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PostPosted: Mon Feb 11, 2008 6:01 am 
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Based upon what I have read, control room walls when angled need to be a minimum of a six degrees.

John's sae plans are certainly based on this. However from what I can gather, this is only enough to stop flutter echo and not necessarily to create a RFZ.
In this situation should I be adding absorbers to the first reflection points? Again, based on some of John's design this doesn't seem to be the case as He's using reflective materials in these positions.

On a side note, if I do go with angled walls, I will be having soffit mounted mains, but I also rely on stand based nearfields . Does this mean I should make the front wall totally absorbent?

Cheers

Paul


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PostPosted: Fri Feb 15, 2008 3:59 am 
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Paul101

Good questions. I am interested in the responses to these as well..


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PostPosted: Fri Feb 15, 2008 9:20 am 
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The RFZ is created by using ray tracing. The design goal is no reflections for the first 15, or 20 (the latter is better) milliseconds. The ITU spec writes that reflections within that time period be at least 10 dB lower than the initial sound.

The idea of nearfields is that they are so close to the listener(s) that room treatment, or lack of, does not affect the initial sound from the speakers. So no, you do not have to make the front wall absorptive for the nerafield monitors.

Keep the questions coming! The more you know, the better your space will be.

Andre


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PostPosted: Sat Feb 16, 2008 5:57 am 
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Ok, I understand what your saying, but looking as John's sae plans the walls are at six degrees. This is presumably not enough for a rfz without the use of absorption??


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PostPosted: Sat Feb 16, 2008 12:16 pm 
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If the walls are six degrees and there is no absorption on the splayed walls, then six degrees was enough IN THOSE SPECIFIC designs to provide the desired RFZ. If you can links to specific designs (hopefully with drawings) a better answer can be given.

Keep em coming!

Andre


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PostPosted: Sat Feb 16, 2008 12:52 pm 
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in many cases, you'll see the walls use slats to provide absorption, diffusion, and the angles walls, as well as a face to the area which becomes the bass trapping. this way you're not only creating the RFZ but also maximizing the usages of space. in the case of 6°, its generally considered the bare minimum for elimination of flutter echoes. for really effective RFZ you need wider angles on the walls and ceiling.

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PostPosted: Sat Feb 16, 2008 6:04 pm 
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Hi,I'm also building a small garage studio,and I was wondering.... if I'm ONLY using nearfields,do I need the massive front of wall super basstrap?

My control room before treatments measures only 16ft long,and width is 10ft at front of control room,and splays out to 13ft at back.


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PostPosted: Sat Feb 16, 2008 6:37 pm 
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http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4206

The control design is a good example of what I mean, using sliding patio doors at the point where I would expect first reflection issues.[/url]


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PostPosted: Sat Feb 16, 2008 11:41 pm 
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GMo wrote:
Hi,I'm also building a small garage studio,and I was wondering.... if I'm ONLY using nearfields,do I need the massive front of wall super basstrap?

My control room before treatments measures only 16ft long,and width is 10ft at front of control room,and splays out to 13ft at back.


So your nearfields are your mainfields. Sorry, couldn't resist the pun. :D

Seriously, as I worte earlier in this thread, nearfields are intended to be so close that the room does not affect the initial sound. If you want to get the best out of them, flush mount them.

Andre


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PostPosted: Sun Feb 17, 2008 12:00 am 
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paul101 wrote:
http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4206

The control design is a good example of what I mean, using sliding patio doors at the point where I would expect first reflection issues.[/url]


Fantastic! The design is for a larger than home control room, and a general concept. Re-read my first post in this thread, noting no reflections for the first 15 milliseconds. Then look at the drawing you referenced. The couch gives some idea of how large the room is. Assuming the couch is 7' long and taking up one third the width of the room, the room is 21' wide. Taking into account the splay, the room is around 18' wide by the mixing position.

Initial reflections from the splayed walls will be 15 milliseconds after the first sounds, meeting the ITU spec. Because the room is larger, the implementation changes.

We are getting somewhere. Keep the questions coming!

Happily tilted (splayed),
Andre


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PostPosted: Sun Feb 17, 2008 3:01 am 
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Ok, so considering my control room measures 30ft by 20ft approx, it could prove to be an ideal candidate for this design?


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PostPosted: Sun Feb 17, 2008 3:56 am 
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paul101 wrote:
Ok, so considering my control room measures 30ft by 20ft approx, it could prove to be an ideal candidate for this design?


Sheesh! Give plans, drawings, details. Generic answers are just that. Generic.

andre


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PostPosted: Sun Feb 17, 2008 4:30 am 
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At the moment this is very much at the preliminary stages.

Its part of a building my university has bought up. I have mentioned to them about the possibility of spayed walls, but wanted to fill in the gaps in my knowledge before pushing any more with the idea.

The room is fairly sizable, but Id imagine if I turned round and told them they would need much over a six degree splay, I wouldn't get the idea through due to space loss.

This is why John's six degree design looked great and I questioned whether it would work in this context.


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PostPosted: Sun Feb 17, 2008 7:01 am 
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Great! You are giving information that lets the thread progress. The loss of space only occurs if the surrounding rooms are to traditional 90 degree walls. Also, the so called lost space can be used for bass traps, etc. reducing the amount of "lost space."

Repeating what I wrote in the previous post in this thread, more info please!

Andre


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PostPosted: Sun Feb 17, 2008 8:25 am 
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Unfortunately the outer walls are already constructed, so yes its to be built inside a rectangle.

Room dimensions are almost 30ft by 20. All walls are plaster, floor is concrete.

The ceiling is also a fixed height of around 10ft with ceiling tiles. So no angled ceilings, but enough height to build an acoustic cloud for the mix position.

At the back of the room (20ft wall) are two sliding patio style doors, leading to a drum booth and another small live room. If it was my decision this would have been the front of the room to allow direct sight between engineer and artist, but talk of using cameras and screens for communication seems more likely. I think this is mad, but as I said I have no input on final decisions, I can only make suggestions. :-)

the room is not a typical control in as much as it will need to accommodate students that are in mini lecture groups. Perhaps up to ten at a time. This was part of the worry about space loss.

Sorry, this is all I can think of. Its essentially a rectangular blank canvas.


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