I 'm looking for help with a specific project in this book and I'm hoping this is an appropriate place to ask.
I finished project 11 which was an awesome learning experience. You made a high-speed (audio) oscillator and made its sound waver using a low-speed (sub-audio/control) oscillator just upstream of it. The final schematic is on page 91 of the book. Following the author's suggestions to tweak the circuit to make it my own, I'd like to add a third (very low-speed) oscillator to modulate/control the slow-speed oscillator - so that the entire siren sound slowly wavers up and down in pitch. So I made a third (very low-speed) oscillator similar to the first two and I tried connecting the cathode (output) of its PUT to the gate of the low-speed oscillator's PUT, with a resistor in between - as is done to connect the original two oscillators together. I tried a whole range of resistances from 0 to 1M ohms and it didn't work. Does anyone know what I need to do to make this work? I'd love to be able to make my own synthesized sounds by connecting multiple oscillators in series. Thanks.
Just a thought, since I can't seem to view page 91 online (although the reviews make me want to buy the book regardless!)...
Your essential concept is a good one, being how many an ingenious device was genesized (huh?), and loosely describes how synthesizers in general work, except that you might consider placing oscillators both in series and in parallel with each other, or in series-parallel combinations (or was that parallel-series?), and/or combinations of parallel and series-parallel combi... well, the point, even if I'm not sure what it is, or was, is to experiment, at least within the bounds of safety, which I think is one of this remarkable book's many, um, points.
There is more than one way that a signal can modulate, or change, another signal. Level (volume) and frequency (pitch) are only two ways this can happen. Even placing one oscillator in different places in the signal chain can make quite a difference in the end result. Don't let yourself fall into the trap of thinking that there is only one way to do something. Unless there is only one way.
Until you invent the second way.
Oh--and look up what it means for two signals to mix in a "non-linear" manner.
My reply is real late and I suppose you found the answer all ready. In case you haven't experiment 17 gives you another way to accomplish what you want with a couple of 555 chips. Page 167 to 169 explains it pretty well.