VSF Video Demos

Here are a couple demonstrations of my new filter design the VSF.



Got the transistors working now.  Changed the resistors to 10k and switched to 3904s.

VSF

Finished building the VSF (described below) last night.  I had to disable the transistors since they seemed to be on continuously.  Very nice distorted complex tone colors out of this thing.  I need to change the pots to 100k from current 1M for VCF and 500k for Q.  The Mura I need to change from 100k to 1M.  Go figure. I will try to get an example of the sound up here soon.  I may try to change the transistors so I can get some control voltage response.

Mura Filter

From the Japanese term for the waste of uneveness this filter will create an uneven distortion of the resonance structure both from the transistor and from the diode in the feedback path.  Connections are described in the picture.  Values can be changed somewhat to match standard values.  RS is a rail splitter.  Saving the other side for an LFO to modulate the Fco.  Have not built this yet but it looks pretty cool in the simulator.

Falstad circuit simulator code:


$ 1 5.0E-6 0.9891409633455756 50 5.0 50
r 336 320 272 320 0 4700000.0
c 336 224 336 192 0 1.0E-9 0.00268564673175871
c 432 224 432 192 0 1.0E-9 -1.876367065692067
r 272 320 272 368 0 47000.0
c 272 320 224 320 0 1.0000000000000001E-7 -2.4144869775373956
174 336 192 432 176 0 100000.0 0.9059 Q 100k
a 336 336 432 336 0 15.0 -15.0 1000000.0
w 336 224 336 240 0
w 336 288 336 320 0
w 432 224 432 240 0
w 432 288 432 336 0
g 336 352 336 368 0
g 272 368 272 384 0
O 432 336 432 368 0
174 336 192 240 176 0 100000.0 0.9257000000000001 Fco 100k
g 240 192 240 208 0
w 288 176 336 192 0
R 224 320 192 320 0 2 100.0 5.0 0.0 0.0 0.5
r 336 288 384 288 0 2000000.0
r 384 288 432 288 0 2000000.0
g 384 240 384 224 0
c 384 288 384 240 0 1.0E-11 -0.939194425306891
w 384 176 336 192 0
w 432 240 432 288 0
w 336 240 336 288 0
w 336 160 336 192 0
w 448 288 432 288 0
174 336 160 432 160 0 1000000.0 0.005 Resistance
d 464 160 464 192 1 0.805904783
w 384 144 336 160 0
w 432 160 464 160 0
w 464 192 464 288 0
w 464 288 448 288 0
t 288 128 288 160 0 1 0.45948822583066745 0.4568213771495246 100.0
w 272 160 240 160 0
w 240 160 240 192 0
w 304 160 336 192 0
R 288 96 288 64 0 1 40.0 3.0 2.0 0.0 0.5
174 288 96 304 128 0 1000000.0 0.10400000000000001 Resistance
w 304 112 288 96 0
o 13 4 0 34 20.0 9.765625E-5 0 -1

Note the resonance wave form has a slight sawtooth edge as well as only oscillating on the positive cycle of the square wave.

Very Strange Filter 2

I decided to put this into a case.  I get these boxes at Office Max for about $1.50.  They drill out pretty easily with the Dremel dry wall attachment.  Have all the hardware attached at this point but still need to add the wires.

The top of the box.

This shows the circuit board in the box.  No wires attached yet but all of the components are in place.  This is basically a three part filter.  Probably a bit silly of me to make this without breadboarding it first since I don't really know what it will sound like.

Pendula

Created some sound in Csound based on this video I found on Youtube:


https://soundcloud.com/hmikelson/pendula 






<CsoundSynthesizer>
<CsOptions>
;-RWfo pendula.wav
</CsOptions>
<CsInstruments>
;---------------------------------------------------------
; Pendula
; Inspired by Youtube video of pendulums of various lengths like this one
; http://www.youtube.com/watch?v=eZm_-2O8ovI&list=UUeQEKFH31vvD-InkTGSvCrA 
; Hans Mikelson March 2013
;---------------------------------------------------------
sr = 44100 ; Sample rate
kr = 44100 ; Kontrol rate
ksmps = 1 ; Samples/Kontrol period This must be 1 to make sure to update time appropriately
nchnls = 2 ; Normal stereo
;---------------------------------------------------------
; Pendula
;---------------------------------------------------------
instr 50
idur = p3 ; Duration
iamp = p4  ; Amplitude
il0 = p5  ; Length of pendulum
ib = p6  ; Damping factor for pendulum (smaller damping will ring longer)
ig = p7  ; Gravity
kdclk linseg 0, .005, 1, idur-.01, 1, .005, 0
atime init 0  ; Need to start time at 0
atime = atime + .1  ; Time is incremented each sample
ialpha0 = ib/2/il0 ; Calculate alpha exponential decay factor
aamp0 = 1*exp(-ialpha0*atime) ; Calculate exponetial decay
aout0 = aamp0*cos(sqrt(ig/il0-ib/il0/il0)*atime) ; Calculate the oscillator times amplitude
apan = .5 + aout0/2
outs aout0*iamp*apan*kdclk, aout0*iamp*(1-apan)*kdclk ; Amplify and output
;outs aout0*iamp*sqrt(apan)*kdclk, aout0*iamp*sqrt(1-apan)*kdclk ; Amplify and output
;outs aout0*iamp*kdclk, -aout0*iamp*kdclk ; Amplify and output
endin
</CsInstruments>
<CsScore>
;-------------------------------------------------------------------------
f1 0 65536 10 1
; Pendula
; Sta Dur Amp PendL Damp Gravity
i50 0.0 10 3000  100 0.02 9.81
i50 . . .  90  . .
i50 . . .  80 . .
i50 . . .  70 . .
i50 . . .  60  . .
i50 . . .  50  . .
i50 . . .  40 . .
i50 . . .  30 . .
i50 . . .  20 . .
i50 . . .  10  . .
; Pendula
; Sta Dur Amp PendL Damp Gravity
i50 10.0 10 3000  100 0.02 9.81
i50 . . .  95  . .
i50 . . .  90 . .
i50 . . .  85 . .
i50 . . .  80  . .
i50 . . .  75  . .
i50 . . .  70 . .
i50 . . .  65 . .
i50 . . .  60 . .
i50 . . .  55  . .
; Pendula
; Sta Dur Amp PendL Damp Gravity
i50 20.0 5 3000  200 0.1 9.81
i50 . . .  100  . .
i50 . . .  50 . .
i50 . . .  25 . .
i50 . . .  12  . .
i50 . . .  6  . .
; Pendula
; Sta Dur Amp PendL Damp Gravity
i50 25.0 5 3000  100 0.05 9.81
i50 . . .  90  . .
i50 . . .  81 . .
i50 . . .  73 . .
i50 . . .  66  . .
i50 . . .  59  . .
i50 . . .  53 . .
i50 . . .  48 . .
i50 . . .  43 . .
i50 . . .  39  . .
</CsScore>
</CsoundSynthesizer>

Planar Crystal Live Rig

Demo of the rig.

Planar Crystal Live Rig

My planar Crystal live rig consisting of Waldorf Pulse processed by Lexicon Vortex, Korg MS2000, MPC500 for sampling and sequencing, Thing 2 and Sequencer processed by Kaoss Pad.  Midi clock originates with MPC500 and controls arpeggiator speed on MS2k, Pulse, and KP3. I used Velcro to connect the Vortex to the pulse.