Dear PD experts,

I need special Swept Sine

Common Sweep Wave Generators have three variables (frStart, timeTotal and frStop) with
"linear" (100-200-300-400Hz...) or
"logarithmic" (100-200-400-800Hz...) time scale.

But my project needs special Sweep Wave Generator with just two variables:
frStart = starting frequency of the sine wave
timeTotal = total length of the sweep
and simple formula:
fr = frStart * timeTotal / timeRemaining

If you can help me in finding the solution, please drop me a note!

Best to all!
janez.krizaj@guest.arnes.si

You can calculate the timeRemaining value by using a [line] object to ramp down from the timeTotal variable in timeTotal (ms).

For example if timeTotal = 1000 then ramp from 1000 to 0 in 1000. This would look like the following message to a [line] object:

[1000, 0 1000 (
|
[line]

Then divide timeTotal by the output of the [line] and multiply that result by frStart to get fr.

Check out the attached patch.

http://www.pdpatchrepo.info/hurleur/sweep_gen.pd

Dear Jwif many many thanks. After days of pitchbending and searching other solutions I just made perfect sweep (95 min long!) based on your patch.
Love this community and you also inspired me to start using PD

I would like to send you copy of released DVD (in a couple of weeks) if you please message me your post address,

Best to all!
Janez