This thread could be called "Treat the front portion of your room and be happy" .Interesting, 29 of 30 traps are re-arranged this way.
Ciro
Further treatment is coming. I obviously have more traps than should be necessary in the front half of my room, but it turned out that even my 40 PCI traps were a little more reflective than I might have liked (and 20 of the 30 panels are actually 80 PCI), so I had to do some tilting and angling to finally get my first reflections somewhat tamed. It's admittedly not perfect and definitely not something I'll call my end product. I still have a huge mode at 47 Hz that I fully intend to work on. The problem is that the $$ ran out...not that there was a whole helluva lot to begin with, but still.
Now with all of that said and all the bowing and admitting imperfection out of the way...I have to say that if you're a broke ass musician who loves recording and you can manage to scrape up the grand to fifteen hundred to do something like I just did, don't think twice. You can learn to work with your modes at least to some degree because you can learn your room, but you can never work well with early reflections ear-raping you.
If you're a smart broke ass musician and you read this thread, you can learn how to do it right before you make the investment (unlike me) because some really cool, really smart guys like Hannes have given you pure gold right here.
I'm not done with my room and there will be more to this thread. Hannes has agreed to continue my education as his time and my money permit. That sounds like a hell of a deal to me.
And if Hannes and I never get around to taking the next step, you can count me grateful for all of the advice to this point because this change alone has transformed my mixes from shameful to pretty damn decent because although it's not perfect, the difference in my room before and after is like the difference between blind and nearsighted. I may not see everything, but I'm not tripping and falling over every obstacle either.
I'll get around to working on the back of room treatment and when I do I'll be sure to document the journey here.
If you're interested in hearing some of my work mixed with the current treatments, check out this thread: A Song Called "Rain"
It was recorded and mixed right in the room you see in the photos on this thread.
Later,
__________________
"This thing, we do it for our selfish reasons, but ultimately it's at its best when it's something we give over to the world, so that people other than us can feel the power of the gifts we've been given."
All interesting stuff guys.... Just wanted to state that I bumped this in the hope that bpsrepair and/or Hannes F would update us all as to what happened next and where things are at now. Not that the current discussion is irrelevant..... it is and welcome but hopefully we will also get some more info specifically with regard to the progress of bpsrepair's room....
Max
Max,
Hannes has been pretty busy and I've been pretty broke...now I'm pretty busy, but that means $$ coming in. You've inspired me to PM Hannes and see if he's ready to proceed to the next step. Because of my being busy I wouldn't look for anything new for a month or two, but if Hannes has the time and is up for it, I'm ready. As with all of the other progress, I'll continue to post it here.
I gave a thumbs up to the thread some days ago; Hannes kicks, I follow his advices about the "thicker traps/low density" thing some years ago and it changed the things here!
My room is not too much different (only the size , basically half of your length)I have 12 traps on the front part - better saying, first 1/3 front part, from the front wall to my mix position (1,30 m ---->wall). I´m surrounded also...
Congrats
* I read all the thread, and it´s interesting that the corner ones are the 128kgm/3 (20 traps) .After a little search I discovered that this specific panel brand has absorption above the spectations for a so dense panel (not sure below 125, anyway, you have a good amount...).
Filling some of traps with less dense material (when possible, of course) + rear wall treatment will helps in the 45 waterfall.
since you have so many traps, why dont you try changing the orientation of your corner porous bass traps.
instead of stacking them vertically (2 panels per corner), try stacking them horizontally (4 panels per corner). you'll space the insulation further from the boundary.
it would be a fun exercise (and good measurements for the community to interpret). if you would be so kind as to take new measurements with only changing the corner trap orientations.
Thanks for all the great info provided in this thread and the pics of the room progress along the way.
And I have to say, BIG PROPS for having the balls to step out into the forum and post your journey for all the smart guys to pick apart. You get major kudos for that. You really get to know which of the smart guys in the forum are here to better the world around them and which ones only show up to put on a show at your expense before disappearing. They may think your room treatment is a lost cause, but it's better than being a person with no redeeming qualities to justify a severely tuned intellect. The good news is that it's quick and cheap to change a funky room treatment!!!
Thanks for all the great info provided in this thread and the pics of the room progress along the way.
And I have to say, BIG PROPS for having the balls to step out into the forum and post your journey for all the smart guys to pick apart. You get major kudos for that. You really get to know which of the smart guys in the forum are here to better the world around them and which ones only show up to put on a show at your expense before disappearing. They may think your room treatment is a lost cause, but it's better than being a person with no redeeming qualities to justify a severely tuned intellect. The good news is that it's quick and cheap to change a funky room treatment!!!
Keep it coming. Cheers.
Thanks, RScott.
The idea behind this thread was that it would help me while providing some info for other guys in similar situations. I know that my room's better and I think, thanks to Hannes, this thread will help a lot of people to bring their rooms as far as I have brought mine...and maybe it'll help us all get even further.
I was pretty new to GS when I started this thread, so it wasn't so much balls as not knowing what I was asking for. Still, my education both from this thread and from others on GS is worth being picked to pieces by certain individuals. I wouldn't change a thing.
Since my previous post, I've attempted to contact Hannes via PM and email and have received no response so far. Hopefully that means that Hannes is busy on his own projects and making a living.
My room is not finished and the time will come when I'll take the next step by making some tuned traps. My biggest hold up now is that I see now how blindly I went into building the panels. I don't want to make the same mistake with tuned traps.
Since I have as much room for improvement in my knowledge and skill level recording and mixing as I do in my room, I've been trying to better myself in those areas lately. For all of the asinine behavior and comments you can find on GS, it's also an absolute wealth of information and experience. I am endebted to the Gearslutz for all you guys have taught me.
My room is not finished and the time will come when I'll take the next step by making some tuned traps. My biggest hold up now is that I see now how blindly I went into building the panels. I don't want to make the same mistake with tuned traps.
no you don't. See the following thread about tuned traps. I would recommend sticking with broadband.
?
Could you expand on that please. How do you absorb (fix) the modal range with broadband absorbers (velocity based) without ending up with a more or less anechoic space (in the mids and up at least)? The overuse of relatively thin porous absorbers (velocity based) is the most common mistake seen on this forum and the quest for a better solution (pressure based absorbers that absorbs the problem region only) should be encouraged!
That particular linked thread gives an example of a genuine attempt to treat a room with pressure absorbers. It absolutely failed, no difference with or without the difficult expensive boxes. There are several other Gearslutz who have failed in similar ways.
There are dangers in applying any type of treatment, particularly DIY.
However, fibre broadband is benign. It is easy to do , cheap, and it always works as expected. That is why many of us recommend it.
It is unreasonable to refer to our opinions and recommendations as 'the most common mistake'.
It is a considered experienced view, held by many professionals, and as such deserves at least respect.
As I have done since the day Jens joined GS I warmly welcome his advocacy of other techniques rarely used in DIY.
However, this singular repeated technique recommendation has not been backed up with practical advice on how to construct these devices, what fibre, where to put it, minimum sizes, and so on. They fail because of these details. Whealy doesn't predict that.
I say again, the best way to promote the DIY use of a technique is to show the results and how it is done. We have seen spectacular results in a small room treated entirely with perf. There has never been another example given, nor an iota of information of how the traps were actually constructed.
There is an opportunity to contribute positively here. It doesn't start with
'You are all mistaken'
That particular linked thread gives an example of a genuine attempt to treat a room with pressure absorbers. It absolutely failed, no difference with or without the difficult expensive boxes. There are several other Gearslutz who have failed in similar ways.
There are dangers in applying any type of treatment, particularly DIY.
However, fibre broadband is benign. It is easy to do , cheap, and it always works as expected. That is why many of us recommend it.
It is unreasonable to refer to our opinions and recommendations as 'the most common mistake'.
It is a considered experienced view, held by many professionals, and as such deserves at least respect.
As I have done since the day Jens joined GS I warmly welcome his advocacy of other techniques rarely used in DIY.
However, this singular repeated technique recommendation has not been backed up with practical advice on how to construct these devices, what fibre, where to put it, minimum sizes, and so on. They fail because of these details. Whealy doesn't predict that.
I say again, the best way to promote the DIY use of a technique is to show the results and how it is done. We have seen spectacular results in a small room treated entirely with perf. There has never been another example given, nor an iota of information of how the traps were actually constructed.
There is an opportunity to contribute positively here. It doesn't start with
'You are all mistaken'
DD
Dan, name one acoustic designer that relies exclusively on velocity based absorbers when designing control rooms? (EDIT: with the exception perhaps of designers of anechoic or near anechoic rooms such as NE).
Yes, velocity based absorbers are extremely easy to build but the easiest solution is obviously not the optimum one since if it was, it would be used exclusively even in professional settings but this is naturally not the case. For those who wants the easy “solution” to some of their acoustical problems (even if it might create new ones), the use of porous only might be enough, but why exclude the more advanced option even for those who wants to know?
I guess you haven’t used the PAC since if you have, you know that all design aspects of a perforated panel (one kind of pressure based absorber) is presented, even the exact type of wool (since the user must specify the flow resistivity). I have also in numerous threads described how to make both membrane and perforated panels (the two basic types of pressure based absorbers).
If you don’t like pressure based absorbers for any reason, fine, but don’t prevent others from learning a thing or two. This forum is heading nowhere fast if people like you are setting the agenda.
EDIT:
Quote:
Originally Posted by DanDan
However, this singular repeated technique recommendation has not been backed up with practical advice on how to construct these devices, what fibre, where to put it, minimum sizes, and so on.
I will decline from any effort to find a designer who relies on a single technique exclusively. A simple mirror will do that nicely.
Perforations in it would allow seeing through to the other side.....
The Newell and other NE designs have fully live hard stone, glass, and varnished wood front walls and floors. That is a large proportion of the total surface area. They are far from Anechoic, sometimes referred to as Ambechoic. They provide an anechoic path from speaker to ear but provide reflections for sound coming from elsewhere. This avoids the feeling of deadness when say conversing or moving about. Furthermore the trapping uses waveguiding, limp membrane, etc. etc.
I have used the PAC many times here to show predicted scenarios. Seems odd to guess otherwise. I have also espoused another cross platform one which doesn't depend on Microsoft. Porous Absorber Calculator
Furthermore I started the Common Flow Resistivity thread to help anyone trying to use either of these calculators.
Neither of these predictors informed our two GS who constructed failed 2 foot wide pressure traps, of the fact that a panel needs to be a wide enough to flex. Wide enough in the context of it's stiffness, thickness, density, and mounting method. Quite a simultaneous equation there.
I can understand why one might keep trade secrets to oneself.
However to recommend DIY, knowing the absence of these secrets leads to failure, seems reprehensible to me.
I frequently refer to proper LF treatment as the key route to Pro results. I see failure at DIY, thus I recommend RPG Modex Plate Broadband and Corner, Primacoustic Max, or the biggest GIK or Realtraps for that purpose. In that order.
I commend G.E.'s work and his generosity in sharing every detail.
His experiments concluded with a successful panel trap, having tried many variations of panel and perf. Detail was vital. More recently he has show pictures and spectacular performance figures for a VPR design. There is plenty of future here for those who share a genuine interest with respect for the other contributory threads.
I will decline from any effort to find a designer who relies on a single technique exclusively. A simple mirror will do that nicely.
Yes, you obviously rely exclusively on velocity based absorbers. If you for any reason think that I use pressure based exclusively, you obviously haven’t paid attention to what I’m saying in my posts!
Quote:
Originally Posted by DanDan
The Newell and other NE designs have fully live hard stone, glass, and varnished wood front walls and floors. That is a large proportion of the total surface area. They are far from Anechoic, sometimes referred to as Ambechoic.
By who?
Quote:
Originally Posted by DanDan
They provide an anechoic path from speaker to ear but provide reflections for sound coming from elsewhere.
?
Quote:
Originally Posted by DanDan
I have used the PAC many times here to show predicted scenarios. Seems odd to guess otherwise. I have also espoused another cross platform one which doesn't depend on Microsoft. Porous Absorber Calculator
Have you used this one at all? If so, can you please tell me how I can model anything but velocity based absorbers with this thing?
So you’re basically blaming me for every failed panel made on GS?
That particular linked thread gives an example of a genuine attempt to treat a room with pressure absorbers. It absolutely failed, no difference with or without the difficult expensive boxes. There are several other Gearslutz who have failed in similar ways.
There are dangers in applying any type of treatment, particularly DIY.
However, fibre broadband is benign. It is easy to do , cheap, and it always works as expected. That is why many of us recommend it.
It is unreasonable to refer to our opinions and recommendations as 'the most common mistake'.
It is a considered experienced view, held by many professionals, and as such deserves at least respect.
As I have done since the day Jens joined GS I warmly welcome his advocacy of other techniques rarely used in DIY.
However, this singular repeated technique recommendation has not been backed up with practical advice on how to construct these devices, what fibre, where to put it, minimum sizes, and so on. They fail because of these details. Whealy doesn't predict that.
I say again, the best way to promote the DIY use of a technique is to show the results and how it is done. We have seen spectacular results in a small room treated entirely with perf. There has never been another example given, nor an iota of information of how the traps were actually constructed.
There is an opportunity to contribute positively here. It doesn't start with
'You are all mistaken'
DD
Well said.. Ethan Winer does have detailed plans but also admits that these are more for larger rooms then the 99% of the rooms layout around here. I am for tuned traps (we actually do custom ones for customers) but I also understand the limitations of a budget, small rooms and so on. And if someone is concerned with over absorbing the the mids and uppper frequencies then limp membranes can go a long way. Needless to say I believe the following video shows a great layout with broadband with diffusion. Ethan also has something similar to this video with 10 times as much treatment.
With enough good "porous" absorbers, you can definitely improve all but the very lowest modal peaks. The notion that porous absorbers are effective only above 100 Hz or so is incorrect. Yes, improving peaks and ringing at 40 Hz requires a lot of bass trap surface. But the same applies to tuned absorbers. It's not like you can build a single small Helmholtz trap and expect all the ringing to magically disappear. Note that in my video you posted, only four traps at the top of the four wall-wall corners are straddling. All the rest are placed flat against the walls with no air gap, yet there's still a very big improvement down to 40 Hz. And with all that diffusion, the room wasn't even close to dead sounding.
Could you expand on that please. How do you absorb (fix) the modal range with broadband absorbers (velocity based) without ending up with a more or less anechoic space (in the mids and up at least)? The overuse of relatively thin porous absorbers (velocity based) is the most common mistake seen on this forum and the quest for a better solution (pressure based absorbers that absorbs the problem region only) should be encouraged!
I tend to agree with you Jens. With porous absorbers alone, the room may turn too dead and modals could, to a smaller or greater degree, still be a problem. What I feel would be useful is a figure of the necessary size, volume and no of pieces of the pressure absorbers which are needed for a useful attenuation. Those figures you do not get from the Whealy site you refer to for calculation (?). (I have problems to use it because the macros are in English and I can not get the translation to another language to work properly.)
I believe one should not expect that much attenuation from the pressure absorbers, if they are small in volume and few in pieces. Especially if they are positioned at the wrong places … The recommendation I got for limp membrane absorbers with a 3 kg/m² membrane against 80 Hz versus my 33 m² / 73 m³ room was 5 pcs, 390 L ( 13,8 ft³) each, 11 m² in total. For a smaller room, 50 m³ / 21 m² the recommendation was 6-8 m² (49,5-86 ft² versus 225 ft² / 1765 ft³).
The Helmholtz absorber Varitune 6, with variable tuning for the 25-60 Hz range from Svanå, has an internal volume of about 340 L (12 ft³). 1 of these makes a difference if placed correctly at a high pressure point but usually not at all enough difference. So size matters …
It has been determined that a 'Q' or bandwidth of 0.5 to 0.7 is most musical for program equalizers.
You don't use a band pass EQ with a 'Q' of 3 or 4 to equalize a hump in the low end, neither do you use a shelving EQ to attenuate all.
I know I'm getting into controversial territory with this, but I think that everyone here can agree with this...
We use a variety of techniques to obtain balanced acoustics in these small rooms we call studios. I use a lot of membranes and baffles. I use a lot of broadband. Not to mention... a lot of diffusion. So everyone has their technique and there is definitely more than one way to 'skin the proverbial cat'.
Both Ethan and Glenn use membrane on some of their traps - not like I do.. but - like I said about the cat...
Pressure based absorbers are usually more frequency specific and need considerable damping to broaden their range. I can imagine (not yet seen) an RFZ room designed with multiple pressure based absorbers to cover the LF effectively from 250Hz and below with splayed walls for flutter control and minimal broadband absorption for the ceiling and back wall.
The problem with 'good' pressure based absorbers is that their construction can be difficult for most. Not to mention the tuning. All of the pressure based absorption that I use takes the 'limp bag' approach, which tends to be rather broad-band with center frequency around 80-100Hz. These are easier to build and do not require specialized tooling or tuning.
I love a good Helmoltz too, & my favorite is the slat/slot type which is very easy to build and I always recommend building each unit from floor to ceiling and tuning them to at least 4 various frequencies + filling them full with good old attic blanket for damping. They do magic.
That said; Basically, it is so much easier to put up a bunch of good broadband traps and hear an amazing difference right away. Improvements on that have the standard logarithmic curve of time and money expenditure, which many either do not have or do not think that it is worth the bother...
Now if you really want to get into the nuances and 'balance' your room, you'll need some creature comfort 'ambiance'. This can be accomplished with the standard diffusor in the rear as in the RFZ/LEDE approach and/or you can place slats or reflective panels over the traps that are not in the reflection zone (usually in the front of the CR) OR use pressure based absorption panels (broadly tuned - of course).
I DO think that we should discuss the use of the pressure based absorbers and their benefits/solutions. But I don't think that one-size fits all.. especially in acoustics. Like drugs, a little will cure and a lot will kill.
I'd love to see some good, simple designs for pressure based absorbers that work (something that doesn't require a degree to build) for folks that have problem areas that need frequency specific solutions. - WITH confirmation data from testing, please.
Cheers,
John
__________________ John H. Brandt
Recording Studio, Performance Hall & Architectural Acoustics Consultants
(American) in Jakarta, Indonesia
I've said about all I'm going to say about certain treatments to the general public. I eluded to the technique in this post here, but the render is not in accurate dimensions. (if you are clever, you will figure it out + you need to do some calculations) I hope you understand. Most of my new designs/ideas are not shared publicly, the same as many other designers who like to keep their unique designs/techniques to themselves.
I will, within the next year, compile all the build documents for about 100 different acoustic devices that can be built DIY - including testing data into the next edition of my book.
We are working on several local projects here in Indonesia which will give me the opportunity to bring in some of my new designs for testing. I will be happy to share the data with anyone who asks via PM, once it is in.
I know that Jens has testing data on some of his stuff, maybe he would like to share the results, if not the 'how-to'.
It is not difficult to make a limp membrane absorber but one has to be thorough and careful. The ones I made are similar to the one John showed. Mine were made of a frame 200 mm deep, internally subdivided in 2 sections. The front section towards the room was filled with glass fibre to get a roughly 60 mm thick porous absorber. The rubber membrane was placed 15 mm behind the porous absorber, stapled and sealed with silicone, another 15 mm gap before a damping glass fibre board was fixed behind the membrane. Behind the membrane there should be an appropriate air gap versus an air tight backing / lid on the frame work. (The membrane was calculated for 87 Hz. Had I filled the 200 mm deep frame with porous absorber only, I would have received a broad band absorber but less efficient at 87 Hz. The porous absober in front is roughly 60 mm deep, so bass passes more or less right through it.
The air gap distance goes hand in hand with the weight / area of the limp membrane and wanted resonance frequency. This is were the calculation comes in, you can easily find appropriate calculations on how to do this on the net. Never trust manufacturers published figures on density for rubber sheeting or flooring mats. Industrial standard tolerances for rubber sheeting is often +/- 10 on the thickness. This means you can be way off from the start. Measure and calculate actual weight / area of the membrane you intend to use, then calculate the air gap.
Both Ethan and Glenn use membrane on some of their traps - not like I do.. but - like I said about the cat...
I have had good success with using the manufacturers FSK vapor barrier on typical rigid insulation. Not as elaborate of course, but this is my membrane. (Sometimes I use #15 roofing felt spray glued.) Way over looked and under-utilized here. This is a simple solution that can provide a whole host of benefits from "Too Dead Rooms".
Quote:
All of the pressure based absorption that I use takes the 'limp bag' approach, These are easier to build and do not require specialized tooling or tuning.
Quote:
I'd love to see some good, simple designs for pressure based absorbers that work (something that doesn't require a degree to build) for folks that have problem areas that need frequency specific solutions. - WITH confirmation data from testing, please.
From my limited experience, however, I would recommend 4'x4' rather than 2'x8'. Better yet keeping whole sheets intact yielded the best results per square foot.
Sorry John, no data preserved here. I will try to keep all my data from now on.
I have also, in numerous threads, explained in great detail how to construct both membrane and perforated panels. I naturally (apposed to what some might think …) use a combination of pressure based, velocity based absorbers and diffusers and information on the exact application can also be extracted if one reads my post history.
I am actually a bit surprised that some people, quite aggressively argue against the use of pressure based absorbers in studio design. Ok if the person asking wants to go the semi anechoic route; go crazy with velocity based absorbers but in my world, the number of people actively asking for a dead (or close to dead room above approx. 100 Hz or so) is rather limited if not non-existing.
For those new to pressure based absorbers, the benefits compared to velocity based, is that it can absorb low frequencies effectively without being impractically deep and that it reflects above a selected frequency region thus helps avoiding the room becoming to dead above the Schroeder frequency (the modal range). The downsides are that it requires a bit more knowledge to make and if to shallow, the frequency range of efficient absorption becomes narrow.
There will be some posters who are not willing to go the extra mile and fine tune a tuned assembly. It's perfectly appropriate to make them aware of such devices, but likewise it's perfectly prudent for the broadband proponents to heed caution. Knowing when to do this takes a bit of information gathering on the advisor's end. It's seems asking questions to gain insight as to the OP's drive and handiness is more productive than "stick to broadband".
On the other hand, there are posters who are clearly capable and willing to attempt and design such devices. It's these threads where the incessant "no they don't work" "don't do it" posts get a bit tiresome.
I think it's fair to state that the forum, in general, is already brimming with content on velocity absorbers. We have seen many graphs predicting results of pressure traps, and less so execution. If we continue to tell ever able minded individual that "I tried it and failed" this trend is sure to continue.
It's unfair to expect Jens and the other pressure proponents to create a step by step documentation of the process. Especially given the situation specific needs and material variables involved... not to mention their time & knowledge should be worth something.
There are a lot of nuggets out there for those willing to look. Magnets, filling with sand, absorbent % and location, variable tensioning, slat slot ratios for safe designs... why not let Jens take the reigns of threads in which the individual is looking into tuned traps? Just by them asking about the devices, we have to assume at least some amount of reading has already been done. Is it not safe to assume that they already know it's a challenging endeavor and thus the reason for asking questions?
It seems silly, but should we also warn those building corner traps that saws are sharp? Setting up people to fail will only do just that.
P.S. I too have noticed Hannes' absence. I hope all is well.
__________________
phantom power doesn't make your voice sound spooky
Here's what I do. Free if you like, pay if you REALLY like:
Great groove here for a little while, nice to see.
Thanks to those who are contributing actual honest detail. Calculations and predictions do not address the practical details which allow these devices to work or fail.
DIY under guidance of an acoustician, local, or remote, is an entirely different thing. Perhaps human resource trumps any of the material ones here.
Speaking of paying, I continue to recommend the commercial products over DIY for pressure traps. I often point to the custom designed Blackbird studio, which used 38 Modex Plates. One could assume that the designer had plenty of budget and chose these VPRs rather than a personalised custom build.
I doubt that we will see it suggested that someone went crazy with pressure based devices.
Not sure if comparison is really possible , there is no agreed yardstick for comparison of the various techniques.
Perhaps Sabines per 1/3 octave, per cubic metre of device?
I have had good success with using the manufacturers FSK vapor barrier on typical rigid insulation. Not as elaborate of course, but this is my membrane. (Sometimes I use #15 roofing felt spray glued.) Way over looked and under-utilized here. This is a simple solution that can provide a whole host of benefits from "Too Dead Rooms".
Which was my point. There is a way to treat with broadband without making the room (here comes those catchy neg terms) semi anechoic or dead rooms. And just to make clear we do both so I have no skin to loss either way, but 2 main things that have to be considered.
1)Room size
2)Budget
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.Interesting, 29 of 30 traps are re-arranged this way. 
You’re welcome!
I hope all is well.
