Garden mix room near Nottingham, UK

#1

Hi to all!

Following on from my design thread, linked below, today marked the start of construction on my garden building that will be come a mix room.
https://www.digistar.cl/Forum/viewtopic.php?t=687&start=15

Day 1, the groundworks started with a mini digger digging the 80cm or so of ground out for my foundation - a single concrete slab. The floor level of the studio will be 350mm below ground hence the need to dig this deep. As you can see from the end day picture below, the guys managed to dig nearly 2/3 out. One grabber lorry of 22 tonnes has already been taken and there's still a pile of soil on the drive. Glad it wasn't me spending the day barrowing...

#2

Day 4...

In typical British style we had a downpour today but the four guys in the garden just kept going. For two days solid we had two guys barrowing soil from back to front of the house, and I think 3 grabber lorries full taken away.

The photos below show the construction of the foundations - a big hole, a soakaway drain around the perimeter, then a layer of hardcore, then a layer of sand. On top of this the DPM has been laid, with another soakaway drain on the outside to move any groundwater away from the slab and two runs of concrete blocks that will be underground. Within the DPM is insulation around the edge and the mesh, and that's now all ready for the concrete to be pumped in on Monday.

Alongside this they've laid my armoured power and ethernet, raised half the patio and got the ground ready for our raised bed and path to the studio. I'm impressed with what they've achieved in four days.

#3

Any help on getting the images oriented correctly on here gratefully received! They're fine on my computer

#4

Your progress is looking good so far, Gareth.

#5

Thankyou - much appreciated! How on earth did you get the images rotated correctly??

Yes it's looking good. Frustratingly materials costs are going up compared to when I priced up over the summer so already the budget is shifting. That was always going to happen, wasn't it!

#6

garethmetcalf wrote:Source of the postHow on earth did you get the images rotated correctly?

Photoshop.

Affinity Photo and other apps should also be up to the job. If this is a problem area for you, you could send me your prepared photos and I can check, rotate, correct and return them. Send me a PM for my email address, Gareth.

#7

Thanks again. I’ll make sure I take them the same way around or get a bit of software. Just found it odd as preview on my Mac opened them all the correct way around so I didn’t realise there was an issues
Cheers

#8

Aha, you are on a Mac. Open an image in Preview and in the Tools menu you can rotate it clockwise or anticlockwise, 90 degrees at a time. Then File>Save and it will save the rotated image. Bingo!

#9

Thanks again Starlight.

I have an isolation design query - my original plans show double layer of 18m OSB or 15mm plasterboard for the inside leaf, and single layer 18mm OSB then 22mm larch cladding on batterns.

As I’m ordering materials I just thought whether I need two layers of OSB on the outside as well as the larch?!!! My isolation requirements are for mixing music rather than band rehearsal...

Thanks

#10

Looking at your building's location, I am wondering about hot summer evenings when the neighbours are asleep with their windows open and you are mixing. It is my guess that you would not want more than about 35dB to be heard outside your building so as not to disturb your neighbours. What transmission loss do you expect from your current design, Gareth?

#11

Hi
I think 40dB would be reasonable, perhaps 45dB. I won't be monitoring at more than 80dBA for long, but your observation about summer evenings with open windows is a good one.

So I've put the various formula into a spreadsheet and calculated the following. This ignores the mass of the cladding, because there will be an air gap between it and the OSB, but I'm sure it'll do something.

Option 1 - 2 layers plasterboard inside leaf (assumed 26kg/m2), one layer OSB3 outside leaf (assumed 11kg/m2), 15cm air gap

f0 39.9 Hz
f1 366.7 Hz

16Hz, 8.4 dB
32Hz, 14.5 dB
64Hz, 52.3 dB
125Hz, 58.1 dB
250Hz, 64.1 dB
500Hz, 67.7 dB
1000Hz, 67.7 dB
2000Hz, 67.7 dB
4000Hz, 67.7 dB
8000Hz, 67.7 dB
16000Hz, 67.7 dB

Option 2 - 2 layers plasterboard inside leaf (assumed 26kg/m2), 2 layers OSB3 outside leaf (assumed 22kg/m2), 15cm air gap

f0 32.2 Hz
f1 366.7 Hz

16Hz, 10.7 dB
32Hz, 16.7 dB
64Hz, 56.7 dB
125Hz, 62.5 dB
250Hz, 68.5 dB
500Hz, 67.7 dB
1000Hz, 72 dB
2000Hz, 72 dB
4000Hz, 72 dB
8000Hz, 72 dB
16000Hz, 72 dB

Assuming this maths is right, which it might not be, then I'm going to stick with one layer of OSB because those values are pretty good for my needs, and I save quite a bit of money in so doing.

#12

I agree with your maths but what concerns me is the f0 of 39.9Hz. That is the resonant frequency of your MAM system which means you do not want to be working close to that frequency. That is almost E (which is 41Hz), the lowest note on a 4-string bass. Mixing songs that go down to that E could be problematic because at f0 the building will, I believe, provide zero transmission loss as it resonates. Your alternative plan with two layers of OSB on the outer wall brings the resonant frequency down to 32.2Hz, which is the C two whole notes down which looks to me to be helpfully lower than low E on a standard bass guitar - but not if you work with a 5-string bass.

Gareth, is Stuart your designer? I would double-check with him as he can either put your mind at rest or confirm or highlight any potential problems with your plan from an acoustics perspective.

#13

Thanks Starlight - that's a good point. I don't have a designer for this element of the build but with any luck Stuart may chime in on this. I'm not at the stage of having to commit to these decisions just yet.

Cheers
Gareth

#14

Hi

This week started with the pour of concrete into the hole on Monday - 225mm thick. Thankfully the groundworks guys were able to get it pumped from the road down the side of the house.

After a few days of drying the bricklayer came yesterday to build some dwarf walls. They were due back today but they decided the weather was going to be too wet so the two courses of brick on top are still to be done.

#15

That looks good.

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