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building home studio advice needed
Old 4th April 2010
  #91
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Quote:
Originally Posted by amit monga View Post
ok

lets now concentrate only on modes which is our 1st step. only this step will take a few days. up till then we can finalize everything.

i wanted to clear one thing as we are treating right side wall for attaining particular width, why are we not treating both side walls in proportion so that resulted measurement will be same
The side wall we are treating is of great mass, in an effort to mimic the concrete wall on the other side. Erecting the single wall at the distance it is, brings the room's dimensions into that of a desirable ratio. We could, replicate the treatment to both sides, and half the amount of reduction, but why? It would cost twice as much, and cut into the corner where the door is.

Given the level of design, we very well may need area in that corner to build corner bass traps, if Paul's fears become a reality.
Old 4th April 2010
  #92
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Quote:
Originally Posted by [email protected] View Post
what is the current condition of your floor?

is it level?

I'm wondering if we should start with an 1" of self leveling concrete for a good stable, level, and much closer to mode ratio floor. this would allow you to use a laminate wood floor... (i'd say they're close to .2" thick.)

also, i've been wondering about that pedestal. if you knock on it, does it resonate? About how thick is this thing?
this post...
[EDIT] nevermind, I read back that the floor is sound and level. That doesn't change the fact that it is currently 1.2" greater than it should be. what were your plans for finished flooring? and i do still wonder in regards to that pedestals thickness.
Old 4th April 2010
  #93
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Quote:
Originally Posted by amit monga View Post
ok

lets now concentrate only on modes which is our 1st step. only this step will take a few days. up till then we can finalize everything.
no pressure huh

to be honest, today is a day of great superstitions in my country. a day where bearded men are free to rise. although i put little weight to these beliefs, it's my family's wish that i participate. what's a guy to do? also, tomorrow is baseball opening day, and I will be opening...beer, and a lot of it. that's not to say i won't check in here, but my researching abilities between now and Tuesday are nil.

Barring an expert miracle (today is the day for this i suppose), I'd say we are more than a few days away from a solid answer.. particularly since the inner shell's framing design may need to be altered.
Old 4th April 2010
  #94
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sorry, i know i threatened to not talk for a day or two, but if it isn't obvious, thoughts of this room have been consuming me.

i've realized i may have been missing the forest through the trees. i've designed an internal shell room, with slanted walls to eliminate flutter echo... a relatively easy acoustic phenomenon to cure. In doing so, I've created a near impossible (well, for me anyway), to predict low frequency solution. The biggest problem to solve in any room, much less a concrete one. I suggest we start from scratch...kinda. Mode wall may need to be adjusted, though only slightly. I would frame "inside out walls", at the boundaries. Studded walls with a covering layer towards the boundaries. Seal these studs to the covering with caulk, so as to have well defined sealed volumes. This will be MUCH easier to design, not to mention cheaper in labor, as angled cuts are minimized. Filling these "false" walls with insulation, and installing the slats on them, they will be far easier to tune to the axial modes. It will also open up the front end of the room's square footage, allowing more room for slutty gearheh. We will have to still treat the room after this slat shell is constructed, in much the same way we treat a drywalled room. Corner bass traps, reflection panels, flutter reduction... but the slat walls should be doing the bulk of the low frequency work.

now, back to this easter non sense.
Old 5th April 2010
  #95
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hi john,

i think your are right. we should start from scratch.

please do not take any burden. i am feeling guilty. please take your time. only when you have finished and confident with your plan i will start work. its just a matter of days. not to worry about that. also purchasing decisions(insulation, wood etc.) will be easy and accurate after full planning. i will eagerly wait for a new skp file. regarding floor i am surveying for wooden flooring and its thickness. we will come definitely to the recommended measurements.

i have found positive points regarding slat wall in this file.
trapping-bass-in-your-project-studio.pdf

also from Thursday till Monday i will not be available. we are having satsang in our city for 3 days. i have to be there day and night. even i will not be able to sit on computer. so please co-operate for that.
Old 5th April 2010
  #96
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don't feel guilty, this is a project i decided to try to take on all by myself. i do appreciate the understanding that the time frame was daunting.

this new design will be much easier to predict, and your room will sound much better as a result.

now off to baseball!!!!!hehthumbsup
Old 5th April 2010
  #97
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one more thing,

can you verify, (in millimeters is fine), the actual dimensions of common building materials there? I've been assuming them to be the same

2x4
2x6
plywood and mdf common thicknesses, and sheet sizes... are they 4' x 8'?

also, not a bad idea to start looking for a slat material, there's going to be a lot of price differences here based on how exotic you go with wood species.

for the floor, remember, we are now slamming a sheet of mdf to the ceiling boundary, so you're looking for flooring that will take into consideration 1/2" (well you tell me the thickness of mdf) or so we are adding to the ceiling.
Old 5th April 2010
  #98
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i will get back to you with these details as soon as possible.


and ya best of luck for your baseball.
Old 6th April 2010
  #99
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they lost

but thank you, we all won, as the day was beautiful
Old 6th April 2010
  #100
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Quote:
Originally Posted by [email protected] View Post
one more thing,

can you verify, (in millimeters is fine), the actual dimensions of common building materials there? I've been assuming them to be the same

2x4
2x6
plywood and mdf common thicknesses, and sheet sizes... are they 4' x 8'?

also, not a bad idea to start looking for a slat material, there's going to be a lot of price differences here based on how exotic you go with wood species.

for the floor, remember, we are now slamming a sheet of mdf to the ceiling boundary, so you're looking for flooring that will take into consideration 1/2" (well you tell me the thickness of mdf) or so we are adding to the ceiling.

mdf comes in various thicknesses as 3mm , 6mm, 8mm, 12mm , 19 mm etc. but comes in only one sheet size 4' x 8'.

plywood comes in various thicknesses as mdf and it also comes in various sizes as 4' x 8', 6' x 4' etc.

i asked local building stores about slat material. they were not cleared what i am asking. i should clear myself. are slats normal pieces of wood or they are some different or particular material
Old 7th April 2010
  #101
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hardwood boards.

1x4" or 1x3"

1/2 x4" or 1/2 x3"...

formulas are adjustable for thickness to a point. once you find a wood type you like and an affordable thickness.

what about 2x4's and 2x6's... are their thicknesses the same as over here?
Old 7th April 2010
  #102
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my work computer's internet is down, thus no communication today, I started a new plan, I'll see if internet works tomorrow
Old 7th April 2010
  #103
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hi john,

details of materials availability.

1. mdf boards in various thicknesses and only one sheet size 4' x 8'

2. plywood boards in various thicknesses and various sheet sizes.

3. hardwood in various thickness and lengths.

4. wooden flooring is available in 10mm thickness and may go to 12mm after installation.

2x4's and 2x6's pre defined lengths of wood are not available here. carpenter said that he will cut the hardwood into these sizes.

i think i have to show the skp file with each and every measurement to the carpenter. carpenter will then be able to manage and cut all the hard wood dimensions given by you.(may be for studs, stringers or slat wall)
Old 7th April 2010
  #104
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Hi john

i will not be able to communicate with you for 4-5 days. Even i will not be able to sit on computer. So please cooperate for that. but anyways i will be waiting for your posts

GOOD BYE FOR 4-5 DAYS.
Old 7th April 2010
  #105
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understood.

respectfully,

john
Old 12th April 2010
  #106
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hi john,

communicating with your after so many days.
Old 12th April 2010
  #107
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Hi Amit,

I hope your event/holiday went well.

After giving it much thought, and doing research, I believe we should continue with my original plan.

Remember, I had given thought to not angling the walls and ceiling, rather butting them up to the boundary walls... an effort to make low end absorption more predictible. Well, I've been playing around with slat wall calculators, and with a cavity the depth of even a 2x6", to hit our lowest axial modes we would need REALLY thick slats, with REALLY thin slots between them, and it would get REALLY expensive. Not to mention we will still need to employ wall panels to eliminate flutter, thus covering up your slats.

With angled walls, it simply means that the slots are broadband. It's calculated by the closest it is to the wall, and the furthest it is from the wall, and it absorbs everything in between. Being that at the front of the room, we have over 2' of distance, and at the back roughly 6", I believe we will be able to hit the frequencies we want at the front of the room, we will want to possibly increase the depth of the back wall fabric absorber. Front wall, with 1' depth, we will with very thin slots be able to hit the mode with a tuned absorber. I've been tweaking the inner shell framing, to make it more carpenter friendly, as well as bringing the back wall framing in a bit, for a deeper wall trap.

I've been thinking, for the ceiling, perhaps dry walling the majority of the surface, with the exception of open fabric above your head for a cloud, and a perimeter around the room of slats to act as bass traps. THis will help with cost, and also give you a brighter feel to the room, having a light colored ceiling. Not to mention actual lighting is probably better mounted in dry wall rather than fabric and wood. Also, I want to leave slats off of the side walls at reflection zones. Why build traps to go over traps?

I will have the framing plans finalized in the next day or two. Slat/slot calculation can't be achieved until actual room acoustic measurements are done.

Using the tape measure tool in sketchup will tell you the distance between the concrete side wall, and the surface of the constructed boundary wall. Remember, tell carpenter to frame as close to actual boundaries as possible. THe idea is to not only have an airtight seal with caulking, but we want as much mass around those edges as well.

2x4 construction, with lots of random stringers, cavity packed with high density mineral wool, rockwool, fiberglass,... what ever is available in your area... if you have multiple options, go for the cheapest. this stuff need never be seen or heard from... we are just going for mass here. two layers of 5/8" thick mdf. caulk joints and perimeter and stagger the joints from the first layer to the second, so sheets don't end in same place.

Good to hear from you again,

John
Old 12th April 2010
  #108
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Quote:
Originally Posted by amit monga View Post
hi john,

details of materials availability.

1. mdf boards in various thicknesses and only one sheet size 4' x 8'

2. plywood boards in various thicknesses and various sheet sizes.

3. hardwood in various thickness and lengths.

4. wooden flooring is available in 10mm thickness and may go to 12mm after installation.

2x4's and 2x6's pre defined lengths of wood are not available here. carpenter said that he will cut the hardwood into these sizes.

i think i have to show the skp file with each and every measurement to the carpenter. carpenter will then be able to manage and cut all the hard wood dimensions given by you.(may be for studs, stringers or slat wall)
to be clear, I wasn't asking about 2x4's lengths, rather how does the "2x4" dimensions measure? Here, 2= 1.5" and 4= 3.5".

the carpenter should only need to know the height of the inner shell at the corners. Once the outer frame of it is constructed, studs can be fitted. Again, the way I have it framed (with doubled up 2x4's on the corners) is not for acoustics, rather how I think things are framed. Your carpenter is an actual framer, and should adjust my drawings to actual framing techniques.
Old 12th April 2010
  #109
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what a relief after hearing you john after so many days.

i think now its the time to implement the plan. just waiting for your detailed step by step skp file.

as regarding 2= 1.5" and 4= 3.5", i will assume your 2" as 2" and 4" as 4". (all clear measurements)

can u please mark the materials also as plywood used or mdf etc. in skp file.(if possible)


EDITED

I MEAN TO SAY PLYWOOD IS BETTER OR MDF
Old 12th April 2010
  #110
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see posts 49 and 107 for details on boundary wall construction. between this and viewing actual sketchup file for exact measurements, everything should be there. let me know if there are any questions. i will be working on the interior framing modifications.

i would suggest using mdf instead of plywood for this application.
Old 13th April 2010
  #111
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i think traps over traps at reflection points will be good option as you will be relieved from calculating reflection points before keeping the speakers. ( a bit complicated)


another option would be removing the slats at reflection points in the end (while setting the speakers)
Old 13th April 2010
  #112
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Amit,

What I would do if it were my room:

After the mode wall is constructed, take some acoustic measurements. mark the point on the floor where the mic was and note the height. note where your peaks and valleys are in the low end, and how long the low end rings in the waterfall plot.

Now have the carpenter construct the inner shell. The next steps I would do by myself and with friends.

Pack the gap between boundary and shell with insulation, and do another acoustic measurement. Note the changes. You will still have peaks and valleys in the low end response, but they should be far smoother. Now is a good time to figure monitor placement. Do some measurements with slight angle and boundary distances. Find where the room wants them to be.

Now comes the fun part, and the time involved is why I would want to do this without a carpenter. It's time to hunt down the peaks, and improve them with slats. Using a sine signal generator, send the offending frequency through your speakers, and go through the room and find where they are strongest. An SPL meter may come in handy here.

Using the xls spreadsheet for calculating slat resonators, we can input the depth of the wall in that area, and tinker with slot and slat width to hit that frequency. I'd imagine you can rent a miter saw and air nailer, and apply the slats yourself. This is likely to be a long process, and I'd hate to pay a carpenter for such tedious work.

John Sayers' Recording Studio Design Forum • View topic - Corrected Helmholz Spreadsheet

It's likely that each stud cavity will have slats of different spacing, so orientating the slats horizontally is going to be the way to go. Diagonally would look cooler if you're a bit comfortable with the saw.

You'll want to price out hardwood boards for the slats. We're looking at 1x4's or 1x6's. Likely a mix of both. If you can, find a wood grain that's attractive enough, but affordable enough, and let me know the price per board. I'll work a rough estimate on material cost for you.

Also going to need to pick out a fabric for behind the slats, as well as the reflection points. Could very well be the same fabric, but I'd prefer a lighter color where it's exposed for reflections, and a darker color behind the slats... though this is a personal preference. This fabric is going to need to be fire treated, with some type of spray. Not sure what's available in your area.

Still working on that interior framing adjustments, I'll send it to you when I'm done.
Old 13th April 2010
  #113
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hi john,

i had to go through some limitations. before and after comparison(waterfall plot) will be complicated for me at this moment. also it will increase my budget(room analysis software, measurement microphone). so i will not be able to get into all the details but i will definately import spl meter before the slat walls installation. will the spl meter solve our all purpose
Old 13th April 2010
  #114
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an spl meter can be used as the measurement microphone, and room eq wizard is a free download.

https://www.gearslutz.com/board/studi...primer-v2.html

check out this thread for the basics.

when tuning your treatment, room measurement is crucial.

we could guesstimate based on room mode calculator predictions, but that would be lazy.
Old 13th April 2010
  #115
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thanks
Old 13th April 2010
  #116
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no problem

and to be clear, we're talking a physical hardware SPL meter here. I mention this as you talked of importing one.
Old 13th April 2010
  #117
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india is backward in terms of products availability. so i have to import the spl meter from u.s.a. (audiomidi or sweetwater).

i have studied galaxy cm 140 which has ac output. is it ok
Old 13th April 2010
  #118
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Ok, I understand now.

The Checkmate will work fine, though I worry about the specified low frequency response. It measures barely below where we expect our lowest modal activity to be
Old 13th April 2010
  #119
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have u any suggestion which spl meter should i purchase

galaxy cm 140 specifications

Galaxy CM-140 | Sweetwater.com
Old 13th April 2010
  #120
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I have only seen it (spl meter) recommended that it can be used for this function, i have no experience with them in this capacity. even a cheap measure mic like that of the Behringer ECM8000 should work better than the mic in an SPL meter.

If I had to pick between the two, I'd choose the measurement mic, as you can use your ears to determine where in the room the loudest bass build up is, and really that is the only function we are looking for in an SPL.

Having said that, if you already own an omni directional small diaphragm condenser, you can use one of those for measurements.
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