John's soffits do not go all the way to the floor. There's a gap of at least 12 inches at the bottom, to allow sound to enter the area where the hangers are. But regardless of that, your design is not feasible, and not usable for the main speakers at the mix position. Many large control rooms do mount speakers high up like that, but they are meant to cover the rear of the room, where the client couch is. The issues with your design are multiple. First and most important, the speakers are tilted way too far down. The absolute maximum angle that any speaker manufacturer recommends is 15° down-tilt, but even that is excessive. Most recommend no more than 10°, and there is research that suggest the limit should be 7°. Personally, I wouldn't even go that far: I've never designed any room with more than 5° of tilt to the speakers. Why? Firstly, because our ears are not designed for that! Our auditory system depends on very subtle phase and timing differences caused by the pinnae, in order to determine directionality. Sending the sound from way up high at a very large angle, messes that up an alters the sense of directionality of a sound source. So your engineers will not be able to accurately determine panning locations of mics and instruments with the setup you show. To them, the sound would appear to be coming from a different direction than where ti is really set on the sound stage. Then there's the issue of first reflections: With the speakers mounted so high, at such a steep angle, there will be major, abundant, strong reflections off the console and desk surfaces, into the engineers ears, at all frequencies across the spectrum. So not only will the engineer be unable to to determine direction properly, he also won't be able to determine frequency and tone well, since he'll have huge comb filtering issues from those reflections, and he won't be able to hear reverb tails and other subtle hints, as they will be drowned out by the reflections from the console. Those reflections will be well inside the Haas time window, so there will be the smearing effect from that too. Then there's the issue of head movement: As the engineer moves his head forwards or backwards just a little while he is operating the console, he'll be moving his ears very large distances across the speaker axes: There's only one very tiny point where his ears will be on-axis, and at all other points he will be off axis, and very much so. No speaker has good off-axis response at the angles that you would be subjecting him to. Just by sliding his chair forward a few inches to reach the top of the console, he'd be about 30° off axis, and therefore in a very non-linear area of the speaker polar pattern. You'd have to nail his chair to the floor and set up a rigid neck brace to keep his head in the right place! Then there's the issue of the baffle area around the speakers in your design: it does not increase the area very much. Below the speaker, in fact, you have practically no additional area at all, and side to side the area changes: at the top of the speakers, it is also minimal. There are many other issues that I don't have time to go into, but those are the biggies. I'd suggest that you change your design to something more conventional, and more useable: Keep the angle under 7°, and keep the speakers at ear height. - Stuart -How can I sofit mount if I cant have the box all the way to the floor as described from John Sayers?
Soffit mounting?
Originally posted at johnlsayers.com, topic 66.
Thanks Stuart
I think we will just have to go with near field monitors on stands as the window area is almost built.
So when we see speakers high up in a studio does this mean it is mainly for the clients?
Pretty much. And also for "checking the mix" on those big wonderful boomy things that sound so cool when turned up to 11. But they generally aren't used for making mix decisions. At least, they aren't used by smart engineers who understand how human hearing works!So when we see speakers high up in a studio does this mean it is mainly for the clients?
So if you have glass behind the speakers, where are you going to put the front wall absorption that helps to deal with SBIR, comb filtering, and other reflection issues coming off that glass? With speakers on stands, treatment at all first reflection points is a given. If you happen to have glass at that point, then you have a problem... You have to decide if the view is more important than the mix... :shock: Some places do actually prefer the view, which I've never understood: If someone goes to all the trouble and expense of building a great control room, whose very purpose is critical listening as accurately as possible so the engineer can mix well, then why would they want to throw that all out and basically trash the room, just to keep a nice piece of glass in place? For me, the decisions is easy: forget the glass and build the room to do what it is supposed to do. That's not to say that you can't use glass in control rooms: You certainly can! but it has to be carefully designed and positioned so it does not interfere with the primary purpose of the room, which is to mix, not to look good... - Stuart -I think we will just have to go with near field monitors on stands as the window area is almost built.
How about if there were some removable insulated panels that went in for critical listening that deal with the glass issue?
And this is without acoustic absorption infill panels.
I guess when critical listening is required then the panels can be inserted and when not ion use just sit below behind the desk.
What do you think? It is possible right?
Anyone?
I think this will work.
You could do that, I suppose. It should work, acoustically. - Stuart -I guess when critical listening is required then the panels can be inserted and when not ion use just sit below behind the desk.
Thanks. It would be great to use for critical mixing tasks and removed will be great for when we track and connect with the talent.
It does not need to be sealed, and indeed it cannot be sealed due to the need for ventilation, but it is still a good idea to have a massive, rigid partition between the two sections. I also usually angle the two sections differently, to provide better RFZ and to avoid lobing and resonant artifacts as much as possible, as well as to save space.A. Should the particular soffit components (the ones that have the structure to hold the speaker) be sealed away from the rest of the extension which would be filled with absorbent materials or hangers?
No. The air does not ever move through the insulation. The air path is totally free and clear of any insulation. The air is drawn in at the bottom, moves up between the hangers, up past the rear of the speaker, up through the back of the soffit, and out through the top or front.It is noted that the box above the speaker should be loosely fitted with insulation. As i understand, the whole idea is for the air to enter from the bottom freely, heat up at the speaker and go up through the top with resistance, so it loses energy on the insulation, right?
What "dedicated ports in the speaker box"? The speaker enclosure box that surrounds the actual original speaker cabinet has large wide slots in the bottom and top, just above and below the rear panel of the speaker. There is also a deep gap between the rear panel of the speaker and the rear panel of the enclosure box. There has to be, to allow free circulation of air. Their are usually also additional holes in that back panel, to allow for the connection of the power cable and signal cables.But i have seen people on this forum designing pathways for the air to move freely from the dedicated ports in the speaker box..
There are still exit paths for the air there... you just can't see them! They are probably concealed behind the cloud, or they go out through the top of the soffit, not the front. - Stuart -In the end i see photos with fully insulated soffits and them being fully covered with a wooden panel thats has no exit hole for air at all..
HI Guys, my 1st comment/post, not sure if this thread is to old to receive an answer now, my question is, the "acoustic hanger" in your diagram here John, is that "empty space" or is there some sort of acoustic treatment in there?
Cheers
Ashley
Hi Ashley, Welcome! Inside the area marked "acoustic hanger", are acoustic hangers! :) That is the treatment: just like the name implies, there's a series of acoustic hangers in there, built and spaced in the normal manner. they are excellent for bass traps. - Stuart -HI Guys, my 1st comment/post, not sure if this thread is to old to receive an answer now, my question is, the "acoustic hanger" in your diagram here John, is that "empty space" or is there some sort of acoustic treatment in there? Cheers Ashley
Hi All,
First comment on this forum after a few weeks of excited reading :D
I know this thread has been inactive for several months, however, I have just joined, finished reading it and have some initial queries re John's flush mounting design (which I am sure will form the start of a whole slew of questions I will cover in my own thread when the time comes for me to get some feedback on my 5.1 writing room design).
My first question is to do with the compromise of making the lower baffle panel an absorber of reflections from the back of a mixing console or desk as was discussed only a few comments previously. I was wondering if there would be any negative effects on the effectiveness of the baffle if a separate panel was mounted in front of the lower baffle panel. That is to say, that the lower baffle would be constructed completely the same way as the upper baffle panel and both would be mounted flush. Then, separate absorbing acoustic panels would be attached to the front of the lower baffle panel. Would there be any negative effects to the baffle if there was an acoustic panel mounted "unflushly" to the baffle itself?
It is entirely possible that I am misunderstanding the design of the entire bottom cavity here, and that everything from the speaker down is one big broadband absorber - still, would what I have described above negatively affect the performance of either the baffle or broadband absorption of reflections from the back of the desk?
I have attached John's original design for ease of reference.
Secondly, with regards to using active monitors with switches located on the rear of the speaker cabinets, can one just use a standard power bar with a switch on it to switch on and off power to the speakers?
I have my eyes on Hans Zimmer's monitor of choice the Quested VS2108. I presume that these would make suitable candidates for flush mounting due to their shape, front porting, low profile heat sink and the ability to attenuate low frequencies to deal with correcting the power balance issues associated with flush mounting. I believe the options are only -9dB, -3dB, 0dB and +1dB of low-frequency adjustment at 40Hz as this feature is designed for when using a subwoofer. I believe and hope this should still be fine.
Finally, will I find any problems with flush mounting the Left, Centre and Right speakers in my front wall, but placing my Left Surround and Right Surround monitors on stands? My room dimensions are L 6.85m, W ~ 3.2m, H ~ 2.5-3.5m (I will be building an interior ceiling.
I know I am probably covering too much information in this simple query my main curiosity is whether my first idea has any merit. Rest assured that I will be making my own thread to discuss specifics of my room design shortly, so please feel free to ignore the questions regarding the monitors! :)
Thanks very much!
Love this forum
Karim x
Hi Karim, and Welcome! :)
You could do that if you wanted to, yes. It wouldn't look so neat as with John's system, but it would still work OK acoustically.I was wondering if there would be any negative effects on the effectiveness of the baffle if a separate panel was mounted in front of the lower baffle panel.
That's correct: It is! :) The entire section under the shelf and behind the absorber box, is a bass trap, where the active elements are "hangers".and that everything from the speaker down is one big broadband absorber -
Yes, you can do that too. Not a problem. Just remember to turn your speakers on AFTER all your other gear is already running, and to turn them off BEFORE you turn of anything else.Secondly, with regards to using active monitors with switches located on the rear of the speaker cabinets, can one just use a standard power bar with a switch on it to switch on and off power to the speakers?
Speakers do not have to be front ported in order to be soffit-mountable. It is entirely possible to soffit mount rear-ported speakers. Here's an example: www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=20471 Those are Eve Audio SC-407s, which have rather large ports on the rear. And yet, there they are, soffit mounted and performing spectacularly... :) So you don't need to limit your search to just front-ported speakers or sealed boxes. As long as the soffit is designed correctly and the right precautions are taken, there's no problem with that. The heat sink is also not an issue. You just need to leave enough space at the rear of the speaker enclosure box (inside the soffit) to ensure that there is sufficient airflow over the heat sink, to keep things cool. The V2108 does indeed have a low cut switch on the back, but it does not do what you need for soffit mounting. That switch is meant for use with a sub, as you pointed out, and it rolls off below 40 Hz., according to their documentation, it seems (although it's not very clear!). But that's not what you need. With a speaker that size, the baffle step response enter frequency will be fairly high, probably a few hundred Hz, and that's where you need to start the roll-off, in order to correct the power imbalance (or rather, in order to "uncorrect" the power imbalance correction that is no longer needed!). So that switch won't do what you want. However, there's more than one way of skinning a cat, as the saying goes! Any good quality parametric or semi-parametric equalizer that has a low shelving filter on it will do the job. As long as it has enough adjustment in the frequency setting to cover the likely range, and at least 6 dB of roll off, that should be fine. If you also get to select the steepness of the roll-off, that's a nice bonus.the Quested VS2108. I presume that these would make suitable candidates for flush mounting due to their shape, front porting, low profile heat sink and the ability to attenuate low frequencies to deal with correcting the power balance issues associated with flush mounting.
Ahhhh! So this is a 5.1 room! Hmmm... that's a little more complex... You'll need to treat the room rather differently, and design your soffits and the geometry for the surround speakers with great care, to prevent rear-surround reflections from getting back to your ears from in front if you... 5.1 control rooms are just a tad harder to design than plain old 2.0 and 2.1 rooms. Will you be running a bass management system? (The answer to your question is "yes". You can put your surrounds on stands, as long as the stands are massively heavy, and correctly located, and you have the right treatment on the walls next to them, and the front walls.Finally, will I find any problems with flush mounting the Left, Centre and Right speakers in my front wall, but placing my Left Surround and Right Surround monitors on stands?
That's rather confusing! So what will the height of the "interior ceiling" be? Will it be 2.5m, or 3.5m? ANd how will you prevent it from acting as a three-leaf system, in combination with the real isolation walls (which I'm assuming will be two-leaf MSM walls?).My room dimensions are L 6.85m, W ~ 3.2m, H ~ 2.5-3.5m (I will be building an interior ceiling.
, actually, not enough info! A diagram of your room, showing the proposed layout, the proposed isolation system, the proposed treatment, and the proposed soffit design would help a lot to understand what you are trying to do. So please do start your own thread with that information in it, as well as all the other information. I look forward to seeing that! - Stuart -I know I am probably covering too much information in this simple quert
Thank you very much for your answers, Stuart! The reason I have no exact height for the interior ceiling is that it is an aspect of the design which I am searching for advice on The ceiling could be anywhere from 2.35 to about 4 meters high in this particular room! (It is a converted barn with an attic space I could make use of for a higher ceiling) Having said that, the main reason I am not starting my own thread yet is that I do not know if I will definitely be in this room yet. When I know exactly where I am going, I will be sure to inform you all of what the details are so I can properly design my space :) Much love, KarimHi Karim, and Welcome! :) please do start your own thread with that information in it, as well as all the other information. I look forward to seeing that! - Stuart -
Anyone know the link to the new SAE site for this material? Or any similar material whatsoever? Or maybe someone has it saved in any way or form and can share? John, maybe you have it uploaded somewhere to download? Thanks.read this Rosie http://www.saecollege.de/reference_material/index.html cheers john
Here you go: http://johnlsayers.com/Recmanual/index.htm A little late, but better late than never! :) - Stuart -Anyone know the link to the new SAE site for this material? Or any similar material whatsoever? Or maybe someone has it saved in any way or form and can share? John, maybe you have it uploaded somewhere to download? Thanks.read this Rosie http://www.saecollege.de/reference_material/index.html cheers john
Two questions: 1)With open back box, any special requirements to decrease leakage to Live Room? 2)I've seen a couple well known studio builders have boxes enclosed except for the front. Those monitors are passive. Cooling is not an issue in these designs? -MarkFor acoustics and cooling: No, no reason at all. But for structural integrity there's a good reason: that's the only piece that keeps the box square. That might or might not be an issue, depending on the overall design. - Stuart -is there really any point in attempting to enclose the rear panel of the mounting box
Do you mean speakers with ports on the back side of them? The leakage to the live room is resolved by building decoupled inner and outer leaves. The soffit mounting of the speakers is inside of your inner leaf and therefore the speaker design will not change the isolation.1)With open back box, any special requirements to decrease leakage to Live Room?
The designs you're mentioning are soffit mounted speakers. Cooling IS an issue and if you scroll up in this thread and see an image posted of John's soffit design, you'll notice the ventilation arrows in the image. Greg2)I've seen a couple well known studio builders have boxes enclosed except for the front. Those monitors are passive. Cooling is not an issue in these designs?
Greg, Thanks for answering. Yes, I am speaking about flush/soffit mounted monitors. In designers that build CR and LR with say a window between. Wouldn't not having MDF on the back increase leakage (since there is not a true inner/outer leaf? Also, yes I understand about John's image. What about someone like Wes where no ventilation is visible and he uses completely enclosed MDF box (except front). How is that happening? -MarkDo you mean speakers with ports on the back side of them? The leakage to the live room is resolved by building decoupled inner and outer leaves. The soffit mounting of the speakers is inside of your inner leaf and therefore the speaker design will not change the isolation.1)With open back box, any special requirements to decrease leakage to Live Room?The designs you're mentioning are soffit mounted speakers. Cooling IS an issue and if you scroll up in this thread and see an image posted of John's soffit design, you'll notice the ventilation arrows in the image. Greg2)I've seen a couple well known studio builders have boxes enclosed except for the front. Those monitors are passive. Cooling is not an issue in these designs?
There is ALWAYS a complete inner-leaf and a complete outer-leaf. It's a matter of perspective: If you stand in the control room, looking towards the live room, then there are two "leaves" between you and the LR: the first one is the inner-leaf of the control room, and the second one is the inner-leaf of the live room, but from your point of view that second one is the OUTER-leaf of the CR. So, two leaves. The speakers are ALWAYS mounted completely inside the control room. So, you have the complete CR wall around the room, then you have the speaker "soffit" in the room, butting up against the inner leaf. The speaker is mounted in the soffit, poking through the front baffle of the soffit, but behind the speaker, is the inner-leaf wall of the room.In designers that build CR and LR with say a window between. Wouldn't not having MDF on the back increase leakage (since there is not a true inner/outer leaf?
There is ALWAYS ventilation, even for passive speakers. It might not be visible, but it is there. Take a look at the corner control room thread, for example. Here's a view of his almost-completed control room, showing the soffits: As you can see, there is no visible ventilation, but those things certainly are very well ventilated! There's a ventilation path that starts in the hnager section below the speaker shelf, then goes up past the rear face of the speaker, and around the sides, then continues up out the top, through the upper hanger section, and into the HVAC return vents, which are directly above the soffits. An earlier view of the soffit interior, before the insulation went in and the baffles were put on: You can see the ventilation path up the rear of the soffit. That remains open, even when the insulation is in. So even though the ventilation might not be visible, it is still there. It must be. You can't have a device that is dissipating hundreds of watts of power as heat, without ventilation to remove that heat... That's all part of the soffit design: it's not just about speaker acoustics, but also about room acoustics, mechanics, ventilation, and isolation, among other things. - Stuart -What about someone like Wes where no ventilation is visible and he uses completely enclosed MDF box (except front). How is that happening?
Sorry, i dont kow if i missed something.
Why there is a relative thin frontplate on the shematics like a plywood panel ?
Is more mass better for the soffit wall ?
So maybee three layers of gypsum or more wood ?
Or whats the reason to only use 5/8 plywood ?
Which schematic are you referring to? The thread is 15 pages long, with over 200 posts in it... Are you referring to John's diagram on page 1? If so, I'm not sure what you mean by "thin frontplate". The front baffle on that is 1 1/4" thick (about 32mm), with one layer of plywood plus one layer of solid timber. That doesn't seem "thin" to me. Also, that's just a basic conceptual outline, showing the minimum that will work: Most soffits are built heavier than that.Sorry, i dont kow if i missed something. Why there is a relative thin frontplate on the shematics like a plywood panel ?
Yes.Is more mass better for the soffit wall ?
Personally, I don't like using drywall (gypsum board) for soffit baffles, because cutting the hole in it leaves a brittle edge that can flake more over time, with the vibration and pressure. I know some people have done that, but I prefer to use tough materials, such as MDF and high density solid wood.So maybee three layers of gypsum or more wood ?
It does not HAVE to be only 5/8" plywood! You can use whatever wood you want, as long as it will do the job. As I mentioned, that's just a conceptual design, which can be modified to fit specific cases. - Stuart -Or whats the reason to only use 5/8 plywood ?
I was refering to the soffit picture posted from John on site 1 and also on the 3rd post on this site (15) There is written 5/8" Plywood wich is about 1,5 cm. The bottom part of the soffit under the speaker So i thought maybee its to thin to hold the bass frequency inside.Which schematic are you referring to? The thread is 15 pages long, with over 200 posts in it... Are you referring to John's diagram on page 1? If so, I'm not sure what you mean by "thin frontplate". The front baffle on that is 1 1/4" thick (about 32mm), with one layer of plywood plus one layer of solid timber. That doesn't seem "thin" to me.
Ok thank you, i thought maybee there is a reason to not go with more mass.Also, that's just a basic conceptual outline, showing the minimum that will work: Most soffits are built heavier than that.