Function 1/x

ER-301
#21

@Joe did you ever achieve a satisfactory 1/x function? And did its intended application ever materialize?

#22

I did embed a transfer function inside of a sample scanner as a bespoke unit. I think it worked OK as long as you understand and control the input to it, but I was never able to get the final end application to do what I wanted.

#23

So I was also searching for a way to do the 1/x function. Specifically though I just wanted to create an equal volume mix of a couple of oscillators such that, when in phase, the total volume would never surpass 1 (10v).

I discovered this can be done using the RationalVca and hereā€™s a working middle layer example. Iā€™ll explain it in text though so it doesnā€™t necessarily need to be done in the Middle Layer.

  1. Create 4 oscillators and pass each into itā€™s own level VCA
  2. Mix the level controlled outputs together at 1/4 gain.
  3. Sum the level amounts for each (giving a range of [0,4])
  4. Find the difference between the level sum and 4
  5. Place a rational vca after the oscillator mix and set the numerator to 4 and the denominator to the difference in the level sum.
  6. Celebrate.

The idea is that if all the levels are up (level sum is 4) then our ratio will be 4/4 and the signal will remain at 1. If only three levels are up (level sum is 3) then our ratio will be 4/3 and we will multiply the signal by 1.333 to get back to unity.

Hopefully I explained that well, it took me several hours to get right despite being deceptively simple :sweat_smile:

Edit: oh and hereā€™s a video showing it in action https://photos.app.goo.gl/ZSKEkesvGcV4Rnmj6

3 Likes
#24

please bear with it :slight_smile: Im interested on your thoughts (to all- but Joe esp)

3 Likes
#25

Me Joe? I think one of those R values exceeded my IQ value. :slight_smile:

#26

Iā€™m no Joe and itā€™s not with the ER301 directly but I have been using the chaos functions (including that videoā€™s specific equation) on the teletype (Which then goes back into the 301). Check it out!

CHAOS x
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get next value from chaos generator, or set the current value
CHAOS.R x
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get or set the R parameter for the CHAOS generator
CHAOS.ALG x
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get or set the algorithm for the CHAOS generator. 0 = LOGISTIC, 1 = CUBIC, 2 = HENON, 3 = CELLULAR
2 Likes
#27

Since I unfortunately have no experience with creating a spreadsheet in Audacity, do you think you could maybe upload the wav file or explain how to do it? Would love to also ā€˜buildā€™ my ā€˜ownā€™ 1/x unit :slight_smile:

#28

Itā€™s already on my list to do for desolationjones, so Iā€™ll just make it public here when I find the time to dust it off and polish it up. It was sort of a mini-project that was meant to be used inside another, so itā€™s not quite in a functional state at the moment. It will also have some caveats with how it works, because of divide by zero thing.

2 Likes
#29

thats amazing!