New estim tracks for CH videos

[diglet]

I tested contract yesterday, it was great. Passion was harder for me to enjoy, not sure why, will try again later.

Vulcan was different, I feel a bit of pain in the balls at the bottom of each stroke. This file has long stretches of incomplete strokes, I guess it takes time for the nerves to acclimate to the power level and that doesn't happen when strokes are incomplete. I think I would prefer lower power at the extreme part of the stroke and a bit more power in the middle, would that mean more of less tremolo?

I would like to have some details on the math. I tried to work it out by looking at the audio files, but I have to say it's not obvious how these signals translate into stroking.

[FileFlax]

Vulcan was different, I feel a bit of pain in the balls at the bottom of each stroke. This file has long stretches of incomplete strokes, I guess it takes time for the nerves to acclimate to the power level and that doesn't happen when strokes are incomplete. I think I would prefer lower power at the extreme part of the stroke and a bit more power in the middle, would that mean more of less tremolo?

I tried to follow the on-screen action in Vulcan (whenever there is some) since there isn't a beat bar, but maybe the action parts gets lost between the normal "beat like" sections. I don't always go for full length (from top to bottom) strokes either (in any of my files) since I try add different variations to the estim track, but I still try to follow the beat. In a normal CH I would say 70-80% of the beats are strokes from top to bottom, and most of the beats are half-speed since quick actions generate a stinging sensation at the top and bottom (the quick change in phase direction due to short 100-150ms actions). In Vulcan there are some actions that are fairly quick, and my guess is that these could cause some stinging in the extreme parts of the stroke. Try different trodes to make the estim track feel different and some conductive gel helps.

But glad you liked the Contract file!

I would like to have some details on the math. I tried to work it out by looking at the audio files, but I have to say it's not obvious how these signals translate into stroking.

I think it's easiest to explain the math using these oscillator pictures to show the bottom, mid and top stroke position with a tremolo value of 35:

1. Bottom position. Here the phases of right and left channel are 100% (or 180 degrees) out of sync with full volume (100%):
https://mega.nz/file/15kW1QAK#-Jd4UKpg4 ... 4WCbkziExU

2. Middle position. Left and right channel phases are now 50% (or 90 degrees) out of sync. Here the tremolo effect has lowered the volume (linear from 100%) 82.5% (17.5% lower) since I've used a tremolo value of 35 (35% / 2 = 17.5%):
https://mega.nz/file/IptBXJTY#zMKYM9hmr ... gL5iSPtJ24

3. Top position. The phases are now in sync and tremolo effect has lowered the output volume by 35%:
https://mega.nz/file/EpNDHaJC#HpPgzJPnC ... d-NSeUZD1g

Here is a short low quality video where you can see the stroking action (moving phases and tremolo):
https://mega.nz/file/kl90UbYK#b3GyexT8D ... N0j8rVKKc

By lowering the volume the closer the phases get to each other we get less intensity to the head. Hope this makes sense?

[FileFlax]

A big thanks to all comments for the positive feedback!

Here are three more CH estim tracks if anyone wants to try them out:

CH - 4-Play Challenge Edition
Milovana post
Estim file

CH - Binary State [Primal Instinct Version]
Milovana post
Estim file

CH - Crescendo
Milovana post
Estim file

All files work with top = common, mid = left+, bottom = right+

[diglet]

I spent 'a bit' of time thinking about three-phase estim generation...

One thing I noticed is that there are three phases. If we assume frequency is constant, we have three degrees of freedom. How does this work? I propose this notation:



The circle is the unit circle, the area of possible "stroke" positions. a/b/c are electrodes. ab/bc/ac is the rms voltage flowing between the electrodes. The more the position is towards the head electrode, the more current flows through the head electrode.

My belief is that, if we keep the carrier frequency constant, a particular sensation if defined uniquely by the pair (ab, bc, ac). Therefore all of the following are unique sensations:



The numbers indicate the rms voltage between the electrodes, i.e. ab, bc, and ac. I believe the position of the feeling is characterized by the ratio, and the strength is characterized by the magnitude. Change the position, changes the location of the sensations. Change magnitude, changes strength of the sensation. Two separate degrees of freedom.

It is the scripter's job to create a funscript, a path if you will, that defines how the sensations change over time:



You might have noticed that this figure only displays two degrees of freedom, namely alpha and beta both of which are related to position (you might use x and y. Or r and theta)? Where is the third degree of freedom? The third one is the one perpendicular to the image plane, this is just the magnitude of the signal.

After performing 'some' calculations I figured that FileFlax' estim files only use the following range of motion:



I believe this notation makes much more sense than conventional methods.

I wrote some python code to generate stim files according to this schema, this involved a lot of messing around to find 'clean' transformations from position inside the unit circle to the waveforms that sum to the desired RMS voltage. There are a few kinks to be ironed out, but I was able to generate some calibration patterns. The calibration pattern moves over the unit circle, the goal is to adjust the calibration parameters until the strength of the sensation is constant over the whole range of motion so you don't have too much sensation on one small area of your test 'apparatus'. After fiddling with the calibration, the constant strength sensation for my test subject is


(orange: unit circle. Green: calibrated circle of constant strength)

This indicates that the head electrode is significantly more sensitive than the other electrodes, and the balls and mid electrode are approximately equally sensitive. This is why the fileflax range of motion doesn't extend all the way to the right. If you use FileFlax definition, tremolo is 30%. I tested a few patterns that follow this circle, results were pleasant.



The goal is to have a piece of software that contains calibrated parameters for the user specific electrode placement and body dimensions (and gender). Software then generates the audio in real time in response to a funscript file. We can then leverage the existing library of funscript files, funscript editors and funscript routers for estim. It also solves the problem of distributing gigabytes of audio files...

[Electro]

Tri-phase is not a great term in my opinion because it's misleading, I've never been a fan of it being called that because it makes people think it is three-phase, it's not three-phase despite there being 3 connections/electrodes involved because there are only two sources involved and essentially splitting two phases by combining them.

Electrically it is two 2 channels(or phases) but my joining two connections between these channels produces combined-phase electrical effects. Fun fact is that is sortof backwards to how US electrical household wiring works, by center tapping a transformer in electrical wiring we are getting half the voltage (120v) out of a 240v supply, but even that is something different because we aren't center tapping a transformer. In the case of tapping two channels to a single electrode, we instead combine them and by having differences in the waveforms we are creating the sensations that are commonly called tri-phase effects in the estim world because of what you just described when two channel have differing phase positions, it produces a stronger effect when they are matching and when they are opposite of eachother they essentially cancel themselves out at the common electrode while the other electrodes will have increased sensation.

[edger477]

Hi, I felt the urge to chime in.

First time I heard triphase was when I was a kid, in Balkans it is very common that each household has "triphase" AC power - we get ground and 3 wires of AC, each of them is 50Hz 220V, but each of the 3 are delayed by 1/3, so voltage between either 2 of the phases is always 380V - used for ovens, and often for special equipment like motors for cutting wood etc.

The "triphase" estim is similar in a way because when you combine 2 wires you get total of 3, for which you could generate signal that will cause current to run between any 2 electrodes (difference being that in triphase AC the phase difference is constant so it is the voltage so the current always runs between any 2 terminals).

As for adjustments, I like what diglet did, but I think he is overengineering it. I am currently mostly using my amp that has separate l/r volumes to compensate for difference in electrode size/distances but there is one thing that it cannot do. If we use simple funscript converter like one from cfs6t08p, the signal between any 2 electrodes (with everything else fixed) will only depend on position in funscript at that given moment. He has left channel fixed on frequency and right channel shifts to be in or out of phase with left.

I would take his converter and add a calibration setting to it - in simplest scenario you would need left/right volumes at position 0, position 50 and position 100. So 3 pairs of volumes that you would have to acquire by i.e. playing constant l/r signals for frequency you want to use as carrier at those 3 positions and setting volume in each of them. Based on that you could extrapolate volume for each channel on any position between 0-50 and 50-100 (just use linear approximation) and add a block that would do it same as with his amp block now (that fades in/out on pauses), but separately for each channel.

I think this would allow generator to have higher average volume in generated estim and feel the movements better while requiring minimal amount of work to test the concept (still generating mp3 file, playing with ScriptPlayer, keeping current workflow).

I want to try to do it but I am not sure when I will have the time, if anyone else wants to use idea let me know if you start so we don't both waste time on same thing. For start I would just add 6 input boxes on his converter page to enter volumes for 0 L/0 R/50 L/50 R/100 L/100 R (all 100 by default to produce same output as now) and play and test calibration elsewhere (i.e. generate calibration funstim file with position 0-0 for 20 sec, then go 0-50 in 21st and stay at 50 for another 20 sec then go to 100 and then play that and see what volumes feel the best, i.e. with l/r volume controls in sound card properties => balance). Then enter these values in boxes and convert funscript I want.

[diglet]

If this isn't three phase, then brushless motor control is not three phase either. Strangely, I've never heard anyone argue that motor control isn't "real" three phase. The potential at the electrodes (with my software) when rotating around the unit circle is exactly the same as for a brushless motor moving at a constant speed.

You say that this isn't three phase because there are only two sources involved. Consider the following:



Left is clearly a three-phase circuit, both circuits have the same degrees of freedom as far as the current over the resistors is concerned. So right is clearly a three-phase circuit.

[diglet]

I think you're describing what FileFlax calls Tremolo. He interpolates the volume between 1 and (1-tremolo) based on the stroke position.... I'm sure this can be improved by adding more calibration parameters, but your degrees of freedom will still be limited to a single line in the unit circle. You can make the line longer or shorter, or you can rotate it, you *might* be able to curve it in some limited ways, but it will still be a line and this line won't change over the course of the funscript.

To add the extra degree of freedom, we would need a funscript with two independent axis. The hard part, where I spent a good amount of time, is figuring out how to map these three axis to audio channels in a way that makes sense. Generating sensations by directly describing the frequencies and amplitude modulation is something I find not very intuitive, since the actual strength of the sensations is non-linear with respect to phase and amplitude.

[edger477]

I am not sure where would you get this additional degree of freedom when funscript only has one axis, and it is linear position between 0 and 1?

As far as I see it the triphase we have is completely controlled by signals in left and right channels, and because it has to be a waveform due to amplifier/transformer used, the only thing that controls which way the current travels is the superposition of both waveforms, which must be somewhere between "fully in sync" and "fully out of sync".

I think the approach you described would have similar result but it would be much more complex to implement. Maybe you are referring to the calibration as second degree of freedom, but the 6 points I described should be enough to test the concept. If it works, then more advanced version could have a graph that you adjust (so instead of linear change and values at 0/50/100 you could define volume for any position between 0 and 1) but I would want to first implement the simple idea to see how it feels.

[diglet]

Of course, we need a funscript with two independent axes. Or three if we want to dynamically adjust the volume. These funscripts already exist, but they are intended for three-axis strokers.

The first axis is along the length of the penis, commonly referred to as stroking feeling (alpha axis). The second axis is perpendicular, in the direction of the top/bottom of the penis, beta in my diagram. I still need more testing, but I was able to generate sensations focused on the head moving between the frenulum and the glans opposite to the frenulum, and also sensations in the middle of the penis moving between the front and back side of the penis. When moving along the unit circle, the stroking feeling goes down on the underside and up along the top side of the penis.

FileFlax only adjust the superposition of the waveform, with this method you can move the sensation from the head to the mid and bottom electrode. But this approach cannot move the sensation between the mid and bottom electrode, to do that we also need to independently vary the left/right amplitude in response to the funscript. This is the second degree of freedom.

[edger477]

Ah I see now. All funscripts I have have only one axis, but I guess with multiple axes we could then control more channels (so my dual-box would get to connect all electrodes to penis :D)

[zebbg69]

E-stim "tri-phase" has TWO degrees of freedom and is entirely unlike "three-phase" AC power. This is just math: if you have two independent inputs (Channels A & B), then you have two degrees of freedom. It does not matter how many things you compute from these two inputs (A+B, A-B, 2A-B...), you still have two degrees of freedom and a bunch of other linearly dependent variables.

If you compute your A & B from ONE variable, a la cfs6t08p, from a one-dimensional stroker, then you have one degree of freedom, as edger477 points out. The stroker's one single number was used to compute two numbers A & B, which are not linearly independent and still constitute one degree of freedom. If you compute a third number from those two numbers, as in e-stim tri-phase, you still have only one degree of freedom. Three-phase power also has only one degree of freedom, because if I tell you only the leading wave, you can generate the other two by phase-shifting; they are not independent. There is only one sinusoid's worth of information in the whole three-phase arrangement.

If you want to call volume a degree of freedom, that's technically fine by pure math, and it adds a degree to everything I said above. But I think it misses the point that the wave SHAPE alone is normally what we care about. We adjust the volume ourselves during the session, so that's not really part of the e-stim "product" delivered by the author to the stimmer. In other words, if I released an e-stim file on the forum here, and you guys all liked it, and then next month I said "NEW RELEASE" and just uploaded the same thing with a 15% volume boost, I think you all would say, "Come on now, that's the same one!" And you would all just stim it at a lower volume than the previous one... but actually you wouldn't even bother downloading it, because it's the same one. Because for stimming, volume is really not a degree of freedom.

None of this takes away from diglet's contribution, if it makes e-stim "tri-phase" feel better. Better is better, cumming is cumming, and while blissfully drowsy afterward, it does not matter how many linearly independent time-varying quantities were flowing through the information space leading to your genital electrodes.

Knowing that we do not really have three degrees of freedom might help diglet simplify the implementation, but anything that makes these funscript conversions feel better is wonderful. Thank you for your contribution, diglet. Please continue developing it and elucidating it to us, and I look forward to trying it out soon and drifting away too blissfully drowsy to care about semantics.

[edger477]

Three-phase power also has only one degree of freedom, because if I tell you only the leading wave, you can generate the other two by phase-shifting; they are not independent. There is only one sinusoid's worth of information in the whole three-phase arrangement.

While I agree with most of your comment, I have to point out that first degree of freedom (the shift between a&b) can be observed as a x range (0-1 or 0-100) and in that range you have areas where the feeling on one or other channel is too weak or too strong. His idea of "calibration" inspired me to propose that tuning of volumes, essentially adding 2 more degrees of freedom - the volume for l channel and volume for r channel in each of the points on x range. You would fix them for your setup when calibrating, so they would not be "degrees of freedom" anymore - the generated signal would only have stroking, but until you fix them you can change them freely and calibration would potentially allow it to make that signal much better suited for your electrode setup because it would map volume for each point on x range - you can't change volume of each channel 420 times per second to achieve that.

If approach works, and you can produce different sensations by tuning these volumes on different points of x range, this could then be incorporated into funscript->audio generators that don't use files, and you could control those settings on the fly, or even map them from 2nd axis from funscript.

[zebbg69]

Three-phase power also has only one degree of freedom, because if I tell you only the leading wave, you can generate the other two by phase-shifting; they are not independent. There is only one sinusoid's worth of information in the whole three-phase arrangement.

...His idea of "calibration" inspired me to propose that tuning of volumes, essentially adding 2 more degrees of freedom - the volume for l channel and volume for r channel in each of the points on x range.

If you vary the L/R volumes separately, you are adding one degree of freedom: the ratio of the volumes. As before, I am claiming that the overall volume of the waveshape is not a real degree of freedom. But if you change one channel's strength relative to the other, then you are changing the waveshape (of the whole stereo signal), so I agree in counting that as another degree of freedom. So, converting a stroker file to phased FM with variable L/R balance is a two-degree-of-freedom system, one for the stroker x-coord, plus one for the L/R balance. Good idea.

UPDATE! However... if you generate the L/R balance FROM the stroker x-coord, then guess what? It's just one degree of freedom again. Because the single x coordinate generates all. But who cares? (Just your math teacher.) The point is, you have a good idea about using the L/R balance to manage the intensity. And diglet has a good idea! I just haven't invested the time in those phase diagrams enough, but I would be interested in the output files.

[edger477]

If you vary the L/R volumes separately, you are adding one degree of freedom: the ratio of the volumes. As before, I am claiming that the overall volume of the waveshape is not a real degree of freedom.

I do not really think that for majority of funscripts (the ones with one axis) is important how many degrees of freedom we have, my point was that the way how we generate signal from them even one axis can be adjusted, and adjusting volume based on position might solve the issue when one of electrodes feels too harsh because at some points in phase shift it conducts too much current.