hello, i have been reading this forum for a long time now.
its a great resource.
i have a new studio in pomona california, im almost done building it and i encountered
a problem. one of the walls is a double layer brick wall with now air gap.
it seems pretty sealed up. it was reinforced for seismic purposes. new
cement was put on 3 walls for support. plus a new strip of foundation was
poured on the edges. then bolts were attached at the tops for tension.
it was done to code by the landlord before i moved in.
the funny part is i can only hear sound coming from my neighbors place.
but i cant hear noise coming from my place to my neighbors.
so there is sound or vibrations traveling thru the wall in one direction.
its a huge difference between the two. i can hear noise thru the brick wall
from my neighbors like if it was a basic drywall 2x4 wall. not so good.
the sound from my place is not audible unless you put your ear to the wall.
and even then its just a faint vibration.
im thinking the problem is the extra reinforcement causing more transmission
then normal. but wouldnt that go both ways and not just one way?
im gonna go over the wall a double check all holes and gaps.
i checked the roof where the two units meet and my neighbors
roof is a good 5 feet above mine. their A/C condenser/fan is
on my roof also. all the studs and supports are not visible
on my neighbors side. the supports and bolts of my neighbors wall are not
visible in my unit either.
can i dampen the wall somehow?
anything would help.
thanks for your time.
these are my walls
thanks for the reply guys. i dont thing the roof is the problem. but outside sound
comes thru the roof, thats a whole different story. i think they put a sealer/clear coat over my side
and they are still working on my neighbors side. also i have anther room with brick that
you can clearer tell a sealer was sprayed on top of it. i will ask the contractor tomorrow if my wall
was sealed to double check.
upon more inspection, there was quite a few holes on their side. the construction crew
sealed them up, and i also went over my side as well and sealed just about every little hole
possible. its better now, but sound still comes thru.
it wouldn't be so bad if my wall wasn't 16ft tall, and my neighbors is 20ft+
so anything we do will be a serious task. my wall is 30ft long by 16ft high.
so when you say the brick isnt air tight, do you mean the actual brick or the mortar
holding them together. or is it a a combination of both? so if we paint or seal it more
it will stop transmission more? i may try that first before any serious build out.
i really dont want to loose the brick, but as of now its gonna get cover with some
3.5 inch ultra touch insulation.some parts will have thin plywood over it, some
slat, and some just covered with cloth. this should help quite a bit for acoustics
and sound transmission. i put a batt between my ear and the wall and transmission
change to a small murmur.
i dont really want to cover the whole wall with drywall. but if all else fails, its gonna
happen.
oh yeah, we played the drums in both places. sound comes thru both ways now, but my side is
still alot worse.
ok, i put up 2 layers of 3.5 inch ultra touch in 2x4 frames to knock off the audio level. it helped, but
now im getting transmission thru the the side walls. my side ways are 1 foot thick cement with a
layer of bricks on the other side. so i believe its all structural transmission or some other
strange flanking problem. reason being is i can put me ear to the side wall and hear everything
next door. all vibrations.
i also have another room with the same brick construction and im getting no sound leaks at all
in that situation.
brick wall is constructed in a way that every 6th row of bricks are turned sideways to create a
joining in the layers. a soldier row. so these walls would be considered a one leaf design.
from what i have been told and researched.
this building is close to 100 years old.
next door there are 2 big metal i-bar beams reinforcing the building. those both hit the shared wall.
sound is bouncing around in the U parts of the beams.
im thinking about putting anti-vibration (dynamax) pads and insulation in these areas to cut back
on noise and vibration. i think sound is traveling along those to beams and pushing it into my space.
next door has a loft which they are putting wooden flooring on and when they bang on whatever,
the sound is transfered to my place in a stereo fashion do to my 2 side walls.
man, this is a whole lot.
now that i have some doors and widows sealed better, im getting noise from the HVAC.
its sound from next door. its like 2 tin cans with a string in them. i need to stop
it from vibrating, i need to use a viscoelastic damper. it is ran thru a hole in the cement
wall and bolted tight to the rafters. its a pain to take off, but i can access the inside of the
duct easily.
im also going to do the roof with a layer of ultra touch with a black facing. should look
good when its done.
one good thing is i know my neighbors. so im gonna treat their side too.
the highest part of their roof is 30ft. there is close to a 2 second decay
time in room reflections. talking softly gives you a good 1 second reverb
trail. drums sound awesome in there though.
i should have some more pics up soon on the developments.
i have considered build a room inside this room, but its gonna take away from the vibe
and i dont think the landlord will like it much.
the over all sound leakage/isolation is good. not really loud to any of my neighbors.
we did a test with a drum set and i was pleased with the level of sound leaving my place.
my only complaint is the big brick wall with sound coming in.
so yeah, I just found another possible flanking path on my roof. monday we are going to investigate further.
its vent holes from next door leaking sound outside and going in a gap in my roofing, then going down in between
my walls. if this is correct, it would explain alot.
we need to take some roofing material off and check the section and make sure its air tight. i get no water leaks
from rain in that area so its fine in that perspective. we are talking small wholes here i think.
so, i sealed the holes and leaks on the roof, still having problems. its just gonna have to do for now.
its not that bad, tested it with loud music next door and played music at mixing volume in my studio.
its ok. my friends/business partners are next door so it should work out with some scheduling.
i tried the insulation on the ceiling, its too much dang work for the reward.
i need to be up and running like next week so its gonna just have to work.
i built some slat resonators, and i started on my bass traps.
it sounds good actually, just a little more tweaking.
still need to build alot of other stuff.....
They look nice! What kind of wood is that?
It's impossible to see from the photo, but just checking: Are they completely sealed at the top, bottom, sides and back?
Also, are they based on John's design? Looks like they might be.
- Stuart -
yes, they are completely sealed all sides. except for the slats. i have spent too much time on getting flutter and
other reflections out of this space.
the design is john's. i remixed it a little bit, i used 1x2's, 1x3's, 1x4's, and 1x6's.
i think its pine?
different gaps between each board. its 8' tall, but only 6' of slats.
so its 8' x 6'. (total frame is 8'x8')
3.5" to 18" slope
so its a 8 degree angle or so.
i spent several hours finding what reflects, what should be diffused, and what should be broad band absorption.
its been more of a headache than anything.
it will be nice when its done.
my speakers are 3' off the front wall, 6' apart, and I'm sitting at about 40% of the room (6' from speakers)