Project Explained Part 2 - Acoustics Refresher

Ok, so before I get started about the LEDs Projections and Acoustic Treats, I should say that I was wrong about the capacitors, they are actually supposed to be separate (the 0.1uf and 0.01uf ones). It is simply that the fritzing diagram I was going by was slightly confusing, but after a bit more research I discovered that the 0.1uf is for connecting the negative from the TRS input to the Ground Pin6 and the 0.01uf capacitor sits between the positive from the TRS and the Input Pin5 on the MSGEQ7. So there is one issue troubleshot before I even got started, I guess my intuition for electronics is increasing.

So with my dissertation I am interested with how environment can effect your creativity and ability to work in what are inherently quite abnormal environments, no matter what scale of the production spectrum you are at. In my case, it is the bedroom that has been my home for the time I have been at university. A bedroom is not a creatively inspiring environment, I feel confident at this point I can say that. You can get into inspiration coming in dream states with someone else, I'm sure there are plenty who would want to! ;)

So the task is to turn it into one. How do I go about that? Well, first off is the use of coloured lights and projection mapping, as I have discussed more extensively throughout this blog. However, arguably the most important aspect of any environment that you intend to create, practice or listen to music in, are the acoustics.

In my dissertation proper there will be academic references of some of the architechtural acoustics books that are available (there are a few!), however for this project I am going to keep it pretty light on the techy physics side of acoustics. Firstly, because I am not a physician and this is not a physics degree, secondly because some of the deeper reasoning I simply don't understand at this point, but lastly and most importantly, within the bounds of this project it isn't important. I say that because there is a vast amount of easily accessible, tried and tested information on acoustics, which is what I used to guide my choices when I was building my treatments. Short of building rooms from the ground up, or rooms within rooms, there is only a limited number of choices available to someone looking to improve their rooms acoustics. Lets look at a few before I talk about what I did. Oh yeah, no fucking egg boxes allowed.

So firstly, we have the one everyone has seen, and likely owned if you are in this game, acoustic foam. There are a few reasons that this isn't ideal with the bounds of this project. firstly, below 5-600hz, they are pretty much acoustically void. Below is a data sheet from one of the main companies that supplies UK acoustic foam distributers.

This is a similar chart to any other you would see shipped with acoustic foam. It is open celled, polyurethane foam, and what companies like Vicoustic and the rest dont like to tell you is it primarily designed and used in the automotive industry. Regardless, it is used in many a bedroom studio.

When people use foam, it is because they are looking to absorb frequencies that are causing problems in their room, or for whatever noise reduction purpose is required. Foam is particularly effective above 1khz. In the automotive industry, this is good for keeping the vocal range of passangers unaffected by the noise of the engine or other vibrations.

In the sense of a room for making music however, they are less than adequate, certainly if it is just foam being used. Infact if you are just using foam it could do more harm than good in certain environments, simply because killing higend reflections dead whilst leaving anything below about 600hz unaffected can be very off putting. There are very few environments in nature which would emulate these conditions, making it very unnatural sounding. I have experience of this from the first room I called a studio, and in retrospect to what I have now, it sounded terrible! I cant find any pictures of it unfortunately, I think they were on my old laptop (which I fried the motherboard of :/).

Above is a picture of one of the first page images from Google with the search Bedroom Studio (one of the neater examples). I you excuse the panorama image, then you can still tell it is an odd shaped room, with half of it taken up with a bed, a cluttered desk with assorted gear, and a mac (OF COURSE). There is a distinct lack of monitor speakers, no acoustic treatments and not much of anything else come to think of it. At least it is clean. Which I have found definitely improves concentration.


The problem is, that no matter which way you cut it, this room would never be as inspiring to work in as this one.

I genuinely have dreams of one day working in a space like this. It looks very beautiful in my opinion. When comparing the two, one thing hat may hit you straight away is the difference in symmetry. Not only does this ease the eye to the look of the room, it effects the acoustic map of this room greatly. For me, this is a great example of form following function and still looking beautiful, much like a Formula One car or a Beautiful animal. The beauty is intrinsic to the design and the design is intrinsic to how they work.

It is slightly unusual to have mirrored side walls, however by the look of this room there is a lot of absorbtion. Basically everything that you see covered in Grey material in this image will be absorbing frequencies. They are known as Broadband absorbers; they will absorb frequencies across the whole audio spectrum far more evenly.

The reason this is important in terms of listening accuracy is to prevent as much as possible something called Comb Filtering. In small to medium rooms, you get very strong Early reflections. These are the very first reflections of the walls that your ears pick up after the original sound wave. Here is a good image to demonstrate what I am talking about.

The microphone is your ear in this case. the above image shows how sound acts in a room. The image on the bottom shows the effect on the recording in such a situation (see why it's called comb filtering?) This is cause by phase cancellations that are made by the timing difference in when the reflection arrives at the mic (or ear) when compared to the original source. The way to minimise this effect is to absorb all early reflections.

So when comparing these two rooms, we can see that one is going to be massively reflective with lots of comb filtering, and one should not have these issues (I have not been in the room, I bet it doesnt though hahah). We also know why that is bad - Comb filtering will remove frequencies that we want to hear. It will also exaggerate the frequencies that we can.

In terms of Environment effecting creativity, if you cant know what you are listening to is going to sound good in other places, there is an element of doubt that will floating in your mind the whole time you are working. This is speaking from personal experience. So when I was wanting to look at environment effecting my creativity, it couldn't just be visual effects I was trying to use as inspiration. I feel that having professional acoustic treatment not only looks visually inspiring in itself, they can be used as awesome screens for projecting and also for back lighting with audio reactive LEDs.

The next post will be details of how I have used acoustics knowledge to build a range of treatments for my room, and how they are combined with light and colour.