Timeline for Yet another fft question - a vocoder
Current License: CC BY-SA 4.0
19 events
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| Apr 18, 2022 at 21:02 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Dec 19, 2021 at 21:00 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Aug 21, 2021 at 20:05 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
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| Dec 29, 2019 at 0:02 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Aug 30, 2019 at 23:02 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Aug 1, 2019 at 9:07 | comment | added | applesoup | cool that it works now. I'm glad I could help a bit... | |
| Jul 31, 2019 at 22:25 | answer | added | Michal Pawluk | timeline score: 1 | |
| Jul 31, 2019 at 22:09 | comment | added | Michal Pawluk | ... continuation... Applying i.e. hamming window to two 50% ovelapping source buffers reduces frequency leaks at the input however some windowing must be also applied on the output which will obviously not work well on two buffers... However increasing the number of buffers to four with 25% overlap did the trick. Thanks again for your suggestion :) | |
| Jul 31, 2019 at 22:06 | comment | added | Michal Pawluk | Hi @applesoup, I must admit it woul dbe hard for me to explain the poroblem in more detail before however thanks to your hint I have managed to resolve it. I was a bit worried the issue lies in my implementation of fft/ ifft even if it passed any unit test i could throw at it - the problem was actually with the multiplication in the frequency domain as you pointed out. | |
| Jul 31, 2019 at 20:30 | comment | added | applesoup | I think the most important step towards the solution is to break down your problem into smaller pieces: Start with a very basic framework, omitting, e.g., signal B and the frequency-domain processing completely. Find the most reduced version of the framework which still works as expected and which does not produce any artifacts. Then, step by step, add more complexity until it breaks. Then you know exactly which step introduces the problem and you can work on precisely that problem. We here on DSP.SE are very happy to try and help then. | |
| Jul 31, 2019 at 19:10 | comment | added | Michal Pawluk | HI @applesoup I don't think it will be useful if I share the code... I'm using my own java implementation of fft and ifft which after being optimised are not readable anymore - no need for obfucsation :D But I'll follow your hint regarding the impulse response.. Unfortunately I'm quite new to the DSP field, prone to make silly mistakes... | |
| Jul 31, 2019 at 13:17 | comment | added | applesoup | Hi @michal-pawluk, and welcome to DSP.SE. It's hard to follow your algorithm description and understand your question, so maybe you can reformulate your question and add some code. Other than that: Have you tried simplifying your algorithm step by step, down to the basic WOLA framework, to determine when exactly the artifacts appear? In my opinion, it would be helpful to narrow down the source of the problem. Finally, element-wise multiplication of spectra may lead to time-domain aliasing problems since the corresponding impulse response does not fit within one buffer. | |
| Jul 31, 2019 at 10:54 | history | edited | Michal Pawluk |
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| Jul 31, 2019 at 10:50 | review | First posts | |||
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| Jul 31, 2019 at 10:46 | history | asked | Michal Pawluk | CC BY-SA 4.0 |