barn attic studio - acoustics question(s)

[gullfo]

why would the door upstairs break the symmetry? it would seem to better enforce it because the wall surfaces would be consistent versus a "well" which would introduce resonances. depending on the isolation needs, leaving the stairs fully open may be an option. probably best to provide some photos or simple sketch of the space.

[hebe]

yes of course...

[gullfo]

presumably there is a peak in the middle? have you considered turning the speakers to the right? so the ceiling is sloping up and away then treating the back slope? then on either side a floor to slope treatment to shape it a bit more?

[hebe]

thank you for your answers !

yes there is a lengthwise peak in the middle.
on my sketch, the crosswise line is a wood beam (1.60 m from the ground...).

i've thought this disposition was the best in my case (the 38% 'rule', 1 meter between walls and speakers, equilateral triangle between speakers and head, etc.)

i don't get your idea to turn the speakers to the right.

[hebe]

Originally Posted by hebe

(...) i don't get your idea to turn the speakers to the right.

more precisely, i dont understand the following of your explanations.

[hebe]

here is two pictures i've just took there (from the opposite walls in the lenght) :

[2manyrocks]

Another option is to build a trap door for the attic stairwell. A little inconvenient to get in/out, however.

[hebe]

the trap door scenario was my first idea, but i think it will be quickly over boring.
it will be heavy : 3 m² (32 sq ft)

but do you think that i can leave this path open ?
(the room at the ground floor will be nearly empty, i fear that it will generate reverberations)

[GIK Acoustics]

Hello Hebe!

Have you made sure your position in the room is optimal, either by tests or listening? A 1m distance from all boundaries might cause more problems than it would solve. I would test with the speakers all the way against the wall, pulling them out in 4-6" increments and testing until you have the flattest response, and then treating.

I think Glen (gullfo) was thinking your slope was vertically instead of horizontally in your sketch, as he recommended turning your speakers to the right, but then described the position you are already in.

[hebe]

OK, i'll try it this way.
i've read that 1m distance from all boundaries was the best, but it was maybe a bad advice...

well, i have to finish the construction before.
any idea about the necessity to close the path between the storeys ?

[gullfo]

I agree on testing to determine what the open space will do in term of resonance etc. by turning I meant you listening position in the room so you are facing the angled wall and thus putting the stairs behind you rather than to the side.

[hebe]

Ok thank you

[2manyrocks]

I'm not really looking at this from an acoustical point of view. The picture of the space suggests that the stairwell opening eats up a lot of space relative to the overall space.

The weight of a trap door could be overcome with a pulley system or a spring assist like on some attic doors. Or reduce the weight by fabricating the trap door itself using smaller dimension lumber carefully made like a torsion box.

[hebe]

thank you for this idea

[gullfo]

maybe think about carving the space up - making one side acoustically nice and leave the open space next to it and the stairs - treating those spaces to avoid resonances. use the opening by the stairs to act as your LF trapping. here's some images which may explain this better.

[hebe]

wow ! thank you for your kind help

i will think about this solution.