New space - studio in Athens

How thick should my walls be, should I float my floors (and if so, how), why is two leaf mass-air-mass design important, etc.

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almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

Some progress on back wall.
Back wall, sides and ceiling are lined with insulation, floor will be next after placing the hangers.
Doubled the drywall sheets for the HVAC extension box.
I designed and made all the math for the static pressure of the system and it's needs, million thanks to Gregwor for his valuable help!!!
As of now I am in the process of building the HVAC silencer boxes (4 of them).
Attaching some photos:
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Gregwor
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Re: New space - studio in Athens

Post by Gregwor »

Sorry I didn't see your question previously!
Let me ask one more thing.
what if the duct just before the register is bigger than the supposed 0.9 ft2 (that is calculated for the 270CFM)?
Then there is no need for a register at all, I can just use the rigid duct as is, right?
Bigger duct is always a good thing! The register certainly can just be a hole!

Your progress looks awesome. I'm not sure if you're doing things correctly as we don't have your SketchUp file, but it looks like you're making great progress! Keep up the good work! You're thread is inspiring to many (including me) I'm sure!

Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

Thank you for your nice words! Your help is much appreciated!

Yes sketcup is my weak point.
I am designing everyhing in 2D for the moment using corel, but I sure want to post a detailed sketchup plan soon.
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

So my plan for the hanger was originally this:
Untitled-1d 2.jpg
That's because I couldn't find less thick insulation, but I did.
Soundman2020 wrote:That would work, but it doesn't need to be that thick. You can use 2.5cm thick insulation on each side. That allows you to get more hangers into the same space. On the other hand, given the expense of your core material, I can understand you wanting to make your hangers thicker! It will work OK as you are planning, so if the cost would be too high doing a larger number of thinner hangers, then it's fine to do fewer hangers with thicker insulation.
So as Stuart suggested earlier, I can use less thick insulation.

And I can now go with 3cm and 20kg/m3 dense material for each side of the homasote board instead of the 4cm 40kg/m3 and that will leave me space for more hangers.

What do you think, is that a better option?
Gregwor
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Re: New space - studio in Athens

Post by Gregwor »

And I can now go with 3cm and 20kg/m3 dense material for each side of the homasote board instead of the 4cm 40kg/m3 and that will leave me space for more hangers.

What do you think, is that a better option?
20 kg/m3 of fiberglass? 3 or 4 cm or even 5cm thick insulation is fine. Go with with whatever is cheapest. I know where I live Homasote is worth more than gold so I am using 2" insulation in my design to save thousands of dollars.

Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

Gregwor wrote:20 kg/m3 of fiberglass?
Yes it's black colored fiberglass wool
I know where I live Homasote is worth more than gold so I am using 2" insulation in my design to save thousands of dollars.
I found the 2.44m x 1.22m Homasote board that is 10mm thick around 10euros each, so is not cheap but it's ok.
If I just make the hangers less thick and add like 5 to 10 more hangers overall, it's not a big deal, if they indeed are more effective this way..
Last edited by almaelectronix on Sat May 04, 2019 9:38 pm, edited 1 time in total.
Gregwor
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Re: New space - studio in Athens

Post by Gregwor »

I found the 2.44m x 1.22m Homasote board that is 10mm thick around 10euros each, so is not cheap but it's ok.
Those run about 40euros here.

Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

wow!

Also Greg , I am almost done with the ventilation, I will soon post the details!
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

So hanger's plan changed. That's the new one:
hangers fiberglass clean 2.jpg
I will now have 43 hangers instead of 34 with the previous plan.

And bigger too going from total coverage of 140m2 to 203m2

They will be 3.6 meters high :)

Of course there will be some changes here and there because of the door and vent's pipes but you get the big picture.
Last edited by almaelectronix on Sun Jun 02, 2019 8:52 pm, edited 1 time in total.
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

Hi all!

I read that a good ISD gap for an RFZ room falls between 20ms to 30ms with the ideal being towards 25-30ms.
I am trying to find information how to handle longer ISD gap but no luck..

According to my room dimensions (8.7L x 4.45W x 3.95H meters) I get from AMROC that the critical distance is 1.31m ,
while J.H.Brandt’s room mode calculator doubles the critical distance to 2.6m for an EBU listening room.
I suppose the later is the correct one.

Anyway, listening position of 38% percent falls far outside these regions (1.3-2.6m) as it is 3.3 meters,
so it is more likely to place the listening position somewhere between 2-2.5 meters of the length (regarding SBIR, measurements and practical position).
That gives me an ISD gap of 36 to 39ms roundtrip for the back wall reflection.
I am already building the back wall hangers, as you can see on previous posts, and I am also thinking about building a 75cm deep skyline diffuser (18x17, prime 307) for regions 250 to 3500 (LF and HF cutoff calculated for my room and listening distance) though I can not make it bigger than 90x90cm due to the position of the door being close to the center of the back wall.

So ending with my questions,
is this longer 35-40ms ISD gap a problem?
If not then are the hangers and the diffuser enough to return this reflections as a diffusive field's ones and lowered by 20-25db?

Any thoughts would be appreciated! Thanks!
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

ok there's my answer, thanks Stuart :)
Soundman2020 wrote: Therefore, the current best control room designs do return that diffuse field after about 20ms, or maybe 30 ms, or maybe even 50 ms in a large room, and that gives your brain all the clues it needs to figure out the room that it is in, and correctly interpret the acoustic "signature". As long as the "gap" is at least 20ms long, and up to about 50ms, your brain is happy: the room sounds natural, neutral, open, neither too dead nor too live, and you get to hear only the pure, clean, unmodified sound exactly as it came out the speakers, not colored in any way by the room, or by these subtle psych-acoustic effects.

[...]

So, the sound field that comes back at you from behind 20ms (or more) after the direct sound, also has to be at least 20 dB lower than than the direct sound, and it has to be diffuse, not specular. In most control rooms, that is achieved with a combination of acoustically absorptive surfaces (to reduce the level by 20 dB), acoustically reflective surfaces (to send a little bit of the sound directly back, but not much) and acoustically diffusive surfaces, to break up the sound into a diffuse field.

[...]

Now, if your room is bigger, then the ITDG can be longer: 30ms is good too! And you can also have a slightly lower level, such as maybe 25 dB down, especially if he room is large, ... as long as you still have an overall decay time that isn't too short for the size of the room.-
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Still don't know if hangers and this single diffuser will be enough to achieve the desired result but I guess I will find out the hard way..hehe :D
Gregwor
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Re: New space - studio in Athens

Post by Gregwor »

Looks good!

Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

Good to know that I am on the right track! Thanks Greg

Today I figured out that in addition to the central 90x90cm skyline diffuser I can add more diffusers in variable places on the back side.
Two 1d qrd diffusers on left and right part of the back wall ( hanger's false wall) and another two on back side walls, being something like 1x1m big each for frequencies of 350 to 3500hz.
Also 2 skylines on ceiling at the back, right before the false wall, on both sides of the cloud.
I will ray trace to find the exact spots for the placements.

Hopefully this plan will return a diffusive field back to listening position
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

Jumping back..about the front superchunks..
Do you see any advantage of adding a rockwool face layer of 1-2cm, 75kg density (49K.Pas/m2) ?
I am using porous calculator and it tells me that it is better without a face layer..
Any real world experience?
To remind you that my superchunks are 1.42 meters wide and 4 meters high.
20200129_225115_resize_74.jpg
Last edited by almaelectronix on Thu Jan 30, 2020 6:56 am, edited 1 time in total.
almaelectronix
Posts: 107
Joined: Thu Nov 06, 2014 9:06 pm
Location: Athens, Greece

Re: New space - studio in Athens

Post by almaelectronix »

Anyone who has tested something similar?

the chunks are filled with light wool GFR of 5Kpas/m2
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