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

[shybird]

So like I said in a previous post, I'm planning to use two colors of burlap for the room (one lighter and one darker). I plan to use the white polyester batting behind the lighter color to get an even look across the face of the panel. I was wondering if this black 3oz weed barrier might work behind the darker burlap? It says it's permeable to "air, water, and nutrients." Obviously, I'd probably need to go test it out first but was wondering if anyone had some experience or thoughts on this?

https://www.amazon.com/Dewitt-100-Foot-Barrier-Landscape-PBN3100RF/dp/B0016APS6E/ref=sr_1_3?dchild=1&keywords=weed+barrier+3+oz&qid=1594578433&sr=8-3

Thanks again!
Trevor

[shybird]

I found a company that seems to have some great and somewhat unique "burlap" fabric! Check it out (click on a "vintage linen burlap"): https://bestfabricstore.com/burlap-cloth.html

I'm going to call them tomorrow about this "vintage linen burlap" which is actually 100% polyester. The colors look awesome with multiple shades in each color kind of like a "heathered" style. If they say it passes the air test then I'm going to order some color samples. This is the best selection I've seen and their regular burlap appears to be a much higher quality than the standard options as well. A little bit pricier at $6.98/yard but by the looks of it and the way people talk about it in reviews, it might be worth that extra couple bucks.

Some other places I've looked:

https://burlapfabric.com/colored-burlap/60-inch-colored-burlap?zenid=j69hg9r2imcodjl98tc8bp4035(says it's 11oz but after comparing samples to the ATS 10oz burlap, it's actually a slightly looser weave and lighter in general...not sure how consistent these "quality ratings" really are...but this place is worth it for the $4.50 price and wide array of colors if you could get a consistent look with a backing)
https://www.atsacoustics.com/item--Burlap-Fabric-56-inch-wide--1009.html (most premium colors out of stock but good quality...probably don't need a backing but not sure. The lady at ATS said they use a lightweight scrim backing on their lighter color panels)
https://www.bigduckcanvas.com/dyed-burlap-colors.html (crazy cheap at $3.68 per yard! Got some samples coming to test quality)
https://fabricdirect.com/acatalog/burlap-fabric-solid.html#usestorage (will order samples here if the others don't pan out but has fewer color options...good price between $3.99 and $4.59 per yard)
http://www.burlapsupply.com/colored-burlap.html (only sell colors in 30 yard rolls )

On a side note...DON'T BUY BURLAP FROM JOANNS!! It's absolutely worthless. Every store I've been to has the same kind. Loose and inconsistent weave plus they are creased right down the middle!

Hope this helps someone in the future. I will keep posting more resources as I compare all the options.

Cheers!
Trevor

[Starlight]

Burlap (hessian in the UK) is sackcloth so loose and inconsistent weave is part and parcel of this, the cheapest of textiles. Having said that, I like the look of the weave (and the colour) of your first link, the blue vintage linen burlap.

Happy hunting for the right one!

[endorka]

Would love to hear Stuart's breakdown of the fabric issue too.

Likewise! I am sure it will be more concise, clear and accurate than my ramblings

It seems to me that when you add a non-porous layer to the front of these broadband absorbers, they become something of a limp membrane absorber. A tuned device rather than broadband. Strictly speaking these should be sealed to work properly, but it's perfectly possible than your superchunks could approach that, depending on construction.

You might find the "Multi-layer Absorber Calculator" at the following link useful. You can ask it to model and compare two absorbers, identical in all ways except for a very thin front layer with a high GFR;
http://www.acousticmodelling.com/mlink.php?im=1&s11=2&d11=2&v11=500000&s12=2&d12=300&v12=5000&s22=2&d22=300&v22=5000
Absorption coefficient;

Reflection coefficient;

Pretty fascinating I think - the effect seems huge in comparison to the material thickness. You can model actual limp membranes there too. For example Kraft paper has a mass per surface area of approximately 0.1 kg/m2; http://www.acousticmodelling.com/multi.php

Cheers!
Jennifer

[shybird]

Burlap (hessian in the UK) is sackcloth so loose and inconsistent weave is part and parcel of this, the cheapest of textiles. Having said that, I like the look of the weave (and the colour) of your first link, the blue vintage linen burlap.

Happy hunting for the right one!

Thanks Starlight! I appreciate it. Yea, I can understand why so much burlap is loose and inconsistent. Based on its typical uses (not acoustic panels ) you wouldn't need it to be a tighter and more consistent weave. It's so funny because nearly every fabric store I've been in, the workers know what I'm inquiring about before I even ask anything. They're like "Are you building acoustic panels?" hahah especially being in Nashville I'd say it's even more prevalent when a rugged musician dude walks into the store looking completely clueless.

Source of the post Pretty fascinating I think - the effect seems huge in comparison to the material thickness. You can model actual limp membranes there too.

Wow! That is huge indeed! I will play around with these calculators. I wonder now what the GFR of that felt was (that didn't pass the air test). Why don't all these companies understand that they need to perform acoustical tests on all their fabrics and provide that info for the random person building acoustic panels...geeze!

Likewise! I am sure it will be more concise, clear and accurate than my ramblings

Your posts have been extremely helpful! Didn't mean to undercut you at all. I've learned a lot through your help already and definitely very far from ramblings!

Cheers (drinking another beer... ),
Trevor

[endorka]

Likewise! I am sure it will be more concise, clear and accurate than my ramblings

Your posts have been extremely helpful! Didn't mean to undercut you at all. I've learned a lot through your help already and definitely very far from ramblings![/quote]

No worries at all, no offence taken in the slightest. The likes of Stuart & Avare have knowledge way ahead of mine, and I am all too happy that they are prepared to share it.

I also think that blue burlap looks awesome by the way. Hopefully all the other properties of it check out.

Cheers!
Jennifer

[shybird]

Source of the post No worries at all, no offence taken in the slightest. The likes of Stuart & Avare have knowledge way ahead of mine, and I am all too happy that they are prepared to share it.

Ok cool! And yes Stuart is on another level haha. I don't know Avare yet though. Looking forward to reading his stuff as well.

I also think that blue burlap looks awesome by the way. Hopefully all the other properties of it check out.

And thanks! Yes I'm hopeful it checks out. There are a ton of awesome colors too which I'm stoked about. We shall see tomorrow!

[SoWhat]

Greetings Trevor,

Forget the studio, sign to be a contestant on Project Runway. Yes, I agree with Starlight, the blue is very nice indeed.

Also love Woodford

Woodford Reserve is my favorite after-dinner bourbon. Unlike Maker's, which I drink with plenty of ice, Reserve is perfect with just a splash of water.

All the best,

Paul

[Soundman2020]

Source of the post And I just went through and read both of those chapters you recommended. It's written in quite the cryptic language but I think I absorbed a good portion of it lol.

Right! Nobody could ever accuse them of speaking clearly, and explaining well!

Yeah, it's rather technical. But a little easier to figure out, when you look at the diagrams and equations.

And now I'm hoping I didn't jump the gun by starting to build the panels I described in my original post.

Possibly, yes!

1. If you were to add the ideal absorption/bass trapping around a room like this...what would it look like/how would you go about it? I'm guessing a pro carpenter would be building framing directly onto the walls, then filling with a ton of insulation, and finally wrapping with fabric and touching up with an outer trim.

Right, something like that. Assuming you don't want to spend too much, for a room like that I would suggest hangers across the rear wall, deeper in the corners, a good deep, hard-backed, well-angled ceiling cloud, and absorption panels on the side wall first reflection points. Even lower budget would be absorption panels diagonally across the rear corners, and thick absorption across the rest of the rear wall. Floor to ceiling!

2. How do you feel about the 6" panels I've started building as a "budget friendly" alternative? With the initial plan of placing them in wall/ceiling corners, front and back walls,

That will do something, at least, but likely not enough. One major point here: your corner panels need to run from floor to ceiling, not just in the middle. You get more "bang for the buck" in those tri-corners (where two walls meet the ceiling or floor), than you do in the bi-corners (just two walls meeting). The boost is about 6 dB extra, theoretically, but even if that were not the case, you still need a much larger area, covering 100% of he corners, from ceiling to floor.

and as a cloud?

6" for a cloud is good, so you could use those... But do make them "hard backed", and hang them at a good angle. Hard-backing means that you put a thick sheet of MDF, plywood, OSB, or suchlike on the top side of the frame. That has a coupled of positive effects, for relatively low cost.

Could the long decay time be caused partly by sound going through the open doorway and double sided fireplace and then hitting even further walls in other rooms before bouncing back?

To a certain extent, but then I'd expect to see TWO decay rates in the data... in fact, that probably is the case, but the long decay of your room by itself is overpowering the smaller signature from the other room. Once you get your room under control, you'll likely start to see some of the coupling from the other room. That often happens as you treat a room: things that were hidden in the "mush" before, suddenly become visible... and you start scathing you head, thinking "how can the panels I just made cause that new problem?".... truth is, they didn't cause it: they just removed the other ugly stuff that was hiding the "new" problems. So do expect to see the other room start to impose itself on the REW response, as you treat. Ditto with the fireplace: that chimney could have resonances going on...

Do you recommend hanging a door and sealing off the fireplace sooner than later?

Definitely! And when you seal off the fireplace, do it high up inside the chimney so you an use the actual fireplace cavity for bass trapping.... lots of room in there!

- Stuart -

[shybird]

Source of the post Forget the studio, sign to be a contestant on Project Runway.

Hahah...I actually figured out what my affliction in life is...it's called being a "multipotentialite" lol. My gf found this ted talk on youtube: https://www.youtube.com/watch?v=4sZdcB6bjI8

Yes, I agree with Starlight, the blue is very nice indeed.

Thanks! I've officially ordered color samples. Talked to a lady there who said it passed the "air test" and basically has a burlap look with a tighter weave and more color options. It's not stretchy but neither is burlap and it was easy to wrap on the frame so I think that will be a good thing since it isn't prone to wrinkles anyway.

Woodford Reserve is my favorite after-dinner bourbon. Unlike Maker's, which I drink with plenty of ice, Reserve is perfect with just a splash of water.

Had some of the Rye last night just neat. So good! Definitely worth a splash of water when you want to take that extra edge off and get more into the flavors.

Source of the post Possibly, yes!

Thanks for the detailed reply Stuart! Super helpful as always.

And oh no! Haha well hopefully I can find a middle ground and make the room perform much better than the current setup even if I'm resorting to quite a few 6" panels with air gaps....

Right, something like that. Assuming you don't want to spend too much, for a room like that I would suggest hangers across the rear wall, deeper in the corners, a good deep, hard-backed, well-angled ceiling cloud, and absorption panels on the side wall first reflection points. Even lower budget would be absorption panels diagonally across the rear corners, and thick absorption across the rest of the rear wall. Floor to ceiling!

I'm wondering what your thoughts regarding Jennifer's comments are? She mentioned that going floor to ceiling in that back right corner could potentially cause problems since I can't mirror it on the other back corner (due to the door way). Should I only do the upper corners of both so it is symmetrical? If so, I could also hang a panel on the door itself and mirror that on the other side of the back wall. Unfortunately the door jamb is already in place to swing into the room but if I could somehow pry that out and reverse it then maybe it could open out into the other room so I could get absorption on the door itself AND on that adjacent wall next to it.

Maybe theres someway to build a "hinge" corner trap over a moveable doorway?! But my logical mind tells me that has some obvious issues... haha

That will do something, at least, but likely not enough. One major point here: your corner panels need to run from floor to ceiling, not just in the middle. You get more "bang for the buck" in those tri-corners (where two walls meet the ceiling or floor), than you do in the bi-corners (just two walls meeting). The boost is about 6 dB extra, theoretically, but even if that were not the case, you still need a much larger area, covering 100% of he corners, from ceiling to floor.

For the front corners I've decided to go the superchunk/floor-ceiling route for sure. I won't have enough panels if I don't, so it makes sense to go ahead and do this, even with the amount I've already framed out. That being said, the rest of the room is going to have to be panels unless I were to finish building them just to sell a bunch...which is not ideal time and energy wise.

Depending on your answer to the symmetry question above, would a couple of these 6" panels across the back wall upper tri-corners function pretty much the same as a short superchunk in that area (if I also placed a bunch of pink fluffy in the air gap behind them)? ...they would be sideways (covering about a 4' width across the corner) and flush with the ceiling and each other.

6" for a cloud is good, so you could use those... But do make them "hard backed", and hang them at a good angle. Hard-backing means that you put a thick sheet of MDF, plywood, OSB, or suchlike on the top side of the frame. That has a coupled of positive effects, for relatively low cost.

Great! Glad to know these will work for the cloud. What thickness do you recommend for the backing? I will browse around the forum to see if I can answer that question myself too.

I assume this is to help send some of the reflections toward the back wall. And since this room has the brick fireplace jutting out in the center of the back wall, I guess it's even more important to get that covered with absorption? It certainly will eat into the room quite a bit if I cover up the lower portion of the fireplace but willing to do what's necessary. Maybe I could keep a few of these panels as free standing gobos back there on the lower portion. Above the fireplace will be easy as it doesn't jut out quite as far and will have a "flush" look with the mantle below.

That often happens as you treat a room: things that were hidden in the "mush" before, suddenly become visible... and you start scathing you head, thinking "how can the panels I just made cause that new problem?".... truth is, they didn't cause it: they just removed the other ugly stuff that was hiding the "new" problems. So do expect to see the other room start to impose itself on the REW response, as you treat. Ditto with the fireplace: that chimney could have resonances going on...

Wow! I never thought of it this way! That's pretty wild but it makes sense. I've contacted a builder regarding the fireplace but haven't gotten a response yet. I wonder if we could stuff that chimney with FR insulation to reduce any resonances building up there?! haha

Definitely! And when you seal off the fireplace, do it high up inside the chimney so you an use the actual fireplace cavity for bass trapping.... lots of room in there!

A little confused on this. The fireplace is open on the other side to the adjacent room so I figured I need to build a sealed "wall" inside of it (drywall/framing/insulation - air gap -insulation/framing/drywall) to keep from transmitting as much sound to the other room (like with the door I will be adding as well). I could keep the air gap pretty small and also build the "wall" closer to the other side of the fireplace so that there would still be plenty of room for a bass trap there on the mix room side (in front of the "wall"). What do you think?

A BIG thanks to everyone for the help here! I know this room is far from ideal and I won't be able to get it "perfect" by any means considering the various limitations. However, I would imagine even the current plan is going to be a HUGE step up from what I'm currently dealing with while mixing. I will be very much pleased if it makes mixing even 50% more trustworthy in regard to translation.

Cheers!
Trevor

[Soundman2020]

I'm wondering what your thoughts regarding Jennifer's comments are? She mentioned that going floor to ceiling in that back right corner could potentially cause problems since I can't mirror it on the other back corner (due to the door way).

Ahh, right! The door way... Well, if you put a door in there, you could have a "superchunk on wheels" that you can slide in front of it when needed... Or just put very thick absorption on the door itself, shape so that when you open the door it does not catch on the frame.

Also, don't forget that there are TWELVE corners in a room, not just four! There are four vertical corners, right, but there are also eight horizontal corners... such as the one between the rear wall and the ceiling. All corners are fair game for bass trapping You could do something quite large across the top of the rear wall, above the doorway. Horizontal superchunks are not hard to do, and very effective.

And of course, you can combine vertical and horizontal too:

Hangers up in that rear ceiling/wall corner are also an option:

In your case, I would do larger hangers with 2" insulation on each side if possible, plus also a thick insulation panel behind them, on the wall itself, and another on the ceiling itself.

Symmetry is critical for the front half of the room, yes, and also important for rear reflective surfaces (eg, diffusers), but not so critical for the rear bass trapping. So your bass trapping back there could by "unbalanced", in the sense of having more on one side than on the other, as long as you can keep the reflective surfaces reasonably well balanced.

The concept for the rear half of the room is that it should attenuate the sound coming at it from the front half, reducing it in level by about 20 dB (ideally), as well as diffusing it if possible, thus only allowing a more diffuse, lower-level "ambient" field to make it back to your ears from behind you. Ideally, that diffuse field "arrival from the rear" should be delayed by at least 20ms with respect to the direct sound, but that is only possible if the room is long enough. Hence, the general recommendation to have the speakers firing down the longest axis of the room, in order to get the largest delay. It's only when the room is very large that you can set it up "sideways", with the speakers firing along the shorter axis: you need a distance of about 20 feet from the front wall to the back wall, to be able to do that.

Unfortunately the door jamb is already in place to swing into the room but if I could somehow pry that out and reverse it then maybe it could open out into the other room so I could get absorption on the door itself AND on that adjacent wall next to it.

Right! It's actually not that hard to flip the opening sense of a door. It sounds scarily complicated, but really it isn't, if you have some decent basic carpentry skills and decent set of tools. A skilled carpenter can do it in a few hours, but it could take a day or more if its the first time you've done it. Even so, not a big deal in the overall scheme of getting your studio tuned!

Maybe theres someway to build a "hinge" corner trap over a moveable doorway?! But my logical mind tells me that has some obvious issues...

Wheels. That's the simplest. A superchunk actually isn't all that heavy. Build a simple frame on top of some casters, with a baseboard of some type, pile in your insulation, secure it with straps so it won't fall out as you move the thing, and cover with fabric. Make the base broad, for good stability. You don't need to make it as tall as the ceiling! the part above the door can be fixed to the wall, permanently: your wheeled-superchunk only needs to be as tall as the door.

For the front corners I've decided to go the superchunk/floor-ceiling route for sure.

What thickness do you recommend for the backing?

5/8" (15mm) is about as thin as I'd go. 3/4" (19mm) would be better. Note that the cloud will be heavy! Make sure it is well attached to firm mounting points in the ceiling. Use chains and closed hooks, not open hooks, and each chain/hook should be rated to hold at least ten times the actual weight it will be carrying. And have more chains than you really need: many people use only 4 chains per cloud section, but that's not enough to be safe: if one fails, then the remaining three will be unbalanced, and the thing will tilt, placing much more strain on just one of the remaining mounts.... It is better to use 6 or even 8 chains per section. You do NOT want a heavy cloud coming down on your head! So for example, let's say that your cloud weighs 80 pounds: if you us 8 chains, then each one should be handling a load of 10 pounds. Applying the "10x" rule, each chain should therefore be rated for100 pounds. This might seem like overkill, but really it isn't: Don't take chances with things hanging over your head. An 80 pound object falling four feet on your skull can do some serious damage!

I assume this is to help send some of the reflections toward the back wall. And since this room has the brick fireplace jutting out in the center of the back wall, I guess it's even more important to get that covered with absorption?

Right. The cloud hardback does indeed help to re-direct reflections towards the rear wall, where they should be attenuated and maybe diffused. So you need to get the angle right. A common mistake is not putting enough angle on the cloud. There's a raytacing tool in the "Downloads" section of the forum that you can use inside Sketchup, to help you figure angles and reflections.

It certainly will eat into the room quite a bit if I cover up the lower portion of the fireplace but willing to do what's necessary.

Maybe I didn't explain that very well. What I was suggesting is that when you close it off, do that up inside the chimney itself, not at the front of the fireplace. That will be a messy job, and not easy, but the idea is to close off the bottom end of the chimney itself, where it meets the fireplace proper. That will leave the entire fireplace cavity available, to use as a bass trap. Fill it with insulation, put fabric across the front, and you have a bass trap that uses up no space at all! It will still look exactly like it does right now, and won't eat up any space at all in the room, since you will be using the empty fireplace cavity for the bass trapping insulation.

A little confused on this. The fireplace is open on the other side to the adjacent room

Ahhh! OK, now I get it... I was thinking that it was open to your room, not the other room. If it opens to the other room, then you don't need to do anything with it: Fireplaces are typically brick or concrete construction, so there's plenty of mass in there: it's not likely to be much of a problem for your room, so you can just leave it as it is, and it can still be used for fires, if you want!

A BIG thanks to everyone for the help here!

I know this room is far from ideal and I won't be able to get it "perfect" by any means considering the various limitations. However, I would imagine even the current plan is going to be a HUGE step up from what I'm currently dealing with while mixing.

Oh yes! Very definitely! No doubt at all. The key is getting the bass under control. If you get good, tight, clean bass with little modal stuff going on, then the rest of the spectrum sort of starts falling into place as well. It's a lot easier to treat the high end, then it is to treat the low end! So concentrate first on the low end, then work your way up.

One caveat here: the term "bass trap" is misleading. Yes, it "traps" bass, but it also sucks out mids and highs, and in fact it does that much better than it does with bass! Putting enough pure absorption bass trapping in a room to get the low end under control, always means that you now have far too much high-end absorption. Hence you often need to partially cover the bass traps with "things" that can reflect back some of the highs, returning them to the room, so you don't make the place lifeless and dull. One good option here is ordinary plastic sheeting. You an buy it in different thicknesses at Home Depot, and each thickness has a different range of frequencies that it affects, so you an sort of "tune" the treatment a bit like that. So don't put the fabric on the front of your bass traps until you have tested with REW, to see if you need to do that! Just build them all, then test with REW, and decide how much / how thick / where to put the plastic.... then test again. When you are finished testing and tweaking, then put the final finish fabric on.

I will be very much pleased if it makes mixing even 50% more trustworthy in regard to translation.

I reckon we should be abl to achieve better than that!...


- Stuart -

[shybird]

Stuart you are the man! Thank you for all the detailed answers. I've also been reading through your REW analysis on this page (https://www.digistar.cl/Forum/viewtopic.php?f=14&t=208&p=963&hilit=cloud+hard#p963) and finding it super helpful. I try my best to learn from the forum first before asking stuff but sometimes it's challening applying things over to a certain situation in my own room. I'm sure it gets tiring repeating yourself in different ways!

Source of the post Well, if you put a door in there, you could have a "superchunk on wheels" that you can slide in front of it when needed... Or just put very thick absorption on the door itself, shape so that when you open the door it does not catch on the frame.

This just blew my mind. A superchunk on wheels! What a sight that must be hahah. ***rolls superchunk into closed doorway after prima donna vocalist requests more candles in the recording room... "too late sorry!"*** This could come in handy.

Also, don't forget that there are TWELVE corners in a room, not just four! There are four vertical corners, right, but there are also eight horizontal corners... such as the one between the rear wall and the ceiling. All corners are fair game for bass trapping You could do something quite large across the top of the rear wall, above the doorway. Horizontal superchunks are not hard to do, and very effective.

I originally decided to go the panel route because I thought it would be easier and cheaper...but now I realize the opposite might actually be closer to the truth. This makes sense though! I'm going to try to make it work with panels where I can but willing to build additional superchunks and maybe just sell some of these suckers? Or perhaps the main frames can be repurposed and transformed into diffusion panels later?

In your case, I would do larger hangers with 2" insulation on each side if possible, plus also a thick insulation panel behind them, on the wall itself, and another on the ceiling itself.

Ok, so this is the part where I realize I've built way more panels than I will need if they are going to be replace by hangers on the back wall. I also need to do some research on how these are typically made. I'll check other threads for some initial direction on this and report back here with some drawings.

Symmetry is critical for the front half of the room, yes, and also important for rear reflective surfaces (eg, diffusers), but not so critical for the rear bass trapping. So your bass trapping back there could by "unbalanced", in the sense of having more on one side than on the other, as long as you can keep the reflective surfaces reasonably well balanced.

This is great news! Glad to know it's not a make or break situation in regard to low end symmetry for the rear end of the room. That makes sense regarding the front half of the room and high end symmetry throughout.

Ideally, that diffuse field "arrival from the rear" should be delayed by at least 20ms with respect to the direct sound, but that is only possible if the room is long enough.

I remember this idea from 8 years ago! Unfortunately, this room won't hit that 20ms considering it's only about 15' or so in both directions. But like you said, it will still be much better with the treatment done right.

Right! It's actually not that hard to flip the opening sense of a door. It sounds scarily complicated, but really it isn't, if you have some decent basic carpentry skills and decent set of tools.

Roger that! I will plan to flip this then since it will make the bass trap there much more possible (whether it's a superchunk on wheels or thick absorption attached directly to the door).

You don't need to make it as tall as the ceiling! the part above the door can be fixed to the wall, permanently: your wheeled-superchunk only needs to be as tall as the door.

If I go this route rather than attaching directly to the door, I'm envisioning this thing as "triangular" to match the superchunk in the corner above the door...is that correct/possible? Would it have only 3 wheels?! Haha or should I be thinking more of a giant/thick rectangular gobo?

3/4" (19mm) would be better. Note that the cloud will be heavy! Make sure it is well attached to firm mounting points in the ceiling. Use chains and closed hooks, not open hooks, and each chain/hook should be rated to hold at least ten times the actual weight it will be carrying.

Copy that! Would an 1" be EVEN better? I'm guessing at a certain point it's just too heavy. I will be sure to follow your guidelines on all the safety precautions here.

A common mistake is not putting enough angle on the cloud. There's a raytacing tool in the "Downloads" section of the forum that you can use inside Sketchup, to help you figure angles and reflections.

Will add this to my SketchUp to-do list! I remember raytracing...

Ahhh! OK, now I get it... I was thinking that it was open to your room, not the other room.

So sorry! This got lost in the mix somewhere but it is literally a DOUBLE-sided fireplace! So it is open to both rooms. Hence why I was proposing the idea of a "wall" within the fireplace to seal it off from the other room and then leaving as much space on the mix room side of that "wall" for a bass trap flush with the mantle.

Putting enough pure absorption bass trapping in a room to get the low end under control, always means that you now have far too much high-end absorption. Hence you often need to partially cover the bass traps with "things" that can reflect back some of the highs, returning them to the room, so you don't make the place lifeless and dull.

That makes sense and is echoing what Jennifer had mentioned in a previous post. It makes sense though so I will totally make sure to be thorough with the REW tests BEFORE I put final fabric covers on anything.

I reckon we should be abl to achieve better than that!...

That is very reassuring coming from you Stuart! I'm so stoked to finally work in a "proper" room and see how it changes the game for my production/engineering skills. I've always learned to work with what I had but man I am just so ready to have a better handle on the acoustics. It's crazy how many people are mixing music in rooms with a few 4" panels and thinking "oh it's treated now!"

I will report back with a new sketchup drawing based on what I've learned from these last few posts! I will include a rough estimate of materials that I will still need to buy if I go 100% in this direction (with hangers, more superchunks, etc) and how many panels this would cause me to have leftover. Maybe someone can then weigh in on how I can either find a middle ground between the two treatment approaches or convince me to just not worry about the few hundred bucks of wasted 1x8 lumber (already built into panel frames) because the results will be that much better. I could have a small acoustic panel business for a few months selling these things locally if I build them out all the way hahaha. Would rather not go there but if the results would be worth it then I'm willing to ditch a large portion of these panels ***pours up double shot***. Any experiential advice there would be greatly appreciated!

Cheers and thank you thank you thank you!
Trevor

[shybird]

Just gonna go ahead and throw this out there. I've been trying to read up and refresh all day regarding raytracing and the maximum angles necessary. I realize, there is no way to get a RFZ in a room like this without soffit mounting the speakers (something I'm considering but would probably need to pay Stuart for designing this if I'm going to have the slightest chance of building it successfully...not to mention I'd like to keep the upper half of those front windows visible at all costs!). I know how many amazing benefits come with properly designed soffits...it's just such a small room I'm afraid it would just eat into it too much!

That being said, I've drawn a 70 degree vertical ray coming out from the right speaker and it reflects off the ceiling back down behind the current listening position about 18" behind the head. Is there any reason then to pull this cloud forward off the back upper corner like I have it? It would be easier to attach to the walls directly like shown than to actually hang it but I'm assuming I'm misunderstand the purpose of ray tracing in a scenario like this.

If it could stay this way with a hard back, I guess you could still stuff some insulation back there for further low end absorption.

Let me know where I'm going wrong in my interpretation of this raytracing! I went back to read through my old thread from back in the day and Stuart had mentioned how the sound level dies off as the angle increases and I was worrying about some 65 degree vertical ray but that it wasn't even necessary.

[Soundman2020]

Source of the post I realize, there is no way to get a RFZ in a room like this without soffit mounting the speakers (something I'm considering ...)

Think even harder about that! I was wanting to suggest that, but figured you might not be interested... But it truly is worth the effort and investment.

I know how many amazing benefits come with properly designed soffits...it's just such a small room I'm afraid it would just eat into it too much!

Smaller than this one?

That's a design I did for a client in the North Eastern part of the USA a few years ago. Floor area: 97.3 square feet (9 m2). I can't post more details about that, since I don't have his authorization, but I can post the comment he sent me after he built it: "All I can say is HOLY CRAP, this thing is insane. I’ve never heard imaging so clear and such full low end like this! Its pretty incredible! There were points in time particularly over the summer while i was working 17 hour shifts and then building this thing in my time off, that I questioned if I had made the right choice; But this really exceeds anything I could have expected. Bravo on your design Stuart, it’s truly impressive."

Your place is a lot bigger than his...

That being said, I've drawn a 70 degree vertical ray coming out from the right speake

You probably don't need to go so steep: at 70° off-axis, most studio monitors are not putting out a lot in the mids or highs, which is mostly what the cloud will reflect. 50°, or maybe 60°, is as far as you need to go, usually.

By the way, there's a tool I released for free that can help you with this whole ray-trace thing: https://www.digistar.cl/Forum/viewtopic.php?f=9&t=2 Download that, attach it to your speaker at the acoustic center, and play around to see where things are going. You can also attach it to the face of your cloud, of you want, to see where things are coming from! This is a "dynamic component" for SketchUp, and there's lots of controls for you to play with, to hep visualize what might be going on.

Is there any reason then to pull this cloud forward off the back upper corner like I have it? It would be easier to attach to the walls directly like shown than to actually hang it

Clouds are normally placed further back in the room, over the spot roughly half way in between the desk and the speaker. The angle can be quite a bit less than what you have there. In fact, you seem to be attempting to use your bass traps as a cloud: combing both into one?

but I'm assuming I'm misunderstand the purpose of ray tracing in a scenario like this.

You are only looking at the bounce from the ceiling: put the cloud where that ray is hitting the ceiling, then adjust the bounce angle accordingly, to match the angle of the cloud (angle of reflection = angle of incidence). Then you can play around with various angles (yes, raytracing like this is very tedious and grossly boring! That's why I created that tool....), and see where the reflections for each angle are going. When you find that you don't have any low-angled reflections getting to your head, then your cloud angle is probably about right.

Stuart had mentioned how the sound level dies off as the angle increases and I was worrying about some 65 degree vertical ray but that it wasn't even necessary.

Right. Get out the manual for your speaker, and there should be a diagram or graph that shows the dispersion angles for various frequencies. You'll notice that, at w angles (less than about 15° off axis, for most speakers), you get pretty much all the frequencies projected evenly, but as you get beyond that range you star losing the high end. By the time you are maybe 45° off axis, most of the highs are gone, and you just have the mids at subdued intensity too. As you go more still, you even lose the mids. At 90° off axis and beyond, all you have is the very low end. So your cloud will only be reflecting the frequencies that actually reach it, and since there will be fewer frequencies that far off axis, with subdued intensity, there's less sound going out at higher angles.

But play around with the raytrace tool, and see if it helps you understand the angles and issues better. It cam do both vertical and horizontal angles, and it cans show or hide any quadrant, for clarity. I find it useful.

- Stuart -

[shybird]

Soundman2020,

Stuart thank you again!! I will reply in more detail later but yes I did use the ray tracing tool to help with this! I just hid it so you could see that 70 degree angle. I’m going to send you a PM regarding a soffit design quote. I would love to make it happen but I feel way in over my head carpentry wise. Also afraid of things being so permanent in the house but I guess it could be taken down and refinished as normal someday if needed?

I will definitely play with the ray tracing some more. And since the cloud is there to reflect frequencies that are more low/mids since the highs won’t even angle up that much (even when I pull it out from the wall...and yes I was trying to get away with making it more of a bass trap haha)...what frequencies will that hard backing even be able to affect at 3/4 inch thick? I’m assuming a good portion of lows will just go straight through.

Anyways thanks again for your continued help.

Cheers!
Trevor