by f(x) = x / (1+x^N)^(1/N) > for even N. The fractional power is kind of annoying, but if you have a > hardware square root then you can compute this for N=2,4,8 easily

Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique?

2016-12-14 Thread Ethan Fenn
> > * Since f'(0) != 1 for these curves, they're really more like a > combination gain and soft clipper rather than a pure soft clipper. Does > your approach still work if we impose the constraint that f'(0)=1? Apologies, I see that you addressed this very thing later in your answer! On Wed,

Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique?

2016-12-14 Thread Ethan Fenn
Very interesting ideas Robert, thanks. Some observations: * Regarding the use of a polynomial to limit the range of spurious frequency components -- a good goal, but if the input signal actually goes outside [-1,1] this is no longer strictly true. * Since f'(0) != 1 for these curves, they're

Re: [music-dsp] Can anyone figure out this simple, but apparently wrong, mixing technique?

2016-12-14 Thread Stefan Stenzel
Robert, Thanks, excellent writeup! Now I wonder, if I drop the condition that it shall be a polynomial and replace the term (1-u^2)^N with (0.5+0.5*cos(u*pi))^N, wouldn’t this work in a similar way, but with less discontinous derivatives at the endpoints 1 and -1? Stefan > On 12 Dec 2016,