hebal block and insulation questions

Hi guys.... I have been reading this forum for a while but have never made a post. I am in the middle or should i say coming to the end of the construction of my home. The house is so big that i have decided to turn the garage and adjacent bedroom into a live room and control room.... I am a drummer and also play guitar and bass and until now i have only been recording my guitar and bass at home. So my main focus is to get an amazing drum sound so i don't have to pay a fortune on studio time every time i want to produce something.... The garage internals are 3.9wX6LX4.2h. The bedroom is 4.6Lx3.9W Now to my questions Both of the rooms are made from hebel blocks. This is a brand or autoclave concrete or aerated concrete in australia. The blocks are 300mm wide so my walls are fairly think. My main question is has anyone had any experience with these blocks. How good are they as fair as sound isolation is concerned. As i have been building for 3 years now i am at t he end of my budget and i am trying to decided what type of insulation to use on the internal frame. I will be building a complete wall system inside the block wall as shown in the construction guild guide on this site but i am trying to decided weather csr soundscreen rockwool is sufficient. I looked at an audex product but almost died when they told me the price $64 a squ... Also would a normal wall 50mm polly batt be ok. i have looked on the forum but havent seem a post dedicated to insulation. I will post some plans and pics when i get the chance thanks guys

i am trying to decided what type of insulation to use on the internal frame.

Depends on what you mean by "internal frame"! Are you talking about proper fully decoupled "room in a room" construction, where what you are referring to as the "internal frame" is actually the inner leaf? Or are you referring to something else? In any event, insulation does not isolate. It can be part of a system that isolates, sure, (such as an MSM wall), but insulation by itself isn't very good at isolating.

Also would a normal wall 50mm polly batt be ok

OK for what? :shock: :?: 5cm of insulation is pretty thin for pretty much all acoustic purposes, unless you happen to have a problem with only mids and highs that need absorbing for some reason. Asking if 50mm of insulation is good enough, is kind of like asking if 6 feet of rope is long enough: it all depends on what you want to DO with it! In any event, you don't need to use exotic and expensive "acoustic rated" insulation for any of your build: plain old ordinary mineral wool or fiberglass insulation will work just fine, and is way cheaper than the exotic stuff. It does practically the same job for a fraction of the cost. But no matter what you use, 50mm is pretty thin. There are only a few places where you'd need such thin insulation. But if you are talking about the insulation that goes in the air gap between the leaves in an MSM wall, then you should fill the entire air gap for maximum isolation. The minimum recommended air gap is 100 cm, but more is better if you need good low frequency isolation. And of course for drums, you certainly do need good LF isolation. However, it would help if you were to describe in greater detail what you are trying to achieve, using real numbers. For example: how loud are you inside your room, outside your room, in the rest of the house, outside the house, etc. .... and how quite do you have to be in those locations? Only a sound level meter can tell you that. Take the measurements to find out where you are, and where you need to go. I'm guessing that you'll be around 115 dB when you are really inspired with your drumming, but I have no idea how much isolation you are already getting from your existing walls, floor, ceiling, doors, windows, and HVAC, and even less idea what level you need to attain. Once you have those numbers in hand, you can define the best structure that will give you what you want. Then, when that structure is built and measured acoustically, you can define what treatment you need in order to get the final result that you are after. In other words, first you isolate your room, then you treat it. Isolation and treatment are two entirely different things, and can even interfere with each other. Materials that are good for treatment are mostly lousy isolators. And materials that are good for isolation are mostly lousy for treatment. But start with a clear description of what you have and what you want, based on real numbers, then all the rest will fall into place. - Stuart -

thanks Stuart Yes iam talking about a room with in a room situation. I am looking at isolation. I am trying to achive as much isolatiuon as poss. I have houses close by and my goal is to be able to play at any time of the day. I havent finished the room yet so i cant talk any reading that would be of any help.... Basically i am trying to decide what materials will be best and most cost effective on the internal leaf