32 Channel Digital Mixing Desk

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static

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Hi Guys,

I am currently planning my first project which is a 32 channel mixing desk to use for mixing music, but have currently hit a brick wall as i'm quite new to all of this.

I am concentrating on designing one channel of the desk at the minute to keep things simple, then its just a case of duplicating it another 31 times.

I have a few questions if anybody would be kind enough to clear them up for me please

Question 1

First of all I am planning on using a rotary encoder on each channel to control the panning of instruments to the left and right, I want to know if I can use an LED ring around the encoder to determine the pan position rather than a line on a knob, and if so can I get 1 led to stay lit at the 12oclock position on the led ring for each channel until I turn the knob left or right.

Question 2

If I was to open a music project that already has panning on instruments in place would it be easy enough for the led rings around the encoders to pick up on this and display them accordingly?

Question 3

The picture below is exactly what I am looking for but unfortunately it has been discontinued so does anybody have any idea if I can get something similar elsewhere.

RotEncLED_thru_hole.png

Thanks!
 
Do you mean you're doing a control surface?
Doing digital audio mixing in hardware is hard.
I've done something similar and the best way in my case was to do a control surface (knobs/faders) that talks OSC over ethernet to control one of these:
http://motu.com/products/avb/monitor8

1: Yes
2: Yes
3: Design your own PCB? Would require a shift register LED controller, LEDs and a rotary encoder.
 
Thanks for your response!

Sorry yes I mean a control surface that plugs in via usb
How would I go about designing my own pcb? do you mean design it and send it off to be printed?

Thanks
 
That would sure be one valid option. It looks like they have a schematic for it up on their website: http://mayhewlabs.com/products/rotary-encoder-led-ring

So assuming you can still get the parts, it should not take very much work to enter the schematic into your favorite design program, like Eagle or Diptrace (what I use) and then layout a board. Once you are happy with it, you could then send the appropriate files to a board fabricator like OSHPARK, or SEEEDSTUDIO or ... You would then need to find the appropriate parts to populate the board with, probably from some place like Digikey and/or Mouser and then solder it...
 
Thanks again for the information KurtE,

So I have just been having a think and browsing the web for ideas and came across a controller made by avid that gave me a few new ideas, I loaded it into photoshop and simplified it to my needs (see picture below)

So now my questions are

1 Could I use an Oled screen to display the track name and pan information like I have photoshopped into the image

2 Is there a way of actually having an LED gain meter that would work as pictured to the left of the fader

channel.jpg

Thanks again!
 
The short answer to most of your questions is; yes.
The great thing about electronics engineering is that you can pretty much do whatever you want. The difficulty, is achieving what you want within limitations (cost, size, response time, power etc).
 
static said:
Sorry yes I mean a control surface that plugs in via usb
Click to expand...

Whew! Well that is significantly easier and something a Teensy would do with ease.

It sounds like you're dipping your toe into unknown waters for yourself so I would recommend starting by getting a Teensy, a breadboard, a few quadrature rotary encoders, hook it all together with wires and have a go at converting the encoder data into USB MIDI commands.
 
I second what macaba said here, with even another caveat.

That is do you need quadrature rotary encoders or can you simply use something like normal anlaog pots and sliders? If so then all you need to do is an analogRead statement to get the current value, maybe some simple mapping for which levels to light up in your meter...
 
macaba said:
Whew! Well that is significantly easier and something a Teensy would do with ease.

It sounds like you're dipping your toe into unknown waters for yourself so I would recommend starting by getting a Teensy, a breadboard, a few quadrature rotary encoders, hook it all together with wires and have a go at converting the encoder data into USB MIDI commands.
Click to expand...

I seem to work best when I throw myself in the deep end haha, I think if I just make a model of one of the channels on the desk I will have a few parts to play around with, do any of you guys buy your parts directly from china (alibaba) as I have seen a few good deals on there?

Thanks again!
 
KurtE said:
I second what macaba said here, with even another caveat.

That is do you need quadrature rotary encoders or can you simply use something like normal anlaog pots and sliders? If so then all you need to do is an analogRead statement to get the current value, maybe some simple mapping for which levels to light up in your meter...
Click to expand...

Yeah thats something I never considered, Maybe I should keep it simple as you say and it would also work out cheaper too right?
 
Buying from china is a mixed bag. Starting out I strongly suggest your first prototype use main stream supplier parts, even though they will cost more. Then when you know your design is valid think about ordering from cheaper places. You really want to know what you are doing buying from random online stores since you will normally need to do a bit of reverse engineering/code development/tweaking to get the things working. Having an already working part that came with libraries and tutorials on the bench makes working out what needs to be done to get things working much easier. And that tweaking time can easily eat the savings as well. Where it pays off is something like your plan here to have 32 channels, spending a couple of hours finding out that the pinout is different on the displays still leaves you ahead if you got 32 of them. For something you only buy one of... less so.

Plus it's a courtesy to give some money to people who wrote all those libraries and tutorials as well.

Final point is always read the fine print, since the guys living on the edge of the internet parts market shave everything they can, so it's normal to find things smaller, lighter and with less functions than you might assume from the first photo on the page.
 
That is do you need quadrature rotary encoders or can you simply use something like normal anlaog pots and sliders?
Click to expand...

Analog pots are easy. One analog pin and an analogRead statement. Encoders require two digital pins each, three if the encoder has a push button and you want to use it. A software library is needed to read the encoders. So on the surface the pots are the way to go. If you want to be able to do automated mixing, or be able to save and recall setups, the pots are out of the question unless you use the fancy and uber expensive motorized versions seen on some high end mixing consoles. There is no way to "turn" the pot in software, but it is possible to store and recall an encoder setting in software.

This is the kind of decision that is best made early in the design process. I have a nice "analog" synth simulated in a Teensy, but like a MiniMoog, the only way to remember the settings is with a camera! I will be creating an encoder based version, but there isn't a Teensy big enough to read 50+ encoders. It's a project for the future any way, I'll cross that bridge when I get there.
 
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