Signal processing is an electrical engineering subfield that focuses on analysing, modifying and synthesizing signals such as sound, images and biological measurements. Electronic signal processing was first revolutionized by the MOSFET and then single-chip digital signal processor (DSP). Digital signal processing is the processing of digitized discrete-time sampled signals. Processing is done by general-purpose computers or by digital circuits such as ASICs, field-programmable gate arrays or specialized digital signal processors (DSP chips).
Hackaday has published an in interesting series of articles on signal processing, and here are some picks from it:
RTFM: ADCs And DACs
https://hackaday.com/2019/10/16/rtfm-adcs-and-dacs/
DSP Spreadsheet: IQ Diagrams
https://hackaday.com/2019/11/15/dsp-spreadsheet-iq-diagrams/
Sensor Filters For Coders
https://hackaday.com/2019/09/06/sensor-filters-for-coders/
DSP Spreadsheet: FIR Filtering
https://hackaday.com/2019/10/03/dsp-spreadsheet-fir-filtering/
Fourier Explained: [3Blue1Brown] Style!
https://hackaday.com/2019/07/13/fourier-explained-3blue1brown-style/
DSP Spreadsheet: Frequency Mixing
https://hackaday.com/2019/11/01/dsp-spreadsheet-frequency-mixing/
Spice With A Sound Card
https://hackaday.com/2019/07/03/spice-with-a-sound-card/
- check also A real-time netlist based audio circuit plugin at https://github.com/thadeuluiz/RTspice
Reverse Engineering The Sound Blaster
https://hackaday.com/2019/06/19/reverse-engineering-the-sound-blaster/
FM Signal Detection The Pulse-Counting Way
https://hackaday.com/2019/08/28/fm-signal-detection-the-pulse-counting-way/
DSP Spreadsheet: IQ Diagrams< https://hackaday.com/2019/11/15/dsp-spreadsheet-iq-diagrams/
Here is an extra, not from Hackaday, but an interesting on-line signal processing tool for generating sounds
https://z.musictools.live/#95
209 Comments
Tomi Engdahl says:
95% of those who pretend they can tell the difference between a wav file and an MP3 are lying to themselves. I’m talking about 320kbps MP3s, not 128 or below.
A blind test would fool most people (it’s been done). The differences are so subtle that, unless you really listen specifically to hear the differences, you wouldn’t be able to tell lossy from lossless. And who does that? Most people listen to music on the go, or while doing something else, or in less than favorable environments.
And it’s even more true with the mainstream devices that most people possess. Very few people actually own high-end amplifiers and speakers. Most people are not trained to listen to music critically, and just don’t care that much about the sound quality (to a certain extent).
Therefore, MP3 is perfectly acceptable in most cases, but if you prefer lossless formats because you are convinced you can tell the difference, that’s all fine.
For casual listening, it absolutely does not matter if it’s MP3 or lossless.
Oh, yes, and also, not all recordings and mixing are good in the first place.
Tomi Engdahl says:
Grebz Bibert and FM sound processors like early Omnia’s in the 90-ties didn’t like mp3 at all, especially lower bitrates like 128 or 160 kbps.
Tomi Engdahl says:
Grebz Bibert True. But there is also a noticeable step from 16/44.1 and 24/96. It’s not so much the actual specs but the breathing room of more bits which allows imperfect levels to still shine through when turned up.
Tomi Engdahl says:
LAME improved algorithms by adding so many configuration options that didn’t exist in Fraunhofer. The two most powerful ones are: joint-stereo that encodes (L+R) & (L-R) instead of L & R, and Variable Bit-Rate (VBR), though not all players can play or seek it properly xD
Tomi Engdahl says:
Fun fact: the very first mp3 song was Tom’s Diner(Susanne Vega)
Tomi Engdahl says:
Light Transport And Constructing Images From A Projector’s Point Of View
https://hackaday.com/2025/08/07/light-transport-and-constructing-images-from-a-projectors-point-of-view/
Imagine you have a projector pointing at a scene, which you’re photographing with a camera aimed from a different point. Using the techniques of modelling light transport, [okooptics] has shown us how you can capture an image from the projector’s point of view, instead of the camera—and even synthetically light the scene however you might like.
The concept involves capturing data regarding how light is transported from the projector to the scene. This could be achieved by lighting one pixel of the projector at a time while capturing an image with the camera. However, even for a low-resolution projector, of say 256×256 pixels, this would require capturing 65536 individual images, and take a very long time. Instead, [okooptics] explains how the same task can be achieved by using binary coded images with the projector, which allow the same data to be captured using just seventeen exposures.
Construct an image from a projector’s point of view (and more tricks with light transport)
https://www.youtube.com/watch?v=TcXMf0mTh94
Tomi Engdahl says:
White Balance is Broken
https://www.youtube.com/watch?v=WADuXiMZxq4
00:00 – What is White Balance?
00:49 – How is White Balance Broken?
02:03 – Why is White Balance Broken?
02:54 – Comparison with Exposure
04:55 – How to Fix White Balance
05:52 – Takeaways
06:49 – Ps…