Tremulus Lune Symmetry Mod

[robotboy]

Does anybody know what symmetry mod does to the tremulus lune? Just stabbing in the dark, but does it do something to synchronize the pots? I'm buliding it tonight, and I'm wondering if I should apply it.

http://commonsound.org/tremulus/symmetry.pdf

[Gabriel Simoes]

Maybe this will help you figure it out ...
Since I didn't build it I cannot answer you ...

http://commonsound.org/fud/index.php?t=msg&goto=997&S=467e714bfbaa6b40e1dfbd595f41ca31#msg_997

Good luck
Gabriel

[idiot savant]

i remember reading somewhere(on the commonsound forum) that the symmetry mod is a fuller featured version of the ramp up mod.

[ethrbunny]

It looks like its a pair of diodes on either end of a pot. Im guessing it changes the beginning / ending of each trem 'cycle'.

[80k]

i've done it... it just moves where the peak is.  turning it to one side gives you ramp up.  turning it to the other side gives you ramp down.  putting it in the middle gives you a triangle wave.    In between, and you might get, say, a fast rise and a gradual fall.  It's an awesome mod!

[loki]

i'm building it too... but still i haven't understood well the difference between the symmetry, ramp up/down, and sawtooth mods... and if they all can be done together  :?

[robotboy]

Thanks for the replies. I'm going to build it using just the standard five knobs and ramp up/down mod first since I'm not sure how the ramp up / down switch would mesh with the symmetry mod.

[80k]

i'm building it too... but still i haven't understood well the difference between the symmetry, ramp up/down, and sawtooth mods... and if they all can be done together  :?

ok, since all of commonsound's LFO's are pretty much identical (between trem, phase, triwave, etc.), i don't remember how they documented what mods for what pedals.  

but sawtooth, ramp up/down, and symmetry are all the same.  you choose one, and forget the others.  it's a matter of what you would like to do.

I have done them all.

Circuit-wise, they are all identical in the way they use diodes to hasten the rise or fall of the LFO, using pots for ultimate control, or using switches to choose between regular rise/fall or an abrupt one.  Here is the order from least desirable to best, imo.  

- the sawtooth in general is a SPDT mod lets you choose between regular triangle and a sawtooth shape.  depending on the orientation of the diode, you either get a gradual rise and an abrupt drop (a /| shape), or an abrupt rise and a gradual fall (a |\ shape).  This is the least desirable but the easiest to wire.

- an improvement of the sawtooth is to use a 3-way SPDT with a center off position.  Then you can choose between triangle (in the middle off position), and one side will give you the abrupt rise, and the other side will give you the abrupt fall.  

- Separate Rise and Fall speed knobs is an excellent improvement to the 3-way Sawtooth.  This allows more flexibility, because you can choose the speeds separately.  

- Symmetry is exactly the same as the separate rise and fall speeds in terms of what you can achieve, but it is the easiest to work with.  You still have one speed knob that sets the overall speed.  Symmetry just moves where the peak is.  Instead of choosing rise and fall speeds separately, you have one overall speed knob, and the symmetry knob controls the ratio between between the rise and fall speeds.  Result is identical, implementation is different.  

I like Symmetry the most, but i've enjoyed using the separate Rise and Fall speed knobs on my triwave.

The improved sawtooth mod with the 3-way switch is what i have on my phaser, and i like it for the simplicity.  less options, but it's easier to quickly switch to great raygun blasts.

[loki]

thank you for clarifying 80k, i think i'll go with the symmetry mod too... btw i've built the basic circuit and it sounds awesome

[ethrbunny]

80k - ive not seen a schem for the 'separate rise / fall' knobs. Its a cool idea though. When you do that does it change the gap between each pulse or is that still determined by the 'spacing'?

[80k]

80k - ive not seen a schem for the 'separate rise / fall' knobs. Its a cool idea though. When you do that does it change the gap between each pulse or is that still determined by the 'spacing'?

try this: http://www.commonsound.com/triwave/risefall.pdf

i never did it on the tremulus, so i wouldn't know for sure, but i would imagine that spacing still works as before.  The only difference is the shape of the wave form.

so instead of
____/\____/\____/\____

and let's say you maxed out the speed of the rise knob, and left the fall knob alone, you'd get:

____|\____|\____|\____

just a guess though.  if you try it, be sure to report back, as i'd be curious to know how it works out.