OK! I'm going down the homestretch with the design here. I feel like I have everything right, at least as much as it can be. Please help me find any problem areas before I start building the acoustics! BTW, thank you to all who have helped me so far, I have learned so much and feel like I will be ending up with a great design.
So here is important info:
Window has to be there.. thus the need for the extra baffles beside the nearfields.
Ductwork obviously has to be there, but I made sure that my seating position was in front of underneath it, even though the whole ceiling, and underneath the duct work will be well treated.
The soffit angles are 33degrees each with a tilt of 13 degrees. my head is at about 3'8"
uncertainty: the multi paneled reflector to the left of the desk is there to be in similar symmetry with the window to the right side. I couldn't think of a better way to add angles.
the red panels below the window and multi paneled reflector could be slot absorbers if need be. Slot absorbers are what I understand the least, but do I have it right that I will at least have to wait until I do tests before I know for which frequency to build them for? The thing that looks like a slot absorber to the left of the couch is in fact a slot absorber! One or all three of these could be built as slot absorbers, or as broadband panels.
The big red and white things behind the couch are hanging broadband panels.. I have them at 9" deep right now.
All of my absorbtion will be achieved using Roxul safe n sound. already have it.
QUESTION: What angle should I splay the window at? - There are of course two, the other side is the live room. Angle them both down?
All other read and white panels are just regular absorbers.
Tonealive's control room design - did I miss anything?
Originally posted at johnlsayers.com, topic 17625.
I think it would be very helpful to include room dimensions.
Although the relevancy has sometimes been played down, I would think you'd at least want to have one of the 'Experts' give the nod-of-approval.
Dimensions, right. o And I definitely want a couple of expert nods of approval! They have steered me back on the right path many times. Hopefully this time: On path.
Dimensions:
Room width: 11'5"
Room length:o 21' 7"
Room height: 7' 1" under most of the room, 6'5" under the ducts.
window: 5' X 3'
Listening position About 3'6" from the nearfields and about 6' from the mains.
I think the rest could be inferred from those.
ONE extra thought. I might not even bother with that curtain in front of the stairs.
Anyone?
You probably don't need that. There isn't a lot of difference in reflections from glass or drywall for most of the spectrum, so if the left wall is built properly, then it will reflect about the same as the window.uncertainty: the multi paneled reflector to the left of the desk is there to be in similar symmetry with the window to the right side. I couldn't think of a better way to add angles.
That's pretty steep! Even John doesn't go much above 12°, and he knows what he is doing. Most recommendations are to not go beyond 10°, and one very well respected designer suggest that the real limit should be 7°. There are a couple of reasons for this, but rather complex to explain in a few words, and I need to get some sleep right now!each with a tilt of 13 degrees.
Of a 21' room??? That puts you at about 17% of the room depth. Theoretical best location is 38%. Theoretical worst locations are 50% and 25%. Not sure how 17% would work out, but to me it seems that you are too close to the front wall.my head is at about 3'8"
The won't be very effective there, in the middle of the room. Place them close to a wall and you get a free 6 dB boost in effectiveness. Place them close to two walls (eg, a corner) and you get a free 12 dB boost. Place them next to three surfaces (eg, two walls and a ceiling) and you get a free 18 dB boost. But place them in the middle of the room, far from all surfaces, and you get zero boost.The big red and white things behind the couch are hanging broadband panels.. I have them at 9" deep right now.
Not sure what you mean by "splay". That word normally refers to movement about the vertical axis, such that the window remains vertical, but the rear edge is move outwards (away from the room, into the wall). But your SketchUp doesn't show that: It seems to show the glass tilted outwards at the bottom (not vertical) but parallel to the other wall. That isn't necessary. It's one of those common myths, like carpets and egg crates: you do not need to angle your glass vertically for acoustically reasons. Doing so does NOT prevent reflections from happening, or at least, not at any reasonable angle. Try ray-tracing in the vertical plane, and you'll see that you need a huge angle before you can aim reflections away usefully. At small angles, all you succeed in doing, is changing the point on the glass where the reflection occurs: it just happens at a slightly higher point on the glass. That said, you might need to tilt your glass if the lighting in the room is badly designed, and you are getting glare on the glass. But a better solution is to design the lighting correctly!QUESTION: What angle should I splay the window at?
Keep them both vertical, unless you have lighting issues that cannot be solved any other way. You could splay the entire side wall, windows included, to help solve your first reflection problem. That would work. If you angle them, you reduce the size of the air gap between them, thus reducing your isolation ("soundproofing"). You need to keep the air gap as large as you possibly can for maximum isolation, so any tilt on the glass is a bad idea, from that point of view.There are of course two, the other side is the live room. Angle them both down?
OK, now I'm confused! I though you said your head was at 3'8" from the wall? If the speakers are toed-in at 33°, and you have an equilateral triangle, then it is impossible for your head to be 3'8" from the wall and also 6' form the speakers! Something ain't right there...about 6' from the mains.
I think I would move the speakers further along the soffits, outwards, and maybe even relax the soffit angle a bit, to get the mix location further back in the room, and also help a bit with reflections off the side wall. As it is now, your window is right at your first reflection points (for both speakers)! I would most definitely try to fix that. - Stuart -Anyone?
Thanks so much Stewart, you are an invaluable resource. I've learned so much from you and it's amazing how much you work like crazy to help out so many people here.
Regarding the multi paneled reflector, tilted window, and seating position. First of all, for layout and space reasons, the window has to be where it is. And any further down, away front the front of the control room, and I don't have a line of site to enough of the live room. And as far as my mix position: when I said I am at 3'5", I meant my head height. I am in fact about 6' back from the soffit wall. And That is as far back as I can go because any farther and I would be underneath the duct work..ductwork will be down to 6'4, but the underneath will be acoustically treated. But I still don't want to sit under the duct work. So back to the multi paneled reflector and splayed wall. Being where I am, the window is exactly to my right. So in order to avoid flutter echo, I wanted to put a tilt on the window as well as put those multi paneled reflectors exactly to my left so I have symmetry between those areas- instead of putting up absorbtion on the left side to get rid of flutter, and take away the surface type symmetry. AND, I thought the consensus on the minimum angle to avoid flutter echo is 12 degrees total, or 6 degrees for each wall. I won't loose too much room in between the windows tilting the window 6 degrees, and I can surely get those panels greater than 6 degrees. And I already hear you saying, well why don't you still just keep the window straight if you can acheive the flutter avoiding angles out of the multi paneled reflectors. It MIGHT help out with the lighting, and I might go for some cool style points by having the cool looking angled window :lol:
Regarding the 13 degree soffit angle. I suppose for this current design I could chop a couple degrees off of it. Maybe..I'll have to put it in the model. OR, like you said, I COULD put them out farther, use less tilt and more angle..I think I could do it with 80 degrees instead of the standard 60 degrees that I use in the model you see in this thread. Yes, it would help with the reflections off the wall for the speaker closest to that side surface, but the reflection of the farther speaker off that same wall would not be improved. Which is why I might have to make some removable baffles anyway that I can take off when tracking in the live room and put back up for mixing. So the thing becomes,if I make removable baffles anyway, why do the greater soffit angle? The benefits of the 60 degree version are: greater sweet spot, better firing into the back of the room. The benefit of the 80 degree angle would be a lower tilt. You still thnk that is the better option?
Regarding the hanging broadband absorbers in the back of the room. I can't put it in the very back of the room because of those two doors back there, which are the bathroom and an iso booth. Where they are now, they are about 3 feet off the back wall. There is a great improvement to the absorbtion coefficient of materials when moving them 6 inches off the wall. I understand the concept of how bass builds up around surfaces, and of course even more so near multiple surfaces; corners. So 3 feet from the wall is not near enough to the wall to absorb the bass where it is building up...that is what you are saying right? However, how can you say that it won't be very effective there? Bass frequencies are still going to have to pass though it twice to get back to my head. Better against or near a wall where build up occurs, but this will still stop a good amount of low end right? That question is really important to me, can I get a sure answer on that one? But, the main goal is to make sure the low end is taken care of within the whole room. There is a lot of thick absorbtion going on in this room design right now. I have hangers in the bottom of the soffit, 3 inches of insulation on the front of the soffit, 3 inches on those side panels under the window and the reflector, a corner absorber in the back, AND the hanging broadbands. Will this not kill any low end problems that might occur? I also have that slot absorber next to the couch that can be made to accomodate a problem frequency.
couple of ideas - the monitors - keep them to 8° or less vertically and unless you need to the 30° per soffit is highly desirable. if need be with the steeper face of the soffits, dropping the monitors slightly and angled on 30° you should be able to fit it.
on the window - use heavy drapes or movable absorbers when mixing and consider slats on the opposing wall or even slats on both with a clear plexi slat over the window.
run absorption soffits around the room ceiling-wall because you don't have nearly enough absorption in the back and the soffit over the door will help.
what is the HVAC plan?
OK, that would be more desirable for the monitors in the soffit. So then the tradeoff is a less desirable location for the nearfields. They would then have to be placed farther out, wider than the soffit monitors. So I could do a 90 angle for those. I guess it's a matter of priority huh?couple of ideas - the monitors - keep them to 8° or less vertically and unless you need to the 30° per soffit is highly desirable. if need be with the steeper face of the soffits, dropping the monitors slightly and angled on 30° you should be able to fit it.
By slats you mean something like John's side wall absorber design that I included in this post? I hate the idea of a clear plexi slat on the window!! wouldnt that look horrible? lol do you have a picture of an example?on the window - use heavy drapes or movable absorbers when mixing and consider slats on the opposing wall or even slats on both with a clear plexi slat over the window.
Oh ok.. you mean like just a frame that creates a triangular space, filled with insulation covered with fabric? but really?? If I have a 7'X4' 6" thick rear hanging broadband absorber, a corner absorber in one back corner, a couch in the back, and the hangers under the soffit, that's not enough low end absorbtion? not only that, but the absorbtion in the front of the control room will help with low end too.run absorption soffits around the room ceiling-wall because you don't have nearly enough absorption in the back and the soffit over the door will help.
Going to have to just deal with all the ductwork where it is. I am insulating around all the ductwork, framing around it, finishing with drywall. Probably putting that triangular shaped cavity up against it and the ceiling and insulating, cover with fabric. As far as how to deal with the noise coming through it from the tracking room and into the control room, unfortunately, I am going to be limited. I am planning on building some vent size plugs when I need some real good isolation. And check this out. I purchased some Owens Corning type 200 duct liner that I was going to feed down the ducts to cover the bottom. BUT I am not sure about that. I really want to get something inside the ducts but I'm a little worried about this stuff. It IS specifically designed to be placed as a lining on the inside of a duct but it's still a fiberglass based product. when I handle it my arms get a little itchy and when I pat it, you can see particles in the air. ..do I really want to put that into my air supply?!?! :shock: Maybe I'm mistaken on it's use..maybe there is something else that is supposed to cover it?!what is the HVAC plan?
I think the point Glenn was making is that you don't have enough absorption in general and bass trapping in particular, in your room. Despite all that you mention above, the answer to the question that you ask is: No, that is not enough. Theoretically, for a room with those dimensions, you need 436 sabins of absorption to achieve ITU/EBU recommendations. In other words, you need the equivalent of 436 square feet of open window. You only have a total of 968 square feet of surface area (considering all the walls, and the floor, and the ceiling), so you need the equivalent of nearly 50% of your entire interior room surface area being as absorbent as an open window. That's hard to achieve, considering the layout you show. The floor alone is 249 square feet, leaving you just 719 square feet of wall and ceiling space. A large part of what is left is taken up by windows, doors, the soffits, and other things, leaving you precious little space for absorption, and especially for low frequency absorption (bass traps). Thus, Glenn's recommendation for making good use of the ceiling/wall corners, where you get a "free" boost of 12 dB in effectiveness for bass trapping (theoretically). And once again, those absorbers hung in open air are not very efficient: They need to be close to a surface for maximum efficiency, and yes there is a complex relationship between distance/frequency/effectiveness/standing waves/etc.but really?? If I have a 7'X4' 6" thick rear hanging broadband absorber, a corner absorber in one back corner, a couch in the back, and the hangers under the soffit, that's not enough low end absorbtion? not only that, but the absorbtion in the front of the control room will help with low end too.
Exactly. Also, I wanted to mention that your room ratio is not very good: it fails 2 of the 3 tests used by the BBC for accepting a room as a studio, and the Bonello chart is rather ugly, meaning that the modal distribution is not very even, thus good bass trapping is even more important.Where they are now, they are about 3 feet off the back wall. There is a great improvement to the absorbtion coefficient of materials when moving them 6 inches off the wall. I understand the concept of how bass builds up around surfaces, and of course even more so near multiple surfaces; corners. So 3 feet from the wall is not near enough to the wall to absorb the bass where it is building up...that is what you are saying right?
I may be wrong here, but I think you mis-understood Glenn's question. He wasn't asking about what you are going to do to isolate the ducting that passes through the room, but rather he was asking what the HVAC plans are for YOUR room. In other words, where will the vents and ducts be, what sizes will they be, where will the silencer boxes be, what flow rate will you be using, what air velocity are you aiming for, how much cooling capacity do you need, how much de-humidification do you need, how much fresh air do you need to bring in / stale air to be exhausted, fans, dampers, etc. HVAC is often overlooked in home studio design, but it is a critical part of the studio, and needs to be considered carefully, planned carefully, and implemented carefully. Like I said, I may be wrong, but that's the way I understood Glenn's question.Going to have to just deal with all the ductwork where it is. I am insulating around all the ductwork, framing around it, finishing with drywall. Probably putting that triangular shaped cavity up against it and the ceiling and insulating, cover with fabric.
Yes, you really do!!! :) Proper duct liner is designed to go inside ducts, not outside them, and you do need it, both in the ducts that pass through your room as well as those that you will design as part of your own HVAC system. However, you should also be aware that adding duct liner inside an existing duct reduces the cross sectional area to some extent, thus forcing an increase in air velocity, which in turn means more noise... :) Catch-22! But you still need it. - Stuart -I really want to get something inside the ducts but I'm a little worried about this stuff. It IS specifically designed to be placed as a lining on the inside of a duct but it's still a fiberglass based product. when I handle it my arms get a little itchy and when I pat it, you can see particles in the air. ..do I really want to put that into my air supply?!?!