edit: New rev PCBs have 3.2mm mounting holes for 4U and 5U use, footprint for shrouded power header and bigger holes for fitting a wider variety of resistor sizes.
edit: New black and gold panels available! The circuit PCB is unchanged. If you're after an original red panel they are still available at ModularAddict and Synthcube.
Video of what happens when you modulate the stereo width at audio rates:
[video][/video]
Demo video: Full details of what's going on are on the youtube page, but basically there are two filters processing the mid and side separately and the joystick is increasing the width of the panning. Note that because of the way that Mid Side stuff works you're not going to get the full (or any) effect if you listen to this in mono. Headphones or monitors are recommended.
[video][/video]
Another video using it to process a drum loop:
[video][/video]
This is a fairly simple circuit but that said I'm just selling the boards, I'm not offering any guarantee of support or troubleshooting if your build doesn't work. It's not intended as a beginner project so if you've never soldered before maybe start off with something fully documented and supported first.
After reading through the recent thread on including schematics for projects I've decided to offer up the schematic for this. I didn't lay it out thinking anyone but me would ever see it so apologies if it's messy or unclear.
A bit of theory on how it works:
Each of the inputs has an opamp buffer with a gain of -1. (U1 + U3)
The inverted and buffered signals are then sent to the mixing stages (U2 + U4) where they're mixed like so:
M out = (L + R)/2
S out = (L - R)/2
L out = M + S
R out = M - S
As both the input buffers and the mix stages are inverted the signal comes out with the correct polarity.
Gain of the mix stages is given by the ratio of the input and feedback resistors, for example on the M out stage (U2.1) the input resistors are R7 and R9 (10k) and feedback is the resistance formed by the two resistors in parallel R23 and R24 [10k//10k = 5k]
5k/10k = gain of 0.5
The parallel resistors (R23&R24, R25&R26, R27&R28) are used to get a value of 5k with two 10k resistors as 10k resistors are easier and cheaper to come across than 5k, also using all 10k from the same batch should theoretically give you a better match.
If you're aiming for a super-precise result then the sets of resistors to match would be:
R1, R5 - same value
R2, R6 - same value
R3, R11 - same value
R4, R12 - same value
R7, R9, R23, R24 - All the same value
R8, R10, R25, R26, R27, R28 - All the same value
R15, R21, R16 - All the same value
R17, R22, R18, R29 - All the same value
However I got a really precise result without matching.
Interest list below.
Cost is US$30 per set shipped worldwide, US$20 for board only, no panel. Additional sets are US$20/10 with combined postage. Second batch is in so I should have these available for a while. Post here or PM me to be added to the list.
Username (PCB quantity) (panel quantity) Red = paid Blue = shipped
spneca (2)(2)
DJBRUTAL(2)(2)
flts(1)(0)
keninverse(2)(2)
radioelcamio(1)(1)
oberkorn(2)(2)
starspawn(2)(0)
Neutron7(2)(2)
sammy123(1)(1)
fluffymuff(1)(1)
goiks(1)(1)
salocinnomis(1)(1)
ac(1)(1)
calaveras(1)(0)
distracted(1)(1)
m0d01(1)(1)
mmagin(1)(1)
Paranormal Patroler(1)(1)
mikecameron(1)(1)
jarvis(1)(0)
a.b.o.z.(1)(1)
Vcoadsr(2)(2)
Grumskiz(1)(0)
Jcsveth(1)(1)
funky40(2)(2)
Opnotic(1)(1)
n22(1)(1)
