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Author Topic: Broadband traps with "Homatherm FlexCl"  (Read 11489 times)

elmolemon

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Re: Broadband traps with "Homatherm FlexCl"
« Reply #15 on: May 12, 2009, 05:27:05 pm »

I try to enter the the final stage of my planing, but i still got some remaining questions..  Smile


franman wrote on Sat, 11 April 2009 22:16

No.. not at all. In a room that is using ONLY stand mounted mid or near fields, my approach is completely different than in a room with wall-mounted main monitors. In this case, we almost always use deep trapping at the front corners and a soft front design.


Hi Francis,

my room is setup quite similar to the room in the graphic in my first post above! What does your statement mean for my room concerning the front wall behind the stand mounted speakers?

I plan to place absorption panels behind my speakers and the front wall just like in the photo (see first post) above.



Thomas Jouanjean wrote on Thu, 02 April 2009 23:05


I would maintain my attention on the front corner traps, but not necessarily do anything about the front wall itself. (Note to Elmolemon: I don't like absorptive front walls  Rolling Eyes )

Side walls + back walls need attention - be heavy handed with your back walls and corners.




Hi Thomas,

i thought it would make sense to treat not only the front corners (which are already treated), but also the area behind my stand mounted speakers, as they are quite close to the front wall..

You wrote, i should be heavy-handed with the back of my room. How deep can i go with the flexCL without adding air gaps between the layers? I don't have too much space available and it would help me a lot if i had just a rough idea where a single layer of this material reaches its "limit".  I always feel a little discouraged if i read that flexCl is supposed to be most efficient in less deep layers and less efficient in deep layers due to its density..

I've read in the Amsterdam-Mastering construction thread that you use flexCl in layers of 10-12cm and above you also recommended 10-12cm for the early reflection points.  What does this mean for me in relation to the advice to be "heavy-handed" with my backwall? Can i forget about the forum-talk and go deeper without additional air gaps between the layers or would i waste my money on the material? Confused

Thanks a lot in advance!    
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Thomas Jouanjean

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Re: Broadband traps with "Homatherm FlexCl"
« Reply #16 on: May 13, 2009, 09:16:21 am »

Well... You need to calculate / figure out what your room needs and work from there. Did you measure?

My general advice is for sure to use air gaps/ have a distance from the walls! if you have it direct on the walls it will be less efficient (good to have it where there is velocity). If you want bit less deep system you can work with porous + tuned systems.

Attached a very quick and dirty explanation in drawing, it's easier than words. The formula is a good indicator, though in real-life, it does not behave exactly like that. But it's a good start!

Play around, test etc...

index.php/fa/12183/0/index.php/fa/12184/0/
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Thomas Jouanjean
Northward Acoustics - Engineering and Designs
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elmolemon

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Re: Broadband traps with "Homatherm FlexCl"
« Reply #17 on: May 13, 2009, 04:11:45 pm »

Shocked

Thanks a lot Thomas for your effort!!!

I did some measurements with fuzzmeasure and i got some peaks (55Hz & 110 Hz) and dips (72Hz & 144Hz).

From what i see on your graphic, i'm going to leave air gaps between my absorption panels and the walls for sure!  Smile

But to be honest i don't really "get" your graphic.  Rolling Eyes

About the formula: F= targeted frequency? Absorbed frequency? In which scale unit are "T" and "P"?  



Apart from that i don't want to keep on bugging you about the recommendable depth of the flexCL-layers too much, as i know your measurement data is private...  Embarassed

But as flexCL is avaiable in depths up to 18cm, maybe you can give me at least a hint if it makes sense to use it in (single-)layers of 18cm (or even more), without exceeding the absorption abilities of the material or if i should stick to less deep layers for an efficient material/absorption-ratio?
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J.F.Oros

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Re: Broadband traps with "Homatherm FlexCl"
« Reply #18 on: May 13, 2009, 04:31:36 pm »

At least for a theoretical point of view, to see how the absorption curve is affected by various values, you can also try to experiment different absorber thickness and air gaps with the very powerful porous absorber calculator written by Chris Whealy :
http://www.whealy.com/acoustics/Porous.html
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Thomas Jouanjean

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Re: Broadband traps with "Homatherm FlexCl"
« Reply #19 on: May 14, 2009, 05:35:38 am »

elmolemon wrote on Wed, 13 May 2009 15:11

Shocked
I did some measurements with fuzzmeasure and i got some peaks (55Hz & 110 Hz) and dips (72Hz & 144Hz).

[snip]


About the formula: F= targeted frequency? Absorbed frequency? In which scale unit are "T" and "P"?  



So you now have your main pb freqs identified, determine which mode they belong to now Smile and go from there. Room size will tell you that (size vs wave cycle length).

F= estimated lower frequency of efficiency (although, this is based on 1/4 wave theory, which is very debatable in itself. Treatment actually does work much lower than the results you get with this...)

T and P are in meters.
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Thomas Jouanjean
Northward Acoustics - Engineering and Designs
http://www.northwardacoustics.com
http://www.facebook.com/pages/Northward-Acoustics/1062876633 71

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Constantin

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Re: Broadband traps with "Homatherm FlexCl"
« Reply #20 on: May 14, 2009, 06:45:30 am »

Hi Thomas
What do you think about the results of the porous absorber caclulator?
Is this close to your real world experience in the bassfreq.
Since the Formula from Delany and Bazley (i think this calculator is bsed on this)is not good for low freq. what theory of calculating would you prefer?

cheers
constantin Razz
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