Hello, I am new to pd and am trying to make a sweeping oscillator that has a range between 2 changeable frequencies. The issue I am having is making it come back down once it scales up. Can anyone out there give me any guidance?

Hi, welcome to Pd and welcome to this forum.

What exactly do you mean by "sweeping oscillator that has a range between 2 changeable frequencies"? Do you want to have a glissando between two frequencies in a certain amount of time? if so, you can use the [line~] object to generate a continous ramp between two values in a given amount of time. E.g.:

[440, 880 1000(
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[line~]
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[osc~]
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[dac~]

(in case you are not familiar with the schematics we use in this forum, [something] is an object, [something( is a message box and | or __ are patch cords.

As this little schematics above shows, the first message will generate a ramp between the values 440 and 880 in 1000 ms (1s), which are fed to the oscillator object. If you want to have a glissando down, you can add another message to line such as [880, 440 1000( (or simply [440 1000( if you want the [line~] object to start on its current value). And if you want to immediately go to a certain value, simply feed this value to [line~] (although it is usually better to add a short time value in order to avoid any clicks, such as by using [220 40(, which tells [line] to go from the current value to 220 in 40ms).

Take care,
GIlberto

@gsagostinho

You added an extra comma in your diagram. Also you probably want to use [line~] instead of [line] when dealing with audio-rate ramps.

@portabello Thanks for pointing that out, the comma was just a typo, but indeed [line~] is the correct object in this case. I edited my answer above. Take care, Gilberto

This is all very helpful and yes I am not familiar with the schematics used on this forum. I will start applying the method you have demonstrated. I will attempt to use what you have shown thus far and see where it gets me. Thanks for the welcome.

Also, to clarify what I am trying to do is create sine wave that sweeps up and down between 1kHz and 4kHz. The idea is to make an ambulance type sound.

I would try modulating the frequency by another [osc~] object. This should give it a more characteristic sound.

[osc~ 2] <-set 2 to the rate of the sweep in Hz
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[+~ 1]
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[*~ .5] <- the +1 and * .5 are to put the modulating osc into the range of 0 to 1
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[*~ 3000] <- range of frequencies
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[+~ 1000] <- lowest frequency
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[osc~]
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[dac~}

Cool this is very helpful! Thanks for the quick response.

So, this turned out to be exactly what I was trying to do thank you!

If I wanted to elaborate on this specific patch a bit more, how could I add a very short delay to make the sound a bit fatter? Like one would add to an instrument in mix down to fatten the sound. Any ideas?