Hybrid Superchunk-Soffit

Hi everybody Because of the very small dimensions of my room, there is a very small space to put the monitors and the superchunk just behind. So, I'm wondering of mounting the monitors on heavy column made of bricks or cement block and to place it.. inside the Superchunk, like this : This would be a kind of "soffit mounting", because of all the wool all around the monitors, but without a bezel and all the structure all around. What do you think about it ? Does the bezel will produce any phase distortion or frequency problem due to it small dimensions ? The idea here is to avoid to have a big bezel -> expensive and heavy plate of wood which need an heavy and rigid support so as to avoid any vibrations. Moreover this would avoid to make a correction for the monitors, because of the 6dB boost in the low frequencies produced by an "infinite wall" bezel. Your suggestions are welcome ! thank you :wink:

We have to discuss the term "soffit" I think. WHAT do we mean when we say "soffit" mounted speakers. I prefer "flush" mounted, but it's just semantics... The whole idea of soffit or flush mounted speakers is, indeed, the infinite bevel. You get that by extending the speaker's front case with a non-absorping material. So, no, your idea is not "soffit" mounted. But, it's a good idea to have it mounted in a basstrap (suppachunk!) IF you're gonna place the speakers in the corner (which I can understand if the room is small). There's lot's of low-end frq hanging around in them corners, putting a speaker in that hot area is generally not a good idea. So, yeah, covering it up with as much wool as possible would be a very good idea. You might even wanna place a denser material in front to keep it from absorbing too much mid/high frq AND have some sort of bevel anyway. Why not make it a glass-soffit :)

Hi Ro ! I understand now why it can't be called a "soffit" :wink: ... so, what about having no bezel at all, just have wool all around the speaker, with a "joint" made of foam to fill the space between the wool and the speaker ? Another idea : to place the monitors inside a wood box, filled with insulation (such as in a classic soffit mounting) ? like this : All the superchunk would be wrapped with a clothe. The idea here is also to have the cheapest design as possible ...

Why would you put it in a box? What's the idea behind that? Are those monitors active or pasive powered?

Hi Ro The idea comes from what I've seen for the soffit mounting.. I saw a schematic where the monitor was put into a wood box filled with insulation, and 2 hole on the rear for the ventilation. The monitors I use are EVENT TR8 (which are powerful active midfield monitors and can generate lots of low frequencies). I'm afraid that to put the monitors only in the superchunk would not be enough to attenuate the low frequencies. Oh, I should also tell you that I'm producing house music.. so lots of very low frequencies (30Hz to 60Hz) are common :D In fact, the problem for me is to have a cheap and efficient solution. Moreover, time and money are limited (like lots of people :lol: ). So, after reading the forum, two kind of solutions seemed to be adapted for my problem: - to place the monitors on columns just ahead of the superchunks -> cheap, fast and easy to build / take lots of space, maybe could produce excessive problems of bass reflexions. - to place the monitors inside a superchunk, like I propose here. -> would cost more than the first solution, more complicated and longer to build, but could save space and avoid to much bass reflexions. However, in that case, the monitors would make an angle of 50°, or more, from the center line.. I'm not sure it should be good for having a good stereo! what do you think about that? thanks :D

The monitors I use are EVENT TR8 (which are powerful active midfield monitors

Then your current design has a problem: Active monitors need cooling, which implies free space and air flow. But your design calls for a very thick blanket, basically! You would need to modify it somehow so that there is a free passage for air up past the back of the monitors, right from down near the floor somewhere, to up near the ceiling somewhere. Take a look at John's design for soffits to get the idea. Think of a kind of duct a couple of inches deep and as wide as the back panel of the monitor, with a clear, open, free passage for air to move through it and cool the rear of the monitor. - Stuart -

Hi soundman ! yes, you're right, something like this would be ok ?

Yeah, something like that should do the trick, but you'll also need a hole coming out the front of the soffit at the top, to let the hot air out, back into the room! John usually puts his vents a couple of inches down from the ceiling, as far as I recall. - Stuart -

Oh yes, I forgot to draw it, but the ceiling would be just 10 cm higher than the top of the superchunk... but that's a good idea too to make a hole in the front and to make the superchunk as high as the ceiling ! However, i'm still wondering about the problem of absorption of low frequencies inside the superchunk. Do I need to put the monitors inside a tight and strong wood box (as usually on soffit mouting)? What do you think about the problem of no bezel? thanks for your advice ! :)

Oh yes, I forgot to draw it, but the ceiling would be just 10 cm higher than the top of the superchunk... but that's a good idea too to make a hole in the front and to make the superchunk as high as the ceiling !

Yeah, you do want to take the insulation right up to the ceiling. That's where you get the best acoustic effect, so certainly do it that way. I think you'll probably need to build some kind of "chimney" around that airflow space, perhaps with plywood, drywall, or something like that. You want to make sure that nothing blocks the airflow, for example if some of the insulation shifts during installation, and you didn't notice.

However, i'm still wondering about the problem of absorption of low frequencies inside the superchunk. Do I need to put the monitors inside a tight and strong wood box (as usually on soffit mouting)?

Well, yours isn't a soffit! Like Ro implied, if it's not going to be a soffit at all (which yours isn't), then I don't see any need for boxing in your speakers. Your situation is far more like free-standing speakers on stands, and you don't box those in! About the only reason I can think of for a box is to keep the wool from touching the speakers, but that doesn't seem to be an issue with your design: you have the sides and back clear of the wool. I'd say just put your speakers on really dense, solid, heavy, massive stands (like the brickwork columns that you show: that's good!), and decouple the speakers form the stands as well as you possibly can. I guess you are going to build some type of frame around the entire trap, and cover it with acoustic cloth, to hide the "ugly stuff"? If so, then you'll need to figure out how to make a frame around the front of the speaker for the "hole" in the middle of the cloth where the speaker will be. You can probably attach that from to the stand somehow, taking care that it does not actually touch the speaker. You might need some sort of shelf just above the speaker, though to support the weight of the insulation above. You probably don't want all of that resting on your speaker. Especially if you need to take the speaker out for some reason... - Stuart -

Here's what's bother me a bit:

Phazinhead wrote:

The idea comes from what I've seen for the soffit mounting.. I saw a schematic where the monitor was put into a wood box filled with insulation, and 2 hole on the rear for the ventilation. The monitors I use are EVENT TR8 (which are powerful active midfield monitors and can generate lots of low frequencies). I'm afraid that to put the monitors only in the superchunk would not be enough to attenuate the low frequencies. Oh, I should also tell you that I'm producing house music.. so lots of very low frequencies (30Hz to 60Hz) are common :D

The monitors CAN provide much low-end, that's okay. It depends on whatever feed goes into them, house music you say. Okay, lot's of low-end as you mentioned. But you also wanna capture the low-end with your suppachunk. I don't really understand your ideas and thoughts behind that. I mean; you want lowfrq but need it to be controlled. Why are you putting your monitors in the corners inside a superchunk? That's not gonna help much!

In fact, the problem for me is to have a cheap and efficient solution. Moreover, time and money are limited (like lots of people :lol: ). So, after reading the forum, two kind of solutions seemed to be adapted for my problem: - to place the monitors on columns just ahead of the superchunks -> cheap, fast and easy to build / take lots of space, maybe could produce excessive problems of bass reflexions. - to place the monitors inside a superchunk, like I propose here. -> would cost more than the first solution, more complicated and longer to build, but could save space and avoid to much bass reflexions. However, in that case, the monitors would make an angle of 50°, or more, from the center line.. I'm not sure it should be good for having a good stereo! what do you think about that? thanks :D

I would atleast go for option 2. Put the monitors in front of the trap. That way your monitor is free-standing and can exhaust it's heat. You'll also benefit from having more volume in the basstrap (much more!). You room is tiny, I understand, but placing them monitors in the corner isn't the best solution. Especially when dealing with just low frq as you mentioned. Oh, don't worry about bass-reflection. There isn't much. Mids and Highs reflect easy, lows don't. Put your speakers on heavy stands and build good bass-controlling-devices (traps).

Thanks guys for your replies !!! it help me a lot !! this is exactly what I was traying to know : what was the best solution to have controlled low end with a small room and small space. The EVENT TR8 can go very low and my aim is not to have a "sound system", I mean I don't want to make a night club in my room, but just to have a controlled and precise low end, so as to be able to work it, not to have a huge and big bottom to make the shake the walls :lol: But in any case, placing the monitors on heavy stands in front of superchunk and bass trap is the most simple, easy and cheap solution.. so let's go for this ! ... mmm a last question : what about a real soffit/ flush mounting in a such small room (if you want to see what it looks like, check the layout there : viewtopic.php?f=3&t=11357&start=45) thanks again !

to have a controlled and precise low end, so as to be able to work it, not to have a huge and big bottom to make the shake the walls

Well, coming full circle here: What you mention there is EXACTLY what real soffits do!!! Not the type you were trying to design here, but real flush mount soffits with large, massive, dense, flat front panels)! They focus and tighten up the bottom end amazingly, giving you much better control. Of course, if you flush mount (soffit mount) then you do need to have something that can roll of the bass response of your speakers by 6 dB at the bottom end, since the soffit WILL boost the bass by 6 dB: it forces the speaker to radiate into half-space, so according to the laws of physics, that will give a 6dB boost. Many active monitors already have controls on the back that allow you to dial in 6dB roll-off, for exactly this reason. If yours don't, then a good parametric equalizer will do that for you, accurately. Get one that introduces the least amount of phase change.

what about a real soffit/ flush mounting in a such small room

My control room will be very small too (2.57m high, 2.26m wide, 2.81m long), and I will be building flush-mount soffits for my speakers. My soffit panels will be made of concrete, since that is a very dense material that can be molded to the exact shape I need, and it doesn't need to be very thick due to the high density, so I can gain a couple of precious millimeters of room space like that! I'll just build a frame the size and shape that I need, and pour concrete in it. Bingo! Instant soffit panel! So yeah, you can do flush soffit mounts in a small room. I'll be using some of the space below the soffits for a bit of bass trapping, and the space between them for absorption. My bass traps will be in the rear wall-wall corners, the rear wall-ceiling corner, the side wall-ceiling corners, and part of the front wall-ceiling corner (the part between the soffits). I expect that will be enough! Check my design thread later this weak, and there should be an updated model there, with all the details of what I'm planning to do. - Stuart -

Hi Soundman, thanks for all ! Yes, the soffit mounting is the most expensive and complicated but this is what allow to have the best control of the sound... and this is why I'm asking all thoses questions, I'm trying to evaluate how much it is more efficient than mounting the monitors on stand... my budget is a bit tight at the moment and I haven't plenty of time too... this is why I'm trying to know if building a soffit is really necessary for the result ! The correction of -6bB for low frequencies will be included in the monitoring system I'm going to design for controling the monitoring between the pair of EVENT TR8 which will be mounted in the soffit, and the former pair of Tannoy REVEAL which will be only on stands. I'm going to look at your thread now :)

"Soffit (from French soffite, Italian soffitto, formed as a ceiling; directly from suffictus for suffixus, Latin suffigere, to fix underneath)" There was a time when speaker monitoring was installed in an overhead cavity built downward and as an extension from the existing ceiling, decades ago. We still say soffit, and it is still an incorrect orientation. Just a little history I learned :)

We still say soffit, and it is still an incorrect orientation.

Very true! Ro reminds us of something like that every now and then. It should really be "flush mount", not "soffit mount", but old habits die hard, as they say... It should also me MSM wall, not MAM wall, but lots of folks still call it MAM. And of course, it really should be "aluminium", not "aluminum", but try telling that to the yanks.... :) - Stuart -

All true. In my line of work if you say soffit, people look up, not towards the corner of the walls. It's like calling a rafter a joist or a joist a stud, then Ro would say, "semantics." :idea: