D. I. Y. Polys
johndykstra
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#91
16th November 2011
Old 16th November 2011
  #91
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Hey.

Anyone thinking of building their own bad panels: Don't.

Related, anyone thinking this is clever tool, it's not:

Drill Guide and Chuck-36/37 at The Home Depot

Piece of monkey $h!T. After countless hours of prep: painting, drawing the grid, mapping the hole pattern.... this "tool" drills about as accurately as a wild guess from a blind man. The rods have too much flex and the harness slides like poop on 'em and the chuck has a ton of play in the bearings. A little play at the chuck translated to the end of a 6" long bit... Oh. Then it ceased up completely.

I first attempted an oak block with a cross hair, and 1/2" hole through the center to aid me in drilling straight through all the panels. That was going gang busters until it wore out after ~20 holes... that when I bought that thing.

I still plan to see this through, but after a few crooked holes, my excitement level has dwindled to "near unmeasurable".

I plan to build a similar jig as the first wood block, but with washers countersunk into the wood. Will probably wear the drill bit out quick, but.... I 'm at a loss at this point. Maybe I just need 100 more oak block jigs.
#92
16th November 2011
Old 16th November 2011
  #92
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What a drag. Though it seems as though it would take way too long with that. I don't suppose drilling free hand is possible? I wonder what the margin for error is with the BAD panel system.
johndykstra
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#93
16th November 2011
Old 16th November 2011
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I'm not too worried about panels one and two. 3-9 is where crooked may become big ovals in leu of two circles.
#94
17th November 2011
Old 17th November 2011
  #94
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Quote:
Originally Posted by johndykstra View Post
Hey.

Anyone thinking of building their own bad panels: Don't.

Related, anyone thinking this is clever tool, it's not:

Drill Guide and Chuck-36/37 at The Home Depot

Piece of monkey $h!T. After countless hours of prep: painting, drawing the grid, mapping the hole pattern.... this "tool" drills about as accurately as a wild guess from a blind man. The rods have too much flex and the harness slides like poop on 'em and the chuck has a ton of play in the bearings. A little play at the chuck translated to the end of a 6" long bit... Oh. Then it ceased up completely.



I first attempted an oak block with a cross hair, and 1/2" hole through the center to aid me in drilling straight through all the panels. That was going gang busters until it wore out after ~20 holes... that when I bought that thing.

I still plan to see this through, but after a few crooked holes, my excitement level has dwindled to "near unmeasurable".

I plan to build a similar jig as the first wood block, but with washers countersunk into the wood. Will probably wear the drill bit out quick, but.... I 'm at a loss at this point. Maybe I just need 100 more oak block jigs.
(My bolding). I just did. 15 BADs, no problems at all with my old Portalign tool. Well, I actually I cheated a bit, I drew 3 panels onto one large sheet of plywood, aligned 5 sheets on top of each other and drilled the 5 sheets at the same time. Still, some 1530+ holes takes a bit of time and is quite tedious work.

Check out this link: AccuDrill Drill Guide | Toolmonger If you can get across a Portalign on ebay, I would buy it right away. The one I have is 35 years old and still up to notch. ( I may throw in some pictures later on how I made the panels.)
johndykstra
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#95
17th November 2011
Old 17th November 2011
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Thanks for the info.

I went back at it last night. After having a few less than perfect holes in my pattern, I've thrown perfect out the window, and am ripping through. I tripled 2 days worth of output in a matter of a few hours. I'm back to my oak block guide, and while it isn't perfect, it sure beats the cumbersome purchased tool.

We'll see how they look when I'm done, but I'm preparing myself for a fabric covering at this point.


What material did you use? Just how flimsy do the single sheets become when fully perforated? I have them all sandwiched and clamped, and don't want to free them until completion. Since I didn't have enough luan to alter all of my absorption panels, I purchased a few additional hardboard blanks. So I'm drilling through 13 pieces....ugh. The blowout on the back side of the hardboard is crazy. That bottom sheet is for sure worthless when this is done.
#96
17th November 2011
Old 17th November 2011
  #96
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Quote:
Originally Posted by johndykstra View Post
We'll see how they look when I'm done, but I'm preparing myself for a fabric covering at this point
we have seen how a fabric can have significant effects on absorption coefficient of a schroeder (1D and 2D) diffuser (AA&D) - does anyone have any data on covering a binary amplitude diffuser with fabric? i would imagine this would still contribute to absorption coefficient ?
johndykstra
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#97
17th November 2011
Old 17th November 2011
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Certainly it will have effect. But this is how RPG markets their device.
#98
17th November 2011
Old 17th November 2011
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Quote:
Originally Posted by johndykstra View Post
... The blowout on the back side of the hardboard is crazy. That bottom sheet is for sure worthless when this is done.

Try putting something else under the last board. Even painters tape might help.
#99
18th November 2011
Old 18th November 2011
  #99
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Quote:
Originally Posted by johndykstra View Post
Thanks for the info.

I went back at it last night. After having a few less than perfect holes in my pattern, I've thrown perfect out the window, and am ripping through. I tripled 2 days worth of output in a matter of a few hours. I'm back to my oak block guide, and while it isn't perfect, it sure beats the cumbersome purchased tool.

We'll see how they look when I'm done, but I'm preparing myself for a fabric covering at this point.


What material did you use? Just how flimsy do the single sheets become when fully perforated? I have them all sandwiched and clamped, and don't want to free them until completion. Since I didn't have enough luan to alter all of my absorption panels, I purchased a few additional hardboard blanks. So I'm drilling through 13 pieces....ugh. The blowout on the back side of the hardboard is crazy. That bottom sheet is for sure worthless when this is done.
I used pine plywood, Swedish B-quality, meaning 1 side looks good aesthetically, while the backside is still generally smooth and OK but has “repair patches”.

Thickness 4 mm = 5/32”, size 2000x1000 mm = about 78,75” x 39,37”.

IF you have the exakt hole pattern and panel size as RPGs, you need not worry about flimsyness if it is plywood or oil treated masonite (high quality hard board). I would be more careful with manual handling if it is MDF. The BAD panels I have on the side walls in my room are from the same kind of plywood but standard size 2440x1220x4 mm = 96”x 48” x 5/32”, with 2 rows of 4 BAD panels on each plywood sheet. As you see the plywood sheets are also slightly curved outwards, 7,5cm / 3” over a 24” length. Hole pattern is identical to RPGs as well as hole diameter 12,5 mm / 1/2”.

http://www.component.se/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=9823

To prevent tear out:
1 Do not use a regular drill bit with a regular 118° cutting angle, instead for cleanest hole use a forstner bit or a spiral bit with a tip (only for wood), like the picture.
2a Use a scrap piece under the panels. If you use a large particle board or MDF, screw the panels to the scrap piece (use small diameter screws) here and there so the panels get tighly packed also in the middle. Later when most holes are drilled, replace the screws and drill the holes in their place.
2b I aligned and nailed my 5 plywood sheets to boards (standing on edge) at the ends and one in the middle, size 3”x1”. Then inserted and clamped a 3”x1” across the width under the package, With my grid size 19x19 m mm (¾” x ¾”) I could drill 3 rows of holes, then unclamped the scrap piece, turned it over and clamped it for another 3 rows of holes. I replaced the scrap piece with a new one as it got too torn up. 1 row of 16 holes through 5x4 mm plywood took me about 5 minutes to drill.
3 Use highest possible rpm on the drilling machine (but do not overheat the drillbit). Drill "quite slowly" through the package, you should let the bit "shave away" the wood, not push it through the wood.

http://www.jula.se/mediaarchive/6060499/main/180282-jpg.jpg

If you curve the panel you get some temporal scattering/diffusion as well, according to RPGs papers with about 5-6 dB (if I remember correctly)

Last edited by Adhoc; 18th November 2011 at 12:23 PM.. Reason: Some additional info
johndykstra
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#100
21st November 2011
Old 21st November 2011
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Good stuff, thanks Adhoc. Your room is beautiful.

I'm not worried about the blowout at this point, as it's already present... no sense worrying about that last sheet now, but good info for others going down this road. Again, I'd advise against it. If anyone does want to tackle this, get a corded drill. I've got a 19 volt Craftsman with three batteries and I'm lucky if I can get through listening to one record without going through all three batteries. Corded drill goes into service tomorrow.

I'm about 1/3 of the way through now. Home stretch?
johndykstra
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#101
28th November 2011
Old 28th November 2011
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Originally Posted by johndykstra View Post
I'm not too worried about panels one and two. 3-9 is where crooked may become big ovals in leu of two circles.
And this is what it boiled down to. The first 2-3 panels came out of the stack looking brilliant. Towards the bottom, not so much. I like to think of myself as handy, with good attention to detail, but I think drilling over 1,000 holes through 13 panels is beyond a d.i.y. effort. A drill press certainly would have helped, but the middle of a 2' panel, not many drill presses have that kind of span.

Did you know that luan plywood (at least at this quality level) is going to have a few, albeit small, hollow spots in the sheet? Likely not a big deal for most applications; but when you are turning it into swiss cheese, this is kinda a big deal. I would have my jig lined up spot on the "x" and almost instantly upon drilling, the bit would kick into a hollow spot on the sheet.

Also, having only a ~1/8" webbing between holes; many chipped out to some degree. Perhaps it was due to having painted one side of them and the pressure of clamping. Perhaps it was having spent the better part of two weeks being clamped and the paint was inconsequential. Irregardless, I would recommend some wax paper, or some sort of protection between each sheet.

The hardboard. (pegboard blanks). Terrible. Furry edges. Not sure what they do to get pegboard drilled out so clean, but these are terrible. I used a very high quality bit, and allowed the drill to do the work (not much pressure). Dunno. Perhaps it has to do with 1/2" holes being too much material to remove in one pass?

Again. I would never NEVER attempt this again. You can purchase binary amplitude grating masks. Do that. It would be totally worth your time.

So how do they sound? The jury is out on this one. I was only able to get 5 (2'x4') of them mounted around the drum corner before practice yesterday. Still 5 more to mount. Examining the drums, for sure it's noticeable in the snare. Way more aggressive.... snappy. Cymbals have more sheen, I want to do a recording and compare to something from before to determine if it's a positive airy quality, of if it's too harsh. Perhaps I need complete coverage before I can fairly judge, but I was hoping for a noticeably airy quality. Not sure I'm getting that.

It is for sure brighter in there. Both acoustically and illumination wise. While practicing, I was having a hard time being distracted by the panels. Likely a combination of: the busy pattern, my scrutiny of crooked holes, and having spend a LOT of time making them. I'm thinking the bulk of them (perhaps save the 1-2 that look great) will end up with a fabric covering. Less distracting visually, and soften the sound just a tick.

I'll take some pictures soon.
#102
28th November 2011
Old 28th November 2011
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Congratulations on the progess and results!

Andre
#103
28th November 2011
Old 28th November 2011
  #103
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+1, John. I know how boring it is to drill all those holes, even though I had the right type of tools for DIY.

My panels are ready, only need some cosmetic wooden strips plus fibre filling of suitable flow resistance. ((Im)patiently waiting for some advice there)

Some pictures of the curved one I intend to use as a cloud between sofa and speakers. Size is 2020x1245x142 mm, prior to and after staining.
Attached Thumbnails
D. I. Y. Polys-img_1354.jpg   D. I. Y. Polys-img_1383.jpg  
#104
30th November 2011
Old 30th November 2011
  #104
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So now you too ... know how many holes it takes to fill the Albert Hall ...
#105
1st December 2011
Old 1st December 2011
  #105
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Quote:
Originally Posted by Adhoc View Post
My panels are ready, only need some cosmetic wooden strips plus fibre filling of suitable flow resistance. ((Im)patiently waiting for some advice there)
RPG's CSI specs say "Core: Semi-rigid fiberglass, density not less than 6 pounds per cubic foot and not more than 8 pounds per cubic foot." and it seems to apply for all thicknesses. I think you could approximate by using the hole size and average spacing to put the panel into Whealy's calculator (perforated panel sheet) then play with various flow resistance materials and thickness until you get what you're after. Maybe not even go that far; just go by the "denser if thinner" rule and go with OC705 if 2", OC703 if 4". Though you probably can't go wrong by going with the RPG values for up to 4".
#106
1st December 2011
Old 1st December 2011
  #106
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I don´t want to kidnap Johns thread but I did just that, -put the figures into the Whealy site. Lesson learned: You can not directly compare published absorbtion figures from RPG with those you get on the Whealy site. Random incidence figures versus normal incidence figures are quite different. See: Perf. panel RPGs BAD vs Whealy site, why so different absorbtion figures?

(In my particular case and going on info from Jens Eklund, it seems better to change from RPGs fibre with high flow resistance to one with lower flow resistance.)
#107
1st December 2011
Old 1st December 2011
  #107
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Hi

Sorry, but I can not stop wondering what you guys are doing here. Four pages of who knows what, and not a single measurments of the room.

Is there any measurements of the traps and does it really work.

In this forum there has been people that has been complaining of this and that of others, you know who you are.

What is this any way???

Thanks
johndykstra
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#108
1st December 2011
Old 1st December 2011
  #108
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Quote:
Originally Posted by johndykstra View Post
Attached is the pdf binder of analysis provided by Jeff Hedback.

There are 5 measurement locations, a close, mid, and far mic from a speaker in the drum corner. And a mid and far from the opposite (organ) corner. Unfortunately, I neglected to realize a 1k notch engaged on the test tone channel strip during capture. Jeff and I are executing a new capture soon, but thought I would share this in the meantime.

A big thanks to Jeff, he's a top notch dude.

Attachment 229375
They're right here Twins.

Though it should be noted this is a recording space, not a critical listening space. Measuring and it's criteria are not as critical.
#109
1st December 2011
Old 1st December 2011
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Quote:
Originally Posted by johndykstra View Post
They're right here Twins.

Though it should be noted this is a recording space, not a critical listening space. Measuring and it's criteria are not as critical.
Hi

I missed it, I see it know. Where is the rest????

But I am not impressed if this is for a recording space. But I still miss data of the traps. BEM data or whatever it is called, I hope you understand what I mean.

I really prefer my listening space over that recording space, Sorry.

Thanks
johndykstra
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#110
1st December 2011
Old 1st December 2011
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You're welcome?

I have no data on the traps. They are not a commercial product. Which traps are you refering to? THe polys are a relatively simple mechanism... don't think anything needs explanation there. The corner traps are 4" rockwool straddle traps... pretty standard. The clouds are 2" +1.5" gap rockwool. Wall panels are 2" + 1"gap of OC703 with a newly added binary amplitude grating mask. The design of which is derived from RPG's "bad panel". You could look into the measured specs of that product if you wish a comparison, though given my shoddy hole pattern, and a few purposely altered holes for originality, I'd never claim these to actually "be" an RPG product, or that their performance is as good.

I too would prefer your listening room.... but for what in your case? Listening to music? No doubt. Recording a full band? I'm gonna go with my room there.

What is it you are unimpressed with? What criteria are you using when judging a recording space? How would you have set out treating this room differently for recording? I have very low ceilings to deal with here, as it is in the basement of a residential building. This is primarily a private use facility, with the occasional friend project. I wish I had 12' ceilings. I wish I had the volume to add a lot of character to my recordings. I don't. These binary panels were an attempt to bring some character back into a dry environment. I haven't had the opportunity to really run them through the paces, thus the jury being out. But tell me... if I did have measurements before and after the installation of the masks, would you be able to tell me objectively which scenario will sound better for drum recordings? How about acoustic guitars? What graphs would you look at to tell you objectively what will sound better subjectively? I am a firm believer in graphs to illustrate the accuracy of a critical listening room. Graphs to explain what sounds "better"?.... I'd rather use my ears.

Make no mistakes. You are free to have your opinion on my workmanship, and while I will admit the critisism stings a bit, I will loose no sleep over your opinions. I have been in a lot of home studios with rooms ~ this size. I'll take mine over all of them.

I feel like your above post may be a bit of backlash resulting from critisism of your room. I get it. But look back, I think you'll find I've offered much praise, and only critiqued that it may or may not have been measured on the same standards that one would use for a critical listening space... but still being a fabulous pleasure listening environment. That IS what you are using it for correct? And the only reason I ever did critique the methodology of your space, was that most of the readers here are looking for control rooms. If one of them were to stumble upon your beautiful room, they could be lead to believe that that was your goal... a control room. The distinction of the two was my only "beef" if you will.

All the best,

John
#111
1st December 2011
Old 1st December 2011
  #111
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johndykstra...

I will explain it for you and I appreciate your comment of my room, you have been most gentle in your reply, don't worry about the "beef".

Just for know I have little time to explain for the moment, time is running away.

I will be back.........

Thanks
#112
1st December 2011
Old 1st December 2011
  #112
Gear maniac
 

John,
How deep will your new BAD panels be? Enclosed are diagrams with normal incident from Soundflow which I received from Jens E, might be of interest for you.
The red 33 kPa-curve is for 96 kg/m³ ( 6 lbs/ft³) rigid glass fibre roughly equivalent to OC 705. The kPa-value is assumed but should not be too much off. The 6 kPa is for light weight home insulation (Isover Piano) and 8,8 kPa for Roxull Flexibatts.

Note performance differences for large and shallow depths and chosen fibre. I have Ø10 mm holes => perforation about 9 % while you have Ø12,7 mm, perforation % = ?, depth = ?
Still, the trend should be roughly similar for choice of fibre versus depth of the panel.
Attached Thumbnails
D. I. Y. Polys-144-svarta-katten-tak-bad-9-5-80mm-ull-r-d-33-kpa-bl-8-8-kpa.gif   D. I. Y. Polys-145-svarta-katten-bakre-h-rn-bad-9-2-260mm-ull-r-d-33-kpa-bl-6-kpa.gif  
johndykstra
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#113
1st December 2011
Old 1st December 2011
  #113
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Thread Starter
Quote:
Originally Posted by Adhoc View Post
John,
How deep will your new BAD panels be?
they are covering 2" OC703, fabric backed and spaced ~1" from the wall

They are 1/2" holes on ~11/16" centers. I excluded the last outside rows so 29 total vertical rows, in favor for a beefier webbing. Not metting RPG specs I know, but this is what i did.
#114
2nd December 2011
Old 2nd December 2011
  #114
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Hi

I've been looking one more time of the graphs you provided.
Here is what does not impresse me...

Resonance at 37 Hz, it has not been fixed.
To much peaks and deeps under 100 Hz. It is not even within +/- 5 dB.
There is peaks and deeps at higher freq as well.
Energy decay time have very irregular shape and lots of strong reflection despite the polys.

Burst decay, I need to have more info of how it is measured, what is a organ measurement????? And how can anybody use burst decay to see Early reflections???

If one have to measure in burst deacy one need to use sweep tone with high sampling, 256k. And I really do think that it is not measured in higher SPL.

I bealive that the room is to dead as well, but maybe this is needed for recording.

Enough of that now.

I have to ask you why you think that my room is not good for recording, how can you tell the difference??

If a room is properly done acoustically, for me if it is called CR or LR is the same for me.

Your room does not follow any standard in term of a recording room and if it does, what standard is it??? So, if you like your freq response in your room then you would also accept a loudspeaker +/-25dB in freq response from 20-20kHz.

Thanks
#115
2nd December 2011
Old 2nd December 2011
  #115
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Quote:
Originally Posted by Adhoc View Post
I used pine plywood, Swedish B-quality, meaning 1 side looks good aesthetically, while the backside is still generally smooth and OK but has “repair patches”.

Thickness 4 mm = 5/32”, size 2000x1000 mm = about 78,75” x 39,37”.

IF you have the exakt hole pattern and panel size as RPGs, you need not worry about flimsyness if it is plywood or oil treated masonite (high quality hard board). I would be more careful with manual handling if it is MDF. The BAD panels I have on the side walls in my room are from the same kind of plywood but standard size 2440x1220x4 mm = 96”x 48” x 5/32”, with 2 rows of 4 BAD panels on each plywood sheet. As you see the plywood sheets are also slightly curved outwards, 7,5cm / 3” over a 24” length. Hole pattern is identical to RPGs as well as hole diameter 12,5 mm / 1/2”.

http://www.component.se/forum/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=9823

To prevent tear out:
1 Do not use a regular drill bit with a regular 118° cutting angle, instead for cleanest hole use a forstner bit or a spiral bit with a tip (only for wood), like the picture.
2a Use a scrap piece under the panels. If you use a large particle board or MDF, screw the panels to the scrap piece (use small diameter screws) here and there so the panels get tighly packed also in the middle. Later when most holes are drilled, replace the screws and drill the holes in their place.
2b I aligned and nailed my 5 plywood sheets to boards (standing on edge) at the ends and one in the middle, size 3”x1”. Then inserted and clamped a 3”x1” across the width under the package, With my grid size 19x19 m mm (¾” x ¾”) I could drill 3 rows of holes, then unclamped the scrap piece, turned it over and clamped it for another 3 rows of holes. I replaced the scrap piece with a new one as it got too torn up. 1 row of 16 holes through 5x4 mm plywood took me about 5 minutes to drill.
3 Use highest possible rpm on the drilling machine (but do not overheat the drillbit). Drill "quite slowly" through the package, you should let the bit "shave away" the wood, not push it through the wood.

http://www.jula.se/mediaarchive/6060499/main/180282-jpg.jpg

If you curve the panel you get some temporal scattering/diffusion as well, according to RPGs papers with about 5-6 dB (if I remember correctly)
Hi
Finally I see a picture of your room.

I would like to see your mesurements?

Please, Start a new thread.

Thanks
johndykstra
Thread Starter
#116
2nd December 2011
Old 2nd December 2011
  #116
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Thread Starter
Quote:
Originally Posted by Mctwins View Post
Hi
hi

Quote:
Originally Posted by Mctwins View Post
I've been looking one more time of the graphs you provided.
Here is what does not impresse me...

Resonance at 37 Hz, it has not been fixed.
To much peaks and deeps under 100 Hz. It is not even within +/- 5 dB.
Low frequency enhancement can be viewed as a positive in terms of drum recordings. Imagine if 'when the levee breaks' had been recorded in a 'flat' environment. Vibe. Character. These are the qualities we look for in a tracking environment.

Quote:
Originally Posted by Mctwins View Post
There is peaks and deeps at higher freq as well.
Energy decay time have very irregular shape and lots of strong reflection despite the polys.
Provided in the binder of measurements are 5 captures from 2 sources. Are you suggesting that high frequencies should be even everywhere in the room with no strong reflections? See, this is one more aspect of live room's that varies greatly from what you expect to see in control room measurements. Your sources can radiate from any infinite area(s) in the room. Likewise, your capture(s) are just as random. Hardly the direct point A to point B you measure in a control room. To achieve the evenness you are looking for in these measurements would be a Herculian task, and frankly in a room this size; I believe impossible and not worth the effort. If one were to attempt this in my room, it would be even deader than it already is. Furthermore, it is not uncommon to place a mic pointing up into a bare corner on the other end of the room from the source... a capture that would consist of very high very early reflections... an "effect" mic if you will. Artistic choices like this would not be as effective in a room like what you describe. One more note regarding the captures during the tests that Jeff decoded. The locations of the capture mic were along an axis to analyze trends in distance from the source. I did not take the time to evaluate where these mics were placed, rather kept them in a straight line and moved them further from the source. More time would be spent deciding on a location during a recording. The haphazard nature of these captures and the graphs they display is one aspect that points to a 'better than average mic placement ability' that Jeff described in his binder. A large portion of this is attributed to the polys in my estimation... as after their installation is when I noticed a much easier time in placement evaluation.

Quote:
Originally Posted by Mctwins View Post
Burst decay, I need to have more info of how it is measured, what is a organ measurement????? And how can anybody use burst decay to see Early reflections???
“Organ measurement” specifies the location of the speaker during those captures. It is the opposite corner of the “dead” drum corner in my room. Looking back at some diagrams of my room may shed some light on this. The burst decay was not an effort to read early reflections. That's is what the ETC graphs show. Jeff was simply pointing out the areas of early reflections on the burst decays... to correlate the data. Also, our definition of “early reflections”, and the criteria they should follow is not the same for recording spaces as it is for listening spaces. We avoid early reflections in the control room, so that we can hear the early reflections that take place on the recording.

Quote:
Originally Posted by Mctwins View Post
If one have to measure in burst deacy one need to use sweep tone with high sampling, 256k. And I really do think that it is not measured in higher SPL.
I'm not as versed in measurement technique as Jeff is, so I defer comment on this.

Quote:
Originally Posted by Mctwins View Post
I beleve that the room is to dead as well, but maybe this is needed for recording.
It is a necessity given the internal volume of such a small space. Believe me, I yearn for bigger. Don't we all : )

(boy... between 'organ measurement' and 'i yearn for bigger'.... this thread may pop up on some interesting google searches)

Quote:
Originally Posted by Mctwins View Post
Enough of that now.

I have to ask you why you think that my room is not good for recording, how can you tell the difference??

If a room is properly done acoustically, for me if it is called CR or LR is the same for me.
I stated I would prefer to use my room to record “a full band”. This is based on topology. Your room would be too narrow and long to achieve a good line of sight between performers. On top of that, the highly reflective nature of your room would make bleed an issue without extensive gobo use. I would hazard to guess that recording single instruments in your room may provide better results than mine, but that is not the way I like to work.

Quote:
Originally Posted by Mctwins View Post
Your room does not follow any standard in term of a recording room and if it does, what standard is it??? So, if you like your freq response in your room then you would also accept a loudspeaker +/-25dB in freq response from 20-20kHz.

Thanks
I am not aware of any standards pertaining to live room criteria, outside of transmission loss. Many of the most praised recordings through history (particularly since the birth of rock and roll), have been captured in “less than ideal” locations. The vibe, the character of the environment... these loose terms we use to describe tone are what acoustic measurements would dictate as “inaccurate”.

Your analogy of the loudspeaker... this is exactly what I am talking about. That is an unacceptable spec. of a transducer in a replication scenario. But it is that kind of response swing in part that makes a u47 different than an SM57... and a large stone room different from a room like Alcatraz in Electrical Audio. Vibe. Character.

I'm hoping this will help to shed some light on the differences between control room measurements vs. live room measurements. If we held all live rooms to control room criteria, part of the life and soul would be sucked from some of the great studios in the world. Sterility is best left to the room where decisions are made, not where art is created.

And while we are at it, let's just throw budget into the discussion for kicks. It's clear you have a surplus of disposable income to throw at your hobby. I say hobby, because I am yet to find an occupation in which "sit and enjoy music" is listed under 'skills needed'. I've looked. But for real, good on you. You've worked hard at what ever it is you do to afford you the luxury of dumping money on commercial products to further enhance your hobby. Bravo.

Unlike a good portion of my contemporaries here, this too, is a hobby for me. This room is for my personal enjoyment, not a means by which to profit. As such, I have had to make due with what I have, and what I can build. Moreover, it has to fit within the structure that I have been dealt. I'd love to work in rooms like Electrical Audio.... but something tells me it isn't a hobby room devoted to a local Milwaukee band. The day that happens is the day you get paid to sit and enjoy records.

With respect,

John
#117
3rd December 2011
Old 3rd December 2011
  #117
Lives for gear
 
Mctwins's Avatar
 

John....

Well, there is a lot to digest.

If a put a drumkit ouside your room how will the response look like??

Do one add enhancment when playing outside??

I still believe that the resonances in a room has to be taken care of and in your case it is not, thats all.

I was not suggeting anything of the freq response but it should be more flatter than it is now, measured in a couple of spots in the room. Off course it is difficult to get excact flat everywhere in the room.

I really don't understand what your point is about the budget??

But if you are satisfied with your recording room, then it is fine with me. I was just pointing out that it is not spectacular in any kind, in a measureing point of view.


Thanks
#118
3rd December 2011
Old 3rd December 2011
  #118
Gear maniac
 

Quote:
Originally Posted by johndykstra View Post
they are covering 2" OC703, fabric backed and spaced ~1" from the wall

They are 1/2" holes on ~11/16" centers. I excluded the last outside rows so 29 total vertical rows, in favor for a beefier webbing. Not metting RPG specs I know, but this is what i did.
Going on your grid size and cut to shape right outside it, the (rectangular) panels should be W 506 x L 576 mm ( 19,92"x 22,68") if I understand you correctly. If so, you should have a perforation % of about 20,1% while the RPG BADs should be 18%. This ought to mean the max absorbtion shifts towards a higher frequency, due to the higher perforation %.

How much the deviation from 31 to 29 rows of holes means for diffusion specs, I don´t know. If possible, I would make the front of the panel curved to improve diffusion / scattering figures. According to RPGs specs the improvement is quite substantial with such an easy modification. I would also make the panels as deep as possible. The left hand diagram in post 111 above shows 80 mm depth as average, versus a curve ranging from about 22 mm to max 138 mm in depth behind the panel, the perforation % is about 9,5% = almost half compared to RPGs BAD
Attached Files
File Type: xls Dykstra-BADs.xls (22.5 KB, 126 views)
#119
3rd December 2011
Old 3rd December 2011
  #119
Lives for gear
 

Quote:
Originally Posted by Mctwins View Post
I was not suggeting anything of the freq response but it should be more flatter than it is now, measured in a couple of spots in the room. Off course it is difficult to get excact flat everywhere in the room.
did you even read his commentary?

Quote:
Originally Posted by Mctwins View Post
But if you are satisfied with your recording room, then it is fine with me. I was just pointing out that it is not spectacular in any kind, in a measureing point of view.


Thanks
who talks like this?

John, you handled that previous response well
glad to hear how things are progressing.
johndykstra
Thread Starter
#120
3rd December 2011
Old 3rd December 2011
  #120
Lives for gear
 
johndykstra's Avatar
 

Thread Starter
Hey Local, thank you.

I believe he read it, but perhaps didn't absorb it so to speak. e. Um, it wasn't really for him anyway, as I don't see him taking on the task of treating a live room. My response to his evaluation of my space was more for others who will be recording music.

McTwin,

Any other response I could formulate would only be a regurgitation of what I have already wrote. If you are unwilling to see live room measurements for what they are, then there is really nothing left to add.

Adhoc,

Thank you for reviewing my description of the masks. Your sizing of the grid is ~spot on. The pattern and it's inverse placed directly adjoining are sharing a 2' x 4' :1/8" luan ply. There is a ~ 1.5" strip running vertically on both edges, and a good ~2"+ on the top and bottom. They (the sheets) slide perfectly into a slot already existing on my wall panels. (Pictures are worth a thousand words... bringing the camera over there on Sunday). Converting them into a bent configuration while easy, would require new frames, patching drywall from where the old frames are fastened.... basically I'm at a "let's see what we've got" frame of mind, but always open to alterations.


But to add, I should discuss my future plans. I added the diffusion masks in an effort to gain some decay above 1k... this will (I'm hoping) lessen the difference between the longer modal problems that still exist, and add more T60 overall. It should be repeated that the measurements were pre mask installation. The next step is to reconstruct corners with superchunks, but faced with a poly shaped slat covering. This should tame the existing low frequencies a touch, and add some more scatter.

I'm kind of in a holding pattern here. As many of you know, I'm also working on a control room. At this point, I am mixing and tracking all in this room... this means a computer, monitors, a rack of gear, a mixer, a tape machine... not to mention a full live PA for rehearsals. Needless to say, many of my polys, and "bad panels" are partially/mostly blocked by gear. It's a cluster frick down there right now. So not only is the room compromised with an abundance of gear, but my ability to truly audition changes is also sub par, as it is all contained in the same room. I guess I'm hesitating to make many more tweaks down here until I have a neutral and isolated space to appreciate the changes fully.

So yes, in some regards I kinda "agree" with McTwins assessment. I do see room for improvement in this space. I just don't believe we are holding the end result within the same metric. And if I may be frank, I would never go onto someone's thread who has spent a lot of time, energy and researching to do their best with a creation and tell them "I'm unimpressed" or say it is "not spectacular in any kind". Particularly if I had no idea what I was talking about... or at the very least I would have a constructive plan to offer for improvement before I would critique.
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