John Sayers' Recording Studio Design Forum Archive

Hi All!
I am building my production/recording/mixing studio, and now it's time for build the control room.
I'm trying to build an RFZ control room, with a soft flush mounted speaker inside the front wall.

The room dimensions are:
W=4mt
L=5,2mt
H=3,2mt

I'm thinking to put my speaker (Amphion One18, passive speaker, green in the pics) on studio monitor stand, but inside the wall, and make it flush to the front wall. I also thinking to put inside the wall, around the speaker, in all the cavity, some hanger bass trap panels (like the John design) (yellow in the pics).
In these front wall i have 2 maintenance hatch (blue in the pics), because i have a lot of cable and electrical plants behind the wall.
i have attach some pics to understand what i mean.

Question time...

1) can i put the speaker only on the stand, without cabinet in "open air" behind the wall, or i have to build a "cabinet" around the speaker and fix it really strong at the wall structure?
2) do 2,6cm of drywall work good for front wall surface?
3) i have to uncouple the speaker from the stand using rubber or other material?
4) i have also to put fiberglass in the metal stud?

Soffits need very sturdy, strong, rigid framing. What you are showing is too light weight. This is what typical soffits look like, when down correctly:

FRAMING:
PARTLY COMPLETE, With hangers below a d to the sides (behind the soffit "wing"), and packed with insulation above:
Here's another room:

on studio monitor stand, but inside the wall,

If you do that, the stand would have to be very massive, rigid, and stiff, and you'd have to brace it in some manner, to ensure that it does not move. You would also be using up the space that is needed for hangers down below the speaker. I have found that it is easier to just put a rigid shelf across, just below the speaker, as you can see in the images above.

I also thinking to put inside the wall, around the speaker, in all the cavity, some hanger bass trap panels (like the John design) (yellow in the pics).

Correct! See above. That is, indeed, the best way to do it. Note the very large size of the hangers behind the soffit "wings" in one of the studios above.

In these front wall i have 2 maintenance hatch (blue in the pics), because i have a lot of cable and electrical plants behind the wall.

Move all of that to the center of the front wall, between the speaker soffits. You will not be able to have access to it where it is right now. The soffits, hangers, and absorber box will be in the way.

1) can i put the speaker only on the stand, without cabinet in "open air" behind the wall,

If you did that, how would prevent the speaker from moving?

or i have to build a "cabinet" around the speaker and fix it really strong at the wall structure?

Right! I always build strong, rigid, massive enclosure boxes around the speakers in my soffit mount designs, but I do use Sorbothane rubber pads between the speaker and the enclosure box, to isolate the speaker.

2) do 2,6cm of drywall work good for front wall surface?

In theory, yes, but drywall is not really a good material for this, because it is brittle and flaky. You have to cut a hole through it for the speaker, and that leaves a messy edge. I prefer to use wood: either solid wood (expensive!), or you can build it up from several layers of MDF.

3) i have to uncouple the speaker from the stand using rubber or other material?

That's what I do, yes, but it is not easy. You have to calculate the compression ("deflection") of the rubber correctly, in order to get the system resonant frequency low enough that hte speaker actually is decoupled across all of its spectrum.

4) i have also to put fiberglass in the metal stud?

See above...

Your last image above, with the layout for the studio, shows two "kinks" coming out of the side walls, with the speaker soffits ending just behind those. That will create a large discontinuity in the surface, and will like create artifacts. I would eliminate those, and blend the soffit wings smoothly into the side walls.


- Stuart -

Thanks for answer me Stuart!
So...

Soffits need very sturdy, strong, rigid framing. What you are showing is too light weight.

Ok, you think that i can fix the structure adding wood stud, and every what is necessary for make it sturdy, strong and rigid?

With hangers below a d to the sides (behind the soffit "wing"), and packed with insulation above

Ok, so i have to put hangers below and to the sides of the speaker, and insulation pack above, right?

If you do that, the stand would have to be very massive, rigid, and stiff, and you'd have to brace it in some manner, to ensure that it does not move. You would also be using up the space that is needed for hangers down below the speaker. I have found that it is easier to just put a rigid shelf across, just below the speaker, as you can see in the images above.

Ok, i think that i'll do with the rigid shelf across, and build a speaker enclosure...
But, just a explanation... You have say that you use Sorbothane rubber for decoupling the speaker, but the speaker enclosure is attached in very solid way to the front wall buffer...
So, the speaker decoupled from the enclosure, but the enclosure attached very well to the front wall buffer? I understand well?

Move all of that to the center of the front wall, between the speaker soffits. You will not be able to have access to it where it is right now. The soffits, hangers, and absorber box will be in the way.

I have a problem! The center front wall is large 1 meter, but the distance from the concrete wall of the structure is only 18cm!
If i'll put the maintenance hatch here, i'll can't pass trought it! And I'm not really skinny...
Maybe i can leave them and if it's necessary, just move temporarily the hanger?
What you think about?

Your last image above, with the layout for the studio, shows two "kinks" coming out of the side walls, with the speaker soffits ending just behind those. That will create a large discontinuity in the surface, and will like create artifacts. I would eliminate those, and blend the soffit wings smoothly into the side walls.

Unfortunately i can't eliminate those (i think, maybe), because they are there for angle the sides wall of the room... if i remove there, the sides wall become flat and not angled...
This will cause some reflection problem i think (correct me if I'm wrong)...
Maybe i can fill those spaces with fiberglass, or i can cover it with drywall, or fill with fiberglass and cover?

Ok, you think that i can fix the structure adding wood stud, and every what is necessary for make it sturdy, strong and rigid?

Pull out the metal framing and build it all out of wood.

Ok, so i have to put hangers below and to the sides of the speaker, and insulation pack above, right?

Hangers are preferred where ventilation is required. Super chunks work in the other areas. Or just use hangers everywhere for bass trapping.

You have say that you use Sorbothane rubber for decoupling the speaker, but the speaker enclosure is attached in very solid way to the front wall buffer...
So, the speaker decoupled from the enclosure, but the enclosure attached very well to the front wall buffer? I understand well?

If you don't de-couple the speaker enclosure from the frame, it can be attached to the baffle, but the speaker must not touch the baffle anywhere. It has to "float" on the Sorbothane.

If you go an extra step and de-couple the speaker enclosure from the framing, then it too must not touch the baffle.

I have a problem! The center front wall is large 1 meter, but the distance from the concrete wall of the structure is only 18cm!
If i'll put the maintenance hatch here, i'll can't pass trought it! And I'm not really skinny...
Maybe i can leave them and if it's necessary, just move temporarily the hanger?
What you think about?

I'm not sure why you have to crawl into these hatches. Like Stuart said, why aren't you able to put any important stuff in the center and just leave it accessible? Why don't you just cover this stuff with a fabric covered piece of wood that is lightly tacked on with brad nails or something like that? Then you can remove that panel and get at your stuff.

Unfortunately i can't eliminate those (i think, maybe), because they are there for angle the sides wall of the room... if i remove there, the sides wall become flat and not angled...
This will cause some reflection problem i think (correct me if I'm wrong)...
Maybe i can fill those spaces with fiberglass, or i can cover it with drywall, or fill with fiberglass and cover?

Extend the soffit wings further towards to the front of your room so that they "connect" with your soffit baffles.

Did you do ray tracing to ensure a RFZ?

Greg

Hey Greg!

Pull out the metal framing and build it all out of wood.

Done! Thanks!
Now the frame are really strong and rigid! It does not move for nothing!
All the wood is really massive, and 3 or 4 cm of thikness, holds me without problems, and i'm not light.
Tomorrow i'll do other "wing".

Hangers are preferred where ventilation is required. Super chunks work in the other areas. Or just use hangers everywhere for bass trapping.

Ok, i need to absorb low frequencies... Hangers are really cool, but can i build some fiberglass pack, maybe square, maybe round, to remove easy for access behind wing?
(maybe a fiberglass column?)
Do they work good like hangers?

I'm not sure why you have to crawl into these hatches. Like Stuart said, why aren't you able to put any important stuff in the center and just leave it accessible? Why don't you just cover this stuff with a fabric covered piece of wood that is lightly tacked on with brad nails or something like that? Then you can remove that panel and get at your stuff.

Here in italy there's a lot of regulations on electrical safety, and i must, put all the plant in that corner, because there are really a lot of corrugated...
I prefer to put the electrical plant distant much possible from the audio cables... so i have decided to put all the audio connections in the center of front wall, but there's not other space for electrical plants here!

Extend the soffit wings further towards to the front of your room so that they "connect" with your soffit baffles.

Do you think i simply fill those triangle spaces with some fiberglass, or cover those with drywall?

Did you do ray tracing to ensure a RFZ?

Of course! Below some pics from amcoustics amray... the shape that you see is the correct shape of my room, with correct dimensions...
I have considered 100 degrees as Speaker irradiation.

Do you think that maybe i'll use sorbothane feet, or large pad?

Done! Thanks!
Now the frame are really strong and rigid! It does not move for nothing!
All the wood is really massive, and 3 or 4 cm of thikness, holds me without problems, and i'm not light.
Tomorrow i'll do other "wing".

I know that holds you up when you sit on it, but besides strength, another main characteristic of the soffit framing is to be massive so that it does not allow vibration. Personally I'd build that about 3 times as "heavy" and strong.

Ok, i need to absorb low frequencies... Hangers are really cool, but can i build some fiberglass pack, maybe square, maybe round, to remove easy for access behind wing?
(maybe a fiberglass column?)
Do they work good like hangers?

Superchunks work great but they don't allow for ventilation. Maybe you could install some hangers and design them such that they can be removed from the front.

Do you think i simply fill those triangle spaces with some fiberglass, or cover those with drywall?

They act as an extension to the front soffit baffles, so they too must be massive and rigid. Behind the massive rigid baffle it is smart to use that area for yet more bass trapping. So, large hangers is a good idea. The bottom portion of the baffle can be removed and fabric can cover that area.

Of course! Below some pics from amcoustics amray... the shape that you see is the correct shape of my room, with correct dimensions...
I have considered 100 degrees as Speaker irradiation.

Can you post some more design photos? On the forum it is drilled into our heads to have the design 100% complete before any major construction (like building your soffits) starts. We typically work through peoples designs for quite a while. After everyone on the forum agrees that it is a good design, then the construction starts. Luckily myself and a few other members regularly chime in to help with designs (for free). So please post all of your design photos and calculations so that we can check over things. The last thing we want is to have you build a bunch of stuff then find out it was designed poorly and you have to rip it all down. I see some flex duct HVAC work in your pictures. For most applications flex duct is pretty horrible but it does come in handy for a few things. I'd love to make sure your HVAC is done properly before any more construction happens because HVAC is difficult to change once things like your soffits are built!

Do you think that maybe i'll use sorbothane feet, or large pad?

Again, this goes back to my post above regarding having your design 100% done. You have to decide how you want to mount your speaker and then design it accordingly. We use SketchUp Make exclusively on the forum as it easily allows you to work out every detail of your design before you do it in real life.

I know you're excited to see progress, but it's evident that you haven't completed your design stage. I'd stop the construction stage and finish your design. Again, post pictures and your calculations for us to review. It costs nothing. It will give you confidence in your build. I look forward to seeing the pictures and watching your build take shape!

Greg

I'm trying to build an RFZ control room, with a soft flush mounted speaker inside the front wall.

Are we all on the same page here?
I understand 'soft flush' to simply mean the speakers are sunk into a thick absorbent FW treatment.
DD

I know that holds you up when you sit on it, but besides strength, another main characteristic of the soffit framing is to be massive so that it does not allow vibration. Personally I'd build that about 3 times as "heavy" and strong.

All wood frames are about 4x8cm, and everthing is glued and screwed up.
But i can adding some other wood for make more rigid and massive...

Superchunks work great but they don't allow for ventilation. Maybe you could install some hangers and design them such that they can be removed from the front.

Ok i think i'll do that. Just an explanation... I'll have passive speaker, so i need ventilation just to avoid mold, or there is other reason?

They act as an extension to the front soffit baffles, so they too must be massive and rigid. Behind the massive rigid baffle it is smart to use that area for yet more bass trapping. So, large hangers is a good idea. The bottom portion of the baffle can be removed and fabric can cover that area.

I am talking about two "kinks" coming out of the side walls. Are you talking about these?

Can you post some more design photos? On the forum it is drilled into our heads to have the design 100% complete before any major construction (like building your soffits) starts. We typically work through peoples designs for quite a while. After everyone on the forum agrees that it is a good design, then the construction starts. Luckily myself and a few other members regularly chime in to help with designs (for free). So please post all of your design photos and calculations so that we can check over things. The last thing we want is to have you build a bunch of stuff then find out it was designed poorly and you have to rip it all down. I see some flex duct HVAC work in your pictures. For most applications flex duct is pretty horrible but it does come in handy for a few things. I'd love to make sure your HVAC is done properly before any more construction happens because HVAC is difficult to change once things like your soffits are built!

Ok... i have 2 wall air conditioning machine for controlling the rooms temperature and humidity (with sleep low noise mode).
The flex duct, is only for air recycling, and it's a sound-absorbing duct, positioned not straight but with many curves from live room to control room (Like in Alton Everest - Master Handbook of Acoustics).
Now i'm thinking to put 2 ventilation grids in the front wall, or in the hugh part of the buffle to connect the duct, and buy 2 silenced air fan, and instal behind the right baffle.

Again, this goes back to my post above regarding having your design 100% done. You have to decide how you want to mount your speaker and then design it accordingly. We use SketchUp Make exclusively on the forum as it easily allows you to work out every detail of your design before you do it in real life.

I know you're excited to see progress, but it's evident that you haven't completed your design stage. I'd stop the construction stage and finish your design. Again, post pictures and your calculations for us to review. It costs nothing. It will give you confidence in your build. I look forward to seeing the pictures and watching your build take shape!

Unfortunately, the Italian bureaucracy has many errors, and the problem is, that i need to go fast, because i have a deadline for build the room...
That's because i am going fast, without everything planned good
But, i'll do everything i can, to follow your advice!
I think that i will decouple the speaker from the enclosure, and attack the speaker enclosure to the baffle and the frame.

ok Greg, now i see what i can do tomorrow in the studio, and with SketchUp Make.
Thanks for your time and your help!

- Mattia

Are we all on the same page here?
I understand 'soft flush' to simply mean the speakers are sunk into a thick absorbent FW treatment.
DD

I believe he meant soffit/flush mounted.

This does not mean that speakers are sunk into a thick absorbent front wall treatment. It actually means that they are mounted in a wall such that it creates an "infinite" baffle.

But i can adding some other wood for make more rigid and massive...

Ok i think i'll do that. Just an explanation... I'll have passive speaker, so i need ventilation just to avoid mold, or there is other reason?

I've read that it's good to have ventilation for passive speakers, but in my mind, it just makes sense to future-proof your build allowing you to use active speakers if you ever decide to go that route. Granted, you can typically remove the amp from the back of active speakers, this would prevent you from having to do so. Maybe someone else can chime in with some thoughts on this.

I am talking about two "kinks" coming out of the side walls. Are you talking about these?

There shouldn't be "kinks" anywhere. The wings I'm referring to are just the connecting wall between your angled baffles which you speakers are sticking through and your straight side walls. So, the wings are just more angled walls. Again, they can't be "kinks". They have to be smoothly connected so that they act as a single baffle.

Ok... i have 2 wall air conditioning machine for controlling the rooms temperature and humidity (with sleep low noise mode).
The flex duct, is only for air recycling, and it's a sound-absorbing duct, positioned not straight but with many curves from live room to control room (Like in Alton Everest - Master Handbook of Acoustics).

That book is amazing! However, it did lack great studio isolation techniques, specifically in HVAC. If you use the search feature on the forum and look up "silencer boxes" you will be able to find many threads talking about them. I'd suggest reading the newer threads as the information is more relevant and detailed than older (5+ years) threads!

Also, from what you've written, it sounds like you're sharing stale air between your live room and your control room. That's usually illegal. Where is your FRESH air coming from and where is it going? Pictures would be great.

Now i'm thinking to put 2 ventilation grids in the front wall, or in the hugh part of the buffle to connect the duct, and buy 2 silenced air fan, and instal behind the right baffle.

Your fresh air outlet should be above your "air conditioning machine" as you called it so that it can blow fresh air around your room. The stale air intake should be at the opposite side of your room.

Whatever fan you use, make sure that it can move the correct CFM for your room. Furthermore, the "ventilation grids" as you called them, need to be able to pass that same CFM at slower than 300 feet per minute and the "grids" as you call them should be rated with NC as low as possible. Preferrably =< 15. The manufacturer specs should provide you with the NC rating at x amount of CFM. Achieving the slow air velocity and NC is typically as easy as increasing the outlet size as necessary.

Unfortunately, the Italian bureaucracy has many errors, and the problem is, that i need to go fast, because i have a deadline for build the room...
That's because i am going fast, without everything planned good
But, i'll do everything i can, to follow your advice!

That's a bummer. I'm surprised they gave you a building permit without detailed drawings and plans though. Here, you need quite a bit of detail in order to obtain the permit. And the permit typically lasts 1 year. If you are not done building in that time frame, they will extend it providing you are making some progress.

Hopefully we can prevent some major mistakes. The only problem I foresee will be you asking a question and there might not be anyone on the forum that day or whenever to answer your question. You may have to split up tasks so that you are able to wait for confirmation on certain aspects of your build. If you work REALLY hard on the SketchUp drawing and finish it before you continue construction, that might be the best and will save you time in the end as you'll have all of your questions sorted out and you'll be able to build fast with confidence!

I think that i will decouple the speaker from the enclosure, and attack the speaker enclosure to the baffle and the frame.

It may be smart to ask Stuart (soundman2020) if he can whip up some Sorbothane calculations for you so that you don't have to spend a week sorting through the dumb Sorbothane information. You can't just throw a random amount under your speaker. It's quite convoluted and you have to make sure that your frequency calculations are correct. This is a very delicate part of the design.

ok Greg, now i see what i can do tomorrow in the studio, and with SketchUp Make.
Thanks for your time and your help!

I look forward to it!

Greg

I've read that it's good to have ventilation for passive speakers, but in my mind, it just makes sense to future-proof your build allowing you to use active speakers if you ever decide to go that route. Granted, you can typically remove the amp from the back of active speakers, this would prevent you from having to do so. Maybe someone else can chime in with some thoughts on this.

Speakers are very, very inefficient at converting electrical power into acoustic power. The actual acoustic power coming out of a speaker playing really loud (100 dBC SPL) is maybe around one watt per square meter. So if you could set up a frame at the mix position that measures one meter on each side, and measure the acoustic power going through that frame, you'd get about one watt, typically (give or take a hundred milliwatts or so.)

Now take into account that, in order to create that acoustic power level, your amps are probably pumping out a few HUNDRED watts... do the math.... speakers are highly inefficient, in this sense.

So, if most of the power reaching the speaker drivers is NOT going out as sound, where is it going? Yup: heat. That's where. Speakers are actually very, very efficient at converting amplifier power into heat power! One way or another, the amplifier power that did not go into producing acoustic power, went into heat power. And a fair amount of that "heat power" gets dissipated by the driver itself, inside the speaker cabinet. There are also heat losses in other parts (the flexing of the cone mountings, for example), as well as just lost as heat to the air due to the impedance mismatch, but in a typical speaker, the driver itself is sucking up a large amount of that electrical power, and converting it into heat. That heat then has no place to go, except out through the cabinet walls, and into the air around the speaker. If your speaker is tightly held inside an enclosure box, then the heat works it's way out through that, eventually. But it DOES get out. Then it needs to go some place... You can't just trap it inside the soffit, and allow it to build up....

So, even for passive speakers, I always ventilate the rear face of the speaker cabinet, just like I do for active speakers. I leave a clear, open ventilation path up the back of the speaker, with at least an inch of clearance all around, and a much more if I can spare the space, or if the speaker is large, or dissipates a lot of heat.

OK, for a passive speaker, the surface area of the cabinet is large compared to the amount of heat, so it hardly gets warm at all to the touch if you have it sitting in the meter bridge, or on a speaker stand... but that's only because it is exposed to air all around! Mounted inside a soffit, it's a different story.

You don't need as much for a passive speaker as you do for an active, but it is still wise to allow some ventilation.

Again, they can't be "kinks". They have to be smoothly connected so that they act as a single baffle.

If you use the search feature on the forum and look up "silencer boxes" you will be able to find many threads talking about them. I'd suggest reading the newer threads as the information is more relevant and detailed than older (5+ years) threads!

Yup! Here's some examples... some good, some not so good:

http://www.johnlsayers.com/phpBB2/viewt ... 0&start=45
http://www.johnlsayers.com/phpBB2/viewt ... 9&start=74
http://www.johnlsayers.com/phpBB2/viewt ... 42&start=5
http://www.johnlsayers.com/phpBB2/viewt ... 61&start=0
http://www.johnlsayers.com/phpBB2/viewt ... 5&start=98
http://www.johnlsayers.com/phpBB2/viewt ... &start=157
http://www.johnlsayers.com/phpBB2/viewt ... =2&t=13821
http://www.johnlsayers.com/phpBB2/viewt ... 8&start=44
http://www.johnlsayers.com/phpBB2/viewt ... 2&start=16

it sounds like you're sharing stale air between your live room and your control room. That's usually illegal.

True. And even if it is not illegal where you live, it is still bad practice. You should never have the stale air from one room going into another room. Not good.

If you work REALLY hard on the SketchUp drawing and finish it before you continue construction, that might be the best and will save you time in the end as you'll have all of your questions sorted out and you'll be able to build fast with confidence!

Excellent advice!

You can't just throw a random amount under your speaker. It's quite convoluted and you have to make sure that your frequency calculations are correct. This is a very delicate part of the design.

Absolutely! It's complicated to get right...

- Stuart -

Hey Guys! Thanks for reply!
Happy new 2019 for all of you!

it sounds like you're sharing stale air between your live room and your control room. That's usually illegal.
True. And even if it is not illegal where you live, it is still bad practice. You should never have the stale air from one room going into another room. Not good.

Maybe you can't see good from the bad pics...
I have 2 air duct, one for incoming fresh air, and one for pull out stale air from the studio...
Every duct is soundproofed duct, but maybe i can build a silencer if i need.
I'm working on sketchup for building my room, and soon i'll send some pics!

You can't just throw a random amount under your speaker. It's quite convoluted and you have to make sure that your frequency calculations are correct. This is a very delicate part of the design.

Absolutely! It's complicated to get right...

Ok... I read that i have to calculate the weight of my speaker and the critical frequency of the system. It's right?
Any suggestions or explanation?

I read that i have to calculate the weight of my speaker and the critical frequency of the system. It's right?

You need to know the total weight that you will be "floating", which is the weight of the speaker plus any enclosure box around it (if that's the method you intend to use).

You also need to know the lowest frequency where your speaker will b putting out significant energy, which as around 30 dB below the specified lowest frequency. You need to tune the system to a frequency that is not more than half of that.

If you use a sub along with your mains, then the lowest frequency will be a lot higher than if you just use the mains by themselves. In that case, use the crossover frequency and calculate the -30 dB point based on the slope of the crossover.

Some people make the mistake of thinking that speakers only move up and down, so they only put pads under them, but in reality speaker cabinets vibrate in all three dimensions... So you need to take that into account with your design.


- Stuart -

Hi all!
Finally i have make some drawing in sketchup!
Sorry for some error, i'm using this software only for 1 week...

I have apply some advice that you have tell me...

What do you think about the round absorber to remove for enter behind front baffle in case of maintenance?
If you have some advice or something wrong in this project please tell me!

I have include the project file for let you modify something, if you want.

Hi Matt,

Great work with SketchUp!!!!

Have you done ray tracing in SketchUp yet? I'd like to see that to confirm that you indeed have a reflection free listening position.

What do you think about the round absorber to remove for enter behind front baffle in case of maintenance?

Well, it won't work the magic of hangers and won't be as effective as a stuffed full superchunk style bass trap, but it certainly would do some amount of good for your acoustics.

I've never seen insulation sold in a roll like that though, so how do you plan to find that product or build it? It is a solid chunk of insulation right?

I have include the project file for let you modify something, if you want.

I don't see any link for your .skp file.

If you have some advice or something wrong in this project please tell me!

- You need a layer of insulation (like 2 to 4 inches worth) entirely covering the walls, ceiling and floor INSIDE your soffits.

- You should have a back on your speaker enclosure. Leave a hole in it to pass heat and cabling.

- It might be wise to put a divider shelf above your speaker. This will allow you to stuff a ton of loose insulation all around the speaker enclosure to dampen the heck out of it.

- The shelf the speaker sits on needs a hole cut in it just behind your speaker enclosure for air to pass up behind the speaker. The shelf I mentioned in the previous point would also need the same type of hole in it. That way convection can happen. The other thing you need to include is some chicken wire or something like that to maintain the air path while preventing any insulation from falling into it's path.

- Again, you need to do ray tracing to make sure all of your angles work out properly.

- What are you using for your soffit baffle?

- I can't tell from your pictures where your soffit face changes from the very hard material to just fabric/absorption. The same question applies to your soffit wings.

- It looks likes like there are some 2x4's or some type of dimensional lumber standing upright at the end of your soffit wings (on the door side of the wings). Those will screw up your RFZ as they will reflect sound back towards the front of your room. Remove those. If you're thinking you're going to need some depth on your side walls for acoustic treatment, you won't be able to have as much angle on your wings, or you have to re-think the entire front half of your room as being thinner. Again, this is where your ray tracing will point out issues.

- For ray tracing, you have to do it for your ceiling/cloud as well. This is very very important.

- I know it's only been a week on SketchUp, but before you continue any actual construction, you should design your rear wall. Are you doing hangers back there too? How thick are you able to make it?

- You didn't include your mix position in your pictures. Again, that all comes with ray tracing as well. How far back (percentage) are you going to have your mix position in the room?

- Have you decided where exactly your supply and return diffusers/registers/grilles are going to go in your room?

Every duct is soundproofed duct, but maybe i can build a silencer if i need.

Those look like flex duct. First off, unless they have the same surface density as your walls and provide an equivalent amount of insertion loss as your walls provide transmission loss, they will allow sound to pass and compromise any isolation you've attempted to obtain with your walls. Therefore, if isolation is a requirement of yours, you WILL need silencer boxes. I don't know what is on the other side of the wall where the ducts penetrate the walls. You would need silencer boxes there for sure. Is your room a room in a room design? If so, you will need a silencer box on each leaf. So one for the outer room wall and one for the inner room wall. But, that means for both supply and return. So, a total of 4 boxes. They are going to be very large. You may have to have them inside your room and since the ducts are penetrating your wall right behind your soffit, that will be very difficult to fit your silencers in that location. What you may have to do is build thick sleeves out of MDF and run them to other locations in your room. You could use Stuart's Y style silencer box design and have your supply silencer/outlets at the rear ceiling of your room and your return silencer/inlets up hidden above your cloud. Now, again that all will affect your ceiling height and ultimately your vertical ray tracing.

As you can see, there is still a lot of SketchUp work to do before you start building stuff! Keep at it. Now that you've got a good grasp on using SketchUp, this design stage should go pretty smoothly!

Greg

Hey Greg!
I'm preparing the answer and the modified design for your last post...

i've only a question... How can i do ray tracing in sketchup???
I have installed the raytracer plugin, but i don't understand how can i use it for speaker reflection simulation...