I am still waiting for Foz to reply with an alternative plan for an 8'6" cube room. So far he has posted the suggestion that I set the 30mm panels away from the wall (which is not really practical) and I reckon three panels on the wall absorbs as much as two panels set away from the wall, whilst taking up less space. I don't really know if the theory supports this assertion but I would like to find out. I would also like to know if ceiling treatment would be practical and whether the resulting reduced space in the room would be sufficient for adequate bass trapping.
Greetings Grower and Harvester of Fruit :)
You could do worse than have a look at Mark Edmonds Studio Build Diary http://forum.studiotips.com/viewtopic.php?t=456
It sound absolutely great in there.
I started this thread so anyone wishing to make their own DIY treatment would have a template they could use as a basis for their own treatment. I have taken a "suck it and see" approach and taken ideas from what people have used with success rather than calculating in theory what should work and then building to that specification. I don't reckon that theory can always be translated into the real world with complete accuracy either - as soon as you put a person and furniture in the room you affect the acoustics.
The system I have allowed me to install several panels and easily move them around and add more once I had listened to the room and decided on a second tweak. Treatment to the ceiling or stacking triangles of Rockwool in the corners would be somewhat more permanent and consequently more difficult to adjust. The fitting method I used means I don't have to count on my theoretical calculations making an accurate prediction (my physics and maths is okay but not up to graduate or professional level) for the real world.
At the moment there seems to be a great deal of people quoting figures and pretty graphs at each other and trying to decide whether data is valid or whether we have reached the boundary of physics . This is all very interesting in a way (I am following the infamous real traps thread
as it goes) but this is not much use to people who want to treat their room without getting the calculator out.
I just want people with a working, practical or theoretical knowledge of acoustics to apply it to the real world situations, like my box room. This would helpful to those of us lacking that particular education when we want to make our own acoustic treatment without heading for disaster or expensive mistakes.
I disgagree the StudioTips 4 Devices Test Data
isn't valid for real world use. You don't need a calculator. The data shows a valid comparison of two commercial devices and 2 DIY designs. Of course their are OTHER factors, than sheer acoustic absorption performance, when choosing a method, but absoprtion performance is important none the less.
Regarding practical applications. Corner wedge DIY broadband absorption, along with absoprtive panels on the walls/ceiling to diminish early reflections has bee shown to work in practise many times.
I would also like to know if ceiling treatment would be practical and whether the resulting reduced space in the room would be sufficient for adequate bass trapping.
Ceiling treatment ( assuming enough available height ) is great!
In fact in my studio build I don't have much height at all, so I am taking this approach......
From the listening position I am building a false ceiling that slopes downwards towards the front wall. No one can stand up in this area anyway, due to it being full of furniture ( DAW Workstaion to be exact ;) ), so the reduced height doesn't matter. This false ceiling will be full of rockwool. It will serve TWO purposes. The thicker rockwool above the false ceiling where the front wall meets the ceiling will be broadband standing wave trapping, and as the sloping ceiling gets higher towards the listening position, the rockwool here will serve as an early reflection absorber 'panel'
So to answer your above question, I would say that the ceiling treatment can be a part of the 'standing wave trapping treatment', and not something that leaves less room for trapping ( as I think? you were asking/indicating. I hesitate to use the word 'bass trapping' as standing waves can affect lo-mid performance as well. :)
Also it's a shame you can't put the Early reflection absorbing panels away from the wall a bit. Is space too tight to even put the 30mm panels so there's a 30mm airgap behind them. You'll lower the freqeuncy of efective absoprtion, plus incrasing absorption performance overall.
Bear in mind that when sound reflects off a wall, the velocity of the air particles is zero at the wall. So that absorption right at the walls surface for reflections is ineffective.
Just some thoughts :)