New dream house with studio and workshop.

[Wheresthedug]

Source of the post I can't wait to see how the windows are done!

You and me both

[Soundman2020]

Hi again Alan! Sorry to be arriving for the party so late, but I've been out of action for a while...

Anyway, folks have been giving you some good advice, so I'll just add a comment here and there, as I'm playing "catch-up" on your thread...

Therefore, how thick does my glass need to be to have the same isolation properties as 215mm dense concrete?

Eric already gave you the answer, and you got the picture here I think: While in theory, the glass should match the density of the leaf, that's more for cases where we are talking about lower mass walls, such as drywall or plywood sheathing with siding, or maybe an inch of stucco, or something like that. For high-mass walls your glass only needs to be "thick enough to do the job", as Jennifer pointed out. Which basically means it needs to have enough mass to provide the MSM resonant conditions that you need, for your target isolation number.

Kevin also added the very good advice of going with laminated glass, and I'd add the additional suggestion of going for "acoustic" laminated glass, which uses a thicker, better PVB interlayer, that improves isolation even more. And in terms of the old adage of some people who give expensive advice not always "practicing what they preach", here's a very current and up-to-date personal anecdote. Recently, some noisy neighbors moved in to the house right behind ours. They seem to love having loooonnnnggg parties, almost every day of the week, starting in the afternoon, around maybe 3 PM, and running on and on and on... often until 3 AM! As the party progresses, the talking and music gets louder and louder... Several neighbors have called the cops on them, and they have been warned several times.... to no avail. They turn it down for a bit, or pack up for the day, but the next day they are back at it.

OK, that's the general picture. It is driving us crazy! So, as an acoustician, it would be rather silly if I didn't put my skills to work, and do something on my side! So I did. As with most houses in Chile, our house construction is concrete and brick (earthquake territory:it has to be tough!), so there's way plenty mass in the walls to deal with this issue. It's the windows that are the problem. The house was built back in the 60's, and the glass is just all single-pane regular float glass. And in all of the bedrooms, as well as the living room, the doors are large glass sliders in aluminium frames, so there's a lot of surface area there with low isolation. I am replacing those with IGU's in vinyl-and-steel frames. And the glass will be laminated with acoustic PVB. Because that's what we need here, to get enough isolation!

We got the guy from the door factory last week, to come over to our place, measure, and quote. When I asked if he was aware of acoustic laminated glass, he warned us about the "large" difference in cost, but I asked him to quote us for that anyway, in addition to the "standard" laminated glass. He also warned me that it will "only" get me about a 3 dB increase in isolation. So he knows his stuff, and was very honest about it, which was encouraging. He sort of tried to discourage us from that path due to the costs, which makes me want to like him even more! It turns out that the difference in costs isn't as "large" as we expected. I have heard of cases from some of my clients, in various places around the world, where acoustic laminated glass is WAY more expensive than ordinary laminated glass, but in this case the difference is about 12% of the total cost. That includes the custom made doors and windows, with their various mechanisms and seals: the total cost for the exact same sliding door WITH acoustic laminated glass is about 12% more expensive than the version with normal laminated glass. And my wife and I decided to go with the acoustic PVB version, for sure!

Is it worth to pay all that extra to get just 3 dB additional isolation? YOU BET IT IS! Hell yes! Here's why:

THe blue curve is the "standard" laminated glass, the red curve is the "acoustic" laminated glass. You can see that, even though the overall benefit is perhaps 3 dB, there's a major improvement at the coincidence dip, a little under 2 kHz. The improvement there is more like 8 dB, which is good by any measure. Right at the frequency range for party-music and party yelling, and clanking beer bottles, and suchlike. There's also a rather nice increase in isolation all the way down to about 160 Hz, with only a slight decrease below that (which I suspect is a testing artifact, since there isn't much reason for that, acoustically). A 4 or 5 dB improvement at 160 dB is also noteworthy, and worthwhile.

So this "preacher" is definitely "practicing" here: we are forking over the extra cash for the acosutic PVB, happily, to get that extra isolation. OK, so maybe not "happily", since it's a lot of money to do this! But still, it is justified. The new doors and windows are due to arrive on October 14, so after that I'll report back on how successful they are. But the numbers make sense.

Excuse my long and slightly off-topic waffle, but the point is that using laminated glass with acoustic PVB is justifiable, even with the difference in cost, in most cases. So that's what I'd recommend for you, if you need good isolation for your studio.

as I have stunning views which would be a shame to waste.

All I can say is. WOW! Those are just darn amazing views! Totally worth the investment in large windows. The view of the loch is awesome! Congrats on such a wonderful site for your place.

We have up to 8 loads of timber passing each day.

Ouch! And with heavy trucks, that is mostly low frequency rumble, and diesel engine noise. Good isolation is paramount.

However, the speed limit on the road is only 10mph so the noise is relatively low. The sheep, cows and birds make more noise

What about Nessie?! What type of noise does she make, late at night?

My target is as close to 82db reduction as I can manage (hence 215mm think concrete walls and concrete roof) but in reality if I can manage over 70db I should be OK.

Those are pretty major numbers! You are wanting extreme isolation, it seems! Even more than what we planned for your other place. 70 dB is probably do-able, with deep pockets and very careful attention to detail, but 82? Hmmmm.... Man, that's in the region of "way out there". Do you really need that much?

To put things in perspective: a typical 2x4 stud-framed house wall with drywall on each side and insulation in the middle, will get you in the upper 20's. Maybe 30 dB, with luck. Doubling up on the sheetrock and going to a staggered-stud frame can get you in the upper 30's. Maybe 40 dB or so. Full-blown fully-decoupled wall, with dual stud frames separated by a good gap, three layers of drywall on the outer sides, Green Glue, and the cavity completely filled with insulation, can get you in the mid 50's. Maybe 55 or so, realistically. For 60 and up, you need more mass, and/or even larger air gaps. 70 is about the limit, since that is roughly where the "flanking limit" of a typical monolithic concrete slab would be, To get beyond that, you are getting into "floated room" territory.

The best-isolated studio on the planet, is arguably Galaxy Studios in Belgium. They get just a little over 100 dB isolation. It cost them millions of dollars, and 5 years of heavy construction, after several more years of careful design by the best acousticians around (including Eric Dessart, who lead the isolation design). This is a quote from Eric: "Such a project [is] at the boundaries of what's physically possible,..." This is how they achieved that:

Those are the isolation springs that the main control room sits on. Each room is floated similarly, and each is basically a massive concrete bunker floated within another even more massive concrete bunker, with a massive air gap between them. Huge, in fact.

Construction photos:

That's what 100 dB of isolation looks like. 82 dB is in the same ball-park...

OK, getting back down from the outer reaches of the Galaxy, and returning to planet earth: your concrete walls by themselves will get you in the region of 50 dB isolation, from Mass Law. You can probably get that up around 60 dB, or maybe some more, with inner-leaf stud-framed walls. Getting beyond that is going to need a fully floated room, as Starlight already mentioned.

My question here is still: Do you really need that much isolation?

I don’t have the Marshalls book but I have read Rod Gervais book from cover to cover a few times, plus Philip Newel’s book, and made some progress on Everest’s Master Handbook of Acoustics.

To be very honest: use the Newell book as a door-stop, or a paper-weight. I'm not impressed by much of it, and I know of quite a few other studio designers that hold similar opinions. But the other books you mentioned are good. Not sure if you have seen this thread? https://digistar.cl/Forum/viewtopic.php?f=11&t=13

The problem I am grappling with (through my lack of a detailed understanding) is how the windows perform in this system. The full system is only as good as its weakest link and it appears that the windows will be the weakest link.

The math gets a little ugly, as Starlight showed, and there are actually several different regions of the spectrum that need different approaches, as shown by this simplified graph:

Different physical aspects of the wall are dominant for different regions of the spectrum, so the challenge is to figure out which parts you need to be worried about: For extreme isolation, it's not an easy task... What you would need to do is to first define the number that you are aiming for: there's actually a rather large difference between 70 dB and 82 dB! Even between 70 dB and 72 dB there's a pretty big difference. As George Orwell might say: "Not all decibels are equal: some are more equal than others". At the low end, there's not much difference at all between 25 db and 27 dB isolation: hardly worth talking about. But the difference between 40 dB and 42 dB is definitely going to get your attention, when you look at the mounting piles of dollars (or euros, or pounds...). And the difference between 80 dB and 82 dB is a real eye-opener! It's only 2 dB difference in each case, but the 2 dB between 80 ad 82 is far, far greater than the 2 dB difference between 25 ad 27. Because: Logarithms! The dB scale is logarithmic, so small numbers are tiny differences, while large numbers are huge differences.

So your first step should be to fix a definite goal, and aim for that. Based on that, you can come up with suitable mass for your window glass, as part of the whole isolation system. For 82 dB, we are likely talking about a pair of 2 1/2 inch thick (65mm) "bullet-proof glass" type panes. For the 50 to 55 dB range, it's probably more like a pair of 1/2" (12mm) to 3/4" (19mm) panes.

I have always understood from Rod, Stuart and others that two leaf systems are your friend but three (or more) leaf systems are the work of the devil and should be avoided at ALL costs. However, on of the examples in the Newel book details a quadruple glazed window system. I can’t get my head round how that works

Like I said: Newell's book makes a good door-stop. Here's the best use I found for my copy:

It makes a really good keyboard stand at the far end of my office, right on top of the ancient cassette deck that I also haven't used in years, and brings the temporary keyboard for one of the web servers up to just the right height for comfortable use....

The thing about Newell's book, is that it has a large number of "I did this with 27 layers of these materials", but then no actual explanation as to the theory, or lab results, or in-situ testing, or anything else. You just have to take his word for it that "it worked"... without even knowing what "it worked" even means! And of course, the clients that forked over big money to build those rooms are happy to gush about how well "it worked" too... as would anybody that just emptied a large back account into something! Ask a guy who just poured stacks of cash into a shiny new boat, or sports car, or house, or plane, or whatever, and you'll get the same answer: "Its fantastic!" But do some objective testing, or read the opinions or real-life experts who objectively sailed the same boat, or drove the same car, or flew the same plane, and also did real-word tests with measurable results (power, torque, top speed, climb rate, etc.), then you get the REAL story. There is none of that at all in Newell's book. Just rough drawings of what he did, with vague comments on "the dead-sheet reduces the low mids", and "the unnamed insulation attenuated the highs". Ditto with the triple glazing: no actual testing to show how that works.

Here's the simple truth about single double, and tripe leaf isolation:

Those three curves are a good illustration of the general characteristics of the three. The green line is single leaf, and shows basic "mass law" at work. In this case, the comparison isn't "fair" since the single-leaf is a 500mm thick concrete block(!), while the double and triples are considerably thinner stud framed drywall (2x6 studs for the 2 leaf, 2x4 for the 3-leaf)l, so there's a huge mass advantage to that single leaf example. To put it in the same perspective, slide that green line down the page by about 35 dB, and you would have a more realistic representation of a single-leaf drywall partition. The pinkish color curve is the two-leaf wall, with dual stud frames and and two layers of drywall on the outer faces, and filled cavity. The three-leaf has a dead-sheet in the middle, and if I recall correctly, it is a lead sheet. Now look at the shape of those three curves: the single leaf rises at roughly5 dB per octave, as it should since it is governed by mass law. The 2-leaf isolation curve rises at 14 dB per octave, and the 3-leaf curve rises at about 20 dB per octave. In strict theory, those should be 6 dB/oct, 18 dB/oct and 24 dB/oct, but reality is not theory...

Now, you might be thinking "24 db per octave? Wow! That's GREAT!" ... but look at the graphs again. Even though the three-leaf has much more mass than the 2-leaf, it is really lousy in the low end, and the lower mids too. From about 200 Hz down, isolation drops off drastically! At 125 Hz, the 3-leaf is already a full 10 dB below the 2-leaf, and at 63 Hz, it is a whopping 25 dB lower... So bass guitars, drums, the low end of keyboards, even roaring electric guitars will shine through that 3-leaf as it it was not even there at all! Yes, it does have an incredible 105 dB isolation at 1 kHz, and is off the charts above that, but who cares? You do NOT need 100 dB isolation at 1k!!! the 80 dB from the 2-leaf or massive single leaf is already more than enough here... There is no need at all for extreme isolation in the high end: It's the LOW end that matters, and that's where 3-leaf fails, miserably. In order to get that 3-leaf curve far enough over to the left that it isolates the low end well, you need enormous mass. Just compare it to the isolation provided by the single-leaf concrete block, all by itself.

Conclusion: 2-leaf MSM is the way to go. It beats single-leaf (unless the single leaf is EXTREMELY massive), and it beats 3-leaf as well. Always. So there's no way that Newell's triple glazed windows could have done a better job than a lower-mass double glazed setup.

I recall a thread, years ago on another forum, where someone had their room designed by a supposedly reputable company in the UK... and ended up with a SEVEN LEAF system in some places! I kid you not. Eric and Rod and I and a few others were aghast, and commented on the stupidity of such a design. The maddening thing is that it worked! The poor victim really did get good isolation... but NOT because of the 7-leaf design! It worked simply because there was such a huge amount of mass in all those leaves, that the total isolation was sufficient. Our comments were mostly along the lines of how the poor guy got so badly screwed with the immense cost, and the lost space. He was actually satisfied with the outcome, but Rod was rather upset at the outrageous cost of materials where a simple two-leaf MSM design could have achieved the same results for way less than half the price, and Eric was commenting that it was pretty much impossible to even calculate the acoustic performance of a seven-leaf system, so it was clear to him that the "designer" had basically just thrown in everything, even the proverbial kitchen sink, hoping that something would work!

I get the exact same impression when I read Newell's book: many of the build descriptions read like that: We just threw in every possible building material we could find, and it worked!". OK, so it worked: At what cost? There's actually a thread here on the forum by someone who inherited such a room, and it sounds terrible! He's desperately trying to fix it now.... The combinations of materials, and the explanation h was given, are mind-boggling.

Which is why his book is holding up my keyboard. To put that in perspective, here's here's part of what's on the bookshelf behind my desk....

Those are far more useful than my keyboard stand!

Sorry for the rant, and I'm sure some people will be horrified by my opinion here, but I know I'm not alone among studio designers with that thought....

Anyway, getting more along the thread, Jennifer brought up an excellent point:

Had you considered aiming for a lower f0 than 22Hz?

To get good isolation, you wil indeed need to get quit a bit lower. Not because you need to isolate such low frequencies (or maybe you do: logging truck wheel rumble, diesel engines groaning under load...), but because of the math. Think of it this way: if you look at a whole bunch of Transmission Loss graphs, you soon notice that they all look pretty much the same: a diagonal line, high on the right end, low on the left end, with some squiggly bits in between. (that's a very precise, highly accurate, deeply technical description, please note! ). There are variations, yes, but all TL curves follow that same basic path. All you can do with your design, is to shift the position and the angle of that "diagonal line". The more you shift it to the left, the better your isolation is. The more you shift up upwards, the better your isolation is. And the flatter you make the angle, the better your isolation is. It really is that simple! The goal is a flatter graph, shifted way over to the left, and raised up way high. The best way to achieve that, is by pouring truck loads of money into the project! But on a more serious level, for an MSM wall, the following is true: Increasing the mass pushes the curve up the page. Increasing the air gap and/or damping, pushes the curve over to the left. If you push the curve far enough over to the left, then that is pretty much the same as pushing it up! Think about it.... And "pushing it over to the left" is the same as "lowering the resonant frequency". So even though you might not need to isolate any sounds at frequencies of 15 Hz, the simple fact of attempting to do so means that ALL HIGHER FREQUENCIES ARE ISOLATED MORE! So your isolation at 35 Hz, or 80 Hz, or whatever is greatly improved, by lowering the MSM frequency, which "pushes the entire curve to the left".

One final comment: the construction photos are awesome!

OK, I think I have ranted and waffled enough on your thread: I'll shut up now for a while.... !


- Stuart -

[Wheresthedug]

Thanks for the customarily short and snappy response Stuart

Seriously, much appreciate the input.

Newell book - point taken. It's getting a bit cold in here with the door permanently ajar though. Might need to find an alternative use other than door stop.

Source of the post Kevin also added the very good advice of going with laminated glass, and I'd add the additional suggestion of going for "acoustic" laminated glass, which uses a thicker, better PVB interlayer, that improves isolation even more.

I will investigate that option properly. Glad to hear you practicing what you preach. I spoke to the guy who is doing my glass balustrades etc, which all need to be pretty thick and structurally sound, to see if he could locate 25mm form me. He came back and said, we can get you triple glazed sound proof windows which are used for cutting out sound between offices. They have re3all good acoustic properties and should be much cheaper than building your own with thick glass. After I pointed out why would make good paperweights for my requirements. we decided to leave it that

I reckon I can source 20mm or so fairly easily and maybe even 25mm but I'll wait until I get proper quotes and see where it leaves me.

Source of the post What about Nessie?! What type of noise does she make, late at night?

Wrong loch fortunately.

Source of the post 70 dB is probably do-able, with deep pockets and very careful attention to detail, but 82? Hmmmm.... Man, that's in the region of "way out there". Do you really need that much?

Actually, I read another thread or book recently which said, "what is the best way to achieve 82db isolation to stop the traffic noise and train noise enter the mics? The answer was build your studio in a different location

OK, so 82db isn't going to happen!!!

Do I really need that much? Apparently not. The glen is extremely quiet and sound really carries on a still day. I thought the ambient noise level was going to be around 34db. However, I have been taking some measurements on site over the last week and it seems it is more like 40dBA or close to 50dBC. Therefore, I probably don't need nearly as much isolation as I thought I would. I still don't want to piss off the local community though so the more the merrier (within reason).

Source of the post The best way to achieve that, is by pouring truck loads of money into the project!

I'm running out of that already The groundworks went well over budget and every other stage seems to be about double what the QS estimated. Now it turns out that the roof of the studio isn't going to be flat enough for the external insulation without an additional concrete screed. On the plus side, that should fill any gaps in the structure and add even more mass

Thanks again for the input.

[Soundman2020]

Thanks for the customarily short and snappy response Stuart

You are absolutely right! I really do think I should wax more eloquent, and extend deeper into the details, be more long-winded. These short snappy answers just aren't cutting it....

I reckon I can source 20mm or so fairly easily and maybe even 25mm but I'll wait until I get proper quotes and see where it leaves me.

I would still do the math, to get a better idea of how much isolation you'd be getting in each case. 20mm laminate would probably be listed as "10+10", or maybe "10mm x 2". With the acoustic PVB interlayer, total thickness would be closer to 21mm, perhaps more. But the density of PVB is only about half of the density of glass, so allow for about half a mm extra in the calculations, if you want good accuracy.

Actually, I read another thread or book recently which said, "what is the best way to achieve 82db isolation to stop the traffic noise and train noise enter the mics? The answer was build your studio in a different location

Good advice! Sounds about right to me!

Do I really need that much? Apparently not. The glen is extremely quiet and sound really carries on a still day. I thought the ambient noise level was going to be around 34db. However, I have been taking some measurements on site over the last week and it seems it is more like 40dBA or close to 50dBC. Therefore, I probably don't need nearly as much isolation as I thought I would. I still don't want to piss off the local community though so the more the merrier (within reason).

Any chance you can do a real test out there? EG, get your favorite loudest rock band out there to play their wildest, while you move around the property all over (bike?) and check the levels at key places on your property line. That would give you a realistic set of data points. And take into account that sound can "bend" over long distances, when there are temperature gradients, such as commonly occur over large bodies of water... Also, wind can carry sound to places you didn't expect... but of course, there's never any wind around your place! Technically, sound refracts through the temperature gradients, causing the path to bend up or down, depending on which way the gradient goes. I doubt that will be an issue in your case, but it's good to be aware of it.

The groundworks went well over budget and every other stage seems to be about double what the QS estimated.

Welcome to the wonderful world of studio building! And dealing with contractors... I have yet to meet an honest building contractor, that tells you the truth up-front about his REAL estimate of how much it is going to cost you. I think the last time that a major building project came in on-time and on-budget, was when Noah built the Ark...

But on a more serious note, when we get into the design of the studio itself, we'll use all the tricks in the book to save you money, wherever possible, but without "cutting corners".

- Stuart -

[Wheresthedug]

I hate maths

Re getting loud rock band on site - not possible yet. No real power, too mich crap on site and would probably really alienate the neighbours. I do however have a large diesel generator on site which is damn noisy particularly at low frequencies. So I can measure that in the first instance.

[SoWhat]

I think the last time that a major building project came in on-time and on-budget, was when Noah built the Ark...

....and he used that really expensive waterproof caulk.

[Soundman2020]

Source of the post I do however have a large diesel generator on site which is damn noisy particularly at low frequencies. So I can measure that in the first instance.

That should work. Measure the level up close ("C" weighting, "Slow" response), about a meter or so away from the generator, then get on your horse and ride around all over, taking lots of measurements. You might find some locations where it is unexpectedly loud, or unexpectedly quiet... Sound is strange...

- Stuart -

[Wheresthedug]

Will do.

[ericwisgikl]

Source of the postthen get on your horse and ride around all over,

[Starlight]

Alan, how is your studio coming along?

[Soundman2020]

Source of the post Alan, how is your studio coming along?

I'm wondering the same thing! Any progress with the planning and initial design?

- Stuart -

[Wheresthedug]

Hi Guys,

As with most self builds (particularly during lockdown and the current supply chain nightmare), things have taken longer ( a LOT longer) than expected. We had to put the studio building on hold while we devoted all of our efforts to getting the house finished and moved in. We are now in the house and back on the studio project. I finally have a watertight roof and by the end of this week should also have all the external roof insulation and proper membrane fitted. Might still be a little while until we have all the nice zinc soffits finished but wind and water tight is my main priority just now.

Got all the workshop windows and exterior door in yesterday but haven’t yet ordered any glass for the studio windows. I have been trying to contact Stuart via pm and email to get his advice but haven’t managed to get a reply (which is unlike him - maybe he’s in the huff with me for something ).

Thanks to Jennifer, Kevin, Paul and mega thanks Starlight for all this amazing calculations.

I have been reviewing Rod’s book and Starlight’s posts and think my first move is just going to be to order some decently thick acoustic laminated glass (probably 17.5mm) then decide what I need to do for the second layer when building the internal room. Does this sound like a sensible plan in order to get wind and water tight ASAP in the absence of detailed calcs and a full design (which hopefully I can still get Stuart to do)?

[Wheresthedug]

Latest update ; the roof was finally finished on Saturday so we are close to fully wind and watertight. Hope to board up the remaining windows this week to get watertight until I can make a decision on ordering glass to make the outer leaf windows. Slow progress but st leadt it’s going in the right direction.

[endorka]

Excellent to hear you are making progress. Do you have any photos of the work so far?

Cheers,
Jennifer

[Wheresthedug]

Thanks Jennifer. I’ll try and upload some later this week.