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Author Archives: Nigel Redmon
About synthesizer control voltages
Since I write about simulating classic analog synthesizers (a process often called “virtual analog”), mostly notably in my wavetable oscillator series so far, I wanted to touch on the topic of parameter control signals. Classic synthesizers have knobs to set … Continue reading
Posted in Synthesizers
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Perspective on dither
Recently, I’ve had lengthy discussions on the topic of dither with a couple of different people—of opposite views. One believes that everything should be dithered, including truncations to 24-bit. The other feels that dither is a waste of time even … Continue reading
Posted in Dither
2 Comments
Replicating wavetables
My WaveTableOsc object uses a series of wavetables that are copies of single-cycle waveforms pre-rendered at a progressively smaller bandwidth. By “replicating wavetables” I mean taking a full-bandwidth single cycle waveform, and using it to make a complete set of … Continue reading
Posted in Oscillators, Wavetable Oscillators
6 Comments
About source code examples
My goal is to teach audio DSP principles in a way that is more intuitive than most available material. And part of that goal is to help you to think about the your goals and how to solve them by … Continue reading
Posted in Uncategorized
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Ventilator adapter in a mint tin
I don’t eat mints often, but when I do, they are sugar free… A Leslie speaker simulation Players of Hammond organs and their clones know how important the Leslie speaker is to the classic sound. Modern clones have electronic simulations … Continue reading
Posted in Uncategorized
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A one-pole filter
Here’s a very simple workhorse of DSP applications—the one-pole filter. By comparison, biquads implement two zeros and two poles. You can see that our one-pole simply discards the zeros (the feed-forward delay paths) and the second pole (feedback path): We … Continue reading
Posted in DC Blocker, Digital Audio, IIR Filters
6 Comments
A note about de-normalization
One ugly thing that we need to be aware of, especially for filters, is the de-normalization of numbers. Basically, computer processors try to keep floating point numbers normalized—they try to keep them in the binary form 1.xxxxxx (where each x … Continue reading
Posted in Digital Audio
1 Comment
Biquad C++ source code
I don’t want to get into the business of teaching people how to code—there are a huge number of free resources available on the internet to that do that. But I’ll give a small taste for those trying to get … Continue reading
Posted in Biquads, Digital Audio, Filters, IIR Filters
10 Comments
A wavetable oscillator—end notes
I wrote the wavetable oscillator code from scratch as I wrote this series of articles, using just the thought process I gave. Hence, no references to other articles on wavetable oscillators. The concept of a phase accumulator is fairly obvious; … Continue reading
Posted in Digital Audio, Oscillators, Wavetable Oscillators
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A wavetable oscillator—the code
The wavetable oscillator code follows the basic structure of most audio processing blocks, with three types of functions: at the start: initialization—create the oscillator and its wavetables as needed: control—change the oscillator frequency, and pulse width for PWM every sample: … Continue reading
Posted in Digital Audio, Oscillators, Wavetable Oscillators
9 Comments