[Thomas Jouanjean]

I'm so sorry to hear...

Hope you get better asap!

[franman]

Jeez Constantin.. please get better quickly...

FM

[Constantin]

Hi friends  

I continued with my studiobuild and have some new pics of the progress.
After Thomas words of wisdom i worked on the backwall design of my future controlroom.

Here is a pic of the actual plan.



I also poured the concrete in the samll recording booth and will finisch it with selfleveling concrete next week.

I also build the first 2 doors for the studio. The are made at 3 sheets of MDF. 1st layer 19mm, 2nd layer 23, 3rd layer 10mm.

Door closing is given by a doorcloser and 5 magnets (each 6kg holding power).

Do you have a great tip for a good sealant (rubber) for the doors?


I´m very happy to be able to work without pain  



cheers
Constantin

[Thomas Jouanjean]

Good to see your health is back!  

What are you going to use as membrane?

[Constantin]

For the 2 boxes at the sides i will use 3mm HDF and for the box in the middle i will use a steel plate (1mm or 2mm) not shure until know.

The Steelplate will not resonate over an air cavity, it will be touching a dampening material like basotec.
The 2 Woodpannels will resonate over an airspring, but i will fill some fluffy isover in the box.

I try to tune the woodpannels to about 70hz, and the steelpannel to 45hz.

Good idea?, or waste of time?  

cheers
Constantin

[Thomas Jouanjean]

Steel... Hmmm...

Maybe you want to use a product with a resilience more suited for the use.

Something with good density still. You should not have it as the first layer either.

[Constantin]

Quote:

Steel... Hmmm... Maybe you want to use a product with a resilience more suited for the use. Something with good density still. You should not have it as the first layer either.

It`s a well tested patent from Frauenhofer institute and called VPR (Verbundplattenresonator)

The trick is to use Basotec as the spring so steel is a perfect Membrane for this purpose.
The spring properties of Basotec are much different than air, so i`m not affraid of using this patent for my room.

And it won`t be the first layer, because my client Sofa is in front of the Resonator   ( another big porous (ikea) absorber)



Have you ever heard about these VPR design?

i have good experience with it. no rattle, etc.


cheers
Constantin

[Thomas Jouanjean]

Yup, not the Frauenhofer thing, but dampened membranes, sure.

[Constantin]

here is the resonator i talk about:
http://www.ibp.fhg.de/akustik/ra/vpr/index_e.html


cheers
constantin

[tom eaton]

My RPG Modex plate bass traps are steel.  

http://www.rpginc.com/products/modexplate/index.htm

[Thomas Jouanjean]

tom eaton wrote on Wed, 15 July 2009 22:00

My RPG Modex plate bass traps are steel.   http://www.rpginc.com/products/modexplate/index.htm

And they're good.

My point is: in Constantin's case, I would not use steel. Unless he has ALL data to make sure it's the right thickness, right type (many to chose from) etc.

I generally don't use steel for membrane, but that's a personal choice. Steel works.

[Constantin]

Hi Thomas and thank`s for your advice

Quote:

I would not use steel. Unless he has ALL data to make sure it's the right thickness, right type (many to chose from) etc.

Isn`t it the mass and the springstiffness which is important for the resonantfreq? It`s quite easy to find out the mass of different steel`s.
Or do you talk about the rigity of the membrane as part of it`s amount of absorbtion?

i would be happy when you point out why you wouldn`t choose steel.
Is HDF a better choice?
i can use also MDF (i can get it for free.

I´m happy for all tips i can get from persons like you, since i trust in your advice.

cheers
Constantin

[Constantin]

Update:
The Fan`s for the ventilation system arrived.

For the controlroom i have a EBM Papst W2G130-AA33
[url] http://docs-europe.electrocomponents.com/webdocs/00e6/090076 6b800e6c45.pdf[(url] which gives about 350m

[Thomas Jouanjean]

Constantin wrote on Thu, 16 July 2009 11:44

Isn`t it the mass and the springstiffness which is important for the resonant freq? It`s quite easy to find out the mass of different steel`s. Or do you talk about the rigity of the membrane as part of it`s amount of absorbtion?

They are all important
About steel, they can be very different. They can have the same mass but completely different behaviours. For ex High-strength steel will be very very stiff, and yet have the same mass as a rather elastic type of steel. And so on. So mass/thickness while being a good indicator, is indeed not sufficient...

(Yes, my wife works for the steel industry, no foolin' around with those things at home )

Constantin wrote on Thu, 16 July 2009 11:44

i would be happy when you point out why you wouldn`t choose steel.

I would use a system using air as a spring, with a material with high resilience but still a "hard" material. For ex some thermosplastics (PMMA) are great for that purpose.

If I told you more I'd have to kill you    

But again, steel as you describe it WILL WORK. Just pointing out a few other options out there, which may be more suitable.

[Constantin]

Quote:

If I told you more I'd have to kill you

One day you must do it in reality  
I ask to much !  

Thanks for the Tip with the PMMA, i will have a look at these material.

What do you think about the ventilation dimensions? My research told me, that i`m in a safe area, but the examples/guidlines (DIN EN 13779) i found are based on living rooms and restaurants.

cheers
Constantin