12 corners??

Yeah, it is a large room, I am very lucky. Trouble is (this particular room was built in the 1870s) the builders completely failed to take into account the sonic implications of my stereo..not happy! grrr heh heh

Ignoring the bay window which is very large, the ceiling height and the width of the room are quite close, as I say about 5.4m vs 6m or so, for sure the bay deepens the width for 30% of it but still. I have not plugged those figures into a calculator, but the room has a very strong 110 hz or so peak no matter where you are or where the speakers are. Prob a result of the 5-6m dimension.

This is a bit of term term planning, as the room itself has to be renovated so I can incorporate the treatment at the same time. In most cases I will not 'fix' the treatments in place, I do have to be aware of the heritage/architectural implications of whatever I do.

Will try and rustle up a photo, sure I have a few sitting around.

One thing I could possibly do is build panel absorbers(terminology?), you know the sealed units with a wooden front panel with f/glass inside it. The room next door will have the 1.5m or so wooden panels that line the wall (we were lucky to find some old cedar ones that we can retrofit to the room), so with a bit of arm twisting I may be able to talk the boss into letting me build something similar for my room, but designed for an acoustic purpose.

That would have the advantage (as it would be around the entire periphery of the room) of a lot of surface area that also looks good. Trouble is, they might not be broadband? And it might not happen if the construction, to be effective, has to be six inches or more thick. that might look odd which negates the purpose.

Ok, just took a few quick photos, now to work out how to embed them

think that worked. hope it is not too big, but this shows the height of the corners, the reason why I cannot do any treatments at the ceiling wall junctions, and shows a bit of the bay to give an idea of how it fits in the room.

this is the room I have done up, my actual listening room is the same (mirror rooms). This would be a shot in my room from the speakers looking back at the LP

I prob need a better camera to be able to get the 'entire' room into the shot, this camera is not able to give the feel of the room in it's entirety.

BOY! It took me so long to take the photo and upload it that my reply timed out!

Ok, depends on the definition used for corners, should have realised you meant junctions, sorry

So how high in a room like mine ya reckon? It's also a bit of an artistic thing perhaps, 'what height also gives a nice proportion' type of thing, ie a bit more than just 'acoustic function'.

Put it another way, emotionally I can grasp why some people look for room treatments that are 'invisible'...might be a market there for you Ethan ha ha

Re the wall lining, I could always make varying sized panels in an attempt to at least have differing bands of operation, and yeah it would all be done to look in place, except have the hidden acoustic function. But again, depends on the depth required to get decent absorption.

I should have perhaps shown a pic of my room with the speakers (only showed that one cause the lighting is better and also to show exactly why I can't treat wall/ceiling junctions etc) cause you again mentioned first reflection points.

What is the cutoff point distance wise where you may not need first reflection absorption? My memory is a bit vague, but basically it's all to do with the timing of the reflection vs directed yeah?, which is directly related to distance. Or are you saying basically 'in any conceivable domestic room I cannot envisage one large enough that first reflection absorption is not warranted'

I do have some of those movable office divider type things beside each speaker where the first reflection would be. Lightweight and flimsy, but in any case can't say I notice any difference with it there at all. If they are effective I doubt they'd absorb very low.

So is it also a case for FRA (got sick of typing first reflection absorption) to absorb as low as you can?, ie even there use as thick an absorber as possible? Ideally in FRA how low should you be able to absorb to

thanks Jan

umm, that WAS what I was referring to (and the like), and I hang my head in shame that I was being tongue in cheek (to ethan) and you tried to help me.

sorry about that

I like the latest discovery in room treatment, blocks of tape (as in masking tape thickness)in the corners of the room, sigh.

It is an 'outgrowth' of the enable treatment, seems nothing that the magic of those bits of tape cannot fix. Wait, don't want to give the idea that they are magic tape a la May or anything, no normal tape but in a magic pattern.

Oh well, think I have no choice but to stick with physics, it seems to have some sort of bearing on our everyday lives doggone it.

thanks ethan, you know I feel a little embarressed, of course you're correct, the answer is 'as much as you can', duhh, sorry I should have thought a little more before asking. thanks for taking the time anyways

two inches for reflection points, well straight away that makes any conclusions I have about my thin office dividers as FRP absorbers totally invalid. well worth the time and trouble to try it properly.

I must admit I've seen varying times that people feel are early, I think from very poor memory that 20 ms is at the high end of those figures. Still, what is important is that it is the difference rather than 20 feet from speaker to wall and then wall to LP, 20 feet (or even 10) difference is a LOT.

Can you tell me just HOW you can measure the db difference between direct and reflected?? Another thing I've often wondered about (again, check my terminology), the transition point between near field and far filed listening.

There is some sort of 'formula' that tells you were that point is, dunno, when the two energies are equal (?)

Anyway, I've only just started to wonder cause I now find (after much trial and error to find my 'magic speaker and chair placement) that any slight change of chair or speaker positioning seems to produce big changes. I must be on some sort of 'knife edge', and am wondering if I have found (for my room etc etc) that transition point?

Anyway, similar to my question above, can you tell how it is you manage to measure the direct sound vs 'combined sound' (if that is the basis of what I'm talking about)?

It's all well and good that these terms are thrown around, but unless we can practically measure them they just stay 'terms bandied about' if you follow.

edit

thinking about how to measure how far down the reflection is
I think you need to look at the impulse graph? You should see a 'peak' that represents the initial pulse from the speakers, then at a later time another peak, which I presume is the first reflection.

close?