Home-made Skyline Diffusor

[jeep]

the design was made by jason from GIK Acoustics
i'm using pine for the frame, plywood for the base and balsa for the blocks
it's 950x850x100mm
will go behind me in my control room

this project should have been completed months ago

[jeep]

i swear i can already hear the difference..

[jeep]

balsa strips have been measured and marked, ready to be cut up into over 350 little blocks

[jeep]

i'm about half way through cutting all the balsa to size
..saw dust, everywhere!

i've decided i'm going to spray paint the finished product
should be interesting..


more photos soon

[Omicron_9]

Cool!

[Glenn Kuras]

Originally Posted by jeep

balsa strips have been measured and marked, ready to be cut up into over 350 little blocks

Talk about your labor of love.

Glenn

[datune]

Originally Posted by jeep

the design was made by jason from GIK Acoustics

I don't mean to hijack your thread, but could you please eloborate on this? Did you contract Jason specifically for this design?

[jeep]

Originally Posted by datune

I don't mean to hijack your thread, but could you please eloborate on this? Did you contract Jason specifically for this design?

hey datune, thanks for the question

well he actually designed it out of his kindness and generosity
this was about 6 months ago, when i'm sure he had a lot more free time, even though he seemed very very busy at the time

originally, i made up a design myself, based on a QRD sequence with a prime seed of 19. but then a number of people approached me (mainly jason), offering their help and advice, and stating that my design would not work as well as i thought it would.
there's a good reason why people like jason are designing these products and i'm not!

i've found that most acousticians, engineers etc. in the music business are more than happy to help out wherever they can
i'm actually looking into purchasing some GIK Acoustics products just to support them and show my gratitude


hope that helps..

[datune]

Hey jeep! Thanks for your reply, I've read the other post too.

Keep us posted about progress! Meanwhile I'm going to try and learn more about acoustics (why and when would you place a diffusor, etc...)

[jeep]

Originally Posted by datune

Hey jeep! Thanks for your reply, I've read the other post too.

Keep us posted about progress! Meanwhile I'm going to try and learn more about acoustics (why and when would you place a diffusor, etc...)

will do
i'll hopefully have all the balsa cut up by tonight..

what do you need to know?
i'm no expert, but i've learnt a thing or two over the past couple of years..
might be able to help you out

[datune]

Well, for starters I want to learn when it's best to use a diffusor, as opposed to bass trapping.

[jeep]

almost done..

[jeep]

Originally Posted by datune

Well, for starters I want to learn when it's best to use a diffusor, as opposed to bass trapping.

well i depends on where you're putting it, and what result you wish to achieve
so for example in a control room, you want absorption in the front to get rid of the first reflections from your monitors, and diffusion on th back wall, to breathe some life back into the room. this creates a "reflection free zone" when seated at the correct position within the room

every room is different, and different rooms within studios serve a different purpose, which calls for different acoustic treatment
its not as straight forward as most of us think or would like it to be


do you plan on treating one of your rooms? or are you just interested in acoustics?

thankksssss

[jeep]

Originally Posted by Glenn Kuras

Talk about your labor of love.

Glenn

Glenn, this project is turning out to require about a million times more effort than i expected it to..

Labor of love indeed.

[llatsni]

What width is that balsa?
Biggest i've found so far is 1"x1" in 48" lengths

Do you have the schematic in digital format for our own DIY efforts?

Thanks,
Paul

[Ethan Winer]

Originally Posted by jeep

Glenn, this project is turning out to require about a million times more effort than i expected it to..

Can I quote you? In another forum someone is complaining about how much commercial diffusors cost.

--Ethan

[skatingbasser]

Originally Posted by Ethan Winer

Can I quote you? In another forum someone is complaining about how much commercial diffusors cost.

--Ethan

Yeah, I guess I don't get it. Plug in some numbers in a calculator, get some stock and cut to size. Attach and hang. What am I missing?

[Glenn Kuras]

Originally Posted by jeep

Glenn, this project is turning out to require about a million times more effort than i expected it to..

Labor of love indeed.

Yea but it is going to be pretty cool when it is done.

Glenn

[tigeba]

Originally Posted by Ethan Winer

Can I quote you? In another forum someone is complaining about how much commercial diffusors cost.

--Ethan

I'm probably going to get myself in a heap of trouble defying an expert like Ethan, but considering this is a DIY RPG Skyline, I think its only fair to compare it to an RPG Skyline, not diffusers in general.

I can't say I have ever touched a Skyline in person, but it appears to be extruded polystyrene (AKA Stryofoam). I think it would be fair to be at least a little critical of the commercial price considering how non-labor intensive it is to produce these types of things. Clearly the DIY version is quite labor intensive, and I suspect the commercial version can be produced in seconds. Of course I am willing to be proved incorrect.

I realize its a little unfair to lump a very specialized product like this in with foam-core boards and coffee cups, but I would have to assume they are made with the very same process. And we know how much coffee cups cost

I suspect a realistic assessment might be that the cost is high for reasons other than the cost or difficulty of manufacture in the case of this particular item.

[Jason Jones]

Originally Posted by tigeba

I'm probably going to get myself in a heap of trouble defying an expert like Ethan, but considering this is a DIY RPG Skyline, I think its only fair to compare it to an RPG Skyline, not diffusers in general.

I can't say I have ever touched a Skyline in person, but it appears to be extruded polystyrene (AKA Stryofoam). I think it would be fair to be at least a little critical of the commercial price considering how non-labor intensive it is to produce these types of things. Clearly the DIY version is quite labor intensive, and I suspect the commercial version can be produced in seconds. Of course I am willing to be proved incorrect.

I realize its a little unfair to lump a very specialized product like this in with foam-core boards and coffee cups, but I would have to assume they are made with the very same process. And we know how much coffee cups cost

I suspect a realistic assessment might be that the cost is high for reasons other than the cost or difficulty of manufacture in the case of this particular item.

The upfront tooling cost is HUGE. I have personally looked into it. The problem is that we have literally Billions of coffee drinkers in the world and not quite so many wanting diffusers.

We would LOVE to put out a diffuser with the same design principles as the one I designed for jeep and undercut RPG. But, the upfront costs just don't allow it to work.

Jason

[Jason Jones]

jeep is the man! I am really glad to hear that you are getting it built - can't wait to see more pics.

Jason

[jeep]

Originally Posted by llatsni

What width is that balsa?
Biggest i've found so far is 1"x1" in 48" lengths

Do you have the schematic in digital format for our own DIY efforts?

Thanks,
Paul

paul

the balsa is 50x50x915mm - www.balsacentral.com
no schematic unfortunately..

Originally Posted by Ethan Winer

Can I quote you? In another forum someone is complaining about how much commercial diffusors cost.

--Ethan

I'm starting to realise why they're so expensive..
a lot of time, work and effort is required

Originally Posted by Jason Jones

jeep is the man! I am really glad to hear that you are getting it built - can't wait to see more pics.

Jason

so am i!
i just wish i had started on these earlier
i can't thank you enough for all your help jason
you rock!



cheers y'all

[llatsni]

Originally Posted by jeep

the balsa is 50x50x915mm... no schematic unfortunately

Thanks, just found a good source for balsa in the uk.

Just read your original thread now. All very interesting!
I've been dreaming of making a skyline diffusor for a while, but finding a design has proven impossible, and the math is a little scary.

So, originally, you used the Schroeder formula and incremented the position with each row creating a matrix. Why was this bad? Why is using the Chinese Remainder Theorem to create the matrix better? Can anyone explain how the Chinese Remainder Theorem is used practically to "convert" 1D to 2D?
In the end your current design doesn't seem too different than the original? (i can see diagonally increasing numbers) Can you explain the difference?

Feeling very confused!
Paul

[jeep]

Originally Posted by llatsni

So, originally, you used the Schroeder formula and incremented the position with each row creating a matrix. Why was this bad? Why is using the Chinese Remainder Theorem to create the matrix better? Can anyone explain how the Chinese Remainder Theorem is used practically to "convert" 1D to 2D?
In the end your current design doesn't seem too different than the original? (i can see diagonally increasing numbers) Can you explain the difference?

Feeling very confused!
Paul

I'm going to leave this for the pros..

[Ethan Winer]

Originally Posted by tigeba

Iit appears to be extruded polystyrene (AKA Stryofoam) ... I suspect the commercial version can be produced in seconds.

Yes, and I wasn't as clear as I could have been. Aside from tooling costs, which as Jason said is expensive, it is fast and cheap to make a diffusor from styrofoam. I was more thinking of RPG's big wood diffusors or my company's diffusors. Both are much more complicated. I have no idea what's involved in making RPG wood QRD well diffusors, but it takes two people two hours to make each one of our diffusors.

I don't understand using styrofoam anyway, except maybe if the diffusor will be out of the way of people. It seems very easy to break. If I had foam diffusors on the rear wall of a control room, I'd spend all my time telling people to stay away from them.

--Ethan

[Farmerbrown2200]

It's kind of ironic that the books on the wall behind your absorbers will achieve much the same result as the manufactured difusor. I'm Just a lazy man "thinking out loud". As you were.

Cheers,

fb

[llatsni]

how did i miss this before:
HiFi Speaker Design © mhSoft <%=year(now())%>

@Jeep - does that calculator give you the same / similar results to your design?


EDIT: GAH, spoke too soon, its just the BBC quantized version :(

EDIT2: hmm... a very simple diffusor could be made with the BBC "formula" using 5cm square wood in 5,10,15,20cm lengths, it would be effective from 860 to 3440hz... tempting!

Paul

[andrebrito]

My company is currently starting to manufacture QRDs (2' x 2') in Portugal but we choose another kind of wood besides MDF and even so the cheapest one costs 70 € +VAT.., and I have the same problem as Ethan, labour costs

[andrebrito]

Styrofoam diffusers are much easier to make... RPG also sells them. They have the RPG Skyline LP for home-studios

[jeep]

all the balsa has been cutting
i'm about 3/4 through sanding them
right now i'm having a break because my hand was getting sore..

next step is to glue them to the plywood, paint, then attach to the frame
so close! but yet, so far..



this is me about about to get my sand on