John Sayers' Recording Studio Design Forum Archive

Hi Everyone,

I am a new member. First of all, I would like to congratulate and thank everyone for the kind of work you are doing. This forum is very informative.

I am helping out a friend with his home studio space. It is a very small room. He is a composer and is starting out in the business. He plans on using the room for recording vocals, guitars, banjo, percussion and basically, all acoustic instruments. He has a separate Monitoring room which we have already constructed. The dimensions are 11.9' (Length) x 8.1' (Width) x 8' (Height) . There is a window (6' x 6.6') on the shorter wall and a door on the opposite short wall. We are planning to close the window with 50mm thick Rockwool followed by 2 layers of Gypsum.

For this room, I wanted to try an old school design. I came across it in Mr. Everest's book. I am planning to put semicylindrical plywood panels to cover 80 sq ft of the Ceiling area. For the walls, I am planning to put 8 panels filled with 50mm thick infill. The size of these panels is 5' x 2'. Additionally, we are planning to put an Helmholtz resonator tunable to 125 Hz and below to lower the reverberation on these frequencies. For flooring, we are planning to put a carpet. I am also planning to make a diffuser and tune it for higher frequencies. However, it's not designed yet.

My queries:
1. Please comment on the described design. Let me know your thoughts.

2. When designing a studio and calculating RT60 of the space, we only consider frequencies up to 4000Hz. Why?

3. Since we don't consider frequencies above 4000 Hz, what should we consider? What should be kept in mind? I am facing this issue here as I can predict that frequencies above 4K are going to get dampened in this room (with the mentioned treatment).

4. What are the possible ways of bringing the RT60 (or other parameters) up if we consider frequencies above 4K?

I would really appreciate any suggestions. Thank you.

Welcome! Thank you for reading Alton's book!

The dimensions are 11.9' (Length) x 8.1' (Width) x 8' (Height)

Is there any way to pull any inner gypsum off in order to increase any of the dimensions? Those are pretty much all multiples of one another which isn't good. Unfortunately it's already very small so chopping down a dimension won't really be an option. How big is his control room?

For flooring, we are planning to put a carpet.

With the knowledge you seem to have, why are you suggesting carpet for the flooring? There is a time a place to use carpet for acoustic treatment, but in my opinion in a small room like we are discussing, it's the opposite of what you want.

2. When designing a studio and calculating RT60 of the space, we only consider frequencies up to 4000Hz. Why?

You might find your answer here:
If not, check out some other ISO 3382 literature.

3. Since we don't consider frequencies above 4000 Hz, what should we consider? What should be kept in mind? I am facing this issue here as I can predict that frequencies above 4K are going to get dampened in this room (with the mentioned treatment).

I'm not sure what you mean. We should do our best to consider the entire audible frequency spectrum.

4. What are the possible ways of bringing the RT60 (or other parameters) up if we consider frequencies above 4K?

Are you asking how to increase the decay time of frequencies above 4kHz?

Greg

Hello Gregwor,

Thank you for your response . Please find my answers in-line (in green) with the questions you have raised.

Is there any way to pull any inner gypsum off in order to increase any of the dimensions? Those are pretty much all multiples of one another which isn't good. Unfortunately it's already very small so chopping down a dimension won't really be an option. How big is his control room?

This is a rented place. We are just using the Gypsum to close the Window as the cost for getting a new insulated glass would be high. I understand that the place is quite small but unfortunately, he doesn't have any option. His control room is 12' x 9.41' x 8.1'.

With the knowledge you seem to have, why are you suggesting carpet for the flooring? There is a time a place to use carpet for acoustic treatment, but in my opinion in a small room like we are discussing, it's the opposite of what you want.

I understand. The space has Glazed tiles and carpet was the cheapest option. However, I will consider modifying it I guess

I'm not sure what you mean. We should do our best to consider the entire audible frequency spectrum.

I meant that we don't consider frequencies above 4K when calculating RT60 values since we do not get any Absorption coefficient data above 4000 Hz for any product. This is my concern. I want to take a quantitative approach. Hence, I did the calculations using Sabine's formula but I'm stuck at calculations above 4K. When designing a studio, what sort of calculations be considered above 4K? Is there any parameter (other than RT60) that should be considered when designing a studio of such a small scale? I also remember reading somewhere that RT60 should not be measured for small rooms, I am not sure about it though.

Are you asking how to increase the decay time of frequencies above 4kHz?

Yes.

We have not started the construction yet. We haven't even finalized on the design. That's why I wanted opinions.

Thanks again for the insight and Thank you for the document. I will go through it.

His control room is 12' x 9.41' x 8.1'.

Could you just record in his control room instead?

When designing a studio, what sort of calculations be considered above 4K?

I would design it like you have been and before putting up final cosmetic items, like fabric for example, I would take acoustic measurements and of course listen and then adjust accordingly.

What are the possible ways of bringing the RT60 (or other parameters) up if we consider frequencies above 4K?

Film, slats, diffusion (in a room that small you'd probably be limited to non-numeric based).

Greg

Could you just record in his control room instead?

There isn't enough space. He used to record earlier, but he isn't very happy with the space available. Also, he has a spare room.

Film, slats, diffusion (in a room that small you'd probably be limited to non-numeric based).

I understand.

Thanks Greg. Please let me know if here is anything I can do in the room that will add value.