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Mirror trick to find first reflection on the ceiling
Old 4 weeks ago
  #1
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Mirror trick to find first reflection on the ceiling

Hello,

I am building my new room. And want to get it treated.
I'm aware of the mirror trick to find first reflections on the side walls.
Also heard it to be working to find the first reflections on the ceiling.
Do you confirm that?
Can you expand on this
Thanks
Sergio
Old 4 weeks ago
  #2
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avare's Avatar
 

Quote:
Originally Posted by sergioelectro View Post
Hello,

I am building my new room. And want to get it treated.
I'm aware of the mirror trick to find first reflections on the side walls.
Also heard it to be working to find the first reflections on the ceiling.
Do you confirm that?
Can you expand on this
Thanks
Sergio
Yes sound reflects off the ceiling. It reflects off of reflective surfaces regardless of angle.
Old 4 weeks ago
  #4
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Quote:
Originally Posted by avare View Post
Yes sound reflects off the ceiling. It reflects off of reflective surfaces regardless of angle.
how in pratice, does it work?

Sergio
Old 4 weeks ago
  #5
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Use ETC (REW) instead.
Old 4 weeks ago
  #6
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Quote:
Originally Posted by sergioelectro View Post
how in pratice, does it work?

Sergio
The angle of incidence is equal to the angle of reflection.


Angle A = Angle D.


But this is only for high frequencies. Bass frequencies, as always are a bit trickier...


Basically, for your ceiling, the thicker the better. And use the proper material (the cheapest the better!)

Last edited by JayPee; 4 weeks ago at 05:37 PM.. Reason: grammar!
Old 4 weeks ago
  #7
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Quote:
Originally Posted by JayPee View Post
Use ETC (REW) instead.
How, to locate my first reflections points?
Old 4 weeks ago
  #8
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Perhaps this is the missing info:

Sit where you want to listen.
Have another person move a mirror around flat on the surface until you see the speaker in it. There is the first reflectionpoint.

It does not matter if it's the wall ceiling, floor, or anything else. Collectivly,,, a surface that is assumed to be flat for this.
Old 4 weeks ago
  #9
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You do not need to overcomplicate things. Your ears and speakers should be at the same height, therefore for the ceiling it is simply the midpoint between your ears and speakers. Cover a large area centered around this midpoint.
Old 4 weeks ago
  #10
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If the wall or ceiling is a light color, you don't need a mirror. You can use a laser pointer from the listening position.
Old 4 weeks ago
  #11
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Quote:
Originally Posted by johnnyc View Post
You do not need to overcomplicate things. Your ears and speakers should be at the same height, therefore for the ceiling it is simply the midpoint between your ears and speakers. Cover a large area centered around this midpoint.
ok thanks

Does the area just above the listening position also needs to be treatened?
Cheers
Sergio
Old 4 weeks ago
  #12
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Quote:
Originally Posted by sergioelectro View Post
Does the area just above the listening position also needs to be treatened?
Yes. If there is no treatment on the ceiling, then there can potentially be several physical problems, such as flutter echo, modal resonance, phase cancellation and comb filtering from reflections, with the resulting psycho-acoustic problems that they cause, in "coloring" the sound.

Most studios have a large, thick, hard-backed ceiling "cloud" hung at an angle over the region between the speakers and the mix position.

- Stuart -
Old 4 weeks ago
  #13
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12ax7's Avatar
 

Gravity has very little effect upon sound waves within a room.

They don't care if its a wall or a ceiling.
Old 4 weeks ago
  #14
Sound reflects in similar ways to light rays from 2 octaves above the room's Schroeder Frequency - that's why the mirror trick works.

Last edited by Arthur Stone; 4 weeks ago at 06:42 PM.. Reason: update
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