New studio/house build including John’s small studio design

It's looking good, Ben... But that speaker soffit seems a little on the flimsy side... It needs to be VERY beefy. It has to hold the speaker rigidly, without vibrating. I normally use 2x4 lumber at least, closely spaced, and a couple of layers of 3/4" (19mm) MDF for the shelf that the speaker sits on, plus something similar for the actual front baffle. My customers have been known to cast their soffit baffles in concrete, on occasion... Let me know if you need more details, and I'll send you something by PM... - Stuart -

This [SPAM DELETED. SPAMMER BANNED] might be useful for u. It's about [GETTING YOURSELF BANNED FOR BEING A SPAMMER], have 2 read!

Hi Stuart, Thanks for the heads up on the soffit. I'm sorry I just came across your post and don't know why I missed the email alert. I hope we are going ok, the frame that you can see is just that the rough frame. The shelves that the Adam A7Xs will sit on was planned to be 18mm MDF, but, we have some MDF left over so we can make a composite shelf out of two sheets to make the shelf 36mm thick. I will add that to our list of to do items! The MDF box that we will build around each speaker will also be as snug as possible and made from 18mm MDF too. For the front of the soffit we are planning on creating a composite face made from two sheets of 18mm MDF to give a total thickness of 36mm. These faces will be approximately 850mm wide and about 1700mm tall. Q1: We were planning to use some left over green glue to place between each of the 18mm sheets. Is that a good, bad or pointless idea? We are planning on building/inserting another frame of 90mm x 45mm around each speaker as we are planning on building the option i) speaker soffit a few posts back. The reason is that if we stuff up the bevelling around the top left and right corners of the A7Xs then we only have to make a new smaller face piece and do not waste an entire 850mm x 1700mm sheet. Can I check that the option i) soffit idea drawn a few posts back will be ok?. At this point things are moving a bit more slowly as I am at work 9-5 Mon-Fri and also doing freelance work in the evenings That only leaves Saturday and Sunday. But, we have the ceilings pretty much done (i.e., insulation between the studs covered with one sheet of plastic and then canvas material stretched over that and fixed to finish off. All the baffle box bottoms have been fitted and sealed and I am pleased to say that I can only hear the slightest of slight low frequency HVAC noise in both rooms when the system is on and all doors are closed. That slightest of low frequency sound is marginally louder than the sound of silence which in a funny way is more noticeable than the HVAC. If the space was not isolated then there is no way any HVAC sound would be heard. I'm guessing that I may hear a faint HVAC sound when I get to test recording pure silence in the CR and LR, but, if I do, and if a critical, solo quiet take demands it, then I'll simply turn off the HVAC for the take. For pop and rock I will be very surprised if I will hear anything other than music. I have decided to use LIFX Color 1000 LED smart bulbs in the both rooms and our electrician is no longer a bottle neck as we have essentially installed all the required battens and points ready for him to wire in and connect. Next weekend we hope to build the last two superchunks for the live room and then build a bit more framing to support a further 90mm depth of isolation on the rear wall of the CR. All up there will be 180mm of 32kg/m3 glasswool on the rear wall plus superchunks in each corner. Other than that work we are leaving perhaps the hardest part to last! i.e., finishing the soffits and also building a hard surfaced RZF wall each side of the CR speakers. I'll try to get some pictures up through the week or next weekend. I do wish we could wrap this up more quickly, but, I'm guessing that we will be lucky to be done by Christmas. At least I have about 3 weeks off over Christmas to back in and wrap up anything that is not finished! Cheers, Ben

we have some MDF left over so we can make a composite shelf out of two sheets to make the shelf 36mm thick. I will add that to our list of to do items!

:thu:

The MDF box that we will build around each speaker will also be as snug as possible and made from 18mm MDF too.

There's two options here: Tight fit, as you describe, or using Sorbothane pads between the speaker and the enclosure box to make the speaker "float" inside the box, such that it cannot transmit any vibrations or sound into the soffit structure. I prefer this second option, for obvious reasons, but it's harder to do as there's a series of calculations involved in getting the right size / type / thickness / location for each of the rubber pads.

For the front of the soffit we are planning on creating a composite face made from two sheets of 18mm MDF to give a total thickness of 36mm. These faces will be approximately 850mm wide and about 1700mm tall.

:thu: I have been known to sandwich a layer of MLV in between the two layers of MDF... :)

Q1: We were planning to use some left over green glue to place between each of the 18mm sheets. Is that a good, bad or pointless idea?

That can work too.

But, we have the ceilings pretty much done

Photos! Or it didn't happen...

All the baffle box bottoms have been fitted and sealed and I am pleased to say that I can only hear the slightest of slight low frequency HVAC noise in both rooms when the system is on and all doors are closed.

That's good, but it might be an idea to try to figure out why you can hear anything at all! :) There might be a way of fixing it, if you can identify what it is you are hearing. Is it vibration from the HVAC equipment itself? Air noise? Something else?

Next weekend we hope to build the last two superchunks for the live room and then build a bit more framing to support a further 90mm depth of isolation on the rear wall of the CR. All up there will be 180mm of 32kg/m3 glasswool on the rear wall plus superchunks in each corner.

Do REW tests before and after! Important!

I'll try to get some pictures up through the week or next weekend.

Yup! As the saying goes: "Pics... or it didn't happen!"... :) - Stuart -

Hi Stuart, Things have been slow into the end of the year, but, I do hope that things will pick up over the next few weeks and maybe even wrap up over the Christmas break. Next weekend we will build the last superchunk for the live room and hopefully fit the skirting and cornice. There's not too much more to do in this room which is great! I am also planning on building a 2U high 19" audio patch bay into the final baffle. It will be about 150mm up off the floor. After the live room is done we will finish building the speaker soffits, I can then run an initial REW test before finishing the rear wall and rear traps and testing again. Stuart, is there a source of information that I could reference to work out sorbathane pad amount and location and also understand how the pads impact the box that gets built around the speaker, i.e., is there a standard pad thickness? The speakers will be Adam A7X. I will also try to work out what it is i can hear in the HVAC and see if i can isolate it. The electrician came today so there is finally lights and power in the space which is great. There ar some pictures below:

Hi, This weekend we finished the last superchunk trap in the live room and started running some skirting too. We should be done in the live room by next Saturday with any luck. The conduit between rooms was large enough to easily pull through 3 x D25 cables with 8 x XLR fan break outs at one end. If I'm really keen then I may try my luck in the future and drag a 4th cable through. If this had been a larger build then larger diameter conduit between rooms would have been required. Hopefully we'll get back to Soffits next Sunday. A few pics are below. That's all for now.

Hi, I don't have any pictures today, but, we did finish off the skirting in the live room over the weekend and got on to the soffits again toward the end of Sunday. Who would have thought that cutting angled skirting to join seamlessly at a 45 degree angle was so convoluted and time consuming! I should have bought good old square quad. I have also sourced 8kg/m2 MLV that is 4mm thick (I did try to find something denser but have had no luck to date) and will place an order tomorrow. I'll be placing the MLV between the two 1000mm wide x 1650mm high MDF soffit front panels (i.e., 18mm MDF + MLV + 18mm MDF for each side) and by my calculations that should add approximately an extra 13kg to each speaker soffit face. All up that will be around 54kg (20.5 + 20.5 + 13) per side for the soffit face alone. I hope that is within an acceptable mass range. The only other option at this point (aside from casting concrete :mrgreen: that unfortunately is not going to happen) would be to add a second layer of MLV. I am not sure if that is worth it or not? Next weekend we will be working on the soffits, adding extra horizontal and vertical bracing and blocking to make it as rigid as possible. I will also start making the hangers to place in the lower area under the speaker shelf that has been beefed up with an extra 18mm of MDF. We will also add extra bracing under the double layered speaker shelf to make it as rigid as possible. We will also start building the boxes to enclose the A7Xs. At this point I was not going to place Sorbothane pads between the speaker boxes and the speakers. But, I can see it online for $12.99 AUD for a single 100mm x 100mm x 3mm pad. That's about all for now. I should have some more pics toward the end of next weekend. Ciao, Ben

I don't have any pictures today, but, ...

Well, then, it didn't happen, now did it! :shock: :roll: :wink: :lol: You know what they say around here: "Pics! or it didn't happen!"... :)

Who would have thought that cutting angled skirting to join seamlessly at a 45 degree angle was so convoluted and time consuming!

Just checking here, but you are using a chop saw for that, aren't you?

I have also sourced 8kg/m2 MLV that is 4mm thick (I did try to find something denser but have had no luck to date) and will place an order tomorrow.

That's fine. If you do the math, you'll notice that it's nearly three times the density of drywall... Lots of mass in a thin package. If only it wasn't so expensive!

All up that will be around 54kg (20.5 + 20.5 + 13) per side for the soffit face alone.

Sounds good to me! Nice and dense, with some mild damping going on inside.

aside from casting concrete

You mean like this? : Yeah, I guess that might, perhaps, be possible... :)

would be to add a second layer of MLV. I am not sure if that is worth it or not?

Not necessary. You'll be fine with one layer.

adding extra horizontal and vertical bracing and blocking to make it as rigid as possible.

Right! And don't forget somthing important: The baffle weighs 54 kg! It will need lots of support. And you'll need help getting it lifted and mounted. It's not so easy holding up 54 kg with one hand while you use the other to attach it...

I will also start making the hangers to place in the lower area under the speaker

Just checking: You are using Homasote for the hangers, right?

We will also start building the boxes to enclose the A7Xs. At this point I was not going to place Sorbothane pads between the speaker boxes and the speakers.

:yahoo: :thu: Yes!!! ... However! Do the math! If you really want to float those properly, then you need pads all around the speaker, and you need to calculate the size of each pad correctly...

But, I can see it online for $12.99 AUD for a single 100mm x 100mm x 3mm pad.

That's not the way I do it... I use 1" thick Sorbothane (25mm), by the entire 12" x 12" sheet (usually 50 durometer), and cut the number of pads that I'll need, to the correct sizes. Then I test that I really am getting the correct deflection. This needs precision and accuracy, and some calculating... but the result is that the speaker does indeed float properly, and is decoupled down to frequencies well below its cut off. And that sheet of rubber ain't cheap at all! But if you are serious about floating your speakers properly, that's what it takes. (Hint: Studio Three was done like that...)

I should have some more pics toward the end of next weekend.

Then we'll know if it really DID happen! :) - Stuart -

Hi Stuart, Thanks yet again ... :) ... and best wishes for end of the year celebrations too !!!

"Pics! or it didn't happen!"... :)

There are some more progress pics below :mrgreen:

Just checking here, but you are using a chop saw for that, aren't you?

We have lots of cutting type thingamewhatsamebobs, tools and the like and have been acquiring anything that we don't have as we go. So yes, we do have a sliding drop saw and a nice circular saw, both of which can cut silly angles as required. Still angled skirting that meets at 45 degrees results in quite a funky, non-standard cut. Still we have managed to sort the cuts out so that the joins meet cleanly.

That's fine. If you do the math, you'll notice that it's nearly three times the density of drywall... Lots of mass in a thin package. If only it wasn't so expensive!

Cool ... there is a pic below of the crazy heavy roll ... we will get busy with this bad boy next Thursday.

Sounds good to me! Nice and dense, with some mild damping going on inside.

Also great !!! the soffit framing is also now very rigid and as per the pics below I have started filling the cavities with left over insulation from the inner leaf build. I came across this thread on the forums and hope that we can also get close to the same level of detail and finish: http://johnlsayers.com/phpBB2/viewtopic.php?f=2&t=15430&hilit=soffit+hanger&start=60 ... We are pretty much following this concept, that is also very close to your last set of pics, except we are not casting in concrete :roll: ...

Not necessary. You'll be fine with one layer.

One layer it is.

Right! And don't forget somthing important: The baffle weighs 54 kg! It will need lots of support. And you'll need help getting it lifted and mounted. It's not so easy holding up 54 kg with one hand while you use the other to attach it...

Yep ... we will continue to move very methodically and we will certainly fix that soffit face firmly to the 90 x 45 framing. We have an array of fixings from 75-100mm bugle screws to lighter gauge 50-75mm screws and will use plenty to make sure the soffit face stays in place. We will likely place a temporary support ledge made from 90 x 45 to rest the face on to make it a bit easier to fix it to the framing.

Just checking: You are using Homasote for the hangers, right?

I did read about Homasote on the forums, but, I can't find any locally here in Aus. So I am hoping that the following soft board will be a reasonable substitute: https://www.gunnersens.com.au/info/softboard. I could not get any of this before the end of the year, but, hope to have some by the end of the first week of January next year. While we wait for the hanger board we can finish of the rear wall superchuncks and back wall.

However! Do the math! If you really want to float those properly, then you need pads all around the speaker, and you need to calculate the size of each pad correctly...

Ok, no Sorbothane for me this time. The MDF box surrounding the A7Xs is really quite tight. The speakers just slide in and out and don't seem to scratch which is great. Best wishes for the silly season and new year to yourself and everyone who is still persevering with this odyssey ... 6 months in on the actual build and with fingers crossed the end is almost in sight ... famous last words ... :mrgreen:

6 months in on the actual build .....

... and I noticed that even your dog is totally and thoroughly bored with it all! :)

Still angled skirting that meets at 45 degrees results in quite a funky, non-standard cut.

Not if you use a miter box.... :)

I did read about Homasote on the forums, but, I can't find any locally here in Aus. So I am hoping that the following soft board will be a reasonable substitute

That looks fine. Merry Christmas to you, Ben. (I'm really hoping to see this place finished and fully operational before the next one rolls around!) And a very happy New Year. - Stuart -

Hi Stuart, Yeah both my border collie and my girlfriend would like to see me finish :) Thanks for the Xmas wishes and may Christmas and the New Year be awesome over your way too! For the end of the year I thought I would clean up, temporarily unwrap the couch, drag a little bit of gear in, listen to the speakers for the first time and also try to wrap my head around calibrating REW and posting some initial REW reports. Please bear in mid that the soffits are not complete as shown below, the rear wall does not have final bass traps yet nor have I adde the extra layer of insulation that I have planned for the rear wall. I also still aim to add a ceiling cloud and the best possible RFZ side walls as space allows. So if these initial REW results are valid then I hope to get improvements as the build wraps up and further treatment is added. I have also added a few pics of the CR cleaned up. Hopefully the speaker soffit faces will be on and the rear wall complete before I go back to work mid January. After that it will be a few more weeks I would imagine before we can add the best possible RZF walls at the front coming off the speaker soffit, add a ceiling cloud and then finishing trims. The remaining insulation, wood and supports for the rear wall and rear super chunks is ready to go and should come together quite quickly as we really just need to assemble and install. Merry Christmas and best wishes to everyone for New Year.

Hi, Today we got the first of the speaker soffits up. There are two pics below. The first shows the 8kg/m2 of MLV tacked over an initial 18mm thick MDF sheet and the second image shows the second layer of MDF over the MLV. We still need to close off the right side of the soffit. We will get started on that tomorrow and also hopefully get the left side done too. I am still waiting for the soft board suppliers to open again after the new year. The soft board with form the core of the insulated hangers that will hang under the speaker shelf. This lower area will get covered with fabric to finish off. After the soffits are complete then one or two more days should see the rear wall and final two super chunks in place. After that is all done I'll re-run REW tests and try to work out the best possible RFZ walls that I can fit at the front of the room. I must admit I thought I was all over the RFZ angles many many months ago, but, as the build has progressed I have realised that I really should have allowed for a bit more width in the overall design as the 30 degree angle I am aiming for is going to eat up a lot of space that I'd prefer not to lose. Stuart, after I get the soffits complete and the rear wall done I am hoping to pick your brains if that is ok as to what my best options are. I have a few ray traces that I will post shortly that seem to indicate to me that for the best RFZ solution I'll just have to accept the loss of front space. I am fiddling around with reducing the angle a bit, but, just a few degrees less than 30 looks to be in-effective. It's too late now, but, I really wish I had made the space approximately 500mm wider and adjusted the length to suit. mmm ... :cop: ... that's all for now ...

Hi, Over the last day or so we hopefully finished most of the speaker soffit construction, added an extra 75mm of 32kg/m3 glass wool insulation to the rear wall (165mm tick in total) and finished the rear wall bass traps. Things will go a bit slow again this month, but, I hope to get the hangers under the speakers done and then early February build the best possible length RFZ walls, add some skirting and trims and then paint. That will just leave a ceiling cloud. I have spent the last few days measuring and ray tracing a range of angles to find the best possible solution that allows for a reasonable RFZ zone in front of the desk while also not chewing up too much space. After a lot of ray tracing I am thinking that I will run with 25 degree walls. I have included a scanned picture below that shows 5 degree increments from the right speaker (the left will be a mirror image) plus the main offending angles from the left to show the rough area that should hopefully be free from early reflections. I won't post all the ray traces, but, in summary 24 degrees and less walls resulted in early reflections that got too close to the central mixing position. 26 and 27 degrees also created possible zones, but, the walls seemed to eat up too much floor space (width) relative to the slightly increased RFZ zone. Any greater than 27 degrees and the speakers would just about end up in the RFZ wall rather than the soffit :( All up, provided the RFZ walls at 25 degrees work as intended then I'll be very happy, but, if I ever do this again then I would aim to scale up the layout in all three dimensions. There are a few more pics below and I'll post the initial REW results in a separate post.

Hi again, I have removed the REW file link that was above as those first readings were wrong. I have added some pics below and a link to a new data file that I hope is accurate. This time around I decided to simplify things and dragged my Apollo 8P down to the space so that it could look after all sound in and out. I set up a folding table at the location where the desk will eventually be, placed the Earthworks TC25 at the planned listening location, ran back through the calibration process and fire dup my SPL meter to get as close as I could to 85dB for the test. The test was done after both soffit faces were in place (as shown in the last post), with 165mm of 32kg/m3 insulation on the rear wall and the rear wall bass traps in place too. Here is a link to the data file: https://www.dropbox.com/s/y1k1lvybonjht ... .mdat?dl=0 (12.4MB) Below are a few screen grabs of the waterfall plots. I would be very interested to know if the waterfall charts and the data file look reasonable for a small room (4.4m long by 3.2m wide by 2.55m high). Cheers, Ben

It looks quite reasonable for a room that size. There's the usual SBIR from the rear wall, and there's the usual bass rise (how do you have the controls set on your speakers?), and what might be a floor bounce, but nothing out of the ordinary. I'd say your room might be a candidate for digital tuning. However, there are some issues: the room is a bit too dry overall: You should have a decay time of around 200 ms for that room, but yours is more like 140 ms. The good thing is that it is fairly even across the spectrum, with only a slight dip in the low mids, but it could do with livening up a little. You might want to consider plastic over your bass traps. You might also want to consider some form of diffusion: your room is borderline-big enough to do that, I think. By the way, you are probably looking too closely at your REW data (zoomed in a but too much: you are seeing trees, but not forest). THe setting I normally use for looking at the low end is to set the "limits" button to 18 Hz and 500 Hz for frequency, 35 to 105 db for intensity, and -1440 to +1440 for phase. That gives you a good general view of where you are. You can also smooth the graph a bit: 1/24 octave is reasonable, especially for the high end. One other thing I noticed is an unusually large difference between your left and right speakers, particularly around 135 Hz. Any idea what that might be? What other treatment do you have planned for the room? - Stuart -

It looks quite reasonable for a room that size. There's the usual SBIR from the rear wall, and there's the usual bass rise (how do you have the controls set on your speakers?), and what might be a floor bounce, but nothing out of the ordinary. I'd say your room might be a candidate for digital tuning.

Ok, so nothing too tragic. Can I ask how I would go about digital tuning?

However, there are some issues: the room is a bit too dry overall: You should have a decay time of around 200 ms for that room, but yours is more like 140 ms. The good thing is that it is fairly even across the spectrum, with only a slight dip in the low mids, but it could do with livening up a little. You might want to consider plastic over your bass traps.

I did place plastic over the fronts of the the CR and LR bass traps. The ceiling also has plastic before the final material finish as I had read about the ceiling and traps on the forums. But, I did not cover the rear wall with plastic. I could do that. I could also remove the black cloth cover from the side wall opposite the glass slider, cover with plastic and then put the black finish material back if that might help to liven the space up a bit more and maybe balance the effect of the glass a bit too.

You might also want to consider some form of diffusion: your room is borderline-big enough to do that, I think.

Not that I want to spend extra money that can be avoided, but, are there high quality commercial options for diffusion that could be shown to work at the required frequencies prior to purchase? Or is this something that would require building? Either way before I move in that direction how do I know what frequencies I am trying to diffuse and how does that translate to a solution?

By the way, you are probably looking too closely at your REW data (zoomed in a but too much: you are seeing trees, but not forest). THe setting I normally use for looking at the low end is to set the "limits" button to 18 Hz and 500 Hz for frequency, 35 to 105 db for intensity, and -1440 to +1440 for phase. That gives you a good general view of where you are. You can also smooth the graph a bit: 1/24 octave is reasonable, especially for the high end.

Ok, I'll play around with the view settings and see how the graphs look. I did think that the higher end looked a bit rougher than I had anticipated.

One other thing I noticed is an unusually large difference between your left and right speakers, particularly around 135 Hz. Any idea what that might be?

That might be because of the sliding glass door on one side versus the inside out build on the other. I am planning on a few things that might help to address that a little and also even things out as noted below, but, I am equally happy to get any information that will assist with knowing that I'm on track or if I am missing anything obvious. Then again 135 Hz is quite low and the options below probably won't address that? The RFZ if implemented correctly might go some way to addressing the 135 Hz issue at the listening position though?

What other treatment do you have planned for the room?

* I was planning to place a hard (probably double layer Fyrchek, but, it could be MDF if required) wall set at 25 degrees off the speaker soffits. I was going to fill the smallish cavities behind the left and right RFZ walls with any left over insulation. The angled face of this wall will be approximately 1000mm long based on my ray trace and calculations. The aim here is to make the left and right sides of the room identical from the listening position forward to the front wall. * I would love to wrap up as quickly as possible, but, I am expecting that a ceiling cloud of some kind will assist here too? Assuming that is correct, due to the height available I don't think that the cloud can be angled at more than about 10-12 degrees if it is to extend and finish above the listening position. A few more degrees would be possible if it is not as long. I assume some angle better than none, but, I must admit that I am not quite sure how to ray trace a cloud to be certain about the best possible config for the space. I guess I could try ray tracing different options based on a side view of the room exported out of Sketchup, but, I was thinking that this would be a bit simple and may not predict accurate results? If I used 90x45 or 70x35 timber for the frame, then based on the existing REW values, is there anyway to know if the cloud should be hard backed (i.e. would 6mm MDF be suitable for the back?) and would it also be filled with 32kg/m3 insulation, covered in plastic and finished in material? * I am also looking to potentially place the heaviest possible theatre curtain on a track (on the inside of the space) to cover any remaining glass sliding door during critical listening. I figure that this will not do much for low mids to lows but I was thinking that this could assist with the higher mids and highs? Would this be worthwhile? The material I was considering is this material: http://www.rosebrand.com/product1210/32 ... ur-FR.aspx * Other than that, I am happy to implement any further treatment and or diffusion that I can afford. The only caveat is me being able to understand what frequencies I am aiming to tackle and how best to do that. Thanks again for all your assistance and insight! Cheers, Ben

Can I ask how I would go about digital tuning?

Ahhh, now that's the 64,000 dollar question isn0t it? :) I don't like giving away ALL my secrets in public for free, but PM me if you are interested in going down this path...

I did place plastic over the fronts of the the CR and LR bass traps. The ceiling also has plastic before

How thick is that plastic? You can "tune" the refection/absorption ranges to a certain extent by choosing the right thickness. Plastic is a foil, and obeys the same laws of physics as other foils, so you can apply the equation for foils.

But, I did not cover the rear wall with plastic. I could do that.

Quick test: Run down to your local Bunnings (too late for Masters! :) ), and get bits of plastic in various thicknesses, from really thick to gossamer thin, in sizes big enough to just tack over the existing rear wall with pushpins. Do some tests with REW to see if it works well enough and if so, which one works best. Post the tests here, so we can see them, and help you decide.

Not that I want to spend extra money that can be avoided, but, are there high quality commercial options for diffusion that could be shown to work at the required frequencies prior to purchase?

Yes, but it's a hell of a lot cheaper to build them yourself! I'm rather partial to a low profile fractal-based diffuser that has been developed recently. PM me about that.

Either way before I move in that direction how do I know what frequencies I am trying to diffuse and how does that translate to a solution?

It's evident that you need more life across the board, from lows to highs. That's why I'd suggest a fractal for you, as you can do it in several "layers", each tuned to a different range. Typical commercial units only do one range, but you can cover several, and probably also soften the SBIR coming off the rear wall. That's the beauty of fractals: they repeat at various scales.

* I was planning to place a hard (probably double layer Fyrchek, but, it could be MDF if required) wall set at 25 degrees off the speaker soffits. I was going to fill the smallish cavities behind the left and right RFZ walls with any left over insulation. The angled face of this wall will be approximately 1000mm long based on my ray trace and calculations. The aim here is to make the left and right sides of the room identical from the listening position forward to the front wall.

:thu: that might help iron out the differences between channels. You didn't mention how you have your speaker controls set: there's a bass rise that needs to be dealt with.

I am expecting that a ceiling cloud of some kind will assist here too?

:thu:

I don't think that the cloud can be angled at more than about 10-12 degrees if it is to extend and finish above the listening position.

It might not need to be angled so steeply, and it does not need to extend all the way to above your head. It only needs to go as far as needed to deflect the reflections away from your head, which is generally a foot or so in front of the point above your head.

I am not quite sure how to ray trace a cloud to be certain about the best possible config for the space.

Same way you did it of for the side walls, but do it in the vertical plane, not the horizontal! Actually, you need to do several versions at different off-axis angles, since this is 3D geometry at differing angles up there, but the principle is still the same: Draw lines, bounce them off the surface at the inverse angle, and see where they go. Adjust. Rinse. Repeat.

I guess I could try ray tracing different options based on a side view of the room exported out of Sketchup,

Do it all inside of SketchUp.... Much easier. Keep it in 3D.

is there anyway to know if the cloud should be hard backed

I pretty much always do hard-backing these days, and if it is there for RFZ, ou have no choice! Maybe not on the entire cloud, but at least on the important part, where the first reflections would be, and for a distance beyond that.

(i.e. would 6mm MDF be suitable for the back?)

You like humming membranes singing above your head? :) Seriously, it won't be that bad, but I generally make the back THICK. 19mm MDF is my favorite, but 15mm is also acceptable.

and would it also be filled with 32kg/m3 insulation, covered in plastic and finished in material?

32 kg assuming fiberglass! You could probably go a bit lighter if you wanted: maybe down to 20 or so. It will mainly be dealing with low mids and lows, and you don't want to add too much absorption the the room, since it is dry already, so keep it light and yes definitely cover it in plastic.

* I am also looking to potentially place the heaviest possible theatre curtain on a track (on the inside of the space) to cover any remaining glass sliding door during critical listening.

Probably not worth it. See how it goes once everything else is done, then do some REW tests with an without a piece of insulation taped over the glass where that hypothetical curtain would go.

The only caveat is me being able to understand what frequencies I am aiming to tackle and how best to do that.

What frequencies? That's easy: All of them! :) Just to different degrees, and in different ways... :shot: 8) :roll: - Stuart -

Hi Stuart, Sorry for the delay and thanks for getting back. I will PM as well!

How thick is that plastic? You can "tune" the refection/absorption ranges to a certain extent by choosing the right thickness. Plastic is a foil, and obeys the same laws of physics as other foils, so you can apply the equation for foils.

I used 100um, but, based on the Bunnings website they also have a thicker 200um and I am guessing I should have used that. I got tied up today but will head out to Bunnings in the morning and will grab some of the 200um.

Quick test: Run down to your local Bunnings (too late for Masters! :) ), and get bits of plastic in various thicknesses, from really thick to gossamer thin, in sizes big enough to just tack over the existing rear wall with pushpins. Do some tests with REW to see if it works well enough and if so, which one works best. Post the tests here, so we can see them, and help you decide.

Will do. I should be able to test and post tomorrow afternoon after I clear a few other things. And get the plastic!

It's evident that you need more life across the board, from lows to highs. That's why I'd suggest a fractal for you, as you can do it in several "layers", each tuned to a different range. Typical commercial units only do one range, but you can cover several, and probably also soften the SBIR coming off the rear wall. That's the beauty of fractals: they repeat at various scales.

Ok. I'll read up on fractals.

You didn't mention how you have your speaker controls set: there's a bass rise that needs to be dealt with.

Oops. I did indeed miss that. The Adam A7Xs were set flat, i.e., as they came. I guess I should also try rolling some of the bass off via the rear controls? I'll try that as well and see what REW reports. Can I ask if it is in the 40-80Hz where you are seeing the bass rise?

It might not need to be angled so steeply, and it does not need to extend all the way to above your head. It only needs to go as far as needed to deflect the reflections away from your head, which is generally a foot or so in front of the point above your head. Same way you did it of for the side walls, but do it in the vertical plane, not the horizontal! Actually, you need to do several versions at different off-axis angles, since this is 3D geometry at differing angles up there, but the principle is still the same: Draw lines, bounce them off the surface at the inverse angle, and see where they go. Adjust. Rinse. Repeat. Do it all inside of SketchUp.... Much easier. Keep it in 3D.

Oki doki, I'll start ray tracing again and play with a few overall cloud angles and also adjust the length to see what works. This will probably slip out to the coming weekend. Cheers.

I pretty much always do hard-backing these days, and if it is there for RFZ, ou have no choice! Maybe not on the entire cloud, but at least on the important part, where the first reflections would be, and for a distance beyond that. You like humming membranes singing above your head? :) Seriously, it won't be that bad, but I generally make the back THICK. 19mm MDF is my favorite, but 15mm is also acceptable.

Ok, hard backed it is. I can get 18mm MDF easily from my local Bunnings.

32 kg assuming fiberglass! You could probably go a bit lighter if you wanted: maybe down to 20 or so. It will mainly be dealing with low mids and lows, and you don't want to add too much absorption the the room, since it is dry already, so keep it light and yes definitely cover it in plastic.

Ok, I have left over 32kg/m3 fibreglass but I could also grab some Earthwool fibreglass from Bunnings. Earthwool seems to be available in 11, 14, 17, 20 and 27 kg/m3 and is cheap relative to the 32kg/m3 fibreglass. Thanks, Ben

I got tied up today but will head out to Bunnings in the morning and will grab some of the 200um.

See if they have other thicknesses too. Building supply stores often have three of four different thicknesses. Also look for something very thin, such as "painter's drop cloth". You could even try some garbage bags, cut up and taped together. Be creative! :)

Oops. I did indeed miss that. The Adam A7Xs were set flat, i.e., as they came. I guess I should also try rolling some of the bass off via the rear controls?

Yep. Use the bass roll-off control. Try it at a couple of different settings, but I'd imagine that you'll need it all the way over.

I'll try that as well and see what REW reports. Can I ask if it is in the 40-80Hz where you are seeing the bass rise?

IT starts much higher than that, actually. It seems to be somewhere around 350 Hz., which is about what I'd expect for that size speaker.

Earthwool seems to be available in 11, 14, 17, 20 and 27 kg/m3 and is cheap relative to the 32kg/m3 fibreglass.

I'm assuming that "Earthwool" is mineral wool? If so, then the 27 mg/m3 stuff would probably be fine. But if it is fiberglass, then I'd go for the 20 kg/m3. - Stuart -

Hi, Work is unfortunately back in swing for the year, so time has become a bit more scarce. Still, after work I am trying my best to get a bit of time in to keep things moving forward. I am also flying solo until February as my step dad is in Sydney for a bit. Over the last few days I sealed off the sides of the speaker soffit framing with 6mm MDF (to get a smooth finish over the framing, MDF and MLV). That has now been shaped, drilled, countersunk, sanded, primed and has a first finish coat as per the pics below. Tomorrow arvo I'll add a second coat of red to the soffits and see how that finishes up. With any luck I'll be able to load the speakers back in Thursday arvo, tack some thicker 200um plastic to the back wall and run some more REW tests. Tomorrow morning (Wednesday) I will also order 13mm Canite soft board (a sugar cane by product that is the closest thing to Homasote here in Australia) for the soffit hanger core and 19mm MDF for the RFZ wall, rear wall diffuser and ceiling cloud. I am thinking of double lining the RFZ wall with left over 16mm Fyrchek at the back, separated by left over green glue and then 19" MDF at the front to make painting and finishing a bit easier. The cavity behind the RFZ walls will be stuffed with left over insulation. I also need a bit more framing wood, but, I thought I'd start with the hangers and diffuser first as I have a clear understanding of what I need to do there. The RFZ walls and ceiling cloud will be left to last and hopefully my step dad will be back to assist with that by then. Hopefully without sounding too aloof, when I completed my music degree, I said to myself that study would have no impact on my outlook or approach toward writing and performing music. All I can say to that now is bah! Am I better as a result? All I know for sure is that I am not what I would have been. Likewise, when I started this build the goal was to work it out, dig in and get back to recording asap. Again I say bah! Still in the meantime and on the plus side, lyrics, comps and sketches are building up; while unfortunately time on my instrument and time in my DAW have temporarily dropped away. This is clearly not good. Nor is working for the man to pay the bills. But, there is a distant impression of light at the end of what has been quite a learning curve and I know it will be worth it!

See if they have other thicknesses too. Building supply stores often have three of four different thicknesses. Also look for something very thin, such as "painter's drop cloth". You could even try some garbage bags, cut up and taped together. Be creative!

I'll start with the thicker 200um stuff and go from there :)

Yep. Use the bass roll-off control. Try it at a couple of different settings, but I'd imagine that you'll need it all the way over.

I'll also aim to post new REW results with:

• 100% roll off + no 200um plastic tacked to the rear wall
• no roll off + 200um plastic tacked to the rear wall
• 50% roll off + 200um plastic tacked to the rear wall
• 100% roll off + 200um plastic tacked to the rear wall

I'm assuming that "Earthwool" is mineral wool? If so, then the 27 mg/m3 stuff would probably be fine. But if it is fiberglass, then I'd go for the 20 kg/m3.

Despite its earthy sounding marketing name, Earthwool appears to be fibreglass. It is made by Knauf Insulation here in Australia and Bunnings seem to have access to their full range. Bunnings state it is a mix of glasswool and sand. So I am guessing that it is more fibreglass than mineral wool? Is that a reasonable assumption? https://www.bunnings.com.au/our-range/brands/e/earthwool http://www.knaufinsulation.com.au/content/earthwool-external-wall-batts Here's the few new pics: Cheers, Ben

With any luck I'll be able to load the speakers back in Thursday arvo, tack some thicker 200um plastic to the back wall and run some more REW tests.

Hey! No fair! Thursday came and went already, and there's no sign of your REW tests! :) 8)

I am thinking of double lining the RFZ wall with left over 16mm Fyrchek at the back, separated by left over green glue and then 19" MDF at the front to make painting and finishing a bit easier. The cavity behind the RFZ walls will be stuffed with left over insulation.

Sounds like a good plan.

100% roll off + no 200um plastic tacked to the rear wall no roll off + 200um plastic tacked to the rear wall 50% roll off + 200um plastic tacked to the rear wall 100% roll off + 200um plastic tacked to the rear wall

That would be a good set of tests, yes. And also repeat the "100% roll-off" for any other thickness of plastic that you can find.

Despite its earthy sounding marketing name, Earthwool appears to be fibreglass. It is made by Knauf Insulation here in Australia and Bunnings seem to have access to their full range. Bunnings state it is a mix of glasswool and sand. So I am guessing that it is more fibreglass than mineral wool? Is that a reasonable assumption?

Makes sense. I'd go for the 20 kg/m3 stuff, in that case.

Here's the few new pics:

It's looking GREAT! I must admit.

there is a distant impression of light at the end of

I was a bit worried there for a sec, that the glimmer might have been the headlight of an oncoming freight train, ... but after seeing your latest photos, I'm convinced that's not the case! It really is the end of the tunnel, and it's a bright sunny day dawning outside! - Stuart -

Hey! No fair! Thursday came and went already, and there's no sign of your REW tests!

If I may indulge just a little via the Rolling Stones ... "You don't always get what you want" ... :mrgreen: ... and for sure I know that is true !!! please understand that I had the best of intentions. In fact I shined those intensions beyond belief ... boy did they shine, all the way right up till Thursday and then alas they faded despite applying further intentions and the best science and care that I could muster ... :oops: Still through the week I did apply a second finish coat the the soffits, cleaned up and this weekend I hopped up first thing and started cutting 13mm canite soft board (the closest thing to Aussie Homasote) for the soffit hangers ... there are a few hanger pics below ... I will finish the hangers tomorrow (Sunday morning) and if I am super lucky also hang them too ... then I promise I will tack the plastic and get on with the REW tests ... worst case the REW test will be posted some time this week ...

Sounds like a good plan.

Great !!!

That would be a good set of tests, yes. And also repeat the "100% roll-off" for any other thickness of plastic that you can find.

Ok, I will try to source all things plastic !!!

Makes sense. I'd go for the 20 kg/m3 stuff, in that case.

Cool ... I'll grab some 20 kg/m3 Earthwool at Bunnings tomorrow ... I also ran out of glue making the hangers today so I had planned to visit Bunnings at Belmont in the morning anyway ... :)

It's looking GREAT! I must admit.

Thanks !!! I need to tip my hat to both yourself and my step dad Bryen ... without folk such as yourselves I would not have made it this far ... :yahoo:

it's a bright sunny day dawning outside! \

Indeed it is ... I certainly can not complain ... While I do hear the train a coming there are fortunately few blues to be seen ... may it be so for all ... forever and and a day ... Thanks yet again, Ben

Hi Stuart, I finally managed to run the following REW tests this evening: 100% roll off + no 200um plastic tacked to the rear wall no roll off + 200um plastic tacked to the rear wall 50% roll off + 200um plastic tacked to the rear wall 100% roll off + 200um plastic tacked to the rear wall The waterfall graphs with 1/24th octave smoothing across the full range (35 to 20,000Hz) are below. I thought the full range would show if the plastic, in combination will rolling off various amounts of bass, is helping to keep more of the highs in the room. The original waterfall is below too for a quick comparison. The updated data file is also on Dropbox with all readings in it. It is getting big at around 55MB: https://www.dropbox.com/s/ee08w5ulzmiti ... .mdat?dl=0 I am guessing that the last of the above images (100% bass roll off + 200um plastic on the rear wall) is leaving the most highs in the room. But, is it enough? I also could not find anything else heavier, but, I guess I could either try double sheeting the 200um with 100um to get 300um or even try double 200um if the above results indicate that there is still too much high absorption? Also, after I add a 1200mm x 2400mm diffuser to the rear wall will that essentially negate most of the work that the plastic is doing? Or will plastic running completely across the rear wall, i.e., behind the superchucks, diffuser and lounge, have a cumulative effect on keeping more highs in the room? I am also planning on painting the diffuser black and then sealing it with a few coasts of varnish to make sure it is more reflective than absorptive. I believe that is the correct approach? I also found a bit of time to start fitting the soffit hangers and will continue doing a bit of that each arvo after work. I'll add some more pics later in the week of that. That's all for now. Cheers, Ben

Hi Over the weekend I installed the soffit hangers and have added a couple of pictures below. Next week there is a public holiday as well as the weekend, so I hope to start cutting MDF for the rear wall diffuser and also some framing wood for the ceiling cloud. That's all for now. Cheers, Ben

Hi again, I started building my rear wall diffuser today, I think it's ok to show a few pics. I'm really happy with how this has turned out and much of that happiness is down to Bunnings cutting all the 12" MDF to the required widths. If anyone else is in Australia is going to make one of these bad boys then I'd highly recommend getting Bunnings to cut all the lengths. Of course if you have your own table saw or a really accurate thicknesser/spacer for your circular saw then I guess things would go well. But, hey if Bunnings are willing to do all the cutting for free in about 20 minutes so you can take it all home and start painting or assembling then why not. Tomorrow I hope to assemble the five panels that will make up the 2100mm wide diffuser. I'll probably seal the whole thing in a hard lacquer of some sort courtesy of Bunnings. Hopefully next weekend I'll get started on the RFZ side walls with my step dad and then it's just the cloud and skirting to go. So hopefully by the end of February things should be all but done. There are few pics below. Ciao, Ben