Combining many oscillators?

[synox89]

Hello,

I want to start a project, in which I want to illustrate how acoustic instruments work. My plan is to build several sinus oscillators
and to make a similar tone for example of a flute.

But yet I am far from that. My problem yet is that I lack some electronic knowledge and don't exactly know how to make an Oscillator which should oscillate with the frequency I want to have.
I have found the Armstrong-Oscillator and have build one with a program called Yenka. But it didn't really work so I made some prototype based on logic and eventually it oscillates. (Screenshot of the circuit I made) The problem know is, that I don't know on which parameters the frequency depends. I know that it depends on the Capacity of the capacitor and the inductance of the inductor, but still I need to know how i can determine it precisely so i can get the frequency i need immediately. There is the formula of Thomson - is it applicable to my circuit?

And is the program reliable, I mean, would that circuit Ive made really oscillate, and are there better solutions?

P.s. sorry for my poor language, I am working on it.
Thanks,

Alex

 

[alec_t]

Welcome to the forum!

My plan is to build several sinus oscillators and to make a similar tone for example of a flute.

That is quite an ambitious project. Apart from the oscillators you will need some way to control attack, sustain, decay and release parameters to get a realistic sound.
For an LC oscillator, frequency f is given by the formula f= (square root of (1/LC))/(2*pi).
For such circuits google 'Hartley oscillator'.

 

[cowboybob]

Welcome, synox89!

As a starting point:

https://www.1728.org/resfreq.htm

 

[audioguru]

Your circuit is not an oscillator. An oscillator has positive feedback but your circuit has NO feedback.

You cannot produce a musical tone with a bunch of oscillators. You need the oscillators to be syncronized to be the exact harmonic frequencies of the fundamental sinewave.

Here is your schematic with the Yenka garbage marks removed:

 

[4pyros]

Have you looked at 555 timers?

 

[crutschow]

Have you looked at 555 timers?

For musical sounds you generally want sine waves not square waves.

 

[crutschow]

You should look at music synthesizer circuits.

 

[Nigel Goodwin]

For musical sounds you generally want sine waves not square waves.

Actually not true, you don't really want sinewaves (they aren't musical).

The classic method for making an electronic organ (which is essentially what the OP is wanting) is a series of 12 oscillators (the top octave), then a series of flip/flop dividers to provide all the lower octaves. To generate the musical waveforms you want (which aren't sine) you filter the squarewaves to gives the required shapes.

Note this is VERY complicated.

A good many years ago there were special generator chips for organs, which derived all the frequencies from a single crystal and dived down, but I would imagine they are long since obsolete..

 

[4pyros]

For musical sounds you generally want sine waves not square waves.

Yep the 555 is just the oscillator what you do with it after that is up to you.
There are many 555 synth circuits out there. Including some of the most famous like the atari punk synth.

 

[cowboybob]

... You cannot produce a musical tone with a bunch of oscillators. You need the oscillators to be syncronized to be the exact harmonic frequencies of the fundamental sinewave. ...

(Underlined emphasis is mine).

I take that to mean you're not into Techno Hard Acid, or Jungle Neurofunk, eh AG??

(Forgot to add Trance Psytekk... which, admittedly, starts to hurt your brain)

 

[audioguru]

I take that to mean you're not into Techno Hard Acid, or Jungle Neurofunk, eh AG??

(Forgot to add Trance Psytekk... which, admittedly, starts to hurt your brain)

Acid rock is not musical, it is noise. Distortion is also not musical.

 

[atferrari]

You need the oscillators to be syncronized to be the exact harmonic frequencies of the fundamental sinewave.

Piano harmonics are somewhat inharmonic. Not sure if any other instrument is also like the piano.

 

[Dean Huster]

A sine waveform is very close to that of a flute. A square wave is similar to a clarinet. Without a top octave generator, you have to build twelve generators for each note and then divide each of these with a binary divider string to obtain the notes in each octave below that as Nigel suggests. It was the traditional method used in non-tonewheel electronic organs until Rockwell and Allen organ developed the digital computer organ. Now, most organs use this method and the electronics components count has been drastically reduced. It's almost sickening to see where your money went when you look inside a three-manual Viscount church organ and see hardly anything but a few custom ICs.

 

[synox89]

Thank you for your responses, but i suppose that I should be more precise then. Lets express it this way: The principle I strive is the violin sound creation. I dont want it to be similar, i just want to make an illustration of the similarities between them in terms of the dependency of the frequency on one parameter which you change: putting the finger on a string further and closer - or changing of the capacity of an oscillator . Since we have a different system here from that of a flute (no stepwise separated keys), how could i make an oscillator which changes the frequency by changing the capacity of an oscillator? Is it hard to realize this, by lets say an antenna? So basically a oscillator with a possibility to change the frequency by an antenna.

This would be really helpful.

Alex.

 

[alec_t]

So basically a oscillator with a possibility to change the frequency by an antenna.

Google 'theramin'.

 

[atferrari]

Thank you for your responses, but i suppose that I should be more precise then. Lets express it this way: The principle I strive is the violin sound creation. I dont want it to be similar, i just want to make an illustration of the similarities between them in terms of the dependency of the frequency on one parameter which you change: putting the finger on a string further and closer - or changing of the capacity of an oscillator . Since we have a different system here from that of a flute (no stepwise separated keys), how could i make an oscillator which changes the frequency by changing the capacity of an oscillator? Is it hard to realize this, by lets say an antenna? So basically a oscillator with a possibility to change the frequency by an antenna.

This would be really helpful.

Alex.

Are you talking of "legato" or "portamento"? Understand that the first is sometimes implemented as minute changes of tone that could be heard as a continuous one.

Since I am not into music playing AT ALL, I could be dead wrong.

If you knew this, sorry.

 

[synox89]

Yes, you are correct. I talk about both. The sound should be continuous and the same time there is a portamento, since the frequency should be gliding up or down.

 

[audioguru]

I recall hearing a theremin playing in the background in old movies about ghosts.

 

[cowboybob]

The Beach Boys used theramin once.

Have a listen.

A metal "slide" is is close to, but not touching, an "antenna" which is simply a wire providing a capacitive couple to the theramin circuit.

Plenty of schematics on the web.

 

[synox89]

Well yeah, ive found plenty of all sorts of circuits. My problem is that i am not sure if i am doing them right, because i use a simulation programm called Yenka, but the outcomes dont really work. My knowledge in electronics is not that good...

A Question: If i plug in a Transformator in a oscillator circuit instead of an inductor and wire to only wo one half (so to one conductor), should this circuit oscillate?

An illustration:

And furthermore: shouldn't this circuit oscillate...?

As i said, im not sure if I am doing it wrong or the program. ^^

Alex