Private studio in Slovakia

[Studio45]

Hey Starlight, Wow, that's great progress so far! Keep doing great work!

Cheers!

Francis,

[Soundman2020]

[... that Green Glue is good but also that he rarely uses Green Glue in his builds. John explains why in one of the documents publicly available on his resources page, Sound-Proofing: The Quest. It is only 8 pages and well worth reading but specifically, he compares two STC tests, one from IR761 (which is in Stuart's Document Library) and one by the Green Glue Company. What John shows is that STC ratings are improved by using Green Glue but that STC ratings only cover 125Hz-4kHz. For music we want good performance down to below 20Hz, almost 3 octaves below 125 Hz. At these frequencies John prefers to add an extra layer of plasterboard/drywall to get better performance at all frequencies than use Green Glue for a better STC.

Well, I'd take those conclusions with a grain of salt. To start with, the one single GG result he includes in that paper (from 7 years ago), only tested down to 80 Hz, yet the comparison is against a different test that went down nearly an octave lower, to 50 Hz. It isn't a valid comparison. Yes, he does mention that in the document itself, but then why do the comparison at all, when he recognizes that it isn't valid? He also mentions that he could not find any data on Green Glue, but I guess he didn't look very hard, because there is quite a bit, easily available, from tests conducted at several independent acoustic test labs, in various parts of the world.

One that is rather revealing, comes form the CSIRO (government test facility) in Australia:

That's a valid comparison, showing the rather impressive results. The full report is also available.

In any case, GG is a good product, that works as advertised. Rod Gervais has written extensively about it, both in his books and also on several forums. He was instrumental in getting the Green Glue company to do that testing, years ago, because he didn't believe their claims initially. He challenged them to to prove their claims by getting their product tested in independent labs... after seeing the results, he changed his opinion, and started using the product in several projects, with good outcome. Several of my clients have used it as well, also with good outcome. Notably, the "drum teaching studio" in Australia (the same that I have posted details of the door and window construction, here on the forum). That was part of the key to the success of that build: Green Glue in between the layers in the walls and ceiling:

We only used two tubes per sheet, for economic reasons (this stuff is expensive!), but the outcome speaks for itself: the owner teaches drums in his studio, so he often has two drum kits going full-bore, plus bass and other instruments, yet his neighbor whose front door is just a few meters away, can't hear a thing.

There's a common misconception about this product, so I just put together a post with all of the data that I have on it, for reference. I put it in the reference area, here: The truth about Green Glue At first, I thought of putting this in the "Fake Acoustics" section, but that would be backwards! It should be in the "Anti-Fake Acoustics" section (which I didn't make yet... ), since the rumors about Green Glue are incorrect: the rumors say that it doesn't work well, or that you can get the same results with MLV, carpet glue, construction adhesive, one extra layer of drywall, or "alternative" products, but the truth here is that the rumors area all wrong! None of those comes close to the reality of Green Glue. In reality, to get the same performance as Green Glue, you would need to add at least two extra layers of drywall, and more like three extra layers. That's a really, really bold claim, and I think Andre will agree with me that we didn't really believe that when we saw it... but now we do. So this is not in "Fake Acoustics", but rather in the "Reference Area" itself.

- Stuart -

[Starlight]

Stuart, I appreciate that you don't simply make claims but you go to great lengths to explain truths and challenge misconceptions.

Where you say in The truth about Green Glue, "... don't use it (unless you need very high isolation ..." maybe John deduced from my description, details, data and readings I gave him that very high isolation is not needed. I will find out when I am done.

I have just priced it up: if I had used Green Glue it would have added around 1,600 Euros (£1,450, $1,900) to my build cost.

[Soundman2020]

if I had used Green Glue it would have added around 1,600 Euros (£1,450, $1,900) to my build cost.

Right! It isn't cheap at all, and you probably do not need it. As soon as you complete your inner shell, you can conduct your initial isolation tests: I'm betting you will be fine with what you have. I only recommend GG where people need better-than-typical isolation and have the enough budget to go for more exotic solutions, and that usually is mostly for commercial pro studios, or places like that double-drum studio in Australia. We could have gone for an extra few layers of drywall to get similar results, but that would have taken off a couple if inches in each direction for the studio, which was already on the small side, and the cost was similar to that of GG. So we went with GG in that case.

Stuart, I appreciate that you don't simply make claims but you go to great lengths to explain truths and challenge misconceptions

Right! I try to never make any statements about acoustics, or acosutic products, without first checking all the available data, and working through it. There's waaaaay too much well-meaning but misleading information out there about studios and acoustics (apart from the outright scams and hoaxes!), and I'd much rather be part of the solution, than part of the problem! Wherever possible, I'll always provide all the research I can to back up what I say. That's one of my goals with this forum: keep it solid, sound, scientific, and verifiable, with good research and resources to back it up. I want this to be a place where people can be confident that they can find "stuff that really works" for designing and building their studios.

By the way, your progress has been going pretty well recently! It's looking good, from where I'm sitting.

- Stuart -

[Starlight]

Our builder dropped in for 2 hours on his way home from another job. That gave us enough time to get the four baffle boxes in place.

WARNING: Our studio and baffle boxes have not been designed by Stuart, so pick what you can from here that helps you but Soundman2020 silencers will be different, fully closed and are much heavier.

Last week I caulked some backer rod onto the baffle box edges that will connect with either the wall or the ceiling.

Just before we lifted them into position I ran a generous amount of caulk next to the backer rod. Some edges will be hidden and so it will be impossible to push backer rod into place and caulk these edges once the boxes are in place.

Here we can see what happened: the caulk filled and sealed the gap between the baffle boxes and the wall.

Here are the two baffle boxes on the outside wall ...

... and here are the two inside the studio.

That's all for now.

[SoWhat]

Greetings Starlight,

Brilliant!

One question: Are the boxes on the outside wall secured to the nailers (shelves), or are the nailers just acting as cantilever braces? I saw the metal brackets on the studio side.

I do hope you are going to faux paint them with a gingerbread theme...

All the best,

Paul

[Starlight]

Source of the postOne question: Are the boxes on the outside wall secured to the nailers (shelves), or are the nailers just acting as cantilever braces? I saw the metal brackets on the studio side.

Who was it that once said:

Source of the postIt's so good to have multiple sets of eyes on this!

It is now my turn to thank you, Paul, for spotting the obvious mistake! The baffle boxes are just resting on the nailers. I will attach them this evening or tomorrow.

The difference in my situation is that the baffle boxes outside will be visible, whereas inside there will be a drop ceiling that will hide them.

Source of the postI do hope you are going to faux paint them with a gingerbread theme...

What a great idea! I haven't decided what to do, whether to just paint them or cover them with plasterboard or something before painting.

[Soundman2020]

Source of the post What a great idea! I haven't decided what to do, whether to just paint them or cover them with plasterboard or something before painting.

My vote is for chocolate icing, with multi-colored sprinkles!

On a more serious note: congrats on getting those silencers in place: I bet that was a heavy job, and not so easy... Nice work on the sealing, by the way!


- Stuart -

[SoWhat]

Greetings Stuart,

On a more serious note: congrats on getting those silencers in place: I bet that was a heavy job, and not so easy...

If I am not mistaken, Starlight is in possession of a drywall lift with enough capacity to get those things airborne.

My vote is for chocolate icing, with multi-colored sprinkles!

mmmmmmm chocolate icing aaaaarrrgghhhhhh

All the best,

Paul

[Starlight]

Source of the post... congrats on getting those silencers in place: I bet that was a heavy job ...

Source of the postIf I am not mistaken, Starlight is in possession of a drywall lift with enough capacity to get those things airborne.

You are not mistaken, Paul, but we discovered that the splay of the legs was more than the size of the silencers so we could get them up to ceiling height but not close enough to the wall. So, in the end, we had to manhandle them. Our builder and I had no problem lifting them together. Thanks, Stuart, for the compliment; as you know, they could have been impossibly heavy but they weren't so we managed.

For the exterior silencers, the nailers proved invaluable as we could rest each silencer on them and it took the weight so all I had to do was to keep each silencer upright while my wife handed the builder screws and his electric screwdriver to screw the ceiling batten (or nailer) in place onto the ceiling plate we had put in place earlier.

For the interior silencers, because we had to present each silencer - with gooey caulk on both the wall and ceiling sides - precisely, we prepared two stilts and so when the silencer was in place, my wife shoved the two stilts in place under the silencer, which bore the weight, and I then all I had to do was to ensure the silencer stayed in place while the builder screwed the nailer and L-shaped ceiling pieces in place.[/quote]

Source of the postMy vote is for chocolate icing, with multi-colored sprinkles!

I'll have to work on that. In the meantime, I guess you have seen through my pretence and realised that my caulk is in fact butter icing.

[SoWhat]

Greetings Starlight,

It seems like the installation went pretty smoothly. Did you fabricate the stilts, or did you use those commercial scaffolding-type poles with the platforms on top?

my caulk is in fact butter icing.

I've heard that fondant works well too. It's also paintable.

All the best,

Paul

[Starlight]

Source of the postDid you fabricate the stilts, or did you use those commercial scaffolding-type poles with the platforms on top?

It was a spur of the moment idea. I had taken apart the pallet the plasterboard was delivered on so that we could use the feet for the big nailers inside the studio and so two pairs of 2 metre slats from the top of the pallet were screwed together to give us two 2.5 metre stilts.

All credit goes to Joseph, our builder.

The pallet is in post no. 38 on page 3, here.

[SoWhat]

Greetings Starlight,

Yes, I remember the photo from #38. Looking back at it now, it didn't sink in then how nice the pallet was, perfect for reuse after disassembly.

Full marks to Joseph for his idea. Good carpenters are worth their weight in gold (or pallets, as the case may be). Ours is brilliant too, and I am thankful.

All the best,

Paul

[Starlight]

Here is my studio, a plan view, looking at the yellow AC which is fixed to the front wall (top edge of the image). The smaller rectangle inside the AC is the air intake. The grey area at the top is planned treatment and the grey shape at the bottom will be the cloud.

The ventilation duct will, ideally, deposit fresh, incoming air above the AC's air intake. I have two possibilities: first, my studio's designer has the duct coming to a grille (register) that sits in the (blue) drop ceiling space above the AC, like this:

Stuart wrote in his topic Myth: "My studio does not need HVAC":

Source of the post... you need a very large, sudden change in cross sectional area to get a decent impedance mismatch. At least twice or half the area.

That leads me to another possibility. I could, instead, have the duct run into a plenum which has at least twice the cross section of the the duct and have an outlet opening that drops air above the AC - but not above the treatment or cloud as that seems pointless. Something like this:

What are your thoughts? Can you see the pros and cons of each possibility?

[Soundman2020]

Source of the post That leads me to another possibility. I could, instead, have the duct run into a plenum which has at least twice the cross section of the the duct and have an outlet opening that drops air above the AC - but not above the treatment or cloud as that seems pointless. Something like this:

That gets my vote!

- Stuart -