Curtains before Broad Band absorbers

Discussion in 'Studio' started by flworius, Mar 22, 2019.

  1. flworius

    flworius Noisemaker

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    This is an acoustics Question, but I didn't find a specific sub, so I post it here.
    In my Studio/Mediaroom I have the backside of the table facing my windows. My plan is to put broadband Absorbers in the window bay, like extending the wall and closing the windows as this will be a dedicated Studio/Mediaroom I don't need any daylight in there and I also want to block out some noise of the streets/heat in the summer as they weren't aren't the best. On this wall, I have a Curtain rail and I want to put up curtains along the whole wall to give it a more consistent(as well as a less "freak who walled his windows") look. My Question now is, should I use heavy, acoustic curtains for this purpose or light ones so that the noise can pass and hit the broadband absorber. They would hang like 5-15cm in front of the broadband absorbers. Would heavy curtains be counterproductive here or would they help interacting with the broadband absorbers? Or would they, as I conjecture, help with the lowend, but maybe lessen the broadbands absorbers impact on the highs, as they would reflect some of them?
     
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  3. Olymoon

    Olymoon Impossible is not a fact. It is an opinion. Staff Member

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    Studio? May be more appropriate than mixing and mastering.
    Edit: changer to studio section.
     
  4. Moogerfooger

    Moogerfooger Rock Star

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    Without knowing studio dimensions, surface material and room layout nobody will be able to help you with any kind of certainty. Just as a plain rule of physics, if you were to put a generic heavy curtain in front of a generic broadband trap your upper mids-highs will be reduced to a larger degree than having just the broadband trap alone. Air gap between the 2 absorbing surface will only add to this affect- to a point. How much? Again nobody can know unless you analyze your room yourself with the proper tools. For the record, pink fluffy triangular super chunks with at least a base length of 34” is more effective for 1st & 2nd octave than broadband traps. As a starting guide any small/medium space not specifically designed from the ground up for acoustics I would start with super chunks in all corners that go from floor to ceiling, floor to wall and wall to ceiling. Add as much broadband traps as possible to the walls and ceiling. The object here is to reduce reflections as much as possible and reduce modal and nodal interference. It will never be perfect, but when in a small space it’s “better” to simulate space with time based processors than deal with reflections that are nearly as loud as source material.... Look up Ethan Winer on Gearslutz if you have time. Cheers!!
     
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  5. The Pirate

    The Pirate Audiosexual

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  6. flworius

    flworius Noisemaker

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    Very good and extensive Source of Information, on my "to be read" list for a while now ;)

    Adding this very amateurish ms paint to share my room dimensions.
    The height is 300cm to the subceiling which is made of thin, 8mm iirc, wooden panels and there is about 15cm to the "real" ceiling.
    The window bay is 210 in height, so my plan would be to place in both bays (the rear wall) a broadband absorber with 200x100x20cm.
    Should I treat the wall between the window bays too (with a less deep, maybe 5-10cm) broadband absorber or is it beneficial to keep the mix between treated and untreated (although its the rear wall)?

    room1.png
     
  7. The Pirate

    The Pirate Audiosexual

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    @flworius
    What are the specs of the broadband Absorbers? What are the walls made of? What type of flooring does the room have?
    What monitors would you be using? BTW, nice drawing :like:
     
    Last edited: Mar 23, 2019
  8. The Pirate

    The Pirate Audiosexual

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    You don't want to have a dead room or one without any mid-high frequencies. A good idea in between the absorbers is to install a difusser or nothing at all. It comes down to litening position, speaker placement and early reflections.
     
    Last edited: Mar 23, 2019
  9. flworius

    flworius Noisemaker

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    Id be using Mineralwool with a flow restiance of 5kPa. (Isover)
    All walls are brickwall, front and back i guess heavier cause they are primary structure, left and right are thinner, maybe around 20cm.
    The Flooring is a Laminate.
    Atm I am using Even TR-8, but I might get new ones.

    Thx so far Man.
     
  10. flworius

    flworius Noisemaker

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    Ah ok, I thought about a Diffuser on the front wall(?).... is that what you call it? The wall the speakers are facing and playing at, not the wall behind the speakers(that's the rear wall if I'm correct). Sry English, not first language, always when it's getting technical, it's getting more difficult to say what you actually want to say...
     
  11. The Pirate

    The Pirate Audiosexual

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    What do you see behind the Neves and SSLs in major recording studios? The window to the main recording room. Problem with home studios is that the majority are built with little budget by non-experts. So we see and hear a lot of things that have become the norm but are not what they should be. For example, the use of egg crates.:no: Or regular foam. Or carpet all over the place. For the last 15 years i have been taking care of the IT for one of the biggest architectural firms in the country which specializes in recording studios, theaters, media rooms. So I have seen a lot and heard a lot. If you are patient ( a couple of days) I can ask one of the arquitects/engineers to give me a general idea of what you should do in/with your room.
     
    Last edited: Mar 23, 2019
  12. The Pirate

    The Pirate Audiosexual

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    Front wall is the one you are going to face. Rear wall the one behind you.
     
  13. The Pirate

    The Pirate Audiosexual

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    Check your PM. Im going to send you some books and videos on this subject.
     
  14. flworius

    flworius Noisemaker

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    Man, that would be great. Really appreciate it!
    Regarding the other things you wrote, I know a little bit, but not enough, but I am all the way super chunks, broadband absorbers, diffusers in mixture with reflecting surfaces, Wood/Laminate. I am absolutely no expert, but I am also past the egg crates, foam or carpet everywhere stage ;)

    I always thought of the Window to the recording room as a necessity, but you sound like its a feature/beneficial to have a reflective surface there? not a feature...ain't it?
     
  15. The Pirate

    The Pirate Audiosexual

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    You want to kill early reflections. Here is a trick which is explained by Ethan on the link I sent you. The easiest way to tell where to place absorption to avoid early reflections is with a mirror.While you sit in the listening position, have a friend place a mirror flat against the side walls and move it around. Any location in which you can see either loudspeaker in the mirror should be covered with absorption. It's a good idea to treat a larger area of the wall than you identify with the mirror, so you'll be free to move around a little without leaving the Reflection Free Zone. Once the side wall locations are identified do the same on the ceiling. Although it's more difficult to slide a mirror around on the ceiling, one way is to attach a hand mirror to a broomstick with rubber bands.
     
  16. The Pirate

    The Pirate Audiosexual

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    Again, we go back to Ethan.
    A useful goal for any room where music plays through loudspeakers is to create a Reflection Free Zone (RFZ) at the listening position. The concept is very simple - to prevent "early reflections" from obscuring the stereo image. This occurs when sound from the loudspeakers arrives at your ears through two different paths - one direct and the other delayed after reflecting off a nearby wall.

    Just as damaging is when sound from the left loudspeaker bounces off the right wall and arrives at the right ear, and vice versa. Similarly, early reflections off the ceiling and floor can also harm clarity and imaging. In all cases the reflections obscures fine detail and make it difficult to localize the source of the sound or musical instrument.

    This drawing, viewed from above, shows the three main paths by which sound from a loudspeaker arrives at your ears. The direct sound is shown as black lines. The early reflections - a single bounce off a nearby surface - are the red lines, and late echoes and ambience arrive as shown in blue. In truth, the blue lines are much more complex and dense than the single path shown here, but this is sufficient to explain the concept.

    The general goal of a Reflection Free Zone is to eliminate the red early reflection paths by placing absorbing panels on the side walls in key locations. Not shown, but just as important to avoid, are early reflections off the ceiling, floor, and mixing desk if present

    [​IMG]
     
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