#259

All of these great patch ideas but could one simply use it as a basic VCA with an envelope from Maths? Tried to RTFM but you know… :innocent:

#260

Yep!

Audio to RIGHT In.
CV to Survey
Monitor LEFT out

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#261

Make sure to patch a cable (doesn’t have to be connected to anything) into LEFT In as that is normalled to -5V.

Also patching your CV for the VCA to the FADE input on Mac will let you use the other functions independently with the survey control :+1:

You could also use OFFSET to sum another voice (and have it mixed to LEFT out) with your Mac’ VCA voice.

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#262

Also:
Envelope in to SURVEY
Signal in to any other input on the left side of the module
MAC is your output

SURVEY knob becomes a cv offset

The OR1 input and the SLOPE inputs are 2x gain if nothing is patched to AND1 or CREASE inputs.

If the coldmac manual isn’t making sense, definitely take a look at Martin’s documentation or video!

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#263

Thank you! Found that video later in the day. Excellent stuff indeed. One Cold Mac ordered and incoming.

2 Likes
#264

On my Mac if I do that VCA patch combining my technique with @Ithacus’s idea to use Fade, I find that it doesn’t close fully. Is this to be expected?

#265

I think one of left and right doesn’t fully close on most people’s units whereas the other does…? I think there’s some discussion of it above?

#266

With Survey I can get one of them to close, not with Fade though

#267

It doesn’t. Nature of analog circuits in there.
But the MAC output should fully close. or close to it.

Here is the company’s answer in FAQ.

#268

MAC output should 100% fully close; remember though, it closes when SURVEY is at -5v, not 0v.

#269

I had seen that FAQ answer already, although from my reading of that i was expecting at least one of the sides to close even a bit.

In the current situtation i have:
Dummy cable - LEFT
Audio - RIGHT
Monitor - LEFT
Survey fully CCW

Plugging a second dummy cable into Survey makes no change - as to be expected. But if I plug that same cable instead into Fade, the output opens. Switching around channels and the behaviour is more or less the same, with slightly more bleed this time. So for me, this method as a VCA Is pretty much redundant…

#270

Should close entirely (w/ -5v into FADE):
LEFT(in) going to RIGHT(out)
or
RIGHT(in) going to LEFT(out)

  • nb: if it is not fully closing, just push FADE further negative; if it’s not closing with SURVEY at min, it is because the control may only be reaching -4.85v to -4.95v or so on your module.

Will mostly close, but still have high-frequency content bleed (w/ +5v into FADE):
LEFT(in) going to LEFT(out)
or
RIGHT(in) going to RIGHT(OUT)

This is happening because by plugging a dummy cable into fade, you are breaking the normalization of the FADE jack to the SURVEY voltage, and are now using your dummy cable to control the FADE circuit - since the cable is not plugged in, it looks like 0v to the module, so the FADE circuit is halfway open (equivalent to SURVEY being at noon before you dummied FADE). If you plug the other end of that dummy cable into a voltage source (e.g. a CV offset or envelope), you will now be controlling the FADE circuit identically to how you were controlling it with SURVEY before. Same rules as above apply re: degrees to which the outputs close.

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#271

so to close Fade properly, an envelope would need a -5v offset to close properly? That would clear things up quite a bit, thanks for detailing this!

#272

Correct! This is because the -5v to 5v range is meant to correspond to x-fade/pan locations, so 0v is the natural choice for an equal blend/center panning.

Note that the OFFSET input is not added to the control FADE signal - it is directly added identically to the two outputs, so that you can shift them both in the same direction when using it as a CV panner/xfader.

If you want to use an envelope to control FADE circuit as a VCA, you would ideally want a 0-10v envelope which you would then offset by -5v. You could quickly do this by plugging it into the SURVEY input with the SURVEY knob at minimum, -5v (the input gets added to the knob).

Alternatively, you could actually use Just Friends in Sound/Transient or Sound/Sustain modes but set to very low frequencies, as in Sound/Sustain the outputs are -5v to 5v.

6 Likes
#273

It took me a while but I realized how to use Cold Mac as a mid/side processor, with the help of a module that can invert a signal. My example below describes mid/side for a left/right stereo pair but you can use any two input signals:

  • Left channel audio into OR 1, plus a copy into AND 1 (normalled)
  • Right channel audio into OR2, plus a copy into AND2 (mult needed)
  • OR output is the mid signal.
  • AND output is the side signal.
  • Process each signal accordingly
  • Send the processed mid signal to the OFFSET input.
  • Send processed side signal to the LEFT input.
  • Take a second copy of the processed side signal, invert it, then send to the RIGHT input.

The left and right output is now your mid/side encoded stereo mix. SURVEY/FADE will control the width of the side signal; widest at full cw or ccw, most narrow at noon.

Edit for clarity: as the two side signals are crossfaded they will begin to cancel each other out at the center of the sweep. A dummy cable into FADE will keep it fixed and allow SURVEY to be used freely without disrupting the stereo image.

Here’s a patch I was just running with this set up. Probably not the most obvious example of what mid/side encoding does but it works!

Mangrove FORMANT into the ALL input of Three Sisters #1. The two inputs to Cold Mac are the LOW and CENTER outputs instead of a stereo pair. Each side signal is processed by separate channels of Three Sisters #2. Outputs of Cold Mac go to their own individual channel of a DLD, each with a slightly different delay time.

SURVEY modulated by a cycling Maths function. SLOPE output to FM of Three Sisters #2. CREASE output to feedback of DLD, both channels. Sequenced with Kria.

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#274

this is basically exactly what i want CM for in my patches; thanks very much for the notes

2 Likes
#275

i’m not in front of my system so correct me if i’m wrong, but could you eliminate the need for an inverter by putting the side signal into SURVEY? then a pos version would come out the of LEFT and an inverted side signal would be coming out of RIGHT with the mid signal in OFFSET. m/s all in one!

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#276

Just tested and that does seem to work as well! The only drawback with this setup is you lose the ability to dynamically “widen” / swap the side signals using the crossfader. Patching into the FADE jack disrupts the inversion.

Also, an attenuator on the mid signal (between OR out and OFFSET) can help balance the proportion of the mid/side signals in the final mix!

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#277

ah right! just got excited at the idea of it being self contained. great patch!

1 Like
#278

This is an amazing patch! It’s pretty eye opening to be able to just use my mono effects in pseudo stereo… Is there anything cold mac can’t do?

Here’s a little recording using your technique

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