Greetings to all
I've got a question regarding the angle of the side walls (not the soffit). I've read every where about 6 degrees minimum or optimal, but my questions is if there is a maximum angle ?
Hypothetically talking I've got this room (picture below) and because of size issues and other problems i decided to make the side walls kinda be an extension of the soffit panel (just that this would be absorptive and not reflective like the soffit) Is there any problem with this? or do they have to be like the dotted lines in the picture? (6 degree angle at the end of the soffit)
Also that the front of the room is on the larger wall (i know this isn't optimal) but imagine there was no work around
Note: I'm just showing the inner walls (the ones you can see from the control room) to illustrate this issue easier.
and please ignore the back of the control room, I just want to talk about the surroundings of my sweet spot (side walls and so on)
Thanks
Do you have a door somewhere in this room?
What kind of size issues do you have? Seems you are waisting a lot of your already small room, based on this drawing.
The dotted lines seem to far inward
Could you provide a drawing of the current outerwalls?
Your speakers also seem to be rather close together, and your soffit angles look to be too large for that room. They seem to be at 45°, rather than 30°
- Stuart -
I've got a question regarding the angle of the side walls (not the soffit). I've read every where about 6 degrees minimum or optimal, but my questions is if there is a maximum angle ?
Never mentioned as an optimal here, or anywhere by knowledgeable people. Walls are splayed to control reflections, which depends on the application geometry itself, and to prevent slpa echo. Some people habve recommended 6° as a minimum to prevent slap echo, others 10° and 12°. There are other ways to prevent slpa echo.
IOW there is no minimal or optimal.
BTW acoustics can be daunting and rewarding field to study. Congratulations and enjoy your experience!
Andre
Thanks for the answers, i haven't put the other details you are asking for, because this is an hypothetical case, There fore the speakers are so close together and the angle is 45 degrees, what i wanted to get clear from this question was If it would be good to soffit mount speakers in a such restricted space. I knew that the angle was there so that the reflections would not get back to your ears and be rather "dissipated" in the rear of the room by absorptive material and or bass traps and so on. Please Imagine that there is No other way to arrange the room, Would it be more beneficial in a room of that size to rather put the speakers on stands or still soffit mounting them?
Talking about the side walls, so there is theoretical no bad angle if it is enough to send the reflected sound to anywhere else but not to your ears?
Ouch! Flush mounting is good. It is strongly recommended. I will go so far as to say flush mounting is the second most dramatic thing you can do for your control room sound, after buildling it right to begin with. (I think I just wrote a new phrase for studio design.)
Angled walls are not just for reflecting to the back wall.
Welcome to acoustics, and absorb my signature line. :mrgreen:
Andre
Yeah, I do consider your signature that why i read almost everyday since one year on this page every building and designing thread :P! I just haven't found one talking about a "maximum" wall angle. I know it's just not for reflecting it to the back, I have actually had 2 years of acoustics and wave physics at school. But find in this forum Lots of information because you actually have applied the theory in practice which I haven't. So long answer short, You would still soffit the speakers, even if the room was that small and the resulting space between speakers is that small. Actually I though John often mentioned that one could use 90 degrees soffit when the room wasn't that big and you could not get that far back because you wouldn't be in the 38 % region.
So could the side walls have the same angle as the soffit wall (like an extension of it) Just with a different treatment (absorptive, as it is the early reflections point).?
Thanks
Yes, you CAN go as far as 90° if you need to, but it doesn't look like you do need to, in that hypothetical room.
The other issue I see there is that your speakers are not centered on the soffit panels. The purpose of the soffit is to act as an infinite baffle, which means that you want as much surface area around the speaker as you can possibly get, on all sides. In this hypothetical case, you have your speakers very close to the front edge of the panels. I would move the speakers further apart to maximize the surface area between the speaker and the front wall, which would be good idea anyway as the speakers are very close together. That would have the additional benefit of moving your mix position further backwards, towards where it should be, at around 38% of the room depth (roughly 1 m from the front wall in your example).
Only then would I worry about angling other things to help reduce reflections, flutter, etc.
It seems to me that the logical way of designing a room is to start with the speakers and the mix position, since that is what the whole issue is about anyway. Once you have that geometry in place, then you can start figuring out where other things go in the room, what angles you can get, etc. Those things will kind of suggest themselves, once the basic speaker / mix position geometry is set.
Others might have different approaches, but that just seems the simplest and most logical way of doing things, to my way of thinking.
- Stuart -
Hmm so you say that even if the soffit/side wall is in like in the picture below ( just around the Speaker hard and the rest "soft") the speaker/waves would still consider this "soft" surface as part of the soffit? I thought it would not because as you said it suposed (the soffit) to act as an infinite baffle which is a "hard" surface. Please tell me if i'm wrong.
(sorry for the quick sketch)
Anyway I quite don't get how I'm supposed to be able to still be around the 38% from the front wall if the soffits would be at an 60 degree angle. Wouldn't that send me more to the back wall and therefore to the centre of the room (bad place)?
And i did start with the mixing position as initial reference. I placed my head at the 38% from the front wall of this "bad case scenario". And the only way to remain there and not to not have the speakers closer to each other, was this way. If I did a 60 degrees soffit. and wan't to still be at the 38 % the speakers would be waaayyy closer, than in this situation.
Or am I missing here something?
In your hypothetical room you want to start with the speakers on the 2.63m wall, not the 3.24m, as a matter of orientation. This should make a more allowable situation using Wes Lachot 38% guideline.
Since it is hypothetical, "Also that the front of the room is on the larger wall (i know this isn't optimal) but imagine there was no work around" doesn't apply....;)
Please, As I said before assume the orientation of the room is not changeable, I want to kinda create a "worst case scenario" and its possible "not so bad" work arounds.
since this sounds like a 20 questions thread: is the room this sits in shaped that way or is it a rectangle?
you don't have to limit yourself to a single set of angles. you can use a series of angles to obtain the baffle needed plus guiding the sounds properly as well as housing the necessary absorption and tuning treatments. rooms are 3D although in most cases there is a limit to the angle you can have for the floor :shock:
Sorry if this seems as a 20 questions thread because I actually wanted one answered (about the angles of the side walls, if this could be an extension of the soffit just not being a hard surface).
As I said before I'm only showing the "inner walls" (what you can see from the inside of the room).
I know That it should be on the shorter wall and that I should be arround the 38 % of the room lenght. But i wanted on purpose to give this "imaginary" room not the ability to be set in that way, so that some one would be forced to put the front on the longer wall. (asume that there are doors or not changeable closets or anything that REALLY REALLY doesn't let you to arrange it in the "most beneficial" way). The only thing you can change is the angle of the walls and the decision to soffit mount or not the speakers.
I hope I made myself clear.
Thanks
The only thing you can change is the angle of the walls and the decision to soffit mount or not the speakers.
For me, there would have to be some incredibly good reason to NOT soffit mount them! It wouldn't just be a matter of angles, since there are ways of working around strange angles. Soffit mounting does so much for you that there would have to be an amazingly convincing reason to NOT do it, in any given room.
- Stuart -
OK, so one decision is made. To soffit mount them. Now what about the angles? I was thinking of perhaps not going as far as 6 degrees but rather more and so stop the infinite baffle and also not lose that much of space. is this viable? Or Could I still leave the wall like an "extension" of the soffit just without the hard surface?
Thanks
The main reason for the 6 degrees on the side walls is to avoid flutter echo, not to create an RFZ. RFZ depends on other things about the room geometry. The best way to figure it out is to ray-trace.
I'm also not sure why you are talking about using absorption on the soffit extensions: If they are angled to create an RFZ then they don't need absorption. You only need absorption on first reflection points if you can't get a true RFZ just from angling walls. In fact, if you angle your walls such that you have a true RFZ, with no reflections getting to your ears until well after the Haas time, and at least 10 dB down, then in reality you don't even HAVE any "first reflection points", so you wouldn't need to make them absorbent...
You seem to be mixing up splayed walls, flutter echo, RFZ, soffits and first reflection treatment all in one.
- Stuart -
That was Exactly!!! what I was aiming at, cause I know that all of the things you mentioned are different things that have a different approach in solving possible issues, I wanted to know if this could be like a "MIX" between the whole bunch, A wall that is splayed to avoid flutter echo and standing waves which is absorbent to "suck in" the first reflections. And also which doesn't act as part of the soffit (because it isn't a hard surface).
Is this possible at all? Or are some of the "features" this wall presents not necessary?
I'm pretty confident about my knowledge on standard (common) procedures to solve this issues. But What I'm trying to make are some "experimental" solutions or maybe not and it is quite common. I just want help from you guys that are far ahead from me in the practical aspect of acoustics. Also In experience.
Thanks
I just wanted to add a quick little question that suddenly appeared in my mind. Would it be possible to create walls without actually attaching them to the floor with nails but just with caulk to close the remaining gab? (this wall would still be attached to the ceiling and the side walls) I don't know if the weight of the whole construction would be enough to keep it in place (together with the caulk).
A wall that is splayed to avoid flutter echo and standing waves which is absorbent to "suck in" the first reflections. And also which doesn't act as part of the soffit (because it isn't a hard surface).
Standing waves are not prevented by splayed walls. The standing waves are shifted in frequency and pressure distribution. In a manner which is difficult to predict. If it reflects avoiding flutter echo it is a hard surface.
I just wanted to add a quick little question that suddenly appeared in my mind. Would it be possible to create walls without actually attaching them to the floor with nails but just with caulk to close the remaining gab? (this wall would still be attached to the ceiling and the side walls) I don't know if the weight of the whole construction would be enough to keep it in place (together with the caulk).
Yes, but it requires structural engineering.
Andre
I actually wanted one answered (about the angles of the side walls, if this could be an extension of the soffit just not being a hard surface).
absorption doesn't need to be "soft". the extension of the baffle could exhibit absorption qualities and still be hard materials like wood, metal, concrete, etc.
the attachment to the floor as avare notes is a structure concern. in general you don't want the walls kicking out so only using adhesives (or just caulk) should have proper review. using isolation wall braces may make this possible but your building codes will dictate what can be done.
Thanks, I will surely read it.
I have one short question again, (I guess it is turning into a 20 questions thread :( )
When you calculate the 38% of the room do you do this before anything? because If I measure approx 38% from the existing walls, after wards this position will be far to close to the newly build wall. So I'm guessing the 38% starts from the front Interior wall, and in case the construction is an Inside Out wall? Do you count the distance from where the insulation starts or the drywall that lies behind it?
Thanks
All acoustic measurements always refer to the inner surface of the inner leaf. In other words, the surface that you see once the entire MSM construction has been fully completed, but before any treatment has been installed. That surface is what the sounds waves "see" in the room, so that is what counts for all measurements (ratios, geometry, etc.).
- Stuart -