Crowdsourced mixer design

[Gahlord]

I think DB25 would be a piece of the solution here. You get 24 T/S connections per DB25 port. Put two of them along the back (the weight of the connectors will flip it over if you put it on top). Run some some LED signal level indicators across the top that blink and glow, a little like icicles maybe. Then the the cabling is separated out to whatever you want at whatever length you need because you get that part on your own. The hard part would be finding aesthetically pleasing DB25 ports.

[karst]

personally (can’t stress this enough), I think it’s worth exploring whether there’s some comfortable place in terms of design, features, cost, and size for a simple analog mixer.

we might find out quickly that there’s no real sweet spot (if $120 is the price point, then we almost certainly won’t), but I think it’s worth going a little in that direction. maybe we can find something interesting that significantly undercuts the cost of boutique rotary mixers and is more geared towards musicians rather than DJs.

for a device that can do common audio tasks (mixing), I’m a fan of it working standalone with somewhat understandable controls. I know the power of creating a mixer specifically designed to work within the monome ecosystem almost certainly has more capability, but it’s only going to be convenient for people who are ‘bought in’ to that ecosystem, while representing more cost to those who aren’t.

[Gahlord]

If that’s the approach, and I totally get that, then the question will always be, in what ways are the thing you’re making better than the Q series Behringer?

|Q802USB|Behringer|P0ALM

If someone scratched out the Behringer brand name or spent an additional $100 making a custom box for the Behringer guts would they end up with something better than what is being proposed?

[dianus]

Apologies this is not at all to scale or anything, but wanted to get out what I am now envisioning in my brain

[andrew]

the shield kit / 16n top bottom plate sandwich approach seems like a good route for this or really any desktop DIY product. it’s cheap, can be flat, keeps the design simple & leaves room for customization. putting together a manufacturing chain for a proper enclosure sounds like a Task Indeed.

[Gahlord]

Totally except the DB25 is all the I/O you need, that and the USB port to connect to Norns/elsewhere/power. I also like the idea of a toggle switch for modes, but it’s maybe superfluous.

[dianus]

I included a usb port in the bottom right corner, apologies if that’s unclear! But if folks want to exquisite corpse on this be my guest! I personally like the option of having 1/4in and db25. It would save one piece of gear for mixing and matching formats

[Gahlord]

I def like having easy ports too. I was just thinking of saving money and keeping it just DB25. A few standard TS/TRS would be sweet.

[kbit]

Because Behhinger is a terrible company and creating things is fun? Not trying to being confrontational, I think your point is worthy of further defining what we all value, but I think Behringer as an alternative misses the mark.

(note: I have and use a small Behringer mixer and I kinda hate that I do so I’m absolutely biased )

[murray]

So, is the proposal being formulated an audio interface or an analog mixer? I’m wondering how folks plan to actually mix the analog signals?

EDIT: it feels like this is headed in the ‘audio interface’ direction and doing ADDA conversion is not really minimal or a mixer’s job–my 2c

[Gahlord]

20 characters of fair enough.

[infovore]

it’s going to have to be deeper. that render is kinda impossible, based on the size of standard vertical 3.5m jacks and 9mm pots. there’s no circuitboard inside that thing. it’s a neat picture, but it’s just a picture, that’s all.

[infovore]

I think you’ll have a job making anything with the spec described hit a $120 pricepoint, and I think in that particular post, his tongue was in his cheek: adding to an infinite spec list, and then going for a tiny price point.

If you mean $120 BOM/parts cost, sure, why not. But the expensive stuff in your synth is hardware - jacks, pots, cases and standoffs. Resistors and opamps are peanuts compared to them. And mixers tend to have a lot of hardware.

[Gahlord]

I’ve documented the thinking about it in the topic above and how it relates to the original post’s goals. The current sketch is the result of pursuing a path that offers the greatest affordability within the original post’s goals. I don’t see it being adopted by the others in this topic though.

[feathers]

Another little idea - I like the thought of putting a Korg Nutube or two in there before the outputs. I don’t know anything about these or if that would even work, and would of course drive up the price, but it’s fun to think about!

[glia]

yeah i kinda addressed that tho

i’d expect it to be at least as deep as the 0-coast to handle that jack orientation

[dianus]

I don’t think it’s useful to get stuck in thinking of hardware design conventions. Will this design be a performance focused mixer console, or minimalist interfaceless i2c/midi speaker. I think both are valuable approaches. But I think we should look at Monome’s design philosophy carefully. Norns, Grid, Arc, Crow etc. can all be many things. What’s the point of narrowing the approach. Like if what @Gahlord suggests, there are already cheap mixers on the market. What’s the new value of this pursuit?

[murray]

Fair–it was my thinking that if building such a box with ADDA conversion, a ‘mixer’ could be a single, example application. But then we’re heading into territory where we should really just give norns more audio channels and do the mixing there (multi-soundcard support is pretty raw in Linux, so I’m not sure how you’d build some sort of “expander” for the Norns IO either)

EDIT: I think you have to talk about how you’re doing the signal processing if not for anything else, but cost of materials and effort and imagined life/support of such a thing

[Jonathan_Riley]

Spent wayyyyy more time than I’d like to admit thinking about the quadraphonic mixer. Here are some of the devices I came across and unique features they have.

Research

Dug into the world of quadraphonic mixers/panners late last night.

Buchla 204 Quad Spatial Director

The most interesting thing about the 204, in my opinion, is how the joysticks work. The joysticks rely on light/photocells to track the movement of the sticks. This apparently leads to slew of the signal as the joystick changes position. From the modular synth forum we all know:

I’m curious - is there any slew in the joystick operation due to their relying on the photocells?

I will test it tonight. I think there is a small slew yes.
Also if you send the cv out of the joysticks to the pitch of an oscillator there is a small random modulation happening. It is not still, there is a very little random fluctuation happening because of the light inside.

Another cool thing is that if you press on the faceplate near one of the joystick you can use it as a pressure sensitive thing. It make the light moves inside and affect the CV output."

Video in action: https://vimeo.com/65536545

Buchla 227e

This is what Suzanne Ciani has been using on her recent live sets. Love this one because it really is a fully featured mixed in such a small package. Also has two outs per output and a headphone out that can toggle between front and rear spaces of the stereo mix.

Loopop does a really cool and informative interview with her available here. Super interesting discussion of Suzanne’s process and how she routes effects through quad as well.

Inspiring quote from the loopop video that really inspired my sketch.

If any motion is not synchronized with the actual rhythm, it’s going to add its own rhythm. Spatial movement is rhythm. - Suzanne Ciani

Knas Ekdahl Quad Massager Quadraphonic VCA / Mixer / LFO

Knas is primarily known for the moisturizing spring reverb, but Mr. Ekdahl also produces one of the only stand alone quad mixers that exists.

This uses one joystick to mix four different audio signals. On one hand, super cool concept and very elegantly designed. On the other hand, the design is limited in where sound can actually be panned, preventing some channels from being panned to the other side of a room. Add a few more joysticks and patching options and this one is a winner. I think I might order one of these to test it out.

Another interesting feature is the incorporation of an LFO in the standalone unit itself that can be mapped to any parameter in the unit. Can be used for FM (or is it AM?) by driving both X and Y channels to audio rates.

Here’s the only video I could find on the net.

Serge Quad Locator

Ticks all of the boxes, but doesn’t feel “playable.” Love the emphasis on modulation and CV control of amplitude and location.

Azimuth Coordinator

Apparently, Pink Floyd used these to send sound around a space. No idea how it works, but worth throwing in the ring.

This ended in a quick and dirty sketch in my notebook before bed and a few different use cases.

Notes on scale: No buttons, jacks or joysticks to scale. It’s just a sketch, okay!!! Planned to be roughly the same size as a grid. The CV matrix isn’t to scale, but I was too lazy to redraw. Imagine it running top to bottom between the two sets of joysticks.

Summary

3 use cases

• Quadraphonic panner/mixer
• Midi controller/i2c controller
• CV mangler/processor/generator

Preferably, all of the features included would work for all three use cases. I’ve labelled in my sketch, but placing here as a list I think will be useful. Top and back of unit.

Top:

Mixer/Panner:

• 4 Volume Pots
• 4 X Audio/CV Position inputs (3.5mm)
• 4 Y Audio/CV Position inputs (3.5mm)
• 4 X Joystick Position outputs (3.5mm)
• 4 Y Position outputs (3.5mm)
• 4 Joysticks
• 16 white LEDs that indicating joystick position
• 4 record joystick movement button
• 4 three way switches (Mute, bypass, solo)

Spatial Surveillance CV Matrix (gotta come up with a different name…):
Basically Cold Mac with white leds that function as a VU meter around the outside of the knob.

Back:
4 mono input jacks
4 outputs
Midi port (?)
i2c port
Usb C Port (can power)
External PSU input

Here are some extras I was thinking of because it’s impossible to avoid feature creep:

• Tilt EQ and compressor/warming circuit on outputs (Basically knob.farm ooots before the quad out)
• Simple internal triangle LFO like Quad Massager?
• Inverted XY output? Summed XY output?

The buchla 204 features three things that I feel are essential to the design. (1) Joysticks instead of knobs (2) shorting bar to connect joystick CV to audio position instead of an internally routing the connection (3) Both knob and CV control over signal level. One could certainly reproduce these alone in euro and call it a day.

The chatter in this thread surfaced a few other interesting directions. @zoundsabar raised the idea of a patchable matrix of sorts that could allow CV to be mangled and rerouted, resulting in generative modulation of panning, audio level, or CV. I re-read through @mdoudoroff’s meditations on @Galapagoose’s concept of Patch Surveillance and I think there’s something to be articulated about the intersection of Spatial Direction and Patch Surveillance that I haven’t really grasped yet.

Another lineage that I think the quadraphonic mixer comes out of is Monome and its community’s controllers. I see this device as the (spiritual) hybrid of an Arc and 16n. Midi and i2c integration for use as a standalone controller feels like a logical addition.

Last, I think beyond midi and i2c, raw output of CV to use as a CV generator and mangler would be super useful. No additional steps would be required to make this use case viable, as separation of joystick position and input location affords this use in the design itself.

Open questions:

• Jack placement?
• 3.5mm or 1/4"?
• HQ, affordable joysticks?
• -5v to 5v? 0 to 10v? Both like 16n?
• Mutes? Solo?
• Circuit Design?
• CV Matrix Design?
• What to cut to keep costs down?

I’d be down to work on this with some folks if people are jazzed on the quadraphonic mixer idea.

[wheelersounds]

A few cents:

is 5v enough to power the thing? Most of the mixers I’ve seen require at least 9.

Definitely thinking that a digitally configurable mixer with 4 stereo ins and 4 outs makes sense – joysticks can be mapped to vol/pan/eq/position in quad depending on each individual’s needs?

I recall seeing on a pro tools console some little tiny surround-panning joysticks. I imagine they are expensive but could be nice if they can be sourced.