Quick mirror point question- on the absorber panel or wall?

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Quick mirror point question- on the absorber panel or wall?

Postby Max Dread » Thu Dec 30, 2010 7:54 pm

Hi there

Choosing where to put my side wall reflectors (***EDIT - absorber NOT reflector***) today - and I've forgotten...... When using the mirror technique should I use the mirror pressed up against the wall or should I space it from the wall so that it is in the position of where the front of the panel would be (in my case 17cm away from the wall)? Makes quite a difference so I want to make sure I get it right!!!!

Cheers

Max
Last edited by Max Dread on Fri Dec 31, 2010 9:58 am, edited 1 time in total.
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Re: Quickie mirror point question - on the trap or on the wa

Postby jonessy » Thu Dec 30, 2010 8:37 pm

On the wall.

But if it makes such a big difference then, assuming your absorber and mirror have similar dimensions, you should consider covering a larger area.
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Re: Quickie mirror point question - on the trap or on the wa

Postby BIG8 » Fri Dec 31, 2010 4:23 am

Max Dread wrote:Hi there

Choosing where to put my side wall reflectors today - and I've forgotten...... When using the mirror technique should I use the mirror pressed up against the wall or should I space it from the wall so that it is in the position of where the front of the panel would be (in my case 17cm away from the wall)? Makes quite a difference so I want to make sure I get it right!!!!


Reflectors? you mean absorbers, or is 'reflectors' what side wall absorbers are called these days?

If absorbers, you should make / buy them large enough so that it doesn't matter.
If however, the distance from speakers to side walls is limiting (too close to side wall), then you should make sure the mirror point is on the front of the panels, not necessarily at the centre, but not too close to the trap edges neither.

Cheers,
Hovannes Setrak ISMIRLIAN
Viva checking your mixes outside the mixing room! :D
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Re: Quickie mirror point question - on the trap or on the wa

Postby jonessy » Fri Dec 31, 2010 6:51 am

Why not reflectors?

Nobody said that first impact point treatment should necessarily be absorption.
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Re: Quickie mirror point question - on the trap or on the wa

Postby Scott R. Foster » Fri Dec 31, 2010 7:07 am

How big is the room?
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Re: Quickie mirror point question - on the trap or on the wa

Postby Max Dread » Fri Dec 31, 2010 9:13 am

Hi

Thanks for the quick replies guys.

The room is 2.7m x 4.1m.

The absorbers (my mistake - they are rockwool absorbers not reflectors!) measure 90cm high and 60cm across. The trap itself is 17cm, which is made up of 10cm thick rockwool and an air gap at the back.

The mirror I'm using is not as wide as the traps. So I'm trying to find the spot where the tweeter is as central to the trap as possible so that I'm covered even if I move around a bit on the mixing position. I'm also trying to place it where I can see both speakers so that the absorber minimises early reflections from both.

It's not making a huge difference whether I put the mirror on the wall or space it away by 17cm..... But it's making enough of a difference to make it worth considering which is best.

Cheers

Max
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Re: Quickie mirror point question - on the trap or on the wa

Postby BIG8 » Fri Dec 31, 2010 9:19 am

jonessy wrote:Why not reflectors?

Nobody said that first impact point treatment should necessarily be absorption.


Hi Jonessy :D

mmm.... OP thread subject did say 'trap'. Don't even know if that term is an accepted reference to absorbers... neither have I ever seen reflectors referred to as traps.

As for reflectors (or diffusers) on side wall mirror points, the impression I got from this forum was that it is more a controversial subject/advise rather than an accepted practice, unless one is talking about really wide rooms.

Happy New Year!!! (Beijing will get there faster than where most of you guys are!) :D

Cheers,
Hovannes Setrak ISMIRLIAN
Viva checking your mixes outside the mixing room! :D
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Re: Quick mirror point question- on the absorber panel or wa

Postby Max Dread » Fri Dec 31, 2010 9:59 am

I've amended the post title and original post accordingly.....

Sorry for any confusion.... shold have made sure I had my terms right!
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Re: Quick mirror point question- on the absorber panel or wa

Postby jonessy » Fri Dec 31, 2010 12:25 pm

BIG8,

I also had the feeling that Max meant absorbers which are the most common means of first point treatment; however reflectors can also be beneficial.

But if you ask...:

Sidewall deflectors and diffusers are also quite common in studio design.
The room doesn't have to be wide if you're using geometrical diffusers; most of which do not have a minimum wavelength constraint.

Reflectors can also be bass traps...
If you consider a thin sheet of wood angled at a distance from the wall, then for mid-high frequencies it is a reflector/deflector and for low frequencies it is a trap. :)

Cheers,

Jon.
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Re: Quick mirror point question- on the absorber panel or wa

Postby bert stoltenborg » Fri Dec 31, 2010 6:30 pm

OMG!
Jumping Jeepers!
Jolly Jon is being brainwashed by the Silly Secret Salford diffuser mob!
Scott, to the Bertcave so we can save him!
Tadatadatadatadatadatadatadatada Bertman!

:mrgreen: :mrgreen:

jonessy wrote:BIG8,

I also had the feeling that Max meant absorbers which are the most common means of first point treatment; however reflectors can also be beneficial.

But if you ask...:

Sidewall deflectors and diffusers are also quite common in studio design.
The room doesn't have to be wide if you're using geometrical diffusers; most of which do not have a minimum wavelength constraint.

Reflectors can also be bass traps...
If you consider a thin sheet of wood angled at a distance from the wall, then for mid-high frequencies it is a reflector/deflector and for low frequencies it is a trap. :)

Cheers,

Jon.
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Re: Quick mirror point question- on the absorber panel or wa

Postby BIG8 » Fri Dec 31, 2010 7:01 pm

Jon: thanks for info, makes sense and I appreciate it :)

Bert: get him! :twisted:

All: Good Health, Good Joy, Prosperity & Great Laughs in 2011! :D

Cheers,
Jean
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Re: Quick mirror point question- on the absorber panel or wa

Postby Scott R. Foster » Sat Jan 01, 2011 3:13 pm

Holy smoking abflectors Bertman - hit him with a Bertarang. :D
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Re: Quick mirror point question- on the absorber panel or wa

Postby Ido » Sun Jan 02, 2011 8:21 pm

begging your biffy bardon, BertBrain and the Flashy Fos,
an OT question for Max the mevil:
um, Max, may I ask how you came to get these 60/90 cm dimensions?
i ask because:
1. I'm bored.
2. I use exactly such dimensions for paintings I do, i like the size and ratio.
cheers,
Ido the human dolt
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Re: Quick mirror point question- on the absorber panel or wa

Postby jonessy » Tue Jan 04, 2011 8:14 am

Ahh.. It takes more than postgrad degree to brainwash your humble servant.

However, we should always consider alternatives.
Yes - absorption is prolly the easiest and perhaps cheapest way to handle specular reflections; but that doesn't mean that it is the only way...

The problem is, that we do not understand reflections in sound reproduction rooms that well. Many 'metrics' draw on large room acoustics, in which most things are different.
Loudspeaker-boundary-listener interactions are much more complex than many design methodologies account for, and given that - the lack of reflections is probably the safest bet - for now.

So throw a pair of very good loudspeakers in a reflection-free environment, and it is pretty much guaranteed that you'd get good results.

But this doesn't mean that similar results can't be achieved in a reflection 'full' room.

Wrote a little bit about this on my research page:
http://www.acoustics.salford.ac.uk/prof ... t=project1
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Re: Quick mirror point question- on the absorber panel or wa

Postby Ido » Wed Jan 05, 2011 5:44 pm

jonessy wrote:...The problem is, that we do not understand reflections in sound reproduction rooms that well. Many 'metrics' draw on large room acoustics, in which most things are different.
Loudspeaker-boundary-listener interactions are much more complex than many design methodologies account for, and given that - the lack of reflections is probably the safest bet - for now.
...


yea,
have'nt read ur piece yet, but i think there is a big difference between "nice" diffusion and "accurate" diffusion (where a control should have accurate), and how to quantify the diff bewteen the different types, not just by saying temporal-spacial.
the human ear as we know can tolerate lotsa inaccuracy for sake of nice.
hell, i love nice.
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