John Sayers' Recording Studio Design Forum Archive

I have been asked to build a mobile recording studio...

The width is set at 8.5ft for on the road driving, which means with build out you would have 87" inside width or 7' 3".

With that said what height and length should I use since I could go up to 10.5-11' height and as long as I need?

This is the control room...
The vocal booth I believe that I do not need much just a 3-5ft room with width at 7' 3"

Dave

You might find this interesting.... maybe some clues on how you could do yours:

http://johnlsayers.com/Studio/Mainpage/MP-Mark.htm

- Stuart -

Wasn't there a guy here a few years ago that was working on a mobile production truck? Can't remember if it was here or another forum, though.

There are lots of examples of mobile production studios on the web, usually built in old bread or delivery vans.

Thanks Stuart.. but the page link did not work.

I am not using a mobile truck, it is a "tiny house" trailer and it is framed and built on the trailer from scratch.

David

Stuart - I got to it ...

However - I needed to understand the width and length. I have flexibility with the height and length to make it. Can you help with appropriate dimensions. I am thinking the width is going to end up being 87" - 7' 5". What should the appropriate height and length to go with this.

Use one of these Room Ratio calculators to figure out the best dimensions for your room:

http://www.bobgolds.com/Mode/RoomModes.htm

http://amroc.andymel.eu/

Both of those are very good, and will help you to decide how best to build your room. They give you tons of information that is really useful to help figure out the best dimensions.


But basically, you should worry about maximizing the room volume. That's the first priority for a very small room like this. Largest possible amount of air inside. Then if the calculators show that the ratio is terrible, adjust a little bit. But don't go crazy over ratios.


- Stuart -

Thank you...

I attached the file as I do not know how to read it... From what I see it looks like these dimensions work?

I am assuming that when I put in the acoustic panels it would make some of these frequencies better?

David
www.hoverstudios.pro

If you check those dimensions on the Amroc calculator, you'll see this:

https://amcoustics.com/tools/amroc?l=18 ... 3%20speech

On the right hand side towards the top is a diagram labeled "bolt-area". That's named after a scientists by the name of Mr. Bolt, who figured out that any room ratio within that area in the middle of the graph, is probably going to have decent modal response. The Red "X" in a circle shows where your room ratio is, in relation to the Bolt area: outside, not inside. So try nudging the dimensions a bit, until you get the "X" inside the Bolt area.

I do not know how to read it.

Both of these calculators show you where the modal frequencies will occur. Modes are "standing waves" that form inside the room, created by the walls. They form only at certain frequencies that are directly related to the dimensions of the room. What you are looking for, is a ratio that "spreads out" those modes as evenly as possible in the low end of the spectrum, such that they are not bunched up together in one place, and the spaces between them are as short as possible.

As you go through this exercise, you'll see that it is pretty much impossible to get them spaced out truly evenly! So don't try. Just space them as best you can. A sure indicator of that is when your red X is inside the circle. That's what the "Bolt area" really means: you have a reasonably good ratio. There is no such thing as a "perfect" ratio, nor a "golden" ratio, nor an esoterically superior cubicociodal rhomboidal nor magical gemotricoidal ratio: You can see that for yourself as you adjust the dimensions. NO such ratio exists, despite the desperate attempts of some internet charlatans to convince you otherwise, so they can sell you snake-oil products based on their supposedly magical properties. Beware of those guys! There are only bad ratios, and better ratios. So you only need to play around with the numbers a bit until you are far away from the bad ones, and close to one of the better ones. That's all. There's no point in spending too much time on this. The basic issue is to avoid having modes right on top of each other, and to get the spread around evenly. That's it. At 1 : 1.34 : 2.51, your ratio is rather long and thin for the height, but adjusting the numbers a bit can improve that.

I am assuming that when I put in the acoustic panels it would make some of these frequencies better?

Acoustic panels will not make your modes go away, no. Modes are a fact of life, and are caused by the walls of the room. The only way to make them go away, is to knock down the walls with a bulldozer! So you cannot make then go away. But you CAN "damp" them. That's part of what "bass trapping" does. It reduces the amount of modal "ringing" that would happen otherwise.


- Stuart -

Stuart-

Thank you for all your advice...

I have adjusted the ratios and have one that fits into the Bolt Area..

Schroederfrequency: 227 Hz
Critical distance: 1.65 ft
Sabine Eyring
Equivalent absorption area needed: 136.33 sq ft 125.96 sq ft

What do these mean?

What do these mean?

Schroeder frequency: 227 Hz

The Schroeder frequency is the point in the spectrum where the room acoustics are changing over from being dominated by modal behavior (lower frequencies) to specular behavior. Sort of! More correctly, it's the frequency below which there are not enough modes to provide a decent smooth spread, and above that point, there are enough.

Critical distance: 1.65 ft

The distance at which the reverberant field of the room is the same level as the direct sound from the speakers

Sabine Eyring - Equivalent absorption area needed: 136.33 sq ft 125.96 sq ft

Two methods for calculating the area of absorption that is needed in the room to obtain the recommended RT-60 times. So according to Sabine's method, you would need 136 ft2 of absorption spread around the room, but according to Eyring's method for calculating this, you would need only 126 ft2.

- Stuart -

Thanks again for your advice...

I wanted to switch gears to soffit mounting the speakers...

Can soffit mounted work in a small environment? With Active Nearfields? or do I need to get Passive Nearfields?

How to build it... I have seen the diagram but not understanding it... I know that I have to frame it out and use like a neoprene rubber and give it some circulation but just more clarity on the layout - if you could please?

David

I wanted to switch gears to soffit mounting the speakers...

Good move!

Can soffit mounted work in a small environment?

Yes it can.

With Active Nearfields? or do I need to get Passive Nearfields?

It can work with pretty much any monitor, except for one that are side-ported or which have active drivers on the sides, top or bottom. But for the vast majority of speakers that have drivers on the front and ports on the front or rear, there's no problem at all. It is easier to mount speakers that are rectangular, but it is possible to mount pretty much any shape, including ones that have faceted front faces (like many Adam speakers), rounded edges, or even completely egg-shaped speakers, such as some Genelecs. You just need to be more creative when cutting the front panel to fit the shape of the speaker. But apart from that, i¿you can soffit mount almost anything, and small speaker in small rooms will benefit the most! Active or passive is not a problem. Both are fine.

There are many threads here on the forum where people have soffit-mounted their speakers. Take a look at those. But the basic idea is to build a very rigid, heavy framework, put a very rigid heavy front "baffle" on it with a hole for the speaker to poke through, and either decouple the speaker from the frame with something like Sorbothane pads, or hold it rigidly in place. The areas above and below the actual baffle area can be used for deep, thick, very effective bass trapping. I often use hangers below the speaker and thick absorption above it.

... give it some circulation ...

Right! You do need to leave a path for air to flow up behind the speaker, and even around it in some cases. That can be as simple as a large, wide, long slot cut in the "shelf" that the speaker sits on, and with a chicken-wire "cage" up through the insulation, to prevent it from closing up the path, sort of like a chimney.

- Stuart -

Is there any instructions/diagrams on building a soundproof door?

Is there any instructions/diagrams on building a soundproof door?

In the SketchUp 3D Warehouse, gullfo posted some called "acoustic doors". This isn't instructions per say but it does give you some dimensions and rough idea of how they should turn out.

- You could build the door out of several layers of HDF wood. Router out the edges to allow the 2 perimeter seals.
- Use a commercial door closer instead of a through handle to prevent having to penetrate your beefy door
- Use 4731 seals around the perimeter
- Use an automatic door bottom seal
- You can go and check hinge manufacturer brochures to figure out which hinge model you need, but here is a brand comparing chart for you: - Make sure your jamb is able to hold the weight of the door without any sag or problems. More over, make sure your wall studs can handle the torque that the door will apply to it!

Some people build the core of the doors with sand, MLV and even steel. For most cases though, each leaf of your wall will only offer the isolation matched to a door made out of HDF and the seals I've mentioned above.

Greg

I am bending on this same build...

I want to ask if I build out the control room - 14.75ft x 11.75 W x 9.7ft Ceiling height. Can I use this room width-wise?