John Sayers' Recording Studio Design Forum Archive

Hello All - I am have been poking around this site for years and have finally decided to become a member and seek advice on my upcoming new studio build.

Basic Info:
- Basement has 7'-0" ceilings.
- Dimensions of the overall basement are 28'-10" by 23'-9" with a (3) 2x8 beams (ORANGE) sitting on vertical poles/columns (RED) down the center (lengthwise).-
- There are also 2 additional poles/columns off-center.
- I have (2) 18" subs in boxes that are 29" W x 28"D x 25" H
- Main monitors are Urie 813. boxes are 36"H x 31"W x 22" D
- Desk is an Argosy and is shown pretty close to scale in the drawing. (I am trying to swap out the two desk mounted racks with with ones that are about 6" lower and no flat top)

The room is going to be used for mixing hip hop and reggae and pop mostly, and occasional rock bands. So accurate low end monitoring is a must!
Isolation to the house above is important, My sister going to be living upstairs and want to be able to play fairly loud late at night while she is sleeping.

WALLS:
The outer leaf/soundproof wall I colored the framing BROWN. anything not colored brown is part of the soffit/internal room construction. I plan on building the walls with 2 layers of gypsum on the INSIDE of the framing (2-leaf system with this BROWN wall being 1 leaf) ).

CEILING:
The ceiling (which is NOT shown on the drawing) will be built the same way. I plan on attaching the NEW ceiling joists to the top of the NEW walls - they will have to run parallel to the existing floor joists to maximize height and perpendicular to the ORANGE beam shown. - I don't plan on using any resilient channel from the exiting joist for the new ceiling. For the second "leaf" I plan on "beefing" up the existing ceiling with the method I found on here; glueing 2 layers of gypsum, and furring strips to secure to the bottom of the existing sub-floor and beams, making the 2-leaf system between studio and upstairs.

DrumRoom and VocalBooth will both be built the same way as the control room walls - creating the 2-leafs between them.

There will also be a small bathroom crammed in under the stairs an whatever is left near the goal booth will be the "hang out" room.

Utilities will go in the other remaining space.

Finished Control Room Dimensions: H=6'10" x W=17'-6" x D=10'-11"

My main concerns are this:

1) FLANKING/COUPLING:
In order to maximize space, I had to push back the speakers - now they are very close to the existing poles/columns. My concern is how much flanking/coupling will occur between the subwoofers and the existing RED columns?? Also, is there any structural issues with putting those massive 18" air-moving subs right in between the poles? I mean, if I WANTED to demolish the whole house with speakers - thats where I'd put them lol. Also, the Urie 813 mains are right next to the poles.

Although the poles are actually located WITHIN the control room this way - I should be able to have my wall/leaf still be solid around them, and apply some soft caulk where the gypsum is cut out around the poles. So the main concern is really flanking to the existing Columns/Poles. not DIRECTLY - but within a few inches of air. Also, indirectly through the concrete basement floor, within a few inches.

2) SOFFIT SIZE:
My soffits are starting to getting sort of thin with this design as well - I dont know if this is too much of a concern. The doorway to enter the studio is right where the Sketchup Man is standing and there is basically only a 5" wall right up against the speaker which is its "soffit"

3) TRUE ISOLATION TO UPSTAIRS:
Now when it comes to "beefing up" the ceiling, without question I am going to do the areas above the Control Room and LiveRoom. The area designated as 'hang-out" room, I'm not really concerned about sound leaking into there. However, it would seem that I need to "beef up" the ENTIRE existing ceiling in order to really have a true 2-leaf system - otherwise sound would find a way through a non "beefed-up" ceiling, or even through a single leaf off there is any small hole in the existing floor anywhere.

ANy responses or other suggestion/tips would be greatly appreciated!!!!!

ROOMS LABELED AND LATEST SKETCHUP FILE!

JPEGS HERE

Hi " richroyc", and welcome!

Main monitors are Urie 813.

I think you mean "Urei" not "Urie"? But those things are monsters! I wouldn't use them in such a small room. Don't you have something more suitable?

My sister going to be living upstairs and want to be able to play fairly loud late at night while she is sleeping.

You need to put some numbers to that. You can't plug in "fairly loud" and "sleeping sister" to the equations that predict isolation! You need actual decibel estimates of "How loud will you be" and "How quite does that have to be outside". Subtract the small one form the big one, and the answer is "How much isolation you need".

I plan on "beefing" up the existing ceiling with the method I found on here; glueing 2 layers of gypsum, and furring strips to secure to the bottom of the existing sub-floor and beams,

I think you mis-understood that! The layers of drywall should NOT be glued to each other, nor to the existing sub-floor above you. Rather, they should be held in place by cleats nailed sideways into the joists, and carefully sealed all around the edges with acoustic caulk. Gluing alone is not only dangerous and not even allowed by building code, but also a bad idea acoustically.

DrumRoom and VocalBooth will both be built the same way as the control room walls

Drum Room? As in live acoustic drums? And "Sleeping Sister" is right up stairs, just above that subfloor? OK, so you need major isolation here. Drums are loud, easily hitting 110 dBC. "Sleeping sister" is quite, and probably needs less than 40 dBC to remain "sleeping", rather than "yelling". That's a MAJOR undertaking. That's about 70 dB isoaltion!!! pretty much the limit you can expect from a very carefully designed, very carefully built isolation system. 70 dB is roughly the flanking limit for a typical house, unless you take same major (as in "expensive and complicated") steps.

All of a sudden, this is looking to be a lot bigger project than you were imagining.

Finished Control Room Dimensions: H=6'10" x W=17'-6" x D=10'-11"

That's a REALLY low ceiling, and a very small space, especially considering the gigantic monitors you want to use. I'd really suggest that you might want to rethink that.

The room ratio is also not so good, at 1 : 1.59 : 2.56. That's outside the Bolt area.

In addition, your diagram shows that you have the room set up "sideways", which would be a major mistake for such large speakers. They should be facing down the longest axis of the room, not across the shortest one. With only 11 feet total distance between front wall and back wall, your mix position would have to be about 4'6" from the front wall, and thus only 5'6" from the rear wall: that puts the reflections from the rear wall at about 11ms, which is well within the Haas time. Not a happy picture, if you hope to get a clear sound-stage with excellent stereo imaging.

And with an Argosy desk, I don't see you being able to get so close to the front to start with! From your diagram, it looks like your head is either right at the 50% mark (worst possible location in the room, for modal response), or actually even closer to the rear wall than the front wall! Bad idea: lots of psycho-acoustic smearing or your directional clues going on there. You also seem to have your speakers mounted up high and tilted down, which only makes matters worse, and increases first order reflections of the console/desk.

I would make the room much bigger, and turn it 90°, so the speakers are firing down the long way. And put the door some place where it wont be messing with your acoustics, too.

My concern is how much flanking/coupling will occur between the subwoofers and the existing RED columns??

Probably not a lot, depending on what those columns are made of, but still plenty to blow away your hopes of 70 dB isolation. You'd likely have to soffit around those, to keep them outside of the wall cavity. I had to do that once for a place in Canada. It's a pain, but it worked OK.

Also, is there any structural issues with putting those massive 18" air-moving subs right in between the poles?

Unlikely. There's actually not a lot of energy in a sound wave. It's unlikely that you'd be putting out much more than about one watt per square meter of actual acoustic energy: not even enough to warm your coffee. It SOUNDS plenty loud, yeah, and you might be ´pumping several hundred watts into those beasts, but in real energy terms not much is coming out. Speakers are very, very inefficient at turning electrical power into sound power. You need very, very large surface area and major amounts of power before you can start literally "lifting the roof".

Although the poles are actually located WITHIN the control room this way

Ummm... nope! Sorry. That can't happen. If they are inside your control room, then you have no isolation. You are basically limited to way, way less than what you need. The poles have to be outside of the control room: either in the MSM cavity, or better still, isolated from that cavity by soffiting around them.

My soffits are starting to getting sort of thin with this design as well - I dont know if this is too much of a concern.

Yep, it is. Soffits have to be massively rigid, and have very thick, heavy, massive front baffles. The larger and more powerful the speaker is, then larger, thicker and more rigid the soffit needs to be.

The doorway to enter the studio is right where the Sketchup Man is standing and there is basically only a 5" wall right up against the speaker which is its "soffit"

Your speakers are nearly 3 feet wide (31"). Adding 5" isn't notably useful. Ideally a soffit should add substantial area around the speaker, hopefully at least twice as wide as the speaker. Take a look at how 813's are normally soffit-mounted: there's stacks of real estate around them.

it would seem that I need to "beef up" the ENTIRE existing ceiling in order to really have a true 2-leaf system - otherwise sound would find a way through a non "beefed-up" ceiling, or even through a single leaf off there is any small hole in the existing floor anywhere.

Correct. And since you need huge amounts of isolation ("Live drums" - "Sleeping sister"), you will need huge amounts of mass to beef up that floor, plus a very large air gap... which basically means that you'd never be able to record drums in there anyway. There needs to be a large distance between your overhead mics and the ceiling above to avoid reflections, phasing, comb filtering, and all the other nasties associated with nearby boundaries. with a 7 foot ceiling, you already can't do that, but by the time you have enough air gap and mass to get the isolation you need, your ceiling will be down way lower than 7'. More like 6'. There simply is no way to get good overhead mic'ing like that.

If you need to track drums, then I'd look for another place to do that. I just don't see it happening with such a low ceiling, and a need for major big-time isolation. How about building a stand-alone drum booth out in the back yard? Or maybe taking out the basement floor, digging down another couple of feet, then pouring a new slab down there?

JPEGS HERE

I only see one leaf in those. Where's the other leaf?

Sorry I don't have good news for you here: I'm sure you didn't want to hear all of that! But that's what you came here for, really: to get an honest opinion on your prospects for achieving what you want. Unfortunately, the prospects aren't so good.

That's not to say that you can't use the space you have: you sure can! If its the only space you have, then that certainly is better than having no space at all. But if that's the case, then you have to lower your sights, and aim for a more modest outcome. Major isolation such as tracking live hip-hop and pop drums right under "sleeping sister" is just not going to happen, realistically. You can get good isolation, but unless your sister is very tolerant, or stone deaf, she's not going to be happy about the results. And neither are your customers going to be amazed by the clarity of your drum tracking: with OH mics just inches from the ceiling, that isn't going to happen either.

Ditto for the control room: 30 year old monster vintage speakers that are way too large for the room, and beautiful desk that is way too large for the room, a low ceiling, short axis aiming, and untenable mix position, do not bode well. Yeah, you likely can work to a certain extent in such an environment, but it won't be anywhere close to world-class, and your mixes are not going to translate well.

Sorry to be the bearer of bad tidings, but that's the reality of your situation, the way I see it.

- Stuart -

Stuart - thank you so much for the in-depth reply! I was hoping you would chime in!

Lol yes I mean Urei, they are not knock-offs like my Rolecks watch lol.

I had a feeling I would have to rotate the room 90 degrees (the long way).

Here's why I originally oriented the room this way - I work at another basement studio that has 18" subs, Urei 813's and same height ceilings, and the room is also oriented the wide way. It's the reggae artists Shaggy's home studio. Most of his his hit songs were mixed in that room, and the room sounds phenomenal. And I really like the wide orientation of the room. The oversized speakers just work in that room - For this reason I am somewhat stubborn about keeping the big 813's (and the 18" subs) as part of the design (although I'm sure you are correct; they are oversized for the room). I'll quote the producer who works over at that other studio "there's always a volume knob" lol.

I attached a photo of that studio - this is before they put the Urei's in. Its the pic with the Control 24 in the board.


Redesign:
However, I do understand the logic in orienting the room the long way - So I'll digress on a wide room and sketch up an new design with the room rotated 90 degrees and I'll try to eliminate most of these issues, I'll keep the columns OUTSIDE the control room walls.

Low Ceilings:
Yes I know my ceilings are VERY low - and financially I don't think digging into the foundation will be feasible. I am well aware of the drum overhead issues as I deal with them now in a drum room that has 6'2" ceilings!!! I always tell my clients to track drums in another studio and bring the tracks back but I DO like having the option close by, and I also like to have a place to jam with friends. Drum tracking is last on my list of things I need this studio to be able to do, but mixing is the top of the list.

Speaker tilt:
I did originally have the speakers tilted down about 5 degrees but after realizing how low they are, it doesn't make sense, they will stay straight. (along vertical axis)

A few things to clarify regarding isolation to upstairs;
1) Tracking drums will have to occur while my sister is not sleeping. This is not an issue drums tracking is less than 1% of the work I do.
2) Using the 18" Subs and Urei's may have to be limited to when my sister is not sleeping (I have NS-10's for near fields and late night stuff)

A few questions:

1) Ceiling beef-up"
for beefing up the ceiling, is there anything that goes in between the existing subfloor and the gypsum? just firmly held in place by the cleats and caulked around edges? no air space correct? the air space will be below the gyspum layers (in the depth of the existing joists) and above the new ceiling.

2) Room Ratio - I guess I did something wrong but I thought I was at the 1 x 1:62 x 2.62 golden ratio?

3) Soffit construction:
I still have a lot of research to do on here before I go posting tons of questions. But my main confusion is this: Do I decouple the speakers from the front soffit wall? Is this achieved by building a very heavy (possibly concrete) speaker stands, and then building the soffit, close but not touching the speaker or stand? My confusion comes from seeing many pictures of Urei 813 mounted in soffits, but there is space underneath them. Obviously there is no stand. (see photo and this link - http://www.malvicinodg.com/wp-content/u ... tudios.jpg

4) Air Gap and MSM above ceiling:
I was planning of installing the new ceiling as high as possible to the bottom of the existing joists. I achieved this in my current studio drum room by running the ceiling support beams parallel to the existing floor joists, but up in between them. (See sketch) this should give me about 7" air gap. The new ceiling is 1/2" below the joist. What kind of isolation can I expect with this? (note: I'd be using 2 layers of 5/8" gypsum for both "beef-up" and new ceiling. Do I need to have less "beef-up" in order to match the mass of the new ceiling to the existing floor? for example: 1 layer of gypsum + subfloor = mass of new ceiling?

This design was incomplete and really only showed the control room with no indication of where the other walls would be. I'll make sure I give a clearer picture on the next sketch up file.

I have more questions regarding why the existing column/Poles cant be inside the control room but I wont get into that now since with the new design I will try to keep the poles out of the control room.

No news is bad news as long as I get it BEFORE I build anything lol. You should see my current setup - talk about face-palm (I have the Urei's free standing in a smaller room lol.) Thanks again Stuart you advice is priceless!!

I also attached a pic of my current set-up. I really wanted to get away from those Urei's being so close to eaachother.

If you open the Photos in a new tab they will not be upside down

- Mike

See attached jpeg's of the new layout. I oriented the room lengthwise.

There were a few other things I added, I show the doors and a bathroom. There are also existing waste lines that I have to avoid there will be a new waste line for the new bathroom. They are shown in orange. They lead to a waste trap that the plumber told me needs to be accessible - so I built the wall around that and will put in an access door.

Questions regarding Room Dimensions:
1) Bolt Area - I don't know where I got those other ratios from (its the internet so it must be right?) but I see now how to use the Bolt area chart. My question is; are all areas withing the chart good? In other words - if I am closer to the center of the Bolt Area, is that better than being right near the edge (but still within) the acceptable area? I am just trying to maximize my room size.
2) Low Freq Mode Chart (Trevor Cox 2004) I am also trying to be within one of the dark spots on this chart. My question here is also how important is it to be to one of hose dark areas (areas with the least modal imbalances). I know I will be doing a fair amount of bass trapping so I am just wondering how important this chart is. The room size also become an issue if I follow it too closely.
3) Sacrifice/Trade-Off: Its seems impossible to achieve a Bolt Ratio room AND a 38% listening position. If I make the room longer, I can be sitting towards the front 38%, but then my room is outside Bolt Area. If I make the room withing Bolt area - I am sitting at around 50% - Which is more important?
4) If Soffit front wall is massive - where is room dimension measured from? Do I take my Bolt Area measurement from the front soffit wall? Or from the "shell" outer control room wall, behind the speakers? There is about a 3'-2" difference.
5) any suggestions with walls, angles, room orientation etc… i will need a camera feed to the vocal booth with this setup - I have room to mount a nice flat screen in between the mains since there is not window.

Hello All!

Just an overall update - I've started demolition in the basement (there was an old bar and some areas had 3/8" gypsum on the underside of the floor joists - typical basement ceiling finish stuff) not too much bad stuff up there as far as holes/bad subfloor, pipes - or even electrical wires) There are SOME plumbing pipes which I was already aware of that need re-routed and I have already met a plumber there for an estimate.

Structural engineer also gave me the go-ahead to add 2 layers of 5/8" for "beef-up" wherever it needs.

I am adding a dormer on to this house which will allow me to remove the washer and dryer from the basement, and put it upstairs - clearing up precious studio space. So I'm pretty busy planning and hiring people for that as well.

I am having my 100 AMP existing electrical box (which is basically fully packed with breakers) upgraded to a 200 AMP service with plenty of spare breaker spots for new studio stuff.

So now onto the questions:

So there are some areas where my outer leaf wall will be angled. My understanding is that this outer leaf wall should extend all the way up to the existing subfloor (with beef up added) - which is also part of the outer leaf - creating an airtight seal between wall and ceiling.

I've attached a photo of my latest sketch up design.

The new inner leaf walls and ceiling will not be touching the existing floor joists or subfloor in anyway. This is how I plan on supporting the new ceiling:
Is this the right idea for the ceiling? Can I reduce the 1" space to even less? a 1/2" taller ceiling would help me in my situation (7'-0" bottom of existing floor joist). 1/2" space would leave me with 4-3/4" total airspace between the 2 leaves.

So the question is: Where the outer leaf wall is angled - and it goes all the way up to the existing subfloor - what sort of treatment should I do? See this attached sketch illustrating what I mean.
In the sketch I suggested using backer rod and acoustic caulk along the top where the wall meets the subfloor - and also around the existing floor joists. I guess I'll have to notch the gypsum on and angle instead of straight, since the wall is angled. Is this the right idea for the outer leaf wall?

There's also the question of what to fasten the vertical 2x4 studs to. See the backside of that same outer leaf wall:
Does this wall need a top plate? In other words a horizontally run 2x4 like the inner leaf walls? I'm assuming I don't want to screw through the "beef-up" and into the subfloor.
Or can I just screw the vertical 2x4's into the existing floor joists? Come to think of it - I guess this issue will be throughout the whole outer leaf and not just on the angled portions.

I am just trying to visualize what will actually happen here and how to support the top of the outer leaf - both where it run parallel to the existing joists, and where it runs perpendicular to the existing joists. The picture is not 100% clear for me yet

To fully realize the new ceiling there is also the large support beam that runs the length of my basement. This is going to end up pretty much in the middle/back of my control room. You can see them running in the center horizontally in the first photo. I will have to build the ceiling around that. Here is what I had in mind for that:

At the walls: At the vertical columns (there are 2 in the control rom): And heres what I was planning for the regular part of the ceiling where there are no columns: Any help would be greatly appreciated - I am really happy with this current design/layout despite there being COLUMNS and a BEAM...IN the Control Room.

I like the big size room and I'm hoping I'm not making any major errors here with the planning.

Thanks in advance anyone who can help.

My next post will have a potential major serious problem to address but I need a picture to accompany the question so I will wait until I have that. I have a feeling it may be more of a local code type of question so that why I am scared…..

One thing at a time...

Ok - I was just over at the house for a few hours doing some clean up and more demolition.

Here are 2 photos of the underside of the existing subfloor:
Question - am I screwed?!?!?

All those angled boards that make up the subfloor are probably tongue and groove - but do they require calking/plastering?

Also there is the issue of the many many many many NAILS coming through. I'll hardly be able to firmly press the "beef up" layers to that!

I'm assuming I can't just go and hammer those nails through as they are fastening the floor in place, plus I'd push up the flooring on top of that..

I'm thinking I'll need to hammer them all as flat as possible?

Any suggestions?

Thanks in advance

- Mike

ANOTHER UPDATE!!

So I heard back from the structural engineer.

I can remove the 2 pole that are in the center of my control room!!!! That is great news.

I will have to replace the existing wood beams with a steel I-Beam. This also has the added benefit of it being able to be flush with the floor joists.

I have options as far as the new steel beam.

1) staying with an 8" height, it would be a W8x58 (pretty massive). This would allow the entire ceiling to basically be flush at 7'-0"

OR

2) W12x30 (more manageable). This is a 12" tall I-Beam. The top is flushed up with the floor joists - so the bottom will hang down 4". Much better than the current 7.5" inches the beam comes down to now.

Apparently the 12" beam is cheaper (materials) and the labor is also supposedly easier but I'm not sure how much different it is then the 8" beam.

This has actually become my most urgent and pressing matter now because I need to choose the beam size immediately so I can have that added to the plans and filed with the building dept.

I realize this is not the place to get cost estimates for construction work. But does any one have any idea how much the cost difference is?

Or even the overall cost?

I am willing to spend up to about $4000 to get these damn poles/columns removed - but if it gets more than that, I may just decide to live with the poles/columns.

In the meantime I'm going to get some estimates for the beams and the installation, but if anyone has any experience or think its a bad idea to proceed with the steel beam - please let me know!

Hi All, slight bump here and a few more questions.

Its been ages since I've been on here - the house I bought (which is getting the studio in the basement) is taking way longer than expected to move into. Still a lot o work to be done. But its moving along and so I am back to the drafting board trying to get all my ducks in a row.

Right now I am waiting to get these 2 lally column removed to I can have an open floor. I will be putting in a steel flush header hopefully in the next 2 weeks.
My main question at this time is regarding the ceiling beef up. For the most part I am very luck that the ceiling has no pipes, wires or other obstructions to get in the way of the "beef up" and I've also consulted my structural engineer who approved the use of up to 2 layers of 5/8" gypsum - although I plan on only using 1 layer. In the photo you may be able to see several nails sticking down, presumably the ones used to fasten down the subfloor. I began using an end cutting plier to cut the end of the nails off so I would be able to install the 5/8" gysum flush to the subfloor. I only got a small amount done and I thought - IS THIS OK?!?!?! Will I be loosening the subfloor in some way by doing this?

Ive also attached a photo of the latest layout that I've been working on. This is about the 16th arrangement/design I've had - completely scrapped all the others.

I know there are some issues with the shape of the room - somewhere else I've read the it is bad to have the rear of the room narrower that the front - creates some sort of compression effect or something. I was wondering if anyone had any suggestion regarding the shape/layout of this design. I'm focusing on the control room at this time.





Any advice wold be greatly appreciated! Thanks

Right now I am waiting to get these 2 lally column removed to I can have an open floor. I will be putting in a steel flush header hopefully in the next 2 weeks.

Cool! Don't forget to post photos of how they do that! It's always interesting to see structural engineering at work. I had to do something similar for a studio Canada a while back.

I began using an end cutting plier to cut the end of the nails off so I would be able to install the 5/8" gysum flush to the subfloor.

Nope! Don't do that! There's a reason why the poke through. Cutting them off is not a good idea. Instead, use think planks of sytrofoam (or any other closed-cell foam) pressed over the nails, then put your "beef" over that. Get styrofoam that is just a bit thicker than the length of the nails.

IS THIS OK?!?!?!

Nope!

Will I be loosening the subfloor in some way by doing this?

yep!

somewhere else I've read the it is bad to have the rear of the room narrower that the front - creates some sort of compression effect or something.

Yep!

I was wondering if anyone had any suggestion regarding the shape/layout of this design. I'm focusing on the control room at this time.

Why do you need to narrow it down at the back? Could you flip the CR 180° so it faces the other way, to avoid that? Could you turn it 90° ans swap places with the drum booth to avoid that?


- Stuart -

Stuart!! wow that was fast!

Thanks so much - you just saved me a lot of work! and more importantly now I know the right way to do it ! God I love this forum.

The reason for the odd room shape - or at least the reason it narrows at one end - is because of the existing lally columns (shown in red). However - it doesn't NEED to be set up the way it is - on other words - i could flip it 180 degrees. I guess I went with this way because of the vibe/seemed natural - but knowing now about this compression effect things - I could work up a design with everything 180.

I suppose I could do a 90 a swap it with the drum room - but that room is much smaller. I know I show the drumset in there - and there will be times I have drums going on in there - but the rums are mostly for jamming purposes with friends - not really to record. Although that does occasionally happen. Mostly I'll be cutting vocals in that room and the main thing I want out of this studio is a great sounding control room.

I don't know if you remember Stuart, but I stubbornly insisted upon keeping my Urei 813's as my soffit mounted mains (paired with a (2) 18" subwoofers ) - so a small(er) control room may not cut it.

I'm also posting this really quickly hoping your may still be poking around the forum Stuart - normally I would wait to fully formulate the idea before asking a question - but maybe you can stop me before I go to far in the wrong direction.

I'm working on a soffit design: The ornage-ish boxes around the speaker are going to be 3/4" MDF (2 layers) lined with soborthane (5mm) on theinside, The boxes will be sitting on soborthane or neoprene pads which sit in the concrete CMU blocks. Any suggestion regarding this?

The light colored wood framing (front wall)will not be touching the MDF boxes or speakers. I am NOT planning on tilting the speakers forward at all. Height to the center of the speaker box is roughly 4'-8" ( the tweeter/dual concentric speaker is on the bottom - subwoofer on top) so they are low enough. The tweeter will be aiming right at my head while seated.

My question mainly are about the whole concept. Are these MDF boxes all it takes to direct/restrict the sound-field to a half-dome (180)? Or does the actual soft wall do some of that? I guess I'm confused about two seemingly contradictory things - I know the front soffit wall - the one flush with the speakers - should be massive and rigid. However some of the designs I see on here, directly behind a thin piece of "bezel" wood there seems to be insualtion inside of framing (open to the back behind that of filled with more insulation). Is the just deadening whatever the MDF boxes don't isolate?

I guess I'm having trouble figuring out what areas to "seal" off - if any in around the beck of this soffire wall?

any advice?

Additionally - I am NOT planning on venting these speakers in any way - I have tried numerous times to contact JBL (who I think is who to ask nowadays) about weather these need to be vented since the manual says nothing about it - but they have not responded.


In my current setup I am using the Urei 813's not soffit mounted just standing in th room on wood framed I made.


I have a temperature gun - one of those little handheld laserbeam ones. I aim it at the speaker box before I start a session (powers amps off) and then again after I used for about 10 hours straight. No difference. The boxes are cold always. Cold to the touch.

However - I am EXTREMELY prove to changing my opinion based on what I read on here so if this is really really stupid - please let me know, and I will VENT.

But for now lets assume I don't need to vent these speakers - Can that help me in some way with the design? Could I just box tightly around the speakers and the use the whole area behind the framing for trapping/treatment?

See photo of the Urei 813:
That rectangular cut out is open to the inside - a front port. But it also may help with the heat venting? You can see how far away the drivers are from any exterior surface. Even the back of the boxes stay cold.

Any access for maintenance is by just taking off the speaker basket and you have a big 15" hole for access to the inside.

So - to vent or not to vent?