Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

All about acoustics. This is your new home if you already have a studio or other acoustic space, but it isn't working out for you, sounds bad, and you need to fix it...
User avatar
Soundman2020
Site Admin
Posts: 889
Joined: Thu, 2019-Sep-19, 22:58
Location: Santiago, Chile
Contact:

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#91

Postby Soundman2020 » Sun, 2020-Jul-19, 01:51

Would love to hear Stuart's breakdown of the fabric issue ...
Darn! I'm glad you are only asking easy questions here!!! :lol:

Whew! At least it's nothing complex.... :) That's a relief! 8-)

OK, there's several things at play here. I've covered a couple of them already, such as: GFR = Gas Flow Resistivity = acoustic impedance. Measured in the cryptically named units of "MKS rayls", or also pascal-seconds per meter (Pa * s * m^−1). Which, even more confusingly, is the same as newton-seconds per cubic meter (N * s * m^−3). Or alternatively, kilograms per second per square meter (kg * s^−1 * m^−2). :shock: :roll: :cry: :ugeek:

Now that I have completely confused the hell out of us all, what that really means (as I alluded to above), is that you apply some air pressure to one side of your sample of material, and see how much air flows out the other side. That's it. The relationship between the pressure and the flow, is GFR. It's that simple... (or not!)

What that tells you is how much the material resists air flow (duh! kind of implied by the name: GFR!). When you think about it, sound is just flowing air too (in the sense that the molecules of air don't actually flow very far, but they do "flow" back and forth due to the vibration that we call "sound"). So if you measure the resistance to air flow, you are actually measuring the resistance to sound flow. It's the same thing. Except that more correctly we are talking about how the material "impedes" the flow of sound, rather then "resisting" it... technically, it is not the same thing. In common speech, "resisting" and "impeding" are pretty much synonyms, but not in electronics, physics... and acoustics. But it has basically the same meaning: the material somehow stops some of the sound getting through, or slows it down, or whatever, so that less of it gets through. That's what GFR is all about: acoustic impedance: it answers the question: "to what degree does this material inhibit the flow of gas, or air, or sound?". (To be entirely accurate, I'm taking about specific acoustic impedance here, not just plain acoustic impedance... but don't worry about that yet.... maybe some other day).

So, a high GFR number means "sound has a hard time getting through", while a low GFR number means "sound can get through more easily". Curiously, even air has a GFR number! It is about 400 MKS rayls... which sounds rather silly, as that basically means that air resists the flow of air :shock: but it's not so silly when you think about it a bit more.

But I digress!

If you know about about electricity or electronics, then this might help (if not, then skip to the next paragraph...). Acoustic impedance is very analogous to electrical impedance. With electricity, you apply a voltage to a resistor, and you get current flow. How MUCH flow you get, depends on the impedance value of the resistor. Another word for "voltage" is "electrical pressure" or "potential difference". This is identical with acoustics: you apply an air pressure (pressure difference) across the material, and you get air flow. How MUCH air flow you get depends on the impedance value of the material. With electrical circuits, you measure impedance in "ohms". With acoustic impedance, you measure it in "rayls". But they are very much analogous to each other.

OK, so now that you are even more confused(!) lets simplify: you blow through it, and see how much air comes out. Period. That's about as simple as you can state it. If you blow hard and very little air comes out the other side, then it has "high GFR", or "high acoustic impedance". If you can just blow a little bit and already get a lot of air out the other side, then it has "low GFR", or "low acoustic impedance". If you can't get air to flow at all, no matter how hard you blow, then basically the GFR is infinite, and thus the acoustic impedance is infinite.

So far so good!

Now for the next step: If sound cannot get through, then either it must get reflected back the way it came, or it must be absorbed by the material itself, in one way or another. The sound energy has to go SOMEWHERE! One of the most fundamental principles of physics is that it is impossible to create or destroy energy: only God can do that, but we mere mortals, and all of the processes in the universe, cannot do that. Energy cannot be created or destroyed. Fundamental law of physics. All that is possible according to the laws of physics, is to convert energy from one form to another (or in extreme cases, to convert it to or from mass, in nuclear reactions). So, since there are no nuclear explosions going on inside your studio fabric (hopefully not, anyway!!!), the sound energy that arrives at the face of the fabric MUST go somewhere: it cannot just disappear. The only real options here are: 1) it gets converted into low-grade heat energy (several mechanisms can do that, but basically think: friction). 2) It gets converted into "kinetic energy", meaning that it makes something move, 3) it gets converted into some form of potential energy (complicated!! not going there for now!), or 4) it stays as sound energy, but going in a different direction from where it would have gone (usually meaning that it reflected off the material).

So, to summarizes; the sound that hits the non-breathable fabric and can't get through as moving air, can do one of these: 1) be converted into heat, 2) be converted into movement, 3) be stored, 4) be reflected. That's it. There are no more options.

Right, so the simplest one of those four to explain here is number 4: reflection: the sound hit the material, could not get through as air molecule movement because of infinite impedance, so it bounced right back. That's the most likely, and simplest to understand: simple analogy: the rubber ball hit the wall, could not break through the wall, so it bounced right back.

Number two is also easy to understand: the sound wave hit the fabric, but could not get through so it made the fabric move... just a little, of course: it's not going to blow it across the room! (unless we get back to the nuclear explosion thing...). In fact since the air molecules are just vibrating in place as the sound wave moves along, then the force of those air molecules as they rush in, can cause the fabric itself to vibrate, at the same frequency as the sound wave was vibrating. (Sound is just air molecules vibrating in place: the sound wave rushes along at the speed of sound, but the individual air molecule stay where they are, vibrating around their original location). So that's what would happen in this case: the air molecules hit the surface of the fabric, move it a tiny fraction of an inch, stretching it just tiny amount, but then the molecules run out of steam, so to speak, and the stretched fabric "un-stretches" again, pushing the molecules back where they came from... but then the next wave front arrives, and pushes the molecules the other way again, they hit the fabric, stretch, un-stretch, lather, rinse, repeat... In simple terms, the vibrating air makes the fabric itself vibrate.... and here's the kicker... because the fabric is vibrating, then it causes the air on the OTHER side to ALSO vibrate! Tah-dah! The sound wave gets through, even though the air molecules did not!!!

OK, so now we are all confused again! I just said that infinite impedance means that sound CAN'T get through, and now I'm saying that sound CAN get through! :geek: :?:

Explanation: this is a totally different mechanism. With this situation, the sound can only get through if there is enough energy to make the fabric vibrate, and that depends on OTHER properties of the fabric: not the GFR. GFR only tells you about how the air molecules themselves will move through the material, bumping each other along. But when they CANNOT get through it (because the material does not allow them to move through), then obviously that GFR thing is not happening any more! So now we have gone beyond simple porous absorption, and we are looking at something else: resonance. We are making the entire sheet of fabric vibrate, but it will ONLY do that at one specific frequency, or a set of frequencies, and none of that is related to GFR. Now it has to do mostly with two other parameters: the mass of the material (surface density), and the elasticity: how tightly it is stretched. That's even more complex to get into, but the basis is simple: pluck a guitar string and listen to the note. Tighten the string a bit, and the note goes up. Ditto for a drum head: tap it with a drumstick and it makes a tone: tighten it a bit, and the tone goes up. Loosen it and the tone goes down. Loosen it a LOT, until it is limp, and there is no tone at all! Your drum head is now a "limp membrane"....

So, your non-breathable fabric on your bass trap is very much like that drum head: if it is stretched even just a little bit, it will have a resonant tone. If it is hanging loosely, it won't: it will be a "limp mass"... and will look rather ugly, since it will be all wrinkled and floppy! For any reasonable arrangement, you will undoubtedly stretch the fabric, at least a little. So it will be a membrane, not a limp mass. And thus, it will want to resonate at a specific frequency (or set of frequencies). An when it DOES resonate, it will allow that frequency to get through to the other side, because it vibrates in sympathy with that tone, and thus it transmits that sound to the other side. However, for other frequencies, it wont vibrate, and won't transmit sound. In other words, you have a tuned trap! It is tuned to some frequency(ies)!!!!

For a bass trap, that might, or might not, be a good thing. Probably not.

Now, the interesting thing about membrane traps, is that they can be tuned "tight" (high Q) or "loose" (low Q), depending on a number of things.... which are a bit complicated to go into at 3 AM!!!!. And in general, they transmit not just their own resonant frequency, but also all frequencies lower than that, while NOT transmitting al higher frequencies.. which they simply reflect back the way they came, or turn into low grade heat, or nuclear explosions... :)

And now we get back to what I said about plastic foils earlier: in essence, non-breathable fabric IS a foil! It behaves just the same. It allows some range of low frequencies to get through and reflects back the others. The only real difference here is that the fabric is stretched tight, so it also has a resonant frequency due to that. Which is why I also said before that the equation I gave for plastic foil assume that it is NOT stretch tight, but rather is limp Because if you stretch it tight, even a little bit, then you have a membrane trap! Exactly the same as the fabric.

OK, so after waffling on for many paragraphs, I'll try to get to the point: Non-breathable fabric reflects sound. But it does so differently for different frequencies. It might also absorb some sound (by converting it into low-grade heat), and it might also transmit some sound to the other side, which it does through resonance if it is stretched a little, thus acting as a tuned membrane trap.

Not sure if any of that helped at all!

I think I just confused myself, actually.... :? :!:


- Stuart -



User avatar
Soundman2020
Site Admin
Posts: 889
Joined: Thu, 2019-Sep-19, 22:58
Location: Santiago, Chile
Contact:

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#92

Postby Soundman2020 » Sun, 2020-Jul-19, 02:36

Here's a rough sketch I made for the back wall superchunks going floor to ceiling and also across the top corner meeting in the tri-corners.
I really like that! It looks pretty good to me.... :thu:


- Stuart -



User avatar
Soundman2020
Site Admin
Posts: 889
Joined: Thu, 2019-Sep-19, 22:58
Location: Santiago, Chile
Contact:

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#93

Postby Soundman2020 » Sun, 2020-Jul-19, 02:39

we just can't get the Homasote panels in the UK and it seems to be a crucial part of how these works.
You can't get Homasote, but you CAN get Sundeala... https://sundeala.co.uk/ :) Basically the same thing. It will work fine.

- Stuart -



User avatar
Soundman2020
Site Admin
Posts: 889
Joined: Thu, 2019-Sep-19, 22:58
Location: Santiago, Chile
Contact:

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#94

Postby Soundman2020 » Sun, 2020-Jul-19, 02:55

Stuart suggested acoustic hangers earlier in the thread. Apparently very effective and well worth considering.


Yes I'm still in the dark about how these things work and how they are made. I've heard they have to be cut to certain sizes because the Homasote panel acts as a tuned membrane of sorts?

Hangers work on several principles at once. I've seen some people incorrectly refer to them as "waveguides": while that is, indeed, one of the mechanisms, it isn't the only one, so calling them "waveguides" is incorrect, and imprecise.

The "waveguide" part of it is fairy easy to understand: if the hangers are at an angle to the incoming sound, then the core Homasote panels tend to re-direct the sound wave such that it ends up traveling along them, in between the panels, parallel to the surface... and thus has to fight its way through a LOT of insulation along the way! It is then forced to travel through the full length of the insulation... getting greatly absorbed along the way. Then the little bit that is left hits the back wall, gets reflected, and has to do the same thing going out again: get redirected nad take the long path through all that insulation again.

There is also some resonance going on in the air cavities between each panel and it's neighbor. Not much, but some.. enough to help a little bit.

And there is also some panel resonance going on: the Homasote panels themselves vibrating, just slightly, and the insulation damping that vibration (as well as the Homasote itself doing some damping).

Then there's edge diffraction, where the sound wave strikes the ends of the panels.

Then there's impedance mismatch, as the wave suddenly move from free air, which has one impedance, into the insulation / air / Homsaote combination, which has a very different impedance.

And probably something else that I'm forgetting, but those are some of the ones that are helping. They all add up, and make a vert effective trap.


- Stuart -



User avatar
shybird
Full Member
Posts: 100
Joined: Sat, 2020-Jul-04, 17:29
Location: Nashville, USA

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#95

Postby shybird » Sun, 2020-Jul-19, 15:19

endorka wrote:Source of the post In your shoes I would stick to the superchunk plan rather than going back to the 6" panels. Reason being that while the treated room above was a big improvement, there was still a lot that could have been done better with hindsight. In fact I will be redoing the room with this benefit of hindsight. If I were you I'd take the opportunity to get it correct in the first place.


Thanks for the insight and recommendation! I agree that it makes sense to go ahead and get this right from the start. It's a lot of time/energy either way and I'd hate to feel like I am "settling" yet again with something that could be much better.

Also worth noting that while there was a big improvement, the low end acoustics were pretty decent to start with. I suspect your room is starting from a worse place and thus will require more attention.


Yes, my room dimensions are not ideal by any means! Thankfully the high ceilings give me a bit of extra volume and also room for larger superchunks. But yes, the low end appears to be all over the place even with the little bit of treatment I have already.

Soundman2020 wrote:Source of the post Man, this thread is moving real fast! And you are getting some great advice here!


First off Stuart, THANK YOU for all the questions you followed up on. You must have been feeding off that rare planet alignment that happened last night or something! More like Superman2020! :lol:

And yes, I am trying to move this along as quickly as possible. Really eager to get started on the room. :D And I also agree that everyone has been super helpful and offering great advice and valuable insights. I've already had so many questions answered!

Black. Use some simple, thin, low-cost, fine-weave black fabric under the final finish fabric.


That makes sense! (and also your super detailed response regarding GFR and how sound interacts with various materials answered a TON of my questions) However, everything I have found so far that is fine weave enough to not be see-through also starts failing the blow test. I did find this for cheap on Joann's online: https://www.joann.com/utility-fabric-upholstery-underlining/10173300.html It looks breathable and in conjunction with the burlap, might be enough to hide the framing and whatnot. Does anyone have thoughts on that type of fabric? It's the cheapest thing on their site when you search under "all fabric" and put in the color parameter for "black". The poly-batting I ordered came in but it is also quite transparent and is unfortunately white not black so probably won't work quite as well to hide the framing.

That polyester burlap sample from Best Fabric Store (https://bestfabricstore.com/VINSEA.html) came in and looks amazing! A finer and more consistent weave than regular burlap (even the higher quality stuff), passes the air test, but is still a bit see through (just not as much). It has a much more "modern/clean/professional" look/vibe since it is made of polyester and the colors have some depth of shades to them (which I really like). It's very wrinkle resistant as well and doesn't seem like it will collect lint the way something like felt would...it doesn't have any little fuzzy fibers hanging off which makes me think it will stay looking nice and clean. HOWEVER, it still probably needs a backing to hide the framing so at that point it might not be worth the additional price from the burlap. I now have to weigh the aesthetics with the price.

In simple terms that we normal people can understand: to measure GFR, you put a piece of your test material in some type of frame, you increase the air pressure on one side, then see how fast the air flows through it... which sounds an awful lot like putting a piece over your mouth and blowing!


That sure does add up! :lol: I guess that's what I should've told the people at Joanns when I was walking around the store with a battery powered air mattress pump pressing fabric up against the nozzle... "Don't mind me, just testing the gas flow resistivity of this material." :ugeek:

Continuing more responses in another post...



User avatar
shybird
Full Member
Posts: 100
Joined: Sat, 2020-Jul-04, 17:29
Location: Nashville, USA

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#96

Postby shybird » Sun, 2020-Jul-19, 16:03

Soundman2020 wrote:Source of the post Darn! I'm glad you are only asking easy questions here!!!

Whew! At least it's nothing complex.... That's a relief!


Hahah I guess I gotta be careful what I ask for! :ahh:

And in general, they transmit not just their own resonant frequency, but also all frequencies lower than that, while NOT transmitting al higher frequencies.. which they simply reflect back the way they came, or turn into low grade heat, or nuclear explosions... :)


Everything you wrote in that post was EXTREMELY helpful and then THIS part is what helped me understand the issue I kept not being able to grasp! Basically, the risk of a fine weave fabric that doesn't let air through is not that it's going to reflect everything back into the room (obvisouly not...it isn't concrete) but RATHER that it now has an unknown resonant frequency and is going to reflect (or potentially absorb/turn into heat depending on the material?) any frequency higher than that (but still let through anything lower).

Which means for me, as Jennifer had previously mentioned adds an unknown variable that we can't measure (at least not easily) prior to putting it in the room (since these fabric manufacturers don't provide detailed acoustical information lol). And therefore, it could be reflecting too much of something we don't want or maybe it helps but definitely better to go down that route slowly and with proper REW tests along the way...rather than just buying something that's not breathable and hoping for the best.

I really hope this all helps some other OCD person down the line who has the same question regarding the breathability of fabric and why it's so important! Your post sure helped me, along with what has already been said here. So THANK YOU for the endless effort (and at 3AM to boot!) in helping explain difficult acoustical concepts in an understandable way. I think you need to write a book Stuart! It could be the modern studio design guidebook for people who want to understand how to really DO IT RIGHT. I just see SO MANY studios with super fancy monitors and equipment...I mean tens of thousands of dollars worth of gear when all added up and YET they still just have a couple 2" - 4" panels here or there, no soffits, and they think the studio must be "treated" now. I've been in that boat too! It's so easy to just disregard how much your room is changing what you hear. Really, at the end of the day it should be the FIRST thing to get right because everything else follows. Every producer should use REW on their room at least once before doing ANY mixing so they get it through their thick skull that what their brain is translating at the mix location is not 100% what is actually coming out of those speakers...I think most of this know this and yet choose to spend tireless hours mixing and mixing and mixing rather than taking a step back and investing in making their room WORK.

Sorry for the rant. I'm really talking to myself since that has been the last 15 years of my life haha.

I really like that! It looks pretty good to me.... :thu:


Thanks Stuart! I just need to figure out how to actually build superchunks at that size now! Particularly the ones that are up in the ceiling corners. :shock:

Also, just looking at first reflection points... if I go the soffit route, that back center wall will be the shortest reflection path from speaker to mix position (assuming I have a proper cloud to take care of the first reflections on the ceiling). That being said, my current design doesn't cover up that thick brick fireplace mantle (other than a couple panels above and the bass trap inside the fireplace itself). I'm guessing that would now be the biggest weak spot in my design?

Hopefully I've got enough low end absorption throughout the room via the giant superchunks (maybe will even need some slats in areas to bring back some high end), the soffits would take care of the front wall SBIR issues and side reflection points created by free standing monitors, BUT there would still be a lot of unattenuated sound hitting the middle of that back wall/fireplace and bouncing right back to the mix position (I think the angles would still be there even with soffits?).

SOOO maybe that's where I need to consider some giant hangers (thanks Stuart for clarifying and demystifying the way these work as effective traps!) running from floor to ceiling centered in front of that fireplace/wall above?? It would certainly take up even more space in the room but considering the back wall is pretty close anyways, I'd hate to not do everything I can to reduce the level of those reflections. I love how the fireplace looks so I don't WANT to do this but if everyone here thinks it makes sense to go that route then I totally will. I'm going to be working in this room for many years to come...

Cheers and THANK YOU everyone for the generosity of your time and energy! I'm going to do my best to make this studio sound awesome and look amazing.

Trevor



SoWhat
Full Member
Posts: 277
Joined: Tue, 2020-Jun-09, 12:13
Location: Philadelphia, USA...

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#97

Postby SoWhat » Sun, 2020-Jul-19, 16:45

Greetings Trevor,

I love how the fireplace looks


First, please understand I am being completely serious here.

You could do the treatment and trompe l'oeil your fireplace over it. If a good trompe l'oeil artist does it, no one will ever know the difference!

I'm going to be working in this room for many years to come...


Seems to me, it would satisfy both the sonic and the aesthetic.

All the best,

Paul



User avatar
shybird
Full Member
Posts: 100
Joined: Sat, 2020-Jul-04, 17:29
Location: Nashville, USA

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#98

Postby shybird » Sun, 2020-Jul-19, 19:12

SoWhat wrote:Source of the post You could do the treatment and trompe l'oeil your fireplace over it. If a good trompe l'oeil artist does it, no one will ever know the difference!

You know what, that's a great idea! And not only could that be possible but I could also get a custom printed fabric from ATS with artwork of my choosing! I have several good artist friends here in Nashville that would probably do something amazing for super cheap that we could supersize and put on that back center wall. Not sure how much either of these routes would cost...but definitely worth looking into.

Thanks for that Paul! :idea:

Trevor



SoWhat
Full Member
Posts: 277
Joined: Tue, 2020-Jun-09, 12:13
Location: Philadelphia, USA...

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#99

Postby SoWhat » Sun, 2020-Jul-19, 19:24

Not sure how much either of these routes would cost...


...in for a penny, in for a pound.



User avatar
Soundman2020
Site Admin
Posts: 889
Joined: Thu, 2019-Sep-19, 22:58
Location: Santiago, Chile
Contact:

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#100

Postby Soundman2020 » Sun, 2020-Jul-19, 21:14

I think you need to write a book Stuart! It could be the modern studio design guidebook for people who want to understand how to really DO IT RIGHT.
To be honest, I've been thinking of that for a while... maybe I will do it one day! :)

I just see SO MANY studios with super fancy monitors and equipment...I mean tens of thousands of dollars worth of gear when all added up and YET they still just have a couple 2" - 4" panels here or there, no soffits, and they think the studio must be "treated" now.
Oh yeah! For sure. There's plenty of those out there. And in fact, in a very well treated room, even mediocre speakers can sound good. I'm working with a client in the USA right now on his control room, and that's been going on for about 2 years, I think... He's nearly finished. But about a year ago, after he got most of his treatment done and his soffits completed, with the speakers mounted, he sealed up those speakers with plastic and cardboard to protect them from dust and debris during the rest of the build... then decided that he wanted to have music in there, while he carried on working on the desk and other things. So he dug out an old Panasonic "boom box" home stereo system of questionable quality that he happened t have stored, and set up those little speakers on stands, right in front of his soffits, .... and was totally blown away by how that sounded! He could not believe that his ancient, lousy boom-box could sound so clean, clear, powerful, and precise! Here are his actual words: "I have no way of listening to reference CDs on my JBL mains right now -- so we actually are listening on a Panasonic "boom box" with the speakers up on music stands, in front of the JBLs at the same height, aimed the same way and a mere 2" from the soffits. We listened to a bunch of commercial reference CDs. The room has to be truly amazing! It transforms a lousy* boom box into high fidelity, larger than life listening experience with really well mixed material. All I can say is that we never heard those mixes sound that good and that clear, and I had to keep reminding myself this is just a boom box ! And the mixes still sounded big and powerful walking all the way back to the diffuser, euphonic and euphoric and never feeling sucked out or dull.. That's what you get with so-so speakers in a well-treated room: they sound awesome. But even the best speakers in a poorly treated room will never sound good. People just don't realize that the way a room loads the speakers, acoustically, and the way the sound moves around the room, have a huge effect on the sound at the mix position.

I've been in that boat too! It's so easy to just disregard how much your room is changing what you hear. Really, at the end of the day it should be the FIRST thing to get right because everything else follows.
:thu: Absolutely! Couldn't agree with you more! But most mix engineers and producers think that spending US$ 20,000 on speakers is somehow more important than spending a tenth of that on treatment... Go figure!

Every producer should use REW on their room at least once before doing ANY mixing so they get it through their thick skull that what their brain is translating at the mix location is not 100% what is actually coming out of those speakers...I think most of this know this and yet choose to spend tireless hours mixing and mixing and mixing rather than taking a step back and investing in making their room WORK.

Sorry for the rant. I'm really talking to myself since that has been the last 15 years of my life haha
I hear you, for sure! And agree with every word. I'm going to make this thread a "sticky" for a while, hoping that it will get noticed more, and people will read your words of wisdom!

I just need to figure out how to actually build superchunks at that size now! Particularly the ones that are up in the ceiling corners.
Maybe something like this?
RDMOUS---vertical-meets-horizontal-superchunk.JPG


Also, just looking at first reflection points... if I go the soffit route, that back center wall will be the shortest reflection path from speaker to mix position (assuming I have a proper cloud to take care of the first reflections on the ceiling). That being said, my current design doesn't cover up that thick brick fireplace mantle (other than a couple panels above and the bass trap inside the fireplace itself). I'm guessing that would now be the biggest weak spot in my design?
Right. But rather than lose more space for thick absorption back there, I'm thinking that a single large poly or wedge back there might be a better option. It would look nicer too, and not suck out even more highs like porous absorption would. Might be an idea. If it is decently large (wide and high) it should do the job well. Make it from flexible plywood, with "ribs" inside to give it the shape. Fill it with insulation, and you'll get some bass trapping too. And if you make it in the form of what I call a slot wedge, you could get some tuned Helmholtz action as well! Or you could do something I call a "slatted poly", which is the best of many worlds all at once: A series of vertical slats of varying sizes and/or with varying spacing between them, arranged along the same curve shape as a poly would have. Something like this:
FRCAUS--Slatted-poly-construction-01-SML.jpg
FRCAUS--Slatted-poly-construction-02.jpg
That's on the rear wall of a rather small "corner" control room. It worked very well. Here's a different, more drastic one, for the side wall pillars of a mastering room:
slatted-poly-mastering.jpg


However, everything I have found so far that is fine weave enough to not be see-through also starts failing the blow test. I did find this for cheap on Joann's online:
Try a dress-making store. The type of fabric you want for this, is not used for upholstery. It is just plain old thin cloth, the type used for making light clothing.

- Stuart -



User avatar
shybird
Full Member
Posts: 100
Joined: Sat, 2020-Jul-04, 17:29
Location: Nashville, USA

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#101

Postby shybird » Sun, 2020-Jul-19, 21:16

SoWhat wrote:Source of the post ...in for a penny, in for a pound.

Haha fair enough! :mrgreen:

Soooo I am talking to Stuart about the potential for designing a soffit layout in this room and I'm so antsy to see what it might look like that I made a little model. Obviously this is just a rough idea of what Stuart might come up with and I tried to get some decent angles for a RFZ but sure I'm overlooking some things (nothing considered in the vertical plane yet). And also have NO earthly idea how to build these things properly which is the other big reason I'd need Stuart's guidance. I think it looks pretty cool though. :)

I left the window untouched in the middle because he thinks we might be able to make it work. Also, I don't have a cloud in here or anything above/below the window area.

Should I do it?! This was already far from a normal house and now... :ugeek:

Cheers,
Trevor
Attachments
potential soffit layout 1.jpg
potential soffit layout - 1 top.jpg



User avatar
Soundman2020
Site Admin
Posts: 889
Joined: Thu, 2019-Sep-19, 22:58
Location: Santiago, Chile
Contact:

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#102

Postby Soundman2020 » Sun, 2020-Jul-19, 21:16

...in for a penny, in for a pound.
:thu: and with studios, you can extend that to: "... in for a tonne".! :shock:


- Stuart -



User avatar
shybird
Full Member
Posts: 100
Joined: Sat, 2020-Jul-04, 17:29
Location: Nashville, USA

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#103

Postby shybird » Sun, 2020-Jul-19, 21:44

Soundman2020 wrote:Source of the post To be honest, I've been thinking of that for a while... maybe I will do it one day!

Well I think it would be a best seller in the music production/acoustics world for years to come! You get amazing results in the studios you help design and you explain it in ways that make sense. No easy task on any level!

That's what you get with so-so speakers in a well-treated room: they sound awesome. But even the best speakers in a poorly treated room will never sound good.

That story hammers it home even more! Wow. What have I been doing all these years?! :ahh:

But most mix engineers and producers think that spending US$ 20,000 on speakers is somehow more important than spending a tenth of that on treatment... Go figure!

Yeppppp :roll:

I'm going to make this thread a "sticky" for a while, hoping that it will get noticed more, and people will read your words of wisdom!

:yahoo: hahah I'm humbled. Glad my OCD comes in useful every now and again. Definitely wish I had taken this to heart sooner. You would've thought after that first studio design you guided me through 8 years ago, I would have made something better out of my house. But I was too caught up in thinking I needed to build from the ground up to get it right when in reality I could have use many of the same principles to make this room WAY better than it is currently. I sort of just let go of the whole idea of having a properly tuned room... :cen:

Maybe something like this?


Yes totally! And I remember you posting that photo previously. It seems these are smaller cuts of fiberglass though and I'd essentially be putting two of those triangles together to create an even bigger "face" in the room. This presents a couple issues for me it seems...

1. You now have to support the "seam" on the middle of the face where the two triangle cuts join. Whereas in this photo, you just have wood supporting either end of the triangle and nothing is needed across the middle since it's just a single piece (see rough sketch below). This would only be an issue on the upper superchunks since gravity is working against them.

2. I'm no carpenter and still have a hard time understanding even the exact ways in which that first superchunk is constructed let alone a similar one with twice the depth/face width...hence why I think some blueprints would set me straight. I just don't feel confident enough to start cutting wood and drilling holes! :D

Right. But rather than lose more space for thick absorption back there, I'm thinking that a single large poly or wedge back there might be a better option. It would look nicer too, and not suck out even more highs like porous absorption would.


Well hey that's great news! I'd love to leave that space a bit more open without covering the fireplace! Those designs look really aesthetically pleasing to. I'm thinking this could be one of the last parts of the build I venture into maybe? So we'd have all the REW tests further along and could make a more precise acoustical decision about which of those routes to go? I think I'm getting the hang of this... :shot: (Famous last words. :roll: )

Try a dress-making store. The type of fabric you want for this, is not used for upholstery. It is just plain old thin cloth, the type used for making light clothing.


Sweet! More research! :yahoo: I can't explain why...but I'm truly addicted to research projects...of pretty much any kind. My girlfriend has to pry me away sometimes...and often it's the most random thing. So at least this is important on some level haha.

Thanks again for such detailed replies Stuart! I feel super lucky to know about this forum and will spread the word to anyone I know who could use it.

Cheers
Trevor
Attachments
giant superchunk side cut view.jpg



SoWhat
Full Member
Posts: 277
Joined: Tue, 2020-Jun-09, 12:13
Location: Philadelphia, USA...

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#104

Postby SoWhat » Sun, 2020-Jul-19, 21:46

Greetings Trevor,

Nice design! Well done indeed!

But...

I left the window untouched in the middle because he thinks we might be able to make it work.


...you could cover it with plywood and trompe l'oeil. Haven't you learned ANYTHING???!!! ;)

All the best,

Paul



User avatar
shybird
Full Member
Posts: 100
Joined: Sat, 2020-Jul-04, 17:29
Location: Nashville, USA

Home Mix Room Overhaul - DIY Panel Build - w/ REW Charts/3D Sketchup

#105

Postby shybird » Sun, 2020-Jul-19, 22:43

SoWhat wrote:Source of the post ...you could cover it with plywood and trompe l'oeil. Haven't you learned ANYTHING???!!!

:lol: :P

Oh man when I saw the "but..." I was totally not expecting a joke lol. My anxiety momentarily spiked and then happily turned to laughter. I agree though...why have a real see through window when you could have the illusion of one?! And it would go so nicely with the fake fireplace too. Hell, why even have real speakers! :horse: Just make the whole theme of the place an illusion. "Trompe L'Oeil Studios - You Won't Believe Your Ears" :shot: :roll:




  • Similar Topics
    Statistics
    Last post

Who is online

Users browsing this forum: No registered users and 11 guests