UK Garden Studio – Warm Roof Design and TL calculations

[gullfo]

actually, concrete, steel, hardwood lumber, etc are all great conductors of sound - faster speeds and longer distances... than air and soft things like rubber, insulation, and so on. the trick is to order them correctly to minimize the transfer from a hard (we tend to call mass) boundary to another hard boundary in an effort to reduce energy transmission. earth damped concrete slabs are good. connected earth damped slabs not quite as nice though. decoupled earth damped slabs, very nice. same principles for walls and ceilings. damping and then energy conversions - absorption via sound to heat (like insulation) and speed reduction (air is about 1/10th of concrete in terms of speed). some examples: https://www.engineeringtoolbox.com/soun ... %20rows%20

[kehoe]

Ok so am I correct to say that my isolation is limited by my internal and external walls being coupled at the base making it the weakest link.

Will the base only transmit frequency’s around its resonant frequency.
How will this effect my transmission loss of the structure as a whole?

Pouring a second slab and decoupling it via springs for my inner leaf to be built on would be gladly missed out if possible.


Could you explained the difference between earth damped and earth connected slabs. I can’t quite get my head round how a slab would be damped by earth without being connected to it.

I feel I may be thinking about all of this incorrectly, the lack of sleep from having a new bourn is playing havoc with my ability to understand things at the moment

[gullfo]

earth damped and earth connected are essentially the same thing. one the sound transmission on same slab for two rooms - the frequencies are not restricted to the slab resonance. the slab resonance matter when it comes to decoupled structures to which the slab is exposed. for example: if a floated slab as a MAM spring 10hz resonance, then the only effective transmission through the spring mechanism is 10hz or lower. there is still the possibility of higher frequencies being retransmitted although the mass laws and damping play their part in attenuation of those. so, a concrete box on strings can still transmit energy to the outside world, however, it's significantly reduced, and if the surrounding bits are equally decoupled and damped, then it is negligible.

an earth damped slab is nice. two earth damped slabs decoupled are even nicer.

in a single slab studio, loud / impact sources (drums, bass amps, guitar amps, dancing buffalo, etc) should have an isolation platform to reduce the amount of energy direct sunk into the slab and this will help reduce the levels which span the rooms.