Final Artefacts Demos and Explanations Part 2

I first have to say that formal testing of the system in terms of using it whilst working on music was impossible with my current setup - I dont have two computers. However at the expo I have access to another computer loaded up with music software, so it will be possible to demo the systems together in that capacity.

For these examples, I have run the two systems together as colour organs in order to demo and analyse the efficacy of the systems.

While I am waiting for the videos to upload to Youtube, here is a quick phoo to get the idea and allow me to keep typing!

Before I go on, I want to talk about some of the immediate issues I noticed with te system, that perhaps you too have noticed.

I really hadn't considered the fact that one light source cast on to such a surface would cast shadows onto shorter pillars that were off center. When far enough back, you can hit all the longest pillars easily, however the deeper the other pillars are by relation to the longest, the more extreme the shadows cast become.

There is a way round this, however there is only one - to have multiple projector rigs. this is expensive, space consuming, time consuming and noisey. Realistically, for use as a tool for analyitical insight into audio in the studio, it doesn't have much future. This is certainly not to say that it hasn't been extremely insightful as a method for analysing the light speaker though. It has also been a gret way for exploring the power of FFT analysis for splitting up incoming audio rather than traditional filter based EQ's in the analogue domain, such as the MSGEQ7

At this point the diffuser is unpainted as I relly dont have the time, so there is a very slight tinge of orange to the colour, as seen in the above picture. the colour being shown on the acoustic diffuser then should match the laptop screen, which is extremely similar to what the colour organ above is displaying - a kinda of pinky off white tone. As a note, this means there was a pretty even balance of audio frequencies at that point in time, with a slight tendency towards the lows and highs. Turns out that you can gain meaningful insight into audio from colour ;)

The first of the demo videos of these two in action are taking a while to upload, so for now Im going to get on with seting up my Ableton set ready for testing later on this evening on the flatmates.

I have decided that I'm going to be asking them to listen to a bunch of material chosen by them first, then me, in order to get used to the systems first. During this time, I will be going over a bit of basic colour theory with them to make sure they can understand just what is going on. Once this is done, I am going to go through a set bunch of material such as drum loops and musical stems to demonstrate what certain types of sounds look like, I am then going to ask them to indentify what they are listening to without the speakers, using only the light. If they can determine what they are listening to, roughly at least, without listening, then I would say the system has real legs as a tool for metering audio in a creative manner.

I shall also do an intermediate piece about how a made the colour organ within Resolume. Cheers!

Diffuser PJ Mapping Screen Built!

It is so easy to underestimate how quickly time flies! You may remember two weeks ago I posted about having chopped all the wood and I just needed to get glue, well yesterday I finally got it, and was up until three this morning getting as much as I could done. I ran out of No More Nails about 3/4 of the way through, so I got up first thing this morning and went to get another tube.

Below is a photo gallery of the build from start to finish for your amusement. I have to say, considering the issues I had with the original cuts (breaking a circular saw and having to hand cut half the posts, I am really happy with the results, it looks really beautiful. All that remains now is to let the glue set hard and then get it sprayed matt white, as this will give the best surface finish for the Projections.

1) So as I have touched on before, QRDude is the software I used to create the design for my diffuser. This is a 2D QRD design, with a Scatter characteristic of 333hz, a diffusion characteristic of 666hz and a high frequency cutoff at 3750hz.

2) Here we have all the posts for my build stacked on a secondary baseplate. I intend to build another three of these after university, so I have bought extra MDF for baseplates. The wood used for the posts is Planed treated Red Wood Pine,  44mm x 44mm. The "well" depths vary from 0mm upto 24mm.

3) Here is another baseplate cut and ready to be filled.The well spread is 13, giving the baseplate a width and length of 572mm

4) I decided to go from the two axis first and then build out from there. This isn't really standard practice, you would normally just go row by row, however as I said the circular saw broke, so from 14mm posts down, the hand cut is slightly uneven on a lot of posts. To eliminate the chance of an uneven design, this way lets you glue two sides of every post you place after the axis are done, resulting in a more stable build as you go along.

5) Here you see it at just after the half way point, around one thirty this morning. I knew by this point that I had made the right choice as the lines and block placements were still going smoothly and perfectly.

6) This was just a couple of arty angles before I went to bed.

7) The first of these three was a quick one before I started again today with the fresh No More Nails. This will be painted white as I said, and then placed behind the speakers, central to my mix position. Happy Days!

Project Explained Part 1 - Arduino, MSGEQ7 and Audio to Colour Theory and Practice

I have had tons of stuff going on recently with the project, so today is going to be a catch us on the written side of it all.

First off I feel like I should give you an update on some of the difficulties that I had been having with the LED side of the project. Firstly, once again I am no electrician and this is all new to me, I have done a lot of reading trying to get my head around electronics and I think I have a stronger idea, but to say I fully understand it would be an exaggeration.

Also, without the code and guidance from a man named Russell, who has been helping via online chat through Blogger and Youtube, I certainly wouldn't have achieved this. He will be credited as such in my dissertation.

I have also had difficulty in getting parts. Well, more the time scales that they come. I completely underestimated how long it would take for some things to arrive, my longer breadboard took 5 weeks!!

I am now nearly there though, all I need to get my hands on is a female TRS Jack input for the audio in, and a 10K resistor, though I may just be able to use one of the 220k ones I already have for that purpose. I also need to soldier the button I got into place, as it is not very Breadboard friendly.

Also my ignorance in implementing the code into the Arduino was also holding me back. I have since figured out what it was that I was doing wrong, so now the Arduino is loaded with the code it needs. By the end of this coming week I should have a working audio-reactive acoustic diffuser. I think it may be the first one in the world! Wouldn't that be exciting. The next post today after this shall be dedicated to the Diffuser build and where that is at, but for now its all LED.

So first off, here is an overview of what is going on. Compared to my last post about Arduino control of LED's, you can see the Breadboard that I waited five weeks for is in place. Damn I wish China wasn't so far away. And amazong was more obvious where you were buying from :( Aaaaanyway.

 

So rather than using the power brick plugged into the Arduino, I am just using the stripped ends of the 12v power brick that came with the LED strip. Hopefully Russell can confirm wether this will work or not, if not then I know how to connect it up his way too, that's fine.

Next we have the potentiometer circuit. Once the board is fully equip with the button, this circuit will allow the user to cycle through the 8 states contained within the code. One button click cycles through these states, where the potentiometer controls the intensity of each program.

 The next circuit is doing the hard graft. Above the middle of the Breadboard, you can see 3 capcitors - 33pf, 0.1uf and 0.01uf (Left to Right). You may have already noticed that the two on the right are twisted together. I shall get some clarification exactly why that is, but I think it is to with stepping the signal down from the audio input, which will be connected this week.

Sticking with the image above, I shall explain what the little black box straddling the middle of the breadboard is. It is called the MSGEQ7 and it is really the brains of the operation here. It is a seven band audio splitter - it splits incoming audio into 7 separate frequency bands from Low to High frequencies.
Below is a small snippet of the Datasheet for the MSGEQ7. It shows the most important signal flow diagrams though. You can also see the specific band passed frequencies it outputs information for.

 
So here you can see a physical diagram and block electrical diagram of the chip (Top Right). If you imagine twisting that diagram round 90 degrees to the left, you have the orientation of the chip on the breadboard. So as I said before, the audio signal comes in through the top right pin, Pin5 (in that orientation). One left, we have the Ground Pin6, nothing to interesting. Next, Pin7 resets the multiplexer operation, on the board this is connected . Pin8 controls the chips onboard oscillator, which is responsible for selecting the frequency of the multiplexor, or how fast the strobe cycles through the audio frequency bands. When the input of Pin8 is high, the multiplexor is reset. When the signal goes low again it enables the Strobe Pin4, which is on the lower side of the chip. Pin3 is the Output, which is the Multiplexed signal. This is connected to the fourth analogue input on the arduino (A3) which unfortunately I forgot to wire up for the picture, but is now in place. Pin1 and Pin2 are the positive and negative power inputs for the chip, the power for which is controlled by the second 0.1uf capacitor.

Next we have the third stage of the Board, which is controlling the LED's. So trying to keep it basic, as I said before the MSGEQ7 spits out a multiplexed output, which means a stream of repeating data. That stream of data contains the volume information for each of the 7 frequency bands that the MSGEQ7 split the audio into.

What we need to do then is convert that data into RGB data which can be turned into coloured light that represents frequency via the LED strip. This is the part of the process that the Arduino takes care of.

If you have read my earlier work on this project, you will know that light and sound are inherently tied together, and one octave of the musical scale (F# through to F#, 370hz - 740hz) can be exactly converted to the octave of the visible light spectrum (Deep Magenta/Red through to Dark Blue/Purple, 406.8ghz - 813.6ghz). To get the exact colour to tone, you multiply the audio frequency by 2 to the power 40. Now we have some context for what I say next.

There are (very basically) three levels of colour. These are known as the Primary, Secondary and Tertiary Colours. The primary colours are out basic building blocks - with them, we can make Secondary and the Tertiary colours. Our primary colours are RGB, Red, Green and Blue. When we combine these together, we can (just about) make any colour in the rainbow. For example, if I wanted to create the colour Yellow from light, I would mix together equal amounts of Red and Green light. It is vastly more complex than this, but an easy way to think of it is how beat frequencies work, it's a form of frequency modulation.You can demonstrate this to yourself by use of some simple maths, though some of you have no doubt got it by now... If you take average between any to colour frequencies, you will get another colour.








Basically, if send varying R,G&B voltage amounts to the LED strip, then we will get a colour representation of the full audio frequency spectrum. Bass shall be represented by pure red, the Mids by green and the Highs by Blue. This can obviously be changed quite easily in the code, but for now it shall be remaining the same as I want to test this as a metering source. The three black things you see sticking out the breadboad are N-Channel Mosfets. They are special resistors that you can think of as Envelope Followers and are what control the flow of Red Green and Blue signal to each channel of the LED strip. It smoothing basically.

In the picture below I am holding that yellow cable for the benefit of Russell, hopefully he can tell me whether or not I can get away with powering the LED strip this way. You can see from earlier pictures that the Power Brick was plugged into the top rail of the Breadboard. I think this way I can avoid having to get a power brick with a proper connection, as I chopped the last one off for the last arduino project.

 Finally we have a picture of it all together. The code is on the Arduino, so hopefully once I have the TRS and button attached I should be plain sailing! The next post is going to be in a while after I have had a break. Once it is composed, I might just leave till tomo morn to post as I will most likely be very tired!