Building control room for Foley
Part I: Goals, budget, soundproofing, ventilation
Own and Operate at
Hey, it’s Yuri from Foley First again!
After the pandemic caused uncertainties in 2020, we here at Foley First, decided to start the expansion of our facilities. I wish it were just about building a new Foley stage. Nope, not this time. This situation required the need to build an additional control room for reviewing and processing Foley.
In this article, I would like to outline the entire process of building the studio in detail. I hope this information will be useful to someone and this article will be of interest to you.
Realizing that reading this long article can be a task in and of itself, I split the story into three parts. In the first part, I share my thoughts about what my goals were and how it was conceived to build the room’s soundproofing and ventilation. The second part is about acoustic design. The third article, I describe in detail the process of fine-tuning the studio after the first measurements and present the final result in data and graphs.
So, brew some coffee and take a seat. I hope you find it interesting.
First of all, I must clarify that the thoughts I want to share are not a lesson in the physics of acoustics. Even though this is the fifth control room I’ve designed, I do not consider myself an expert in the science. I do not strive to teach the craft to someone and do not provide commercial services in acoustic design or building budget recording studios for someone other than myself.
I love acoustic design and the mathematics/physics of sound. After the experience I’ve gained, I managed to get some insight on this difficult and often unpredictable science. People can debate the acoustics topic until the end of time, but until you do something on your own, you will never figure out that most of the theory you got through books and forums may not work in the real world, and especially in your room. Acoustics behave in a capricious way and cannot be copied from room to room.
In my opinion, while working with a limited budget, the acoustics are always a compromise.
So, let’s look at the room build.
Room final look.
This is how the completed project looks.
I see that many people value the control rooms/studios purely from a visual and aesthetic aspect. While, I agree that appearance is important to the room for you and your clients, it should never be overshadowed by the room’s primary task — its sound.
I won’t disclose the room’s acoustic specs in data and graphs in this part but will share them in detail in the final, third part of this article. Running ahead, you can find the final room frequency response in the most difficult range in smaller rooms, 40-200 Hz. So far, no decay and waterfall charts you will find here.
The room frequency response snippet has 1/24 oct smoothing. The grid step is 5db. Most importantly, this is a natural acoustic room response, without any EQ or other software/hardware acoustic corrections. The distance from the listener to the speaker is 150 cm.
Goals and expectations.
Before finding a suitable room, I knew exactly what I needed to build and the results I wanted to achieve within the budget I had allocated for this project.
Control room for Foley / office. Not less than 20 sq meters after full acoustic treatment.
After making minor changes to my team at Foley First last year and reorganizing our schedule to be more flexible, I found no time available to do the implementation. For 7 months I turned my apartment into an office. Finding productivity in my normal routine work like accounting, client negotiations and marketing felt impossible (I have wife, 6-year-old gangster, bulldog… well, you know my pain). I was in desperate need of a personal office and larger control room, where I can review and process Foley material at any time without interfering with the teams work schedule here at Foley First.
The nature of the control room I needed was significantly different from the norm. I didn’t need a 5.1 or 2.0 control room. All that was necessary was a neutral-sounding studio, with only the C-channel. It was very important to make the room somewhat live and not completely dead while making sure it wouldn’t be too big for a 8” woofer to fill the room.
Perhaps someday, I will reorganize this space for 5.1 premixes or sound effects editing, but at the moment, this rooms intended use is for Foley reviewing and processing.
Lows. As flat as possible.
I believe that the most important goal in acoustics is to create a room with the low-frequency range sounding as flat as possible without obvious dips, nulls and significant resonances. The goal is to dampen them as much as possible in order to not have any long decays in the entire range. It is crucial, especially for the Foley footsteps group to have full control and accurate monitoring in the range of 50-400Hz. This allows us to fine tune the footsteps and filter out unwanted artifact frequencies Foley pits produce.
Lows are the biggest problem in small rooms. Making the curve in the low to low-mid range as flat as possible was the ultimate goal. It also meant that it would require massive bass absorbers.
In summary, what I wanted to get in the final result:
- 1-channel control room / office with the space not less than 20 sq meters after full acoustic treatment.
- Minimum of soundproofing, but more attention to acoustic design.
- Frequency response on lows / low mids as flat as possible.
- Combined extract-and-input ventilation system.
Budget and deadlines.
Experience played a very important role for accurate budgeting for me. I had a clear idea about how much building materials would cost, how to use them, how much their delivery might cost, which vendors would best suited and what pitfalls might arise during the process. Without the materials, there was a clear understanding of which alternatives could be used to achieve the best results without compromising acoustic properties. I also had a rough idea of what additional cost could arise in unforeseen circumstances while fine-tuning the studio.
Due to the lack of time to draw up a full-fledged estimate before the building started, I could not thoroughly predict all costs, but it was not difficult to devise a budget that rounded up to 1000 USD.
The project deadlines were precisely determined: no more than 30 calendar days for the main construction of the room and no more than 30 additional days for its fine-tuning and launch. Otherwise, prolonged construction and my excessive perfectionism could have severely affected the entire workflow here at Foley First.
The whole situation did not look like “OK, guys, we have an unlimited budget and an unlimited time. Let’s build a dream studio!” but rather, “Guys, we have 60 days, several thousand dollars. We’re building the studio quickly and moving on.”
Of course, it was impossible to get a phenomenal result in such a short time and working with a small budget. As well as not being able to hire a professional acoustic engineer or a company specializing in acoustic solutions and building a studio in a freestanding building with massive soundproofing and acoustic finishes. It was possible to get a very acceptable and viable result with up to 10,000 USD in your pocket here in Russia. I want to emphasize that prices are tied to Russian realities. In other countries, the cost of building materials and services can and will differ often and in a larger capacities.
After building the third studio myself, I decided that I had gotten enough experience as a carpenter and was no longer interested in building more. Therefore, this room was built by hired professional builders. My position was as an acoustic engineer and supervisor.
I’m not sure if I can provide accurate information on the cost of building services. Still, in the third part of the article, I will share a table with local prices for the main building materials that were used in the construction of the studio so that you can compare them with costs in your country to obtain more accurate information on the budget for building this kind of room.
- My budget for the construction of the room, including soundproofing, acoustic finishing, and ventilation system, is under 10.000 USD (or 730.000 RUB, where 1 USD = 73 RUB, Jan 2021). The budget includes the cost of all work, building materials, and their delivery to the site. As well as a ventilation system and installation. It doesn’t include audio gear, desk, chair, etc.
- Turnarounds: 30 days for main construction + 30 days for fine-tuning.
Finding the best place.
In addition to the rooms’ technical nuances that were under consideration, the law always plays an important role here as well. Otherwise, I can fail as a business. That’s a Russian specificity. While building new rooms, I always consider the strategy of fast dismantling in the rooms where we are located. It doesn’t matter if the object is in my ownership or rent. Due to the unstable economy, the planning horizon for business in our country rarely exceeds more than 3 years, haha. Something can always happen that will require you to pack up your things and move out quickly. Thus, out of 100 objects for the potential construction of a studio, only 10 are legally protected and sufficiently reliable.
It is also quite difficult to find out of these 10 objects, the one that will look like an open space room of at least 35 sq meters with ceiling of at least 3 meters, placed far away off the road, without noisy neighbors or without neighbors at all, without elevator behind the wall, etc. All of those obstacles prevent the construction of minimal soundproofing, instead of a massive double frame or brick walls which entails an increase in the budget and turnarounds.
Sacrificing a remote location from the head office, I looked at objects within a radius of 15 km and looked only for those which are close to my ideal. In 2 weeks of searching, nothing even close was found. It forced me to go to plan B — to find a compromise solution in the maximum proximity (up to 500 meters) to the main studios and my team. That was an essential factor.
Well, I found it!
- Large (more than 40 sq meters) open space with finished floor. Possibility of placing massive bass traps and diffusers.
- Separate tambour plus two additional storage rooms.
- All communications are carried out and in working order, which greatly saves the budget.
- Great box-out in the wall to accommodate a large ventilation silencer.
- Quiet neighbors on the adjoining walls. Savings on soundproofing.
- 2 massive concrete walls (40cm + 20cm) with a tambour protect against noise from the street.
- The room is almost square! Say hello to mods and acoustic problems in low range.
- Very low ceiling, which implies almost no soundproofing of the ceiling.
There are the disadvantages, as always, but there were more practical advantages for life. Moreover, I was not looking for the greatest soundproofing, really. It was just fine to be isolated from the noise of the extract-and-input ventilation system, which was later placed in the tambour/technical room, outside the main room.
If I was considering this room for the Foley recording, it definitely would not be suitable.
Following the main idea and keeping in mind all the room’s limitations and after 48 hours of room tone measurements, I did not build any massive soundproofing. I limited myself to a simple single-wood frame solution. In theory, that would be enough to create a sound barrier between adjoining rooms and other rooms to reduce air noise from the ventilation.
Having a room in a room, I also bypassed and kept the engineering communications inside the original room untouched.
All my soundproofing consisted of a single frame made of 50 mm by 100 mm wood filled with 100 mm Rockwool mineral wool and covered with two layers of 12 mm gypsum board on each side. This was sufficient for my work for Foley in this room.
According to science, it is recommended to use vibration-insulating materials between the wood frame elements and the adjacent walls/ceiling. I absolutely agree with this, but I refused to use them, since for some reason, in Russia, these elements are costly, and I did not pursue this “perfect” soundproofing technique. Well, this was not part of my plans at least. It was much more important to have soundproof doors with a sound insulation coefficient that was not lower than the walls.
Let’s be honest. Since the ceiling height did not allow us to build with a soundproofing coefficient similar to the walls with comparable sound insulation, the whole room had a rather low sound insulation coefficient. As we know, soundproofing of the room is a soundproofing of its weakest element.
In fact, we decreased the ventilation system’s air noise and the noise from the adjoining office rooms. The simple sound-insulating structure allowed me to form a room of this size, in which I was later able to place all the elements of the acoustic design as it was intended. Importantly, having built a room in a room without affecting the finish and design features of the original room, I knew that at any moment I could quickly and with minimal costs dismantle the walls and have it back to its original state.
This ceiling was also very simple to build. The low height did not allow me to build good soundproofing. The best solution here would be to place massive hanger bass traps but alas, we have what we have.
To be honest, such a structure’s soundproofing is close to zero, but Rockwool can damp the noise coming from upstairs a bit.
To preserve the room’s critical height as much as possible, I dismantled the existing Armstrong ceiling, changed its height, rewired all the electricity and replaced the old Armstrong ceiling slabs with new Rockwool, which had already sound-absorbing properties. The space between the building’s concrete floor slab and the Armstrong ceiling was filled with 100 mm mineral wool along the entire perimeter.
To be honest, the structure’s soundproofing was close to zero, but Rockwool can damp the noise coming from upstairs somewhat. As the general acoustic design of the ceiling, 120mm absorption was always enough for me, but unfortunately not in the early reflections zone or above the listening position. This is clearly too thin. Of course, there can be no talk of any absorption of low frequencies from such a design. This task will be assigned to the walls. But I am sure it is more than possible to avoid the appearance of standing waves in the floor-ceiling combining the low-mids range and at high frequencies.
After constructing the walls and bypassing all internal communications, entailed the formation of a significant space from the original wall to the soundproofing wall on one side. The usable area decreased from 40.5 sq meters to approximately 31.5 sq meters. Cool!
I didn’t want to cut corners or costs on ventilation for the room where anyone spends a lot of time. In the past, I had to work at local companies without any ventilation at all. After 12 hours of mixing TV features, a brain comes to a boil. It was almost like torture, unlike other productive and creative work where conditions are better. Although the studio rooms of these companies had windows, they were of little use. The favorable and controlled climate in a room with adjustable ventilation, for me, is a guarantee of high efficiency and creativity.
Having the box-out in the wall of my room for a ventilation silencer along with the tambour space for technical needs, immediately determined the ventilation system’s location, air pipes, and their length, which all saved on the budget. In fact, I already used a solution previously on the Foley footsteps stage, everything was very familiar to me. Air in/out was carried out through a small window bordering the street.
I’m a big fan of DIY silencers made from plywood or other hard sheeting with mineral wool inside. This was made according to the “labyrinth” scheme. They are astonishingly effective and dampens perfectly the noise of the flow-through-exhaust ventilation system and isolates the sounds passing from room to room. When one vent is designed to circulate the air from several rooms at once, I used silencers installed in the old large control room, which was dismantled a few years ago and the same silencers are now installed in our Foley props stage. Due to their small structural thickness, they are very convenient to place under the Armstrong ceiling. Several of these installed required a significant ceiling space (LxW), which I did not have. Even if it were possible to place 2 silencers in my technical room, it would be challenging to carry out all the air pipes.
Therefore, when I choose a room, one of the important criteria for me, is to have the ability to place the ventilation system and have space for bulky silencers. Installing the silencers into the wall is always the best solution.
It’s easy to construct this yourself. I refused the “labyrinth” scheme inside the silencer due to insufficient space inside its structure and most importantly, not needing the super-effective/expensive sound absorption. My silencer structure inside looks like two independent and isolated chambers for the supply and exhaust air. It’s important that the air inlet into each of the chambers must be located at the top of the silencer, the outlet at the bottom, or vice versa. The built-in silencer frame is made of 50×100 mm wood and sheathed from the outside with two 12 mm gypsum board layers. The frame of the silencer is integrated into an existing box-out in the wall and is hard mounted. My silencer’s size is 113×105 cm. A 12 mm gypsum board layer separates both chambers inside the silencer from the side of each of the chambers, and the entire formed internal space is filled with mineral wool.
It is important to carefully seal the interior space before covering it with wind proofing material to avoid air leakage.
It is even more important to cover the mineral wool with wind proofing material carefully. Otherwise, microparticles from the mineral wool will fly into the control room along with the fresh air. A good mixer is an alive mixer.
This design significantly reduces the noise from the ventilation unit. Full silence is unlikely to be achieved. Still, if the ventilation unit has a step speed adjustment of the inflow strength, you can find a comfortable balance between the air supply power and the noise that slightly leaks in the room (when working with audio, most likely you will not hear it). If this room were focused on Foley recording, I would definitely give up the constant airflow, replacing the ventilation unit five times more powerful as we have in our Foley footsteps stage.
Whatever one may say, in small budgets/small rooms, it isn’t easy to achieve full silence from a constantly working ventilation system for Foley recording. That’s why, at the footsteps Foley stage, instead of constantly working ventilation I preferred to turn on the ventilation just several times a day to quickly refresh the air. On the footsteps stage, we have installed an inflow system with the capacity of 1000 cubic meters per hour, which allows me to completely change the air in a 100 cubic meters room in a matter of just a couple minutes. No noise during recording, just a little time for venting.
TO BE CONTINUED…
The next part will be about acoustic design.
Building control room for Foley
Part II: Acoustic design and doors
Thanks for reading!
What is important for us in recording clothes for the features. How we do editing of moves tracks and what is crucial. The technique.