New one room studio setup for recording and mixing

[AdirondackAsh]

Hello,

This is my first post to this forum and I appreciate any help I may receive! I have read the forum rules, but please do not hesitate to point out anything I may be missing as I know how busy everyone here is. I hope this is in the right sub-forum, if not please let me know and I will move this posting.

I will loosely call this a "studio build," as in reality my budget and time constraints do not allow me to do a full buildout here but more of how do I get this room to sound better because right now there is a lot of flutter echo and harsh reflections. My budget is around $3500. I really appreciate any help on an approach to improving the acoustics. I have had heard from a non-expert friend who suggested stuffing the back wall and ceiling with fiberglass and adding panels but I have no experience in these matters and have no idea if this is a help or how much is needed.

My setup and needs: I am a guitar player and am mostly recording my own music and occasionally get very loud pushing 130db. Since I am doing my own stuff I can pick and choose the times I record - . My recording setup consists of an MCI 500 series console, headphone system and Urei 809 monitors with an infinity sub. Many guitar amps of varying wattage from 5 to 100 paired with speakers from 1x12 to 4x12. I will be recording electric and acoustic guitar, vocals, live drums, percussion, amplified bass, and amplified electric pianos in that order of occurrence.

Isolation Requirements: As you can tell from my budget, I do not have money to isolate, but fortunately do not really need to worry about neighbors as I only have one and they are rarely there, (however I would like to seal the cracks in the floor as they go straight through to the room below me which is unoccupied storage, and the neighbor is adjacent to this room). The downside to no isolation is of course no protection from exterior noises, but the room is surprisingly quiet with the exception of heavy rain or wind, but as this is my own project, I can work around these times.

Room Description: This will be a one studio in a room that is 24 feet x 29 feet with a sloped ceiling. The ceiling is 12 feet high at the side of the room with the door and 9 feet high at the other end (wall covered in white plastic backed fiberglass). I am on the 2nd floor of an industrial building and the floor is made of 4" concrete poured over metal framing. The side walls that are each 24 feet in length are made of drywall, but running along the top of each wall are steel structural beams suspended by two steel posts. All of this steel is covered in a flaky, softish fireproofing material. My ceiling is the roof of the building and it is covered in fiberglass insulation that is underneath a metal roof. The back wall is this fiberglass with a 1/4 thick hard plastic sheathing.

Electrical: Sub panel with 200 amp service

HVAC: This is an unventilated with the exception of the door but the building is in the shade and it stays cool in the summer with gear on.

Questions:

1) What should be my general approach be in getting this room to sound "better." I know this is subjective, but should I focus on the walls or ceilings first?

2) How much absorption is too much? If I cover the entire ceiling and back wall with fiberglass, not only will this eat up my budget quickly, but will it be overkill?

3) Can anyone recommend a product to fill the cracks in my concrete floor with that will fill the crack entirely and produce a strong air-tight seal?

4) I have concerns with dust from insulation materials such as fiberglass or rockwool after it is installed and leaking through its fabric covering. I have read about covering this first with a very thin layer of plastic - is it consensus opinion that this is acceptable and will not lessen the affect of the insulation? Should I be concerned with putting too heavy of a fabric over these materials like thick muslin that is not transparently acoustic?

Thanks, any insight is greatly appreciated!

[AdirondackAsh]

Hello - Can anyone offer any opinion on the problem with this post and how I can modify it to receive an answer?

Thank you

[Soundman2020]

Hi there "AdirondackAsh". And WELCOME!

You sure are a patient fellow! I would have been bumping my post a week ago already, in your shoes...

Sorry about the delay, but times are hectic right now: the forum is busy, and it looks like I'm the only one answering questions at present... and there's just one of me! End of year (hectic), and I'm working on several studio designs in various places around the world, so sometimes threads like yours sort of fall through the cracks.... I'm real sorry that it happened! Feel free to send me a PM with a "bump", if you get ignored for so long in the future...

This is my first post to this forum and I appreciate any help I may receive! I have read the forum rules, but please do not hesitate to point out anything I may be missing as I know how busy everyone here is. I hope this is in the right sub-forum, if not please let me know and I will move this posting.

You did fine! The problem is me, not you... I wish I had more time to be able to take care of both my paying customers and also the forum, but time is limited.... and paying customers have to take priority! So sometimes I'll a little slow on responding to forum threads. Not by desire! By necessity. If I could figure out how to fit another 5 or 6 hours into each day, and another two or three days into each week, then I'd be fine!

I have had heard from a non-expert friend who suggested stuffing the back wall and ceiling with fiberglass and adding panels but I have no experience in these matters and have no idea if this is a help or how much is needed.

Hmmm.... wellllll... let's just say that would not be a lot of help! Or rather, it would help to a certain extent, but only if combined with the rest of the stuff that also needs doing. By itself, it would accomplish very little.

My setup and needs: I am a guitar player and am mostly recording my own music and occasionally get very loud pushing 130db. Since I am doing my own stuff I can pick and choose the times I record - . My recording setup consists of an MCI 500 series console, headphone system and Urei 809 monitors with an infinity sub.

From what you say, it sounds like this is going to be bother a control room and also a live room at the same time, right? So you'll be tracking your instruments and vocals, then you'll be mixing the tracks, all in the same single room. Correct?

Isolation Requirements:

Understood: No isolation on the cards. Not enough budget, basically, and you can work around incoming external noise.

The ceiling is 12 feet high at the side of the room with the door and 9 feet high at the other end

That defines the basic orientation of the room: The speakers should be up against that 9' high wall. That's your front wall.

HVAC: This is an unventilated with the exception of the door but the building is in the shade and it stays cool in the summer with gear on.

You might need to think about a small mini-split unit at some point: Studio HVAC is not just about temperature, but rather also about humidity. Many acoustic instruments and some mics are sensitive to changes in humidity, so you should ideally hold the humidity around 40% permanently.

1) What should be my general approach be in getting this room to sound "better." I know this is subjective, but should I focus on the walls or ceilings first?

First you should focus on getting your mixing area arranged with the correct layout and geometry, and the correct basic treatment, to get the acoustic environment that a control room needs: neutral, flat, character-less. Then with that in place, you should worry about the rest of the space, and setting it up with whatever character you prefer. So basically, split the room into two "zones".

2) How much absorption is too much? If I cover the entire ceiling and back wall with fiberglass, not only will this eat up my budget quickly, but will it be overkill?

It would not be overkill, no, but it would also not be necessary for the entire room. You will probably need that over the mixing area ("control room"), but you can do something more live, with less insulation, for the tracking area.

3) Can anyone recommend a product to fill the cracks in my concrete floor with that will fill the crack entirely and produce a strong air-tight seal?

If that crack in your concrete is letting air through, then you have a much, much bigger problem than you think! That's a major structural issue. Before doing anything else, you need to get a structural engineer to look at that, to tell you just how serious it is, and what can be done about it. However, from the photos, it doesn't look like that is a structural crack through the entire slab: it looks more like surface cracking from an improperly cured slab. Are you SURE you are getting air coming though that crack?

4) I have concerns with dust from insulation materials such as fiberglass or rockwool after it is installed and leaking through its fabric covering.

Depending on what type of insulation you use, then problem might be greater or lesser. If you use something like OC-703, it comes in semi-rigid panels that have a bonding agent holding the fibers together, sort of, loosely, but if you use "pink fluffy" or plain mineral wool, the problem could be worse.

It also depends on where the insulation is located: If it is above your head in the cloud or on wall panels near where you sit or play, then yes, that' might be an issue. If it is at the back of the room behind the couch, it's probably not an issue at all.

And finally, it also depends on the purpose of the panel.... see below.

I have read about covering this first with a very thin layer of plastic - is it consensus opinion that this is acceptable and will not lessen the affect of the insulation?

Plastic is a good way of retaining any loose fibers, yes, and thin plastic on the cloud above your head is a very good idea.

Will it have an effect on acoustics? Absolutely! Yes! And that's a good thing, because it allows you to "tune" the panel, to a certain extent. Plastic is considered to be a "foil", acoustically. It blocks sounds above a certain frequency, based on its thickness (or more correctly, its surface density). The thicker it is, the more of the spectrum it blocks. Very thin plastics, such as the very light weight films that painters use as drop-cloth to cover furniture, only affects the very top end of the scale. Very thick plastic, such as you'd put under the foundations of a building, has a major effect all the way down to the low mids.

So you can use this to decide what type of plastic to use to cover your panels, depending on their function. For example, bass traps are typically very large, very deep, and cover large areas of the room... which means that in addition to treating the low frequencies a bit, they absolutely kill the highs, sucking out all the clarity and detail. So you generally want to cover the face of your bass traps with plastic that is thick enough to reflect back the highs into the room, and only allow the lows through into the trap itself.

Should I be concerned with putting too heavy of a fabric over these materials like thick muslin that is not transparently acoustic?

depends on the fabric! All of your acoustic panels should only ever be covered with "breathable" fabric. "Breathable" means that if you hold a piece of that fabric across your mouth and nose, then you are still able to breathe reasonably well, without noting too much resistance. If you can't breathe, or you end up sucking and blowing crazily like you just ran a marathon, then it's no use as a cover on your acoustic panels.

Thanks, any insight is greatly appreciated!

- Stuart -

[AdirondackAsh]

Hi Stuart! Thanks a lot for your reply - I understand the business of everyone here and I appreciate ANY time you have to contribute to helping me. Thank you! In regards to my patience in waiting for a reply I look at it this way: Why rush ahead and do things the WRONG way, which in the end will cost much more time and lost effort in fixing things than simply doing it correct the first time around by taking into account the decades of experience and knowledge that you will impart?!

From what you say, it sounds like this is going to be bother a control room and also a live room at the same time, right? So you'll be tracking your instruments and vocals, then you'll be mixing the tracks, all in the same single room. Correct?

Correct. This is a one room setup for tracking and mixing. I wish I had the budget to build a control room but I simply do not!

That defines the basic orientation of the room: The speakers should be up against that 9' high wall. That's your front wall.

Herein lies a problem and maybe there is a way to fix it? With the orientation of the door It is very difficult to set up this way - So I am set up in reverse with my back a few feet off of the wall that is 9 feet high with the speakers pointing at this wall at about a distance of ten feet or so. Is it catastrophic or just problematic to set up in this orientation?

By the way, I forgot to mention that I have a temporary setup in a room exactly the same dimensions down the hall that is more of a workshop - I have spent the last year and a half working on my equipment and fixing old tube amps and the like that I collected in various states of disrepair. I have not recorded anything in this room and am lucky to get a room down the hall open up that I can treat before I move into.

The way I have it set up now the mix position is in the middle of the room, with each side wall being equal distance away, about 12 feet. This wastes a lot of space and I was wondering if I can move the mix position to one side of the room? I know geometrically this causes a problem but now that I am looking at actually recording and mixing I realize I need the space and would like to move the mix position so one ear is about 6-10feet from one side wall and the other ear is about 14-18 from the other side wall.

I wonder how much this complicates things in terms of getting an accurate sound field at the mix position and if this is doable or just a really bad idea??

You might need to think about a small mini-split unit at some point:

Agreed and will be looking into this with the landlord.

First you should focus on getting your mixing area arranged with the correct layout and geometry

Does moving to one side and having the 12 foot wall as the front wall mess things up royally as explained above?

You will probably need that over the mixing area ("control room"), but you can do something more live, with less insulation, for the tracking area.

Good to hear that I can do things correctly AND save some money at the same time!

If that crack in your concrete is letting air through, then you have a much, much bigger problem than you think!

I looked into this and brought this up with the landlord after you mentioned your concerns and they are just superficial settlement cracks - not structural. There isn't air coming through these cracks, my mistake! I also found a good two part epoxy floor seal to fill these cracks and they make a nice smooth surface.

Plastic is a good way of retaining any loose fibers, yes, and thin plastic on the cloud above your head is a very good idea.

Great! I'm happy to hear I can do this and it can be turned to an advantage! There is a wide range of polyethylene available at the local home improvement store ranging in thickness from .31mm to 6mm. The thin stuff is labeled as "dense polyethylene" so I wonder if its reflective properties can be guessed at based solely on it's thickness or are there different formulations of polyethylene that would have two different thicknesses reflect in different ways. It's probably more or less equal based on thickness, and "dense" may just be a marketing term to sell the thin stuff, but of course I don't know!

I found this information on a website listing NRC'S (https://svetlanaroit.files.wordpress.co ... alues2.pdf

Plastic [3mm]
250Hz: 0.34
500Hz: 0.25
1000Hz: 0.19
2000Hz: 0.15
NRC: 0.23

I also located this information http://www.iperf.org/perforating/knowle ... materials/

The bottom of the page has an interesting chart showing different thickness of Poly - but in their test there is a perforated metal sheet in front of it. I have no idea how to interpret this data and if these are reliable sources or not so apoloigies in advance if I am just muddying the waters here!

I am very intrigued by your suggestion that I can tune the room and the panels by using different kinds of plastic! But at the same time maybe a little perplexed on where to start?

So you can use this to decide what type of plastic to use to cover your panels

Another point of confusion - The many different kinds of rock wool out there.. I have a supplier nearby that carries 8lb PCF rockwool in 2'x4' 2 inch thick panels which is handy dimensionally because the home improvement stores seem only to have the 16inch by 4ft 3 inch thick Safe N' Sound Roxul brand.

I would like to go ahead and start making the ceiling cloud and also some wall panels that can then be moved around into different parts of the room. I feel silly for asking this because I know there is so much more that goes into it, but can you offer some advice on what thickness of rockwool at what density I should use to get started on the cloud and wall panels? And should I just go with the thinnest plastic I can find for these panels which I was thinking of making 4x8 ft and 2x4ft in size?

Thanks Stuart!! I very much appreciate it!

[Soundman2020]

Herein lies a problem and maybe there is a way to fix it? With the orientation of the door It is very difficult to set up this way -

Now I'm confused! If you set up the room correctly with the speakers against the 9' wall (which has no door in it), then the door in the 12' wall will be nearly 20 feet behind you! How can that door interfere with that?

So I am set up in reverse with my back a few feet off of the wall that is 9 feet high with the speakers pointing at this wall at about a distance of ten feet or so. Is it catastrophic or just problematic to set up in this orientation?

Somewhere between "catastrophic" and "even worse"!

Here's the issue: You should NEVER have a reflective surface close behind your head, since the reflections, SBIR, modal issues, and bass build-up will be wreaking havoc with your psycho-acoustic perception of sound. Psycho-acoustics is a branch of acoustics that deals with how our ears and brains process sound, and he we interpret what we hear. It's fascinating, actually! But you don't need to know to much about it, except this: having your head close to a wall is a really, really, really, REALLY bad thing. It screws up the frequency response, and produces a whole bunch of artifacts that will absolutely trash your ability to clearly hear the sound as it actually is.

Maybe "tragically apocalyptic" would be a better term...

You need at least 10 feet between your ears and the rear wall, absolute minimum, so that there is at least 20 feet of "round trip" for the sound waves that went past your ears, hit the back wall, and returned to your ears. Since sound moves at a speed of about 340 m/s, that's roughly 1 foot every millisecond, so a 20 foot round trip means a delay of 20ms, which is right on the edge of the Haas time. That's how much time your brain needs to register that the reflected sound is an "echo", and NOT part of the direct sound. If your brain though the reflection was part of the same sound, then that would screw up its calculations, and it would tell you that the direct sound from your speakers was at a different frequency from that it really is, and coming form a different direction than where it really is.

In other words, the room would cause your brain to lie to you about the tone and the direction. Psycho-acoustics.

Therefore, you need to get your head as far away from the back wall as you can, within reason, in order to give your brain a chance to tell you the truth about what you are hearing. 10 feet is the absolute minimum. 20 would be much better. Your room is big enough to do that....

The way I have it set up now the mix position is in the middle of the room,

... which is the worst possible place! The middle of the room is where all of the first-order modal issues will be at there absolute peak, and all of the second order modal issues will be at their absolute null. The frequency response at that that point in the room is a series of humongous mountains and treacherously deep chasms. Not a good place to have your ears if you want to hear the actual sound coming from your speakers.

This wastes a lot of space and I was wondering if I can move the mix position to one side of the room?

Nope! You need symmetry. Your left ear needs to hear the same acoustics as your right ear. If not, then your stereo imaging will be skewed, and you will subconsciously try to compensate for that in the mix. Your mixes might sound fine in the room, but since the room is lying to you about the sound stage, your mixes will sound grossly twisted when played anywhere else...

Your head must be on the room center-line, such that you have the same distance from your head to each side wall.

would like to move the mix position so one ear is about 6-10feet from one side wall and the other ear is about 14-18 from the other side wall.

As long as you can persuade everyone who will ever listen to your music to block one ear with a piece of paper, and the other ear with a chunk of cardboard when they listen to your music, then that's fine...

If not, they you need to set up your mix position symmetrically.

I wonder how much this complicates things in terms of getting an accurate sound field at the mix position and if this is doable or just a really bad idea??

Of those two, I would choose option B. (But if you wanted to add an option C of "grotesquely disgusting", I think I'd switch top option C....)

Does moving to one side and having the 12 foot wall as the front wall mess things up royally as explained above?

Yep. No doubt.

I looked into this and brought this up with the landlord after you mentioned your concerns and they are just superficial settlement cracks - not structural. There isn't air coming through these cracks, my mistake! I also found a good two part epoxy floor seal to fill these cracks and they make a nice smooth surface.

Then your floor is done! Yaaay! You can't get a better floor than a good old solid concrete slab.

there is a wide range of polyethylene available at the local home improvement store ranging in thickness from .31mm to 6mm.

Ummmm.... are you SURE that is all measured in millimeters? 6mm is about 1/4".... I doubt that you'd find polyethylene in sheets one quarter inch thick at Home Depot! Maybe you are confusing "mm" with "mils"? 6 mil plastic is the typical stuff that is used under building foundations, but it is NOT 6mm thick! It's about 0.15mm thick... One "mil" means one thousandth of an inch. "6 mil" is six thousandths of an inch, or 0.006". an inch is 25.4mm, so 0.006 x 25.4 = 0.1524mm....

The thin stuff is labeled as "dense polyethylene" so I wonder if its reflective properties can be guessed at based solely on it's thickness

Plastic is a foil. It behaves like all foils. "dense polyethylene" implies that it is HDPE plastic. The density is around 950 kg/m3, so the surface density of 6 mil HDPE would be roughly 0.145 kg/m2, (roughly 0.03 PSF). In other words, a piece measuring 10 feet by 10 feet will weigh about 3 pounds.

6 mil plastic is about 80% "transparent" to sound at 656 Hz (allowing 80% of that frequency through to the other side, reflecting back 20%, or coefficient of reflection = 0.2). The curve rises to about 99% reflection above that, at about 6 dB/octave, and falls off to practically 0% transparency below that, at the same rate.

Thinner stuff moves that 80% point up the scale. Thicker stuff moves it down.

are there different formulations of polyethylene that would have two different thicknesses reflect in different ways.

Yes. There's also MDPE and LDPE, but I would expect that the stuff they have in Home Depot is likely to be HDPE. There's not a huge difference in density. There might be other plastics that are not polyethylene.

I found this information on a website listing NRC'

Yes, but that's for 3mm plastic, not 3 mil plastic! 3mm is pretty thick....

I'm also wondering of there's a typo in that table, since they say that 3mm plastic has the exact same properties as 1.5mm of steel plate, which doesn't sound right to me! The density of steel is about 8 times greater than HDPE: around 7900 kg/m3 (steel) vs 900 kg/m3 (plastic)....

I also located this information

Yes, but that's micro perf foil! A very different animal. Not comparable. Very different acoustics going on there.... That's a tuned resonant device, based on the Helmholtz resonator principle.

But at the same time maybe a little perplexed on where to start?

I would start by setting up your room correctly:

Speakers tight up against the 9' wall, leaving only 4" gap between the wall and the rear corner of the speaker, where you will insert a 4" thick panel of OC-703.

Speakers on stands, such that the acoustic axis of the speaker is 48" above the floor. (NOTE!!!! "Acoustic axis"!!! Not the top or bottom of the cabinet, nor the middle of the front panel, nor the tweeter, but the actual acoustic axis. Check the manual for your speaker, aor ask the manufacturer.)

Speaker stands must be HEAVY! No, that's not heavy enough! Think again. I mean HEAVY! As in MASSIVELY heavy. Some people stack up concrete blocks to achieve that, others use bricks, and others use hollow steel section with a large cross section, and will them with sand. That type of "heavy".

Set up the stands so that the acoustic axis of each speaker will be 102" from the side wall. Therefore the speakers will be 84" apart. Now set up your chair facing that front wall, on the room center-line and 119" from the front wall. That's where your ears need to be. Now set up a vertical pole 135" from the front wall, also on the room center-line (in other words, 16" behind your head). Use a mic stand or something similar for that. Set up a laser pointer taped to the top of each speaker, directly above the acoustic axis, and perfectly perpendicular to the front face of the speaker. Rotate the speakers in place on the stands until both laser dots are hitting the exact same spot on the vertical pole. Double check all the measurements again.

Bingo! Your speakers and mix position are set up in the optimum location for that room. Now you can move your desk in front of the chair so that it is in a comfortable position for you to mix. Don't move the chair! Move the desk. Arrange the rest of the room BEHIND that setup. Nothing between you and the speakers.

Another point of confusion - The many different kinds of rock wool out there.. I have a supplier nearby that carries 8lb PCF rockwool

Way too dense. What you want is 3 PCF mineral wool, or 2 PCF if you are using fiberglass. 8 PCF would be lousy for bass frequencies. Way too heavy. It would do well for high frequencies, though! But you need much lighter stuff for low frequencies.

I would like to go ahead and start making the ceiling cloud and also some wall panels that can then be moved around into different parts of the room.

The treatment around the mic position will go in very specific places. That includes the cloud, the panels between the speakers and the front wall, and the panels on the first reflection points on the side walls, the bass traps in all four corners, plus probably a few others to even out the response a bit. For the bass traps, I would do 36" superchunks in each of the four vertical corner, floor to ceiling, and see how it goes with that. You might need some more in other corners, but start with those four first.

I feel silly for asking this because I know there is so much more that goes into it, but can you offer some advice on what thickness of rockwool at what density I should use to get started on the cloud and wall panels? And should I just go with the thinnest plastic I can find for these panels which I was thinking of making 4x8 ft and 2x4ft in size?

Not silly at all!!!! The only silly question is the one you DIDN'T ask...

Your cloud will need to be hard-backed. i would suggest 3/4" OSB for that, or maybe 5/8" MDF. It will need to be large enough to cover most of the area between the speakers and the desk. It might be better to break it up into two or three smaller clouds, hung close together (like the one in this studio http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 ). I'd also suggest that you angle them (lower over the speakers, higher over the desk, same as in the link above). Build them with 2x4 framing, and use 3" OC-703 between the framing members on the lower side, then a sheet of THIN plastic (1mil would be fine, but NOT 1mm!! ), then cheap black fabric, then the final finish fabric of your choice. On top of the cloud you can put more insulation, and that could be more OC-703, or "pink fluffy", or mineral wool. Make that thick.

Thanks Stuart!! I very much appreciate it!

- Stuart -