New studio design for 30'x40' space in India

Hi, We are planning to build a recording studio in our Yoga Center in South India. Am hoping I can get some advice and suggestions on the design. We are going to build it in the left lower corner of our Suryakund complex. (Follow the link to see it on Google maps) We have an area of just over 30' by 40' with a ceiling height of 12'. The whole structure is composed of huge granite stones and our ceiling is made from 6" thick granite slabs with 2" concrete on top. (This is where members of the public walk to go from the suryakund to the temple). To support the weight of the granite slabs there is a steel beam structure inside. The floor is concrete. We have a budget of $20K. We have our own experienced construction and carpentry teams who build everything in our center, although have never attempted anything like this before. The primary purpose of the studio is to record our in-house music team. Our main instruments are vocals, acoustic & electric guitar, bamboo flute, sitar, keyboards, as well as many different types of traditional Indian percussion. Currently we record most of our songs one track at a time, but we now want a large, versatile live room where we will have the option to record full songs with the whole group playing all together. It should sound and feel great so that we all enjoy playing there. We record a large variety of types of music including chants, meditative instrumental music, and vibrant percussion and dancing songs. To get an idea here is a sample of music from our last album. We also have some huge 3' diameter leather skin drums (like timpani in an orchestra), which we use in recordings of chants. In our recordings we struggle to reproduce the thundering impact that they have live, so we want a room which will help us with this. We want a single main control room which we will use for recording and mixing our main projects, and a smaller ancilliary room which we will use for parallel work on minor projects. I've been reading about various CR designs (non-env, LEDE, RFZ etc), but I really don't know which one would work best for us, and was hoping for some suggestions in this regard. We're not planning to use this studio commercially - only for our own projects, so we don't need a room which will impress clients - just whatever will enable us to record and mix as accurately as possible. Due to the positioning of the supporting steel beams and poles (which cannot be altered), we have some restrictions in our room layout (assuming that we don't want a metal pole inside any of the rooms). I have attached a to-scale sketchup plan of our space, with the beam structure (the internal brick walls have not been built - just my initial idea. The grey blocks are all granite stones, which have all been placed - as you can see from the first pic). This is my initial idea. Here, the control room is about 13' x 17' with 11.5' height, and the live room is 14' x 29' with 12.5' height. (We've dug down an extra foot in this area to give more height). The ambient noise level is fairly low (although I have not taken any measurements yet - will do so soon). The adjacent space will be used mostly for reasonably quiet office work. However there is a powerful water pump which is located about 30' away from us. It has been placed in a 20' deep well in the ground, and a thick brick wall completely blocks our area from the area where the pump is. But you can still hear a background humming. Also you can hear the sound of water falling into the Suryakund pool from a height of about 50'. We initially had planned to have a ducted AC system, but due to budget constraints we are looking at using split AC units instead. I'm expecting to need mainly brick, plywood and rockwool, which are available to us here. Also we have easy/low-cost access to large quantities of granite I don't expect anyone to design the studio for us, but whatever advice can be offered will be much appreciated. I have a few initial questions: 1. Is it ok to have the steel poles in between an outer brick wall, and an inner de-coupled wall? (These poles are 5.5" wide and are directly connected to the granite ceiling and concrete floor ). If we were to do this, how much space would we need to leave in the air gap, and between the pole and the inner and outer walls - without risking any sound transmission? Would this be wasteful of space? With this large an air-gap, should we fill it with rock wool (otherwise we could save money by not using it) 2. Is it worthwhile splaying the inner (or outer) walls / ceiling to create a reflection free zone in the CR, and if so, where can I find more resources which will help me calculate the angles and overall shape of the room. 3. To save money somebody suggested doing the whole studio entirely with thick PUF (polyeurathene foam) pre-fabricated panels. Should I be considering this? 4. Does anyone have any good suggestions for what monitor speakers to buy. I think we'll be flush mounting them. They don't need to sound amazing off-axis, since we're mainly interested in listening from the mix position, and I don't need anything which offers the ability to calibrate its response to the room. (Also they should not cost more than our entire studio budget, and be available in India). I won't have internet access from 28th Apr to 12th May, so will respond after that, assuming nobody replies earlier. Many thanks in advance. Swami Kevala

Hi Kevala, and welcome. :)

I've been reading about various CR designs (non-env, REDE, RFZ etc), but I really don't know which one would work best for us, and was hoping for some suggestions in this regard.

I'm a fan of RFZ design, since it makes so much sense in general, and is applicable to all types of recordings. The goal with RFZ is to have the room as neutral as possible, acoustically, so that it neither adds to nor subtracts from the natural direct sound coming from the speakers. It should not "color" the sound at all, or rather, as little as possible.

just whatever will enable us to record and mix as accurately as possible.

Yup. That would be RFZ. :)

Due to the positioning of the supporting steel beams and poles (which cannot be altered), we have some restrictions in our room layout (assuming that we don't want a metal pole inside any of the rooms).

It might be possible to move some of the support columns slightly, but you will need a structural engineer to tell you if that can be done, and if so, how to do it. In some cases I have done that for studios that would have been very difficult to shape with the columns in the original positions. Your columns seem to be reasonably well positioned, except for those that would end up in the back of the control room with your layout. So don't rule out the possibility of moving things yet: It might be possible, but only a qualified structural engineer can say for sure.

Here, the control room is about 13' x 17' with 11.5' height, and the live room is 14' x 29' with 12.5' height. (We've dug down an extra foot in this area to give more height).

The size of the rooms is fine. That should work well, although some adjustments might be needed to get a better room ratio for the CR.

there is a powerful water pump which is located about 30' away from us. It has been placed in a 20' deep well in the ground, and a thick brick wall completely blocks our area from the area where the pump is. But you can still hear a background humming.

That is likely flanking noise, from what you say: vibration of the pump motor being transmitted directly into the ground and/or well walls. Is that pump correctly mounted on proper vibration mounts? If not, then I would suggest that you do that first. Those are either metal springs or resilient rubber pads, or a combination of both, that isolate the pump from the base. They need to be designed correctly for the weight of the pump, and the dominant frequencies of the noise: Mason Industries can help you with that. Check their web site, or call them. It is much, much easier (and cheaper) to solve that problem at the source, by isolating the pump itself, rather than trying to isolate the entire studio from the pump.

We initially had planned to have a ducted AC system, but due to budget constraints we are looking at using split AC units instead.

You will still need ducts. Split systems will be able to cool and dehumidify the rooms, yes, but that's only part of HVAC: you still need ventilation to bring in fresh air from outside, and to exhaust the stale air from the rooms. That ventilation system must be designed for the size of the rooms, and the occupancy, such that there is a sufficient supply of fresh air (oxygen) and removal of the same amount of bad air (CO2, odors, etc). The ducts and fans must be the correct size, and you need silencer boxes where the duct go through walls, in order to allow the air through while blocking the sound. HVAC is a major part of studio design, and probably the part that is least considered initially.

I'm expecting to need mainly brick, plywood and rockwool, which are available to us here. Also we have easy/low-cost access to large quantities of granite

Excellent! Those are all great building materials for studios.

1. Is it ok to have the steel poles in between an outer brick wall, and an inner de-coupled wall?

Yes, that's fine. As long as there are no poles that would end up inside a room.

If we were to do this, how much space would we need to leave in the air gap, and between the pole and the inner and outer walls

That depends on how much isolation you need, and the design of the walls. There are equations for calculating that, based on the number of decibels of isolation that you set as your design goal. Determining that is all part of the design process.

Would this be wasteful of space?

No. The wall has to be designed to give you the amount of isolation ("transmission loss") that you require. The size of the air gap will be determined by the equations, based on your isolation needs and the building materials that you use. So the space taken up by the wall isn't "wasted": it is the amount of space that is necessary. Since your poles are over 5" wide, I would suggest using the "inside out" method for building the walls in the areas around the poles. That allows you to optimize the total wall structure to make the best use of space without compromising isolation.

2. Is it worthwhile splaying the inner (or outer) walls / ceiling to create a reflection free zone in the CR,

In my opinion, yes! :) Others might not agree, but RFZ is the design that makes the most sense, to my way of thinking.

and if so, where can I find more resources which will help me calculate the angles and overall shape of the room.

Right here! The forum is packed full of information on RFZ. If you search for that using the search feature, you'll find hundreds of references, with many examples of how people have done it. The way you determine the angles is by "ray tracing", so search for that term as well.

3. To save money somebody suggested doing the whole studio entirely with thick PUF (polyeurathene foam) pre-fabricated panels. Should I be considering this?

No. The acoustic properties are not what a studio needs. Those "sandwich" panels are sometimes promoted as being "good for soundproofing", but if you look at the actual test results, the truth is evident... :)

I think we'll be flush mounting them.

Excellent! Then RFZ design is even more appropriate for you.

4. Does anyone have any good suggestions for what monitor speakers to buy. ... They don't need to sound amazing off-axis, since we're mainly interested in listening from the mix position,

The issue isn't so much how they sound, but rather how they perform! :) Perfect reference monitors are supposed to have no sound of their own (no coloration in either frequency, time, or phase), so they should "sound" totally neutral. They should have flat response across the entire spectrum of interest, and be able to maintain that even down to low frequencies at all playback levels, inside the room. Off-axis response is important, in the sense that it must be considered as part of the RFZ design: you should be aware of which frequencies will be hitting which parts of the walls and ceiling, so you can place suitable treatment in the right locations. Personally, I'm a big fan of Adam speakers, and probably a pair of A7x's would work well in your studio. However, considering those drums you want to record, as well as some of the other Oriental instruments, I'd suggest adding a Sub-10 subwoofer, or something similar, to extend the coverage down low enough. Genelec might be another good option. I would also suggest Klein & Hummel, but those are probably out of your price range.

and I don't need anything which offers the ability to calibrate its response to the room.

Right, assuming that you are talking about those silly gimmicky things that have the "ability" to adjust their EQ to "fix" room problems: You certainly do not need those. But what you do need is controls on the speaker itself that allow you to adjust the bass response, to compensate for soffit mounting, and also having a treble roll-off control can be useful. Hopefully, the above will get you on the right track. - Stuart -

Thanks for the quick response Stuart,

The goal with RFZ is to have the room as neutral as possible, acoustically, so that it neither adds to nor subtracts from the natural direct sound coming from the speakers. It should not "color" the sound at all, or rather, as little as possible.

Yes, that's exactly what we want.

It might be possible to move some of the support columns slightly, but you will need a structural engineer to tell you if that can be done, and if so, how to do it. In some cases I have done that for studios that would have been very difficult to shape with the columns in the original positions. Your columns seem to be reasonably well positioned, except for those that would end up in the back of the control room with your layout. So don't rule out the possibility of moving things yet: It might be possible, but only a qualified structural engineer can say for sure.

It's not possible to move them. The whole superstructure was built by our own construction team two years ago. At that time we had the opportunity to have the poles shifted a bit based on our proposed studio requirements, but it didn't end up happening exactly as we wanted. I asked if we could move one of them so we could have a wider CR window. The problem is that the ceiling above is made of 6" thick granite slabs, so there is a huge force weighing down on the poles. On top of the granite is 2" of poured concrete. They told me that it is very brittle, and even a very slight movement of the supporting beam would be enough to internally crack it. Also the poles have really deep foundations (6' deep full of granite rocks), to stop them sinking. Moving one would be a big job.

The size of the rooms is fine. That should work well, although some adjustments might be needed to get a better room ratio for the CR.

For the CR, the height from the concrete floor to the bottom of the granite ceiling is 11' 9". The distance between the outer edges of the two 5.5" steel poles that are flanking the room widthways is 14' 4" - so if we built the outer brick wall hard up against them that would be the width. (When I wrote my initial post I was confused about which side of the poles I needed to put the walls). The length of the room can be whatever we want - but if we make it more than around 17'6" it will eat into the space behind, which we had thought about using for an additional minimally-treated editing room. I believe these dimensions come nearish to one of the "good" ratios (based on the realtraps modecalc software).

That is likely flanking noise, from what you say: vibration of the pump motor being transmitted directly into the ground and/or well walls. Is that pump correctly mounted on proper vibration mounts? If not, then I would suggest that you do that first. Those are either metal springs or resilient rubber pads, or a combination of both, that isolate the pump from the base. They need to be designed correctly for the weight of the pump, and the dominant frequencies of the noise: Mason Industries can help you with that. Check their web site, or call them. It is much, much easier (and cheaper) to solve that problem at the source, by isolating the pump itself, rather than trying to isolate the entire studio from the pump.

I doubt the pump is mounted on any vibration pads. As far as I know the pump is directly on the earth floor (no concrete base) at the bottom of the well. That's a great idea, and something we can definitely do. We will contact Mason as you suggest.

You will still need ducts. Split systems will be able to cool and dehumidify the rooms, yes, but that's only part of HVAC: you still need ventilation to bring in fresh air from outside, and to exhaust the stale air from the rooms. That ventilation system must be designed for the size of the rooms, and the occupancy, such that there is a sufficient supply of fresh air (oxygen) and removal of the same amount of bad air (CO2, odors, etc). The ducts and fans must be the correct size, and you need silencer boxes where the duct go through walls, in order to allow the air through while blocking the sound. HVAC is a major part of studio design, and probably the part that is least considered initially.

Yes, that had just dawned on me actually :roll: I think I need to do some more homework in this area before I ask any more about this...

That depends on how much isolation you need, and the design of the walls. There are equations for calculating that, based on the number of decibels of isolation that you set as your design goal. Determining that is all part of the design process.

Of course. Before I write my next post I will have bought a SPL meter and taken measurements of our drums and the external ambient noise. Although the SPL meter won't tell me how much sound is getting transmitted vibrationally, through the steel pole/beam structure. Is there any way of determining this?

Since your poles are over 5" wide, I would suggest using the "inside out" method for building the walls in the areas around the poles. That allows you to optimize the total wall structure to make the best use of space without compromising isolation.

Ok, that seems like a good idea.

No. The acoustic properties are not what a studio needs. Those "sandwich" panels are sometimes promoted as being "good for soundproofing", but if you look at the actual test results, the truth is evident... :)

Any links? Would be useful for convincing others (esp. those in charge of the budget :D )

Personally, I'm a big fan of Adam speakers, and probably a pair of A7x's would work well in your studio. However, considering those drums you want to record, as well as some of the other Oriental instruments, I'd suggest adding a Sub-10 subwoofer, or something similar, to extend the coverage down low enough. Genelec might be another good option. I would also suggest Klein & Hummel, but those are probably out of your price range.

Ok. Why the A7X as opposed to A8X? Also what model of Genelec do you think would work for us. (I know somebody who distributes them in India - so might be able to get them discounted) Thanks again for all the excellent advice. Kind Regards Swami

Was just reading through this. This might be a bit off topic, but do you know why was there granite used in the ceiling? Also, you should be careful with drilling into the granite. Depending on size and location of the holes, they can weaken the strength of the granite by a rather large factor, and the last thing you want is a sudden failure of the ceiling.

do you know why was there granite used in the ceiling?

Granite was used for our ceiling because it's primary purpose is not as a ceiling; it's a floor for people to walk on. If you see the first photo in my original post, you can see people walking up some steps to a raised area. Our studio is below that.

Also, you should be careful with drilling into the granite. Depending on size and location of the holes, they can weaken the strength of the granite by a rather large factor, and the last thing you want is a sudden failure of the ceiling.

We won't be drilling into the granite slabs. There are lots of steel beams supporting all the slabs. (I only showed the main ones in my sketchup drawing - but there are lots perpendicular to these, spaced every 3 feet). We plan on attaching some hooks to these beams, from which we will suspend our false ceiling. Will be away from email until 12th May. Looking forward to getting some more suggestions on our plan in the meantime :) Will respond as soon as I'm back.

Note: Since I haven't had any replies yet, I'm editing this post as my ideas develop - rather than make a new post, as I feel this will make the thread more readable in the long run. Apologies for any confusion this might cause if you've already read it :) ---------------- So I did some basic measurements with an SPL meter. The surrounding ambient noise is mostly around 50 dbA, peaking at around 65-70. Our drums are around 110 dbA. However the meter I used only had A weighting - so these figures might be a little low. Here are some pictures of our space: I'm also attaching my latest sketchup plan. (Doors are just shown as gaps in the wall / windows coloured blue) Here's a screenshot Right now I'm trying to figure out what's the best way to construct the walls (given that we will be situated in the same building as people doing office work who need it to be reasonably quiet). I've gone for an 8" thick brick wall (outer shell) around the CR and the LR, and I'm trying to decide how to do my inner leaf. Here, our people are used to doing brickwork more than woodwork, so it might actually be easier to do it in brick. Unfortunately when the concrete and foundations were poured, I didn't know enough to ask them to make isolated slabs based on our proposed wall locations. So I could do a 2nd brick wall with a 7" air gap, but resting on the same brick foundation - which effectively couples them - doesn't it? So here's my question: Is it better to have the extra mass of a double brick wall, or better to have a gypsum, stud inner wall, because it might transmit less through the ground connection? (I could even try to get the concrete slab chipped away and reset at the wall edges if the isolation would make a big difference). The hard/dense speaker/soffit wall may be easier to do in brick, also an inner brick wall also has the advantage that it can support more of my ceiling weight... which brings me to my next question.... How should I do my ceiling? I see the general trend is to use wooden beams, but we don't use wood that much in our construction here. I think our construction team would find it easier to put up some kind of steel or aluminium frame and rest it on the brick walls. We also have the advantage of the existing steel beams which we can use to take some of the load via wires. I plan to attach hooks to the existing beams (which are spaced 3' apart) and hang the inner ceiling from them on wires. There's not too much noise from above. Everyone walking above is barefoot, and the worst case scenario is a bunch of children running around, which you can hear as a very muffled thumping through the existing 8" granite + concrete - but otherwise its pretty quiet already. We have 11.5/12.5 feet of height in our CR/LR, so I'm guessing I should leave about 2' gap for insulation and ducting. Does that sound right? But if anybody has any ideas I'd love to hear them? I spent some time figuring out the RFZ geometry and doing some ray tracing (which I found strangely addictive), and I've got a clear 2' circle around the mix position without any 1st reflections (although I haven't shown the rays in the pic). So I'm reasonably happy with the angles. However, I'd like to know what is the standard way of doing the wall treatment for the angled parts of the wall (the yellow triangular bits in my drawing)? From my understanding they should be as hard and reflective as possible so they redirect the sound away. I also wanted to use the same concept in the vertical plane. I toyed with the idea of an angled ceiling, but then figured it would be much easier to construct and acoustically seal a cuboid room, and then hang a hard backed cloud to angle away the ceiling reflections. I had the same thought about the angled side walls too... Since the only part where the angling makes a difference for RFZ is a small fraction of the wall height in the region of your head height, why not just make straight walls and put the hard reflective surfaces in the zone where they are needed, and maybe superchunks above and below... Also, have I left enough space behind my speakers (which I've modeled on the Adam A7X)? My Live Room is 33' long by 17' wide. I'm guessing this isn't a great ratio as its almost an exact multiple. Does anyone have any suggestions about what I should do - or is it not a big deal? I tried to make the room as big as possible given the available space, so we could get a good reverberant sound for our big kettle drums. Just to let you know, the small room on the left of the CR is a recording booth, and the L-shaped room behind the CR is going to be somewhere where somebody can do editing work (or minor project work, which dosn't need proper acoustic treatment - and where somebody can work and actually get some natural sunlight! The area to the right of the CR will be a kind of lobby area where people can hang out before going for a recording session. Stuart - you recommended the Adam A7X's, whose dimensions I've used in my plan (13.5" x 8" x 11"). Can you tell me how many inches up the speaker the acoustic axis is. I can't find that information anywhere. I'd really appreciate any suggestions / improvements on any of this. I'm new to this, so I don't want to be making any huge blunders. Ok, now onto HVAC.... Our large live room (15' x 33' x 11' = 5445 cf) will be used in vastly different scenarios. Sometimes it might contain just a single person recording a guitar. At other times it might have the whole band of 12 people rehearsing with all their amps and monitors plugged in. I need a system that will provide adequate HVAC for both extremes without being inefficient. First consideration is air ventilation alone. I saw Rod's recommendation of 15 cfm per person based on the ASHRAE standards for "music room", but I don't think they are considering that it is an acoustically sealed room, since they give the same figure for general office environment... so I'm going to take a figure of 25 cfm per person. Now assuming I use ducting which has a cross section area of 1' x 1', then for 1 to 12 people, I need 25 to 300 cfm respectively. Is it possible/worthwhile to get a controllable fan that will allow me to control the fan speed based on the number of people in the room? Now, I know I also need to calculate the static pressure of the ducting/room system to complete this calculation... but this requires me to have the ducting layout figured out, which I don't have yet. There are a couple of options for routes to get fresh air. The shortest route would be to go directly outside the exterior wall which connects to the outside world, underneath some stone steps (which you can see in the first photo I posted in this thread). I have two questions: 1) How loud would this fan be? It's a serene public space opposite a temple, so it shouldn't be noisy (like the sound of a typical outdoor AC compressor unit on a regular split AC). 2) Would this also mean that the fan is too close to the room itself thus being a source of noise for the room? If so, how far away should the fan ideally be placed? Once I know this I can plan the layout of my ducts and then work out the static pressure. Next consideration is cooling/AC. The only realistic place that I can see for putting one or more compressor units (due to the unsightly appearance and the loud noise), is around the side of the main building, away from the general public (in the same maintenance area where the big water pump is, but still next to the outside). However, that is about 100 ft away from the studio. Is it possible to just run the coolant line alone for the majority of this distance, only inserting it into the ventilation ductwork closer to the studio (thus saving on having to build large run of ducting)? Apologies if this is a dumb question... I only started learning how AC units work this morning, so I could be missing some basic knowledge. As always, looking forward to any advice Thanks in advance Swami

Just came up with a possibly better alternative layout... Here I've turned the CR 90 degrees to get more space. Added sliding glass doors to the live room, and a "skylight-cloud" to create my RFZ while also letting natural light in the room! Looking forward to hear what you think...