Re: [music-dsp] Orfanidis-style filter design

2011-12-09 Thread Ethan Duni
I find that the best way to avoid paying for access to scholarly knowledge - both in legal terms and in effectiveness - is to email the author, express interest, and ask for any material they can send you. Most times, you'll get something free, legal, newer and with helpful insight straight

Re: [music-dsp] Square-summability for the ideal low pass filter

2014-01-14 Thread Ethan Duni
IIRC this is one of those situations where you get to define the value of the integral at that point however you like (i.e., either the limit from one side or the other, or a convex combination of both) and all the math then works as expected under that convention. Or just point out that it's

Re: [music-dsp] DACs for Dummies (was: can someone precisely define for me what is meant by proportional Q?)

2014-02-14 Thread Ethan Duni
The analog bench gear in that video made me nostalgic... I can almost smell the solder fumes :] E On Thu, Feb 13, 2014 at 6:01 PM, Andrew Simper a...@cytomic.com wrote: I was really enjoying the proportional Q thread, so in an attempt to keep in on topic here is a thread where people can

Re: [music-dsp] DACs for Dummies (was: can someone precisely define for me what is meant by proportional Q?)

2014-02-17 Thread Ethan Duni
I recall from the first measurement shown on the analog spectrum analyzer the source sine wave had 2d or 3d harmonic distortion component of -70 dB. My power amps are noticeably better than that. But then they don't have the heterodyne circuits you need for an analogue frequency analyser

Re: [music-dsp] DACs for Dummies (was: can someone precisely define for me what is meant by proportional Q?)

2014-02-17 Thread Ethan Duni
, Theo Verelst theo...@theover.org wrote: Ethan Duni wrote: I recall from the first measurement shown on the analog spectrum analyzer the source sine wave had 2d or 3d harmonic distortion component of -70 dB. My power amps are noticeably better than that. But then they don't have

Re: [music-dsp] Iterative decomposition of an arbitrary frequency response by biquad IIR

2014-03-04 Thread Ethan Duni
Seems to me that you could just reformulate an EM algorithm to work directly on the actual (magnitude) responses of the biquad stages, and so bypass the step of converting from a Gaussian response to the actual biquad response (along with its attendant error). The only obvious wrinkle that occurs

Re: [music-dsp] The Uncertainties in Frequency Recognition

2014-03-11 Thread Ethan Duni
In the mathematical sense, we could take a Fourier Integral of these signals neatly added together, and the outcome would be 3 spikes at the respective frequencies, with the proper amplitude. No, you get *6* spikes, since these are real-valued signals. So there are components at both the

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

2014-03-13 Thread Ethan Duni
And an AD converter with 2.5 MS/S and 24 bits accuracy sigma delta which should be great for measurements and undisputably great sampling behavior for perfect delay lines, etc.: http://www.analog.com/en/analog-to-digital-converters/ad-converters/ad7760/products/product.html (eval board:

Re: [music-dsp] Nyquist-Shannon sampling theorem

2014-03-27 Thread Ethan Duni
Hi Doug- To address some of your general questions about Fourier analysis and relationship to sampling theory: Broadly speaking any reasonably well-behaved signal can be decomposed into a sum of sinusoids (actually complex exponentials but don't worry about that detail for now). There are

Re: [music-dsp] Nyquist-Shannon sampling theorem

2014-03-27 Thread Ethan Duni
Hi Doug- Regarding this: Terms like well behaived when applied to the functon make me wonder what stipulations might be implied by the language that you'd have to be a formal mathmatician to interpret. As an example, I don't even know what the instrinsic properties of a function may be in this

Re: [music-dsp] Nyquista?Shannon sampling theorem

2014-03-27 Thread Ethan Duni
Yeah this is sometimes called bandpass sampling or under sampling ( http://en.wikipedia.org/wiki/Undersampling) and is commonplace in the context of like RF communications and such. But it can also come up in audio applications, for example critically sampled filter banks. I.e. say you split a

Re: [music-dsp] Nyquist-Shannon sampling theorem

2014-03-27 Thread Ethan Duni
it is, at least, if you accept the EE notion of the Dirac delta function and not worry so much about it not really being a function, which is literally what the math folks tell us. I may be misremembering, but can't non-standard analysis be used to make that whole Dirac delta function approach

Re: [music-dsp] Nyquist-Shannon sampling theorem

2014-03-27 Thread Ethan Duni
...@audioimagination.com wrote: On 3/27/14 5:27 PM, Ethan Duni wrote: it is, at least, if you accept the EE notion of the Dirac delta function and not worry so much about it not really being a function, which is literally what the math folks tell us. I may be misremembering, but can't non

Re: [music-dsp] Dither video and articles

2014-03-28 Thread Ethan Duni
Not to be overly antagonistic, but: I can easily hear the difference between a 192 or 96kHz 24 (or 22 bits + exponent) bit and downgrading to 48 or 44.1 / 24 bit OR to 192 or 96 kHz 16 bits. Let alone both, easily audible. If you are hearing obvious differences between those settings, it's a

Re: [music-dsp] Dither video and articles

2014-03-29 Thread Ethan Duni
So this talk of compressors in the playback chain brings up an important point. The usual results about CD rate/depth being sufficient are referring to the signal delivered to the final analog audio output. We all know that higher rates and depths are appropriate/required for intermediate

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

2014-05-08 Thread Ethan Duni
It would appear to me that the human hearing system is an LTI system. It doesn't react in a linear fashion to frequency or loudness, but it perceives the same signal the same way at all times, disregarding aging, hearing loss, etc. One of the easiest ways to see that hearing must be nonlinear is

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

2014-05-08 Thread Ethan Duni
the human hearing system is kind of an LTI... only at very low level processing. The consistency of measured signal (= perceiving the same signal the same way at all time as somebody wrote here) is present in the ear canal up to brainstem - inferior colliculus. My understanding is that there are

Re: [music-dsp] Correctable signal processing (to arrive at wire connection)

2014-05-08 Thread Ethan Duni
So in the digital sense, or in combination with the analog domain, is it reasonable to think about correctable operations, which as it were can be inverted, so that applying a digital signal transformation *and* it's converse, we end up with the same signal or something similar. I think you mean

Re: [music-dsp] Simulating Valve Amps

2014-06-22 Thread Ethan Duni
rbj another semantic to be careful about is transfer function. we mean something different when it's applied to LTI systems (the H(z) or H(s)) than when applied to a diode. the latter semantic i don't use. i would say volt-amp characteristic of the diode or vacuum tube. or if it was a

Re: [music-dsp] Simulating Valve Amps

2014-06-23 Thread Ethan Duni
rbj Urs Regarding the iterative method, unrolling like you did y0 = y[n-1] y1 = g * ( x[n] - tanh( y0 ) ) + s y2 = g * ( x[n] - tanh( y1 ) ) + s y3 = g * ( x[n] - tanh( y2 ) ) + s y[n] = y3 is *not* what I described in general. it *is* precisely equivalent to the example you were

Re: [music-dsp] On the theoretical foundations of BLEP, BLAMP etc

2014-07-01 Thread Ethan Duni
This means that in principle any piecewise polynomial signal with bandlimited discontinuities of the signal and its derivatives is also band limited. Sorry if I'm missing something obvious, but what is a bandlimited discontinuity? E On Tue, Jul 1, 2014 at 1:17 AM, Vadim Zavalishin

Re: [music-dsp] On the theoretical foundations of BLEP, BLAMP etc

2014-07-01 Thread Ethan Duni
without the minimum phase approach. Even at 44.1 kHz, the lowest rate you’re likely to make a synth, it would take quite a few samples to result in enough delay to matter. On Jul 1, 2014, at 12:29 PM, Ethan Duni ethan.d...@gmail.com wrote: If you reset the output of a sine wave generator so

Re: [music-dsp] Frequency based analysis alternatives?

2014-07-09 Thread Ethan Duni
What are the alternatives to the FFT? Have wavelets been used for real world solutions? Sure, wavelets get used. Maybe more in image/video than audio, but I'm certain someone can come up with some examples of wavelet audio applications. If an app needs much higher time resolution and there are

Re: [music-dsp] Instant frequency recognition

2014-07-17 Thread Ethan Duni
Sinc interpolation would be theoretically correct, but, remember, that this thread is not about strictily theoretically correct frequency recognition, but rather about some more intuitive version with the concept of instant frequency. What is instant frequency? I have to say that I find this

Re: [music-dsp] Real time variable time stretching

2014-08-19 Thread Ethan Duni
Maybe I'm missing something obvious, but shouldn't the filter bank itself be constant? I.e., no change in the overlap or windowing. The time stretch/compression is obtained by extrapolating/interpolating the analysis parameters, not by shifting around the synthesis filter bank relative to the

Re: [music-dsp] Real time variable time stretching

2014-08-19 Thread Ethan Duni
to the one exposed here http://www.ece.uvic.ca/~peterd/48409/Bernardini.pdf, but modified to work in real time processing frames of fixed size. 2014-08-19 21:30 GMT+01:00 Ethan Duni ethan.d...@gmail.com: Maybe I'm missing something obvious, but shouldn't the filter bank itself be constant

Re: [music-dsp] Fast exp2() approximation?

2014-09-02 Thread Ethan Duni
Well, your standard options for computing 2 to a fractional power are either polynomial approximation or table look-up. If I'm reading it correctly, the approach you quoted there is a second-order polynomial approximation. You can gain accuracy at the cost of complexity by dialing up the

Re: [music-dsp] #music-dsp chatroom invitation

2014-10-09 Thread Ethan Duni
values in the time domain is pretty much irrelevant to the question of what its entropy is (particularly when those values themselves are taken as variable, as you are doing here). E On Thu, Oct 9, 2014 at 9:35 AM, Peter S peter.schoffhau...@gmail.com wrote: On 09/10/2014, Ethan Duni ethan.d

Re: [music-dsp] #music-dsp chatroom invitation

2014-10-09 Thread Ethan Duni
to strong conclusions like this. You'll get a lot farther if you invest a bit into understanding the theoretical framework for this stuff. E On Thu, Oct 9, 2014 at 9:48 AM, Peter S peter.schoffhau...@gmail.com wrote: On 09/10/2014, Peter S peter.schoffhau...@gmail.com wrote: On 09/10/2014, Ethan

Re: [music-dsp] #music-dsp chatroom invitation

2014-10-09 Thread Ethan Duni
- since there is no dependence on previous samples, there is a constant amount of surprise in each sample, corresponding to the entropy of the distribution the noise is drawn from. E On Thu, Oct 9, 2014 at 10:00 AM, Peter S peter.schoffhau...@gmail.com wrote: On 09/10/2014, Ethan Duni ethan.d

Re: [music-dsp] #music-dsp chatroom invitation

2014-10-09 Thread Ethan Duni
capacity of human audio perception. E On Thu, Oct 9, 2014 at 11:11 AM, Peter S peter.schoffhau...@gmail.com wrote: On 09/10/2014, Ethan Duni ethan.d...@gmail.com wrote: Let's assume I have a sinusoidal signal. Let's assume I amplify it to 10x. Where does new entropy come from? It comes from

Re: [music-dsp] #music-dsp chatroom invitation

2014-10-09 Thread Ethan Duni
... since the original question of r b-j was: how can the human ear convey the high amount of digital PCM information contained on a CD? Right, my point is that the digital PCM info on a CD typically contains a *lot* of data that is redundant to human audio perception, and which gets

Re: [music-dsp] #music-dsp chatroom invitation

2014-10-09 Thread Ethan Duni
I did not claim anything about entropy of continuous signals, Aren't we talking about impulses in auditory nerves (among other things)? Those things live in the analog domain. I was only talking about the entropy content of digital PCM signals that could be estimated using standard digital,

Re: [music-dsp] #music-dsp chatroom invitation

2014-10-10 Thread Ethan Duni
own is fine, but your response to attempts to enlighten you is counterproductive. If and when you get serious about understanding this stuff, this list is here to help. E On Fri, Oct 10, 2014 at 4:21 AM, Peter S peter.schoffhau...@gmail.com wrote: n 09/10/2014, Ethan Duni ethan.d...@gmail.com

Re: [music-dsp] Some DSP with a dsPIC33F

2014-10-12 Thread Ethan Duni
Sounds like a fun project Scott. One question though: Sample rate is approximately 44.6 kHz. What's with the non-standard sampling rate? E On Sun, Oct 12, 2014 at 5:25 PM, Scott Gravenhorst music.ma...@gte.net wrote: I've been working on a MIDI Karplus-Strong synthesizer using a Microchip

Re: [music-dsp] entropy

2014-10-14 Thread Ethan Duni
Although, it's interesting to me that you might be able to get some surprising value out of information theory while avoiding any use of probability ... Hartley entropy doesn't avoid any use of probability, it simply introduces the assumption that all probabilities are uniform which greatly

Re: [music-dsp] entropy

2014-10-14 Thread Ethan Duni
The Hartley entropy is invariant to the actual distribution (provided all the probabilities are non-zero, and the sample space remains unchanged). No, the sample space does not require that any probabilities are nonzero. It's defined up-front, independently of any probability distribution.

Re: [music-dsp] entropy

2014-10-14 Thread Ethan Duni
The relevant limit here is: lim x*log(x) = 0 x-0 It's pretty standard to introduce a convention of 0*log(0) = 0 early on in information theory texts, since it avoids a lot of messy delta/epsilon stuff in the later exposition (and since the results cease to make sense without it, with empty

Re: [music-dsp] entropy

2014-10-20 Thread Ethan Duni
I might find myself in the situation where I am given a nonuniform distribution. Then Shannon and Hartley formulas would give a different answer. And the Hartley formula would be inapplicable, since it assumes a uniform distribution. So you'd have to use the Shannon framework, both to calculate

Re: [music-dsp] Thinking about the frequency content of repeated impulse responses

2014-10-20 Thread Ethan Duni
Of course it is only a theoretical matter, but we have a sensible spectrum for our repeating envelope generator, say at 1 Hertz, with a low pass filter set to 2Hz, possibly with an actually limited spectrum, that we can multiply with another wave, which can also be frequency limited in such a way

Re: [music-dsp] Statistics on the (amplitude) FFT of White Noise

2014-10-31 Thread Ethan Duni
Say we're only taking one length of the FFT transform, and are only interested in the volume of the various output bins. Now, how probable is it that we get all equal frequency amounts as the output of the this FFT transform (without regarding phase), taking for instance 256 or 4096 bins, and 16

Re: [music-dsp] Statistics on the (amplitude) FFT of White Noise

2014-10-31 Thread Ethan Duni
I am not sure if the PDFs are preserved across transforms from one orthonormal basis to another, and the answer to your question would depend on that (Of course it would also depend on several other parts of the phrasing of your question that aren't clear to me). My intuition is that PDFs are

Re: [music-dsp] Statistics on the (amplitude) FFT of White Noise

2014-10-31 Thread Ethan Duni
There is a theorem that goes something like this: If you have white noise expressed in one orthonormal basis, and you transform it to another orthonormal basis, the result will still be white noise. There is certainly no such theorem. For any noise signal you can define a basis that contains

Re: [music-dsp] Statistics on the (amplitude) FFT of White Noise

2014-10-31 Thread Ethan Duni
. You're talking about something quite different. E On Fri, Oct 31, 2014 at 3:42 PM, Andreas Tell li...@brainstream-audio.de wrote: On 31 Oct 2014, at 23:31, Ethan Duni ethan.d...@gmail.com wrote: If you have Gaussian i.i.d. noise, you can apply any unitary transform you want and you

Re: [music-dsp] Statistics on the (amplitude) FFT of White Noise

2014-10-31 Thread Ethan Duni
On Fri, Oct 31, 2014 at 4:16 PM, Andreas Tell li...@brainstream-audio.de wrote: On 01 Nov 2014, at 00:06, Ethan Duni ethan.d...@gmail.com wrote: The correct statement would be that an arbitrary unitary transform of a Gaussian white noise signal is *expected* to give a gaussian white noise

Re: [music-dsp] Statistics on the (amplitude) FFT of White Noise

2014-11-01 Thread Ethan Duni
...@iki.fi wrote: On 2014-10-31, Ethan Duni wrote: Transforms between orthogonal bases are basically rotations. I.e., they are linear operators that produce each component of the output as a linear combination of input components. Generally, then, the Central Limit Theorem tells us

Re: [music-dsp] Statistics on the (amplitude) FFT of White Noise

2014-11-03 Thread Ethan Duni
, Andreas Tell li...@brainstream-audio.de wrote: On 01 Nov 2014, at 02:39, Ethan Duni ethan.d...@gmail.com wrote: The expectation value of the signal over the ensemble of all unitary transforms with a suitable measure (like Haar). The expected value you describe is equal to the zero signal

Re: [music-dsp] FFT and harmonic distortion (short note)

2014-12-08 Thread Ethan Duni
what other presumption is there? i, personally, have never seen a sequence of samples of audio or music that was not equidistant and linearly sampled. it's what we call uniform sampling. Some of this new stuff in compressive sensing/sparse reconstruction involves non-uniform sampling. Not that

Re: [music-dsp] FFT and harmonic distortion (short note)

2014-12-09 Thread Ethan Duni
zeros happen to line up with the bin frequencies. E On Mon, Dec 8, 2014 at 3:28 PM, Jerry lancebo...@qwest.net wrote: On Dec 8, 2014, at 2:33 PM, Ethan Duni ethan.d...@gmail.com wrote: what other presumption is there? i, personally, have never seen a sequence of samples of audio

Re: [music-dsp] 14-bit MIDI controls, how should we do Coarse and Fine?

2015-02-04 Thread Ethan Duni
it takes a little less than a millisecond to receive a 3-byte MIDI message. should we put in some kinda delay (like a sample-and-hold) on that which prevents updating the net control value until 1 or 2 milliseconds after either the MSB or LSB is received? or slewing the net control value (slewing

Re: [music-dsp] Thoughts on DSP books and neural networks

2015-02-04 Thread Ethan Duni
My filter has 2 poles and 1 zero. Unlike the Cookbook filter, which has 2 poles and 2 zeros. I think that automatically assumes, the transfer function cannot be equivalent. No, that does not follow. A filter with two zeros can produce all of the transfer functions that a filter with one zero can,

Re: [music-dsp] Efficiently modulate filter coefficients without artifacts?

2015-02-03 Thread Ethan Duni
I completely agree! I find it mentally easier to think of energy stored in each component rather than state variables even though they are the same. So for musical applications it is important that a change in the cutoff and resonance doesn't change (until you process the next sample) the energy

Re: [music-dsp] Thoughts on DSP books and neural networks

2015-02-05 Thread Ethan Duni
, as a special case of the general 2 pole biquad filter. On 05/02/2015, Ethan Duni ethan.d...@gmail.com wrote: You just stick the extra zero(s) off at z=infinity. Does 'z=infinity' mean it's at the origin? I'm not 100% sure of the terminology used here. - Peter -- dupswapdrop -- the music-dsp

Re: [music-dsp] Thoughts on DSP books and neural networks

2015-02-05 Thread Ethan Duni
P.S. Anyone who knows how to effectively turn ideas into money while everyone can benefit, let me know. Patenting stuff doesn't sound like a viable means to me. Well, that's exactly what patents are for. I'm not sure why you don't consider that viable. Is it to do with the costs and time required

Re: [music-dsp] Dither video and articles

2015-02-05 Thread Ethan Duni
There is just no way A/B testing on a sample of listeners, at loud, but still realistic listening levels, would show that dithering to 16bit makes a difference. Well, can you refer us to an A/B test that confirms your assertions? Personally I take a dim view of people telling me that a test would

Re: [music-dsp] Dither video and articles

2015-02-06 Thread Ethan Duni
Thanks for the reference Vicki What they are hearing is not noise or peaks sitting at the 24th bit but rather the distortion that goes with truncation at 24b, and it is said to have a characteristic coloration effect on sound. I'm aware of an effort to show this with AB/X tests, hopefully it

Re: [music-dsp] Efficiently modulate filter coefficients without artifacts?

2015-02-03 Thread Ethan Duni
when filters blow up because of varying coefficients, don't they settle down some finite time after the coefs stop varying? In a digital implementation? Probably not. Once you have some Inf or NaN values in your state, you're going to keep getting garbage out forever unless you explicitly reset

Re: [music-dsp] Efficiently modulate filter coefficients without artifacts?

2015-02-03 Thread Ethan Duni
wrote: On 2/3/15 2:01 PM, Ethan Duni wrote: I completely agree! I find it mentally easier to think of energy stored in each component rather than state variables even though they are the same. So for musical applications it is important that a change in the cutoff and resonance doesn't change

Re: [music-dsp] Efficiently modulate filter coefficients without artifacts?

2015-02-03 Thread Ethan Duni
questions. E On Tue, Feb 3, 2015 at 5:13 PM, robert bristow-johnson r...@audioimagination.com wrote: On 2/3/15 7:07 PM, Ethan Duni wrote: well, the output states, y[n-1] and y[n-2], will change if coefs change. No, those have already been computed and (presumably) output at that point. It's

Re: [music-dsp] Dither video and articles

2015-02-10 Thread Ethan Duni
So to you, that Pono player isn't snake oil? It's more the 192kHz sampling rate that renders the Pono player into snake oil territory. The extra bits probably aren't getting you much, but the ridiculous sampling rate can only *hurt* audio quality, while consuming that much more battery and

Re: [music-dsp] Dither video and articles

2015-02-10 Thread Ethan Duni
. On 2/10/2015 1:13 PM, Ethan Duni wrote: I'm all for releasing stuff from improved masters. There's a trend in my favorite genre (heavy metal) to rerelease a lot of classics in full dynamic range editions lately. While I'm not sure that all of these releases really sound much better (how much

Re: [music-dsp] Dither video and articles

2015-02-10 Thread Ethan Duni
bristow-johnson r...@audioimagination.com wrote: On 2/10/15 1:51 PM, Ethan Duni wrote: So to you, that Pono player isn't snake oil? It's more the 192kHz sampling rate that renders the Pono player into snake oil territory. The extra bits probably aren't getting you much, but the ridiculous

Re: [music-dsp] Dither video and articles

2015-02-10 Thread Ethan Duni
How do the crest factors of these different sawtooth waveforms compare? I'd expect one with randomized phase to have a much lower crest factor. Which is to say that I'd expect the in-phase sawtooth to activate a lot more nonlinearity in the playback chain, which explains why that one is easy to

Re: [music-dsp] Approximating convolution reverb with multitap?

2015-03-18 Thread Ethan Duni
Yeah if you simply pick out a few peaks you can get the general shape of the reverb decay, but you miss all of the dense reflections. Multi-tap delay on its own is fine for the early reflections, but the rest of the reverb response is more dense as Steffan says. Keun Sup Lee did some work along

Re: [music-dsp] oversampled Fourier Transform

2015-03-31 Thread Ethan Duni
If you just want higher frequency resolution, you don't need to do any oversampling in the time domain. Just zero-pad the time domain signal out to whatever long length you want, and then use an FFT of that size. E On Tue, Mar 31, 2015 at 3:12 PM, MF ukel...@gmail.com wrote: given a N-point

Re: [music-dsp] recursive SIMD?

2015-04-14 Thread Ethan Duni
Your intuition is correct that SIMD can't use the output of one sub-operation as an input to another in the same vector. This poses a problem for stuff like recursive filters particularly. For FIR filters it is not as much of an obstacle, since the output at any particular time is only a function

Re: [music-dsp] oversampled Fourier Transform

2015-04-01 Thread Ethan Duni
For the theoretically inclined: approximating a full Fourier Transform requires time interpolation of the samples to a (possibly much higher) sampling frequency, and on top of that a very long FFT, and proper analysis of the results of the FFT. It sounds like you are talking about trying to

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-03 Thread Ethan Duni
Also a good starting place for beginners are the xiph show-and-tell videos (probably been posted here before, but whatever): https://xiph.org/video/vid2.shtml E On Wed, Jun 3, 2015 at 3:05 PM, Ethan Duni ethan.d...@gmail.com wrote: Perfect sinusoids/square waves/etc. only exist

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-03 Thread Ethan Duni
Perfect sinusoids/square waves/etc. only exist as mathematical abstractions. A good starting point would be to get a feel for what, say, the square wave coming out of an analog synthesizer actually looks like - the noise floor, the distribution of harmonics, frequency jitter, under/overshoot, etc.

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Ethan Duni
Now the assignment is as follows: can we, given the output signal coming from our filter which was fed the input signal, and the filter coefficients, compute the input signal ? Invertible digital filters are invertible, up to numerical precision. Are you wanting to talk about finite word length

Re: [music-dsp] Did anybody here think about signal integrity

2015-06-08 Thread Ethan Duni
If you try to take the Fourier transform integral of a exp(j*omega_0*t), it will not converge in the sense, how an improper integral's convergence is usually understood. You will need to employ something like Cauchy principal value or Cesaro convergence to make it converge to zero at

Re: [music-dsp] Sampling theorem extension

2015-06-09 Thread Ethan Duni
Could you give a little bit more of a clarification here? So the finite-order polynomials are not bandlimited, except the DC? Any hints to what their spectra look like? How a bandlimited polynomial would look like? Any hints how the spectrum of an exponential function looks like? How does a

Re: [music-dsp] [ot] what is GL_TEXTURE_2D_MULTISAMPLE??

2015-06-07 Thread Ethan Duni
Wow, good answer! E On Sat, Jun 6, 2015 at 4:34 PM, Sampo Syreeni de...@iki.fi wrote: On 2015-06-06, Alan Wolfe wrote: I am so sorry... meant to send this to myself to investigate later, my name starts with A and my address book has this as A for some reason. Please ignore... or feel

Re: [music-dsp] Sampling theorem extension

2015-06-19 Thread Ethan Duni
at 12:49 PM, Sampo Syreeni de...@iki.fi wrote: On 2015-06-12, Ethan Duni wrote: Thanks for expanding on that, this is quite interesting stuff. However, if I'm following this correctly, it seems to me that the problem of multiplication of distributions means that the whole basic set-up

Re: [music-dsp] Sampling theorem extension

2015-06-26 Thread Ethan Duni
, and then downsampling? Is there mileage to be had by combining oversampling with BLEP? E On Thu, Jun 25, 2015 at 1:34 AM, Vadim Zavalishin vadim.zavalis...@native-instruments.de wrote: On 24-Jun-15 21:30, Ethan Duni wrote: Could you expand a bit on exactly what it means to apply the BLEP method

Re: [music-dsp] Sampling theorem extension

2015-06-10 Thread Ethan Duni
vadim.zavalis...@native-instruments.de wrote: On 09-Jun-15 19:23, Ethan Duni wrote: Could you give a little bit more of a clarification here? So the finite-order polynomials are not bandlimited, except the DC? Any hints to what their spectra look like? How a bandlimited polynomial would look

Re: [music-dsp] Sampling theorem extension

2015-06-12 Thread Ethan Duni
to sampling/reconstruction of well-tempered distributions in the first place. No? E On Thu, Jun 11, 2015 at 2:00 AM, Sampo Syreeni de...@iki.fi wrote: On 2015-06-09, Ethan Duni wrote: The Fourier transform does not exist for functions that blow up to +- infinity like that. To do frequency domain

[music-dsp] This seems relevant to the list of late

2015-08-12 Thread Ethan Duni
https://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect E ___ music-dsp mailing list music-dsp@music.columbia.edu https://lists.columbia.edu/mailman/listinfo/music-dsp

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-19 Thread Ethan Duni
a first-order interpolator. quite familiar with it. Yeah that was more for the list in general, to keep this discussion (semi-)grounded. E On Wed, Aug 19, 2015 at 9:15 AM, robert bristow-johnson r...@audioimagination.com wrote: On 8/18/15 11:46 PM, Ethan Duni wrote: for linear

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-18 Thread Ethan Duni
Assume you have a Nyquist frequency square wave: 1, -1, 1, -1, 1, -1, 1, -1... The sampling theorem requires that all frequencies be *below* the Nyquist frequency. Sampling signals at exactly the Nyquist frequency is an edge case that sort-of works in some limited special cases, but there is no

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-18 Thread Ethan Duni
a nyquist frequency sinusoid when you run it through a DAC. E On Tue, Aug 18, 2015 at 1:28 PM, Peter S peter.schoffhau...@gmail.com wrote: On 18/08/2015, Ethan Duni ethan.d...@gmail.com wrote: Assume you have a Nyquist frequency square wave: 1, -1, 1, -1, 1, -1, 1, -1... The sampling

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-18 Thread Ethan Duni
no bearing on the frequency response of fractional interpolators. I'd suggest dropping this whole derail, if you are no longer hung up on this point. E On Tue, Aug 18, 2015 at 2:08 PM, Peter S peter.schoffhau...@gmail.com wrote: On 18/08/2015, Ethan Duni ethan.d...@gmail.com wrote: That class

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-18 Thread Ethan Duni
, the aliasing issue works like this: I add two numbers together, and find that the answer is X. I tell you X, and then ask you to determine what the two numbers were. Can you do it? E On Tue, Aug 18, 2015 at 2:13 PM, Peter S peter.schoffhau...@gmail.com wrote: On 18/08/2015, Ethan Duni ethan.d

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-18 Thread Ethan Duni
be used there. But the example of the weird things that can happen when you try to sample a sine wave right at the nyquist rate and then process it is orthogonal to that point. E On Tue, Aug 18, 2015 at 1:16 PM, robert bristow-johnson r...@audioimagination.com wrote: On 8/18/15 3:44 PM, Ethan Duni

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-18 Thread Ethan Duni
In order to reconstruct that sinusoid, you'll need a filter with an infinitely steep transition band. No, even an ideal reconstruction filter won't do it. You've got your +Nyquist component sitting right on top of your -Nyquist component. Hence the aliasing. The information has been lost in the

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-19 Thread Ethan Duni
and it doesn't require a table of coefficients, like doing higher-order Lagrange or Hermite would. Well, you can compute those at runtime if you want - and you don't need a terribly high order Lagrange interpolator if you're already oversampled, so it's not necessarily a problematic overhead.

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-18 Thread Ethan Duni
for linear interpolation, if you are a delayed by 3.5 samples and you keep that delay constant, the transfer function is H(z) = (1/2)*(1 + z^-1)*z^-3 that filter goes to -inf dB as omega gets closer to pi. Note that this holds for symmetric fractional delay filter of any odd order (i.e.,

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-19 Thread Ethan Duni
. E On Wed, Aug 19, 2015 at 3:55 PM, Peter S peter.schoffhau...@gmail.com wrote: On 20/08/2015, Ethan Duni ethan.d...@gmail.com wrote: I don't dispute that linear fractional interpolation is the right choice if you're going to oversample by a large ratio. The question is what

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-21 Thread Ethan Duni
, not a discrete time signal of whatever sampling rate. E On Fri, Aug 21, 2015 at 2:09 AM, Peter S peter.schoffhau...@gmail.com wrote: On 21/08/2015, Ethan Duni ethan.d...@gmail.com wrote: In this graph, the signal frequency seems to be 250 Hz, so this graph shows the equivalent of about 22000/250 = 88x

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-21 Thread Ethan Duni
, 2015 at 1:24 PM, Peter S peter.schoffhau...@gmail.com wrote: On 21/08/2015, Ethan Duni ethan.d...@gmail.com wrote: It shows *exactly* the aliasing It shows the aliasing left by linear interpolation into the continuous time domain. It doesn't show the additional aliasing produced

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-21 Thread Ethan Duni
...@gmail.com wrote: On 21/08/2015, Ethan Duni ethan.d...@gmail.com wrote: Creating a 22000 Hz signal from a 250 Hz signal by interpolation, is *exactly* upsampling That is not what is shown in that graph. The graph simply shows the continuous-time frequency response of the interpolation

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-21 Thread Ethan Duni
The details of how the graphs were generated don't really matter. The point is that the only effect shown is the spectrum of the continuous-time polynomial interpolator. The additional spectral effects of delaying and resampling that continuous-time signal (to get fractional delay, for example)

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-21 Thread Ethan Duni
to what I'm saying in the first place. It is indeed a waste of your time to invent equivalent ways to generate graphs, since that is not the point. E On Fri, Aug 21, 2015 at 2:56 PM, Peter S peter.schoffhau...@gmail.com wrote: On 21/08/2015, Ethan Duni ethan.d...@gmail.com wrote: The details

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-21 Thread Ethan Duni
1) Olli Niemiatalo's graph *is* equivalent of the spectrum of upsampled white noise. We've been over this repeatedly, including in the very post you are responding to. The fact that there are many ways to produce a graph of the interpolation spectrum is not in dispute, nor is it germaine to my

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-21 Thread Ethan Duni
of the noisiness no matter how much data you throw at it). E On Fri, Aug 21, 2015 at 5:47 PM, Peter S peter.schoffhau...@gmail.com wrote: On 22/08/2015, Ethan Duni ethan.d...@gmail.com wrote: We've been over this repeatedly, including in the very post you are responding to. The fact

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-20 Thread Ethan Duni
In this graph, the signal frequency seems to be 250 Hz, so this graph shows the equivalent of about 22000/250 = 88x oversampling. That graph just shows the frequency responses of various interpolation polynomials. It's not related to oversampling. E On Thu, Aug 20, 2015 at 5:40 PM, Peter S

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-17 Thread Ethan Duni
Yeah I am also curious. It's not obvious to me where it would make sense to spend resources compensating for interpolation rather than just juicing up the interpolation scheme in the first place. E On Mon, Aug 17, 2015 at 11:39 AM, Nigel Redmon earle...@earlevel.com wrote: Since compensation

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-20 Thread Ethan Duni
If all you're trying to do is mitigate the rolloff of linear interp That's one concern, and by itself it implies that you need to oversample by at least some margin to avoid having a zero at the top of your audio band (along with a transition band below that). But the larger concern is the

Re: [music-dsp] Compensate for interpolation high frequency signal loss

2015-08-19 Thread Ethan Duni
rbj and it doesn't require a table of coefficients, like doing higher-order Lagrange or Hermite would. Robert I think this is where you lost me. Wasn't the premise that memory was cheap, so we can store a big prototype FIR for high quality 512x oversampling? So why are we then worried about the

Re: [music-dsp] about entropy encoding

2015-07-14 Thread Ethan Duni
Well, I was thinking about this as well. How about a 1bit square wave then? Such a signal is deterministic and so has entropy rate of zero. Your bitflip counter would not be sensitive to duty cycle. The simpler bit counter would be. I don't see why entropy should change with duty cycle since I

  1   2   >