NOISE2, a white and pink noise source in a single chip

Posted by & filed under Noise, PIC/Programming, Synth DIY.

It’s been around ten years since I developed the original Druid NOISE 1B chip to produce good quality white noise. Finally it gets an update, and the new NOISE2 chip can produce pink noise as well as white noise, so there’s no need for external “pinking” filters. Here’s what it sounds like, white noise and pink noise:   Here’s the spectrums for the two outputs. Note the scales on these two graphs are different, so you can’t compare one to the… Read more »

An LED bargraph audio level display

Posted by & filed under PIC/Programming, Projects.

Replacing the LM3914/LM3915/LM3916 with a PIC Most designs you see for audio level LED bargraph displays use the LM3914/LM3915/LM3916 series chips that are no longer made. However, the chips are simple, so we can replace them with a PIC and build a nice LED bargraph driver on a single chip. So why do you need this thing? You need this if you want to display an audio level and make sure it doesn’t go above some well-defined threshold, usually the level at… Read more »

Practical LFSR random number generators

Posted by & filed under Noise, PIC/Programming, Synth DIY.

The linear feedback shift register is one of the most useful techniques for generating psuedo-random numbers. I’ve used this method for creating noise generators and as an element in the random modulation generators I spent a long time developing for my Protowave synth. If you’re not really clear how an LFSR works, have a look at one of the many pages online (links below). This page isn’t here for that. In short, an LFSR takes a series of bits from… Read more »