Re: [music-dsp] Time-variant 2nd-order sinusoidal resonator

2019-03-04 Thread Olli Niemitalo
A simple way to stabilize most quadrature oscillators including Martin's quadrature oscillator is to multiply each state variable by a temporary variable: g = 1.5 - 0.5*(u*u + v*v) where u and v are unit-amplitude quadrature oscillator outputs. The correction does not need to be done very

Re: [music-dsp] Time-variant 2nd-order sinusoidal resonator

2019-03-03 Thread Olli Niemitalo
On Thu, Feb 21, 2019 at 11:16 PM robert bristow-johnson wrote: > But Martin, if you let this thing run for days on end, would not eventually > the amplitude of the output change a bit? Short answer: yes, sometimes significantly for audio purposes when using 32-bit float state variables, but

Re: [music-dsp] Time-variant 2nd-order sinusoidal resonator

2019-02-21 Thread Olli Niemitalo
On Fri, Feb 22, 2019 at 9:08 AM robert bristow-johnson < r...@audioimagination.com> wrote: > i just got in touch with Olli, and this "triangle wave to sine wave" > shaper polynomial is discussed at this Stack Exchange: > > > >

Re: [music-dsp] tracking drum partials

2017-07-27 Thread Olli Niemitalo
Thomas, you could try https://github.com/mangledjambon/drumbooth to separate sinusoidal and impulse-like parts of sounds, and then do your additive analysis on the sinusoidal part only. The deconstruction is based on Derry FitzGerald HARMONIC/PERCUSSIVE SEPARATION USING MEDIAN FILTERING, Proc. of

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-27 Thread Olli Niemitalo
Sampo, it is not the poles and zeros that alternate on the real line but the poles of the two all-pass filter paths. The 90 deg phase difference band is almost from 0 to Nyquist. In my filter pair they are from 0.001 pi to 0.999 pi. On z-plane those corner frequencies are at (0.95, 0.003) and

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-05 Thread Olli Niemitalo
typofix: "and their companion poles" -> "and their companion zeros" -olli On Sun, Feb 5, 2017 at 1:52 PM, Olli Niemitalo <o...@iki.fi> wrote: > 90 deg phase difference all-pass filter pairs... Lemme wave my hands a bit: > > It's been years, but I recall

Re: [music-dsp] ± 45° Hilbert transformer using pair of IIR APFs

2017-02-05 Thread Olli Niemitalo
90 deg phase difference all-pass filter pairs... Lemme wave my hands a bit: It's been years, but I recall I first tried a structure with complex conjugate pairs of poles (and their companion poles to make the filters all-pass). Globally optimizing that using Differential Evolution, the poles

Re: [music-dsp] Microphones for measuring stuff, your opinions

2014-08-28 Thread Olli Niemitalo
To make a reference microphone from scratch, one can use reciprocity calibration. You take three uncalibrated mics that can act as low-power speakers as well. Not all mics are suitable for this. Then you pair the three mics the three possible ways. For each pair, the first mic of the pair will act

Re: [music-dsp] Instant frequency recognition

2014-07-16 Thread Olli Niemitalo
will be satisfied. At least that part of your theory seems consistent. -olli On Wed, Jul 16, 2014 at 1:39 PM, Vadim Zavalishin vadim.zavalis...@native-instruments.de wrote: On 16-Jul-14 12:31, Olli Niemitalo wrote: What does O(B^N) mean? -olli This is the so called big O notation. f^(N)(t)=O(B^N

Re: [music-dsp] a weird but salient, LTI-relevant question

2014-05-08 Thread Olli Niemitalo
If there, by chance, happens to be a feature in the noise that catches the ear and creates a sort of (possibly first subconscious) memory, then the choo-choo effect will be more audible as that feature can be more easily recognized again, reinforcing the memory. I generated 10 seconds of Gaussian

Re: [music-dsp] Inquiry: new systems for Live DSP

2014-03-14 Thread Olli Niemitalo
On Fri, Mar 14, 2014 at 4:46 PM, Richard Dobson richarddob...@blueyonder.co.uk wrote: On 14/03/2014 14:27, Olli Niemitalo wrote: http://yehar.com/Fast%20Track%20Ultra%2048%20kHz%20output-input%20ir.jpg It looks more like a minimum-phase lowpass filter. The marker at sample #29 indicates what

Re: [music-dsp] Frequency bounded DSP

2014-01-03 Thread Olli Niemitalo
There are no exactly bandlimited functions that have non-zero-length constant-valued intervals in the time domain. So any transients in an exactly bandlimited time domain signal will have to be premeditated. You can't keep a signal exactly bandlimited if you make a causal decision at some point in

Re: [music-dsp] OSC problem on STM32F4Discovery

2012-04-10 Thread Olli Niemitalo
On Tue, Apr 10, 2012 at 12:06 PM, Julian Schmidt julian_schm...@chipmusik.de wrote: okay, i used exactly RBJs code with 1024 samples tablesize and  I get a  -60 dB spectral distortion floor. That's again what no interpolation would give, so probably there is a bug in the interpolation code,

Re: [music-dsp] OSC problem on STM32F4Discovery

2012-04-10 Thread Olli Niemitalo
On Tue, Apr 10, 2012 at 12:06 PM, Julian Schmidt julian_schm...@chipmusik.de wrote: okay, i used exactly RBJs code with 1024 samples tablesize and  I get a  -60 dB spectral distortion floor. That's again exactly what no interpolation gives, so probably there is a bug in the interpolation code,

Re: [music-dsp] OSC problem on STM32F4Discovery

2012-04-10 Thread Olli Niemitalo
On Tue, Apr 10, 2012 at 6:54 PM, Nigel Redmon earle...@earlevel.com wrote: Clicks, especially 2-3 seconds apart doesn't describe aliasing Here are clicks created by aliasing for you to listen (loudness warning!):

Re: [music-dsp] OSC problem on STM32F4Discovery

2012-04-09 Thread Olli Niemitalo
If you don't interpolate the wavetable then you may be simply getting some aliasing problems. Every Nth cycle of the generated waveform will be one sample shorter than the others, and that will sound like a click. Try setting your phaseInc to an integer value. Also, somewhere along the analog

Re: [music-dsp] OSC problem on STM32F4Discovery

2012-04-09 Thread Olli Niemitalo
On Mon, Apr 9, 2012 at 7:17 PM, Julian Schmidt julian_schm...@chipmusik.de wrote: setting the phase increment to an integer value solves the problem. [...] adding linear or cubic interpolation makes it a little better, but the pulsing is still very audible. [...] The nearer i get to an

Re: [music-dsp] OSC problem on STM32F4Discovery

2012-04-09 Thread Olli Niemitalo
On Mon, Apr 9, 2012 at 11:32 PM, Julian Schmidt julian_schm...@chipmusik.de wrote: I really think it is an aliasing problem. but not due to the wrong wavetable content, but due to a cheap audio codec with poor filters. [...] even when i output a single 440hz sine i get harmonics starting at

Re: [music-dsp] OSC problem on STM32F4Discovery

2012-04-09 Thread Olli Niemitalo
On Tue, Apr 10, 2012 at 12:25 AM, Julian Schmidt julian_schm...@chipmusik.de wrote: Am 09.04.2012 23:22, schrieb Olli Niemitalo: On Mon, Apr 9, 2012 at 11:32 PM, Julian Schmidt julian_schm...@chipmusik.de  wrote: I really think it is an aliasing problem. but not due to the wrong wavetable

Re: [music-dsp] very cheap synthesis techniques

2012-02-29 Thread Olli Niemitalo
On Wed, Feb 29, 2012 at 1:37 AM, Andrew Jerrim andrew.jer...@gmail.com wrote: [On bytebeat:] Oooh, Olli - that's fantastic! Wouldn't that make a great little phone app :) There's Glitch Machine for iPhone/iPad, does much the same but in reverse Polish notation.

Re: [music-dsp] stereo-wide pan law?

2012-02-10 Thread Olli Niemitalo
On Fri, Feb 10, 2012 at 8:48 AM, Ross Bencina rossb-li...@audiomulch.com wrote: On 9/02/2012 11:02 AM, Jerry wrote: (Good grief, people.) You want the *very famous* Bauer's Law of Sines: ... Sin theta_I   (S_l - S_r) --- = --- Sin theta_A   (S_l + S_r) Solving for S_l^2 +

Re: [music-dsp] stereo-wide pan law?

2012-02-08 Thread Olli Niemitalo
Knowing that you're panning chorus voices to be summed with the input signal gives something to work on. Let's say there's just one chorus voice and someone sets up the delays, volume and whatnot so that it is actually identical to the input signal. Now, it would be unreasonable if, compared to

Re: [music-dsp] stereo-wide pan law?

2012-02-07 Thread Olli Niemitalo
On Tue, Feb 7, 2012 at 12:20 PM, Ross Bencina rossb-li...@audiomulch.com wrote: Hi Everyone, Does anyone know if there's a standard way to calculate pan laws for stereo-wide panning ? By stereo-wide I mean panning something beyond the speakers by using 180-degree shifted signal in the

Re: [music-dsp] anyone care to take a look at the Additive synthesis article at Wikipedia?

2012-01-16 Thread Olli Niemitalo
No, it was my doing that the paragraphs had the synth name as their first word(s). We don't have the or a/an in the Finnish language, so I'm not always sure if they are needed, like in front of names (of synthesizers) here. But I'm going to claim that most of that text looked even worse before.

Re: [music-dsp] A theory of optimal splicing of audio in the timedomain.

2011-07-15 Thread Olli Niemitalo
That won't be a problem if you measure the correlation locally, but how exactly? Certainly anything outside the cross-fade region should be excluded from the measurement. And inside it matters most wherever the mixing ratio is close to 50-50, as in that cases phase difference of the two signals

Re: [music-dsp] A theory of optimal splicing of audio in the time domain.

2011-07-14 Thread Olli Niemitalo
On Thu, Jul 14, 2011 at 9:22 PM, robert bristow-johnson r...@audioimagination.com wrote:      g(t)  =  1/sqrt( (1+r)/2 + 2*(1-r)*(p(t))^2 ) might this result match what you have? Yes! I only derived the formula for the linear ramp, p(t) = t/2, because one can get the other shapes by warping

Re: [music-dsp] A theory of optimal splicing of audio in the time domain.

2011-07-13 Thread Olli Niemitalo
On Sat, Jul 9, 2011 at 10:53 PM, robert bristow-johnson r...@audioimagination.com wrote: On Dec 7, 2010, at 5:27 AM, Olli Niemitalo wrote: [I] chose that the ratio a(t)/a(-t) [...] should be preserved by preserved, do you mean constant over all t? Constant over all r. what

Re: [music-dsp] Factorization of filter kernels

2011-01-19 Thread Olli Niemitalo
Find the roots, pair the complex conjugate roots and distribute the pairs and single real roots evenly (how exactly?) in the two filters. Matlab at least has facilities finding roots of large polynomials. -olli On Wed, Jan 19, 2011 at 4:56 PM, Uli Brueggemann uli.brueggem...@gmail.com wrote: