Thanks, Dan. So if I did it like this, yes I would have to completely rely on absorption in order to trap certain reflections and stop them from getting to the listening position, even those reflections that would otherwise arrive sooner than 20ms. However, I am yet to decide exactly how all encompassing this needs to be...the typical recommendations are for any reflections of 500hz and up to be attenuated at least 20db and arriving at the listener's ears no sooner than 20ms after the direct sound. With lots of thick broadband trapping up in the ceiling, below the proposed windows and on the sidewalls/rear walls I don't think any energy above 500hz would even survive once it hits the treatment. What do you think? I am battling between 2 main designs right now, one with soffit wings and one without. The design with soffit wings takes up a hell of a lot more space since I am aiming for a massively wide sweet spot of over 11' and 5' deep. Which means the speakers themselves need to protrude further into the room and the wings take up considerable space in order to connect them at the correct angle to the side walls to produce this console wide sweet spot. The design without soffit wings gains me an extra 5 square meters! But, I have the issue of either getting rid of the windows on the side walls altogether or making them work but without sacrificing floor space to do it. Getting rid of the windows would solve a lot of issues for me and here's my thoughts on why: As we know in an ideal world it would be nice to have a full spectrum RFZ at all frequencies, but even with the perfect geometry deflecting the waves this is not possible once you get down to where the energy stops behaving like rays and becomes more omni. The other thing I do not like about a geometric RFZ is outside the zone the response is screwed again, which makes me think that relying purely on absorption is a better way to go. It is possible to absorb all reflections coming off of the side walls with the correct treatment especially since the angle of incidence means that the energy is passing through the absorption diagonally, thus increasing the thickness of absorption that the waves "see". This is especially true if both broadband and membrane traps are used for example, resulting in a room wide reflection free zone. This is the concept of non environment rooms. But, having the windows would make it a much nicer and more practical place to work. I'd have natural light coming in through the window on the right with a nice view out to the natural world, and a view into the iso booth on the left. Perhaps, I cannot have it all, but I still want to try. Any advice greatly appreciated as always! PaulThat's an interesting idea. It could work but only if you have the ceiling height and absorption. Will you get a 20ms+ travel time on the waves before they return? Also what about below the angled bits? Have you ray traced whether a ray heading off axis down and reflecting just below the angled bits and then off the floor and back up towards the mix position. DanWhat do you guys think of angling windows vertically instead of horizontally at first reflection points? For me, it could save a lot of floor space, since then I wouldn't need "soffit wings"
Studio build in Wales, UK...again!
Originally posted at johnlsayers.com, topic 21409.
You might be trying to get a reflection free zone this wide, but do your monitors even support the same fidelity at such an wide angle? You might avoid destructive interference but the sound stage will be screwed 6' off axis anyway. If you go full non-environment room like you said, you cut off almost all reverberation, are you comfortable with that? RFZ seeks to improve comfort of the listener by maintaining sound energy in the room in a non destructive way.The design with soffit wings takes up a hell of a lot more space since I am aiming for a massively wide sweet spot of over 11' and 5' deep. Which means the speakers themselves need to protrude further into the room and the wings take up considerable space in order to connect them at the correct angle to the side walls to produce this console wide sweet spot.
You're right very low frequencies don't behave much like rays, but mid-lows do to a degree still send most of their energy "directionally". You say you can absorb all reflections off side walls. I'm pretty certain Newell has 1m thick wall treatments to achieve this. Are you doing this? Because that sounds like a lot of floor space is lost there. Does it really save space over RFZ? How are you planning on using membrane traps? You can't use them at first reflection points if you're using absorption there. I haven't got the research to hand at the moment, but I believe membrane trap effectiveness will be reduced if behind absorption. DanAs we know in an ideal world it would be nice to have a full spectrum RFZ at all frequencies, but even with the perfect geometry deflecting the waves this is not possible once you get down to where the energy stops behaving like rays and becomes more omni. The other thing I do not like about a geometric RFZ is outside the zone the response is screwed again, which makes me think that relying purely on absorption is a better way to go. It is possible to absorb all reflections coming off of the side walls with the correct treatment especially since the angle of incidence means that the energy is passing through the absorption diagonally, thus increasing the thickness of absorption that the waves "see". This is especially true if both broadband and membrane traps are used for example, resulting in a room wide reflection free zone. This is the concept of non environment rooms.
Dan, I'm enjoying this discussion, hopefully it is helping both of us to increase our knowledge of the subject, so here's a few more of my thoughts. My quested mains have extremely wide dispersion, its something stupid like 80 degrees per side, and Roger Quested recommends that the listener be 80-100cm in from the point of the triangle where the axis cross. Of course, I do not expect it to be full range dispersion all the way out to 80 degrees, but soft some drivers are very flat and very wide and I would expect pretty flat up to about 30 degrees per side. In my design without soffit wings I am angling my speakers at 25 degrees instead of 30, which helps with this requirement as well as producing a much wider image the width of the console as well as at the couch. Yes good points about treatment taking up a lot of space, but the two designs I am contemplating have the same side wall treatment so it will not eat up more space by not doing soffit wings. Newell’s designs often have relatively shallow side walls as well since adopting more modern methods of absorption than the traditional hangers. But I am not going to go full NE style for the reason you mentioned, but I want to include some aspects of the concept into my design as well as aspects from other designs. I would be more inclined to go with a balanced non environment ala John Brandt but with a few twists. My basic concept is alternating broadband absorption and bass trapping (via membranes) everywhere except areas that do not direct reflections back to the listening position which will have reflective surfaces and/or diffusion, those areas are for the listeners self noise cues to put the listener at ease. Really the only difference between my two designs is the front wall in each. One is further forward with soffit wings with windows and the other does not have the wings and relies purely on absorption instead of deflection at first reflection points, the rest of the treatments would be the same. Regarding membrane traps, yes I remember you bringing up this point of absorption in front of membranes effects the membranes themselves and there is a recommended distance that should be maintained between them. https://www.gearslutz.com/board/studio- ... -mass.html this is an interesting read, it seems that high Q membrane would ideally be tuned in place IF your intention is to hit a room mode, but my interest in using them is to absorb LF reflections not necessarily absorb modal ringing (more on this later) It’s also done by newell, Hidley, Thomas northward, Wes lachot they all use membranes with absorption in front. According to the book architectural acoustics absorption can even be applied in front of helmholtz resonators since the insulation in front does not effect the air going into the device. Of course, you need to take into account what frequencies are going to be attenuated (and by how much) before they then reach the device behind, and then you must tune the device to that range. I have come up with a membrane design which has a 550mm cavity with good absorption between 30-50hz, the center frequency being 40hz with a fairly wide Q for a membrane. Broadband absorption can be applied over this to stop the membrane reflecting mids and highs. I’ve also come up with a diffuser/helmholtz/absorber a bit like the resonators you’ve built under your speakers, but using a fractal design which has high - mid frequency diffusion and then low frequency absorption (between 60-70) thanks to the slots and the waveguides inside the cavity. Well, it works in theory but will it work in practice? It’ll be fun finding out. So, I am aiming to achieve broadband absorption and low frequency control with minimum depth. I will also achieve this by not having really heavy inner walls but allowing a lot of low energy to escape through into the adjoining rooms (apart from the live room) such as the hallway, entrance and machine room. I do not need total isolation in those areas so I am using them as giant membrane cavities with the thinner inner walls acting as the membrane, this should help reduce the modal ringing I mentioned earlier. Sorry for the long reply, I need to just upload my designs so that you guys can get a clearer image of what I’m going on about! So I’ll do that ASAP. Feel free to share what you think of my ideas and again I appreciate all the advice I’ve been given so far. PaulYou might be trying to get a reflection free zone this wide, but do your monitors even support the same fidelity at such an wide angle? You might avoid destructive interference but the sound stage will be screwed 6' off axis anyway. If you go full non-environment room like you said, you cut off almost all reverberation, are you comfortable with that? RFZ seeks to improve comfort of the listener by maintaining sound energy in the room in a non destructive way.The design with soffit wings takes up a hell of a lot more space since I am aiming for a massively wide sweet spot of over 11' and 5' deep. Which means the speakers themselves need to protrude further into the room and the wings take up considerable space in order to connect them at the correct angle to the side walls to produce this console wide sweet spot.You're right very low frequencies don't behave much like rays, but mid-lows do to a degree still send most of their energy "directionally". You say you can absorb all reflections off side walls. I'm pretty certain Newell has 1m thick wall treatments to achieve this. Are you doing this? Because that sounds like a lot of floor space is lost there. Does it really save space over RFZ? How are you planning on using membrane traps? You can't use them at first reflection points if you're using absorption there. I haven't got the research to hand at the moment, but I believe membrane trap effectiveness will be reduced if behind absorption. DanAs we know in an ideal world it would be nice to have a full spectrum RFZ at all frequencies, but even with the perfect geometry deflecting the waves this is not possible once you get down to where the energy stops behaving like rays and becomes more omni. The other thing I do not like about a geometric RFZ is outside the zone the response is screwed again, which makes me think that relying purely on absorption is a better way to go. It is possible to absorb all reflections coming off of the side walls with the correct treatment especially since the angle of incidence means that the energy is passing through the absorption diagonally, thus increasing the thickness of absorption that the waves "see". This is especially true if both broadband and membrane traps are used for example, resulting in a room wide reflection free zone. This is the concept of non environment rooms.
I am really intrigued by the idea of using Homasote as part of a membrane absorber.
The material itself is strange since it's classed as a structural panel but also an insulation board. It is porous, not massively dense (I believe it's between 5-6kg/m2 for 1/2"?) and flexes. It has self dampening but not particularly great at decoupling other structures. It is light weight and would not make a good isolation product by itself. It is in between limp and rigid...all of this makes me wonder how it would act as a membrane.
I have absolutely loads of the stuff left and may do some experiments where I make some large 4'x8' membrane traps with it, perhaps 2 on the rear wall to see what effect (if any) it has.
I even wonder if it would be good as part of a sandwich in a full wall treatment - thick fluffy insulation behind it with a 2-4" layer of Rockwool in front. A sort of modex plate but without the steel plate. I read a thread in which John used panels of homesote (or equivalent) with insulation on the face and then wrapped in fabric on a rear wall of one of his builds.
My gut instinct thinks it will increase absorption around 100 - 200hz as it has an okay absorption co-efficient around 125hz IIRC. I see the main advantage of this is in an inside out wall where it could act as a constraint layer in the absorber, resistance to flow, improving absorption behind it in the stud cavity, decreasing overall required depth for low frequency absorption, while also providing a more solid and durable surface than a fabric covered light fluffy panel.
It would also be easy to tear down if it made things worse/didn't achieve anything.
What do you guys think? Anyone else tried it?
Paul
My last couple of posts haven't sparked much interest or discussion, and I doubt this update will be overly exciting either, especially since this really isn't that relevant to studio building since it's about making large holes in what's supposed to be an isolated structure. however, for the sake of completeness I present to you the story of my newly installed soffit vents:
I was trying to avoid adding these soffit vents as much as I could since it seemed 1. a shame as it'll make holes in my studio and 2. it's a lot of work for a temporary solution. But, the more I researched interstitial condensation the less risk I wanted to take, so I bit the bullet and just got on with it.
It was a challenge for many reasons; the first was I had actually blocked up the area above the top plates where the walls meet the roof with 4x2s and OSB, so there was no longer a gap there. It was too thick to drill through with a hole saw easily, especially without risking going through the actual top plates... and to top it off, I had built large corner traps over the exact area I needed to get to.
There was no way I was ripping all that out, so after a lot of mental problem solving, I just decided to put some holes lower down, below the top plates. Since the holes are opening out into the corner traps it means I can just make a pathway through the insulation for air to get in and under the roof deck, and they won't be seen from the inside. When it comes to blocking them up it will be super easy since I'll just lay a long strip of OSB over the whole lot and seal round the perimeter before putting a layer of extra mass on the rest of the walls.
Initially I was planning to just drill one hole for every rafter bay and stick a round plastic vent in. This is what I did first of all and then after re-reading the roof venting recommendations again I realised I should have a 70mm round vent every 160mm O.C. I had no where near enough vents... no problem I thought, I can just drill extra holes all the way along until I have enough... the problem is the framing gets in the way so I cannot achieve the required 1 vent every 160mm. The other problem is each 70mm vent only provides 1600mm of ventilation, not 3848mm (total area of the 70mm circle) because the closed portion of the vent takes up over half of the total area!
So, I need 1600mm vented area every 160mm in order to provide me with a continuous 10mm gap for the entire length of the studio.
What I worked out was if I put 3 holes without vents per rafter bay that would provide me with 138,528mm2 worth of openings, which is more than enough since I only need 73,000mm2. Surprisingly, if I was to put a vent in each one of those holes then I would only end up with 57,600mm2.... not enough....and I couldn't really squeeze more holes for vents up there since the framing is in the way.
So I decided to leave 3 open holes in the walls, and box them I'm with proper soffits around them with vents every 160mm.
I have to say, it seems like a hell of a lot of vents...
It was a fairly straight forward thing to build, the only thing I regret doing is drilling all the holes before test fitting the panels. This is because I marked the hole positions perfectly straight and cut them out exactly to the line, however, because the wall is slightly off square it means that the vents look like they're not going in a completely straight line due to the wall pushing the panels out slightly in the middle. It's subtle, but could have been avoided if I screwed the panels up first, then ran a string line to mark the line for cutting out the vents. Not the end of the world, this is only temporary anyway. Still, handy to know for the future.
I've only done one side at the moment, but when I do the other side I'm hoping it'll be faster. Then I can get on with doing more of the exciting stuff and hopefully my condensation woes will be behind me.
Paul
Hello & howdo' Paul?
I have been following your build with great interest although I haven't contributed to the discussion (this is simply because I don't think I have any thoughts of value to offer on the specific topics you mention and I've been up to my armpits in tanking compound for the last few days)! However, I'd like to say that for someone who is beginning their own build, it's massively helpful and informative to see and read about how your studio is progressing, so please know that it's appreciated!
- Not a phrase you hear every day! This information will be invaluable as part of the body of knowledge, so thanks for your thoroughness.. . . the more I researched interstitial condensation the less risk I wanted to take
I'm sure it will pay off for you in the long run, your full attention to detail is a good indicator that it will.it's a lot of work for a temporary solution.
Plus one for that sentiment! John.hopefully my condensation woes will be behind me.
Hi John, fellow brit, I am doing good thanks, howdo' you? (btw, I'm not actually welsh, I'm originally from Bristol :D)
Thanks for your kind comments and encouragement, it means a lot to have people show interest in my build and I am glad that I can help others learn what not to do :D
Paul
Update:
Got the other soffit vents finished today, now I can *hopefully* get on with finishing the interior.
Has anyone come up with a way to make thick treatment walls covered in fabric less "squidgy" and more resilient without compromising the absorption behind?
Do people find that the stretched fabric is strong enough of a barrier to stop menacing clients from accidentally damaging the walls e.g. picking, leaning up against, tearing, putting headstock through etc...
Paul
At a theatre located at Disney Land in California it looked like they had a metal mesh (think 1 square inch openings) all over the walls probably for this exact reason. Personally, I will probably just include a note in my studio contract asking people not not lean against the fabric covered walls. It is a real concern but hopefully it never becomes an issue. . . GregHas anyone come up with a way to make thick treatment walls covered in fabric less "squidgy" and more resilient without compromising the absorption behind? Do people find that the stretched fabric is strong enough of a barrier to stop menacing clients from accidentally damaging the walls e.g. picking, leaning up against, tearing, putting headstock through etc...
Good tip Greg, I also had the idea of using a metal mesh but behind a layer of Dacron and fabric, so that it is not visible, seems about the only reasonable way of achieving it other than using slats everywhere, which I don't know if I want on my rear wall. Seems Disney land probably took a leaf out of the BBC's book and built a version of the absorbers found here: https://www.bbc.co.uk/rd/publications/r ... OACQKqLKgg Now that I have finished all the temporary vents I've been making my ceiling hangers better. It's clear that Homasote does not keep it's form very well at all if not properly supported at anything other than a completely vertical angle when hanging, and even though they are not that heavy they seem to bow under their own weight. Ideally I would like to have used chipboard or ply for the hangers, just like Newell does, but I didn't want to add extra weight to my ceiling so I decided to continue using the Homasote but strengthen it with some thin scrap battens I had. This seems to be just enough to stop them bowing, but also keep them lightweight. I'm also going to make them easy to take down if I ever need to in the future (like when I build my outer shell and can put back the extra insulation behind the hangers without risking condensation again) so I am going to screw eye hooks into the hangers and the ceiling and use little carabiners to hang them. Just waiting for the carabiners to arrive and then I can get on with putting them back up again. I have an exciting and slightly inconvenient delivery arriving tomorrow; A very much in need of TLC Trident 80C console. I bought it a few months ago since the guy was going to just throw it in a skip, it needs a huge amount of work as it has suffered water damage and most of it is corroded. The work is not the issue though, it's the fact that I can no longer afford to keep it in storage, and the only place I have room for it right now is the unfinished studio. Ideally I would have liked to have got the room to the stage where it just has basic treatment, but empty, so that I can measure the room. I was almost at that stage when I noticed the water dripping down from the ceiling, so had to stop everything and sort that out. Now the floor is down and the basic treatment is almost complete but I'll have a big console in the room! So, not too sure what to do about that at the moment. Any ideas? I can still measure the room, but would have been nice to have it empty first. And to top things off, the cheap calibration mic that I decided to risk buying doesn't have a calibration file and doesn't seem to even work! :? so I'll need to wait until I can get a decent one in order to make the first measurements. Any recommendations? I was looking at the Dayton Audio EMM-6. My plan right now is to get the basic treatment in and cover it with some removable frames covered in Dacron, take some measurements and then move the gear in. Then, gradually add the extra treatment and build the speaker wall. The reason being, firstly I do not know what extra treatment it will need without measuring, and secondly I just cannot decide on what design criteria I want to follow in terms of the environment. I'm working on 4 different designs at the moment which I'll upload soon, and then I'll make a decision based on room measurements and feedback from you guys, and whichever one makes most sense to me. It will help me decide once I have a basic environment to work in, so I can test out different layouts and workflow ideas and build the treatment and wiring layout around that. The other reason is I just don't have enough money coming in right now to do much! I think we're all in the same boat with that one though. That's all for now, PaulAt a theatre located at Disney Land in California it looked like they had a metal mesh (think 1 square inch openings) all over the walls probably for this exact reason. Personally, I will probably just include a note in my studio contract asking people not not lean against the fabric covered walls. It is a real concern but hopefully it never becomes an issue. . . GregHas anyone come up with a way to make thick treatment walls covered in fabric less "squidgy" and more resilient without compromising the absorption behind? Do people find that the stretched fabric is strong enough of a barrier to stop menacing clients from accidentally damaging the walls e.g. picking, leaning up against, tearing, putting headstock through etc...
Good to hear about your progress Paul.
It's truly terrifying how quickly building burns cash - despite being an optimist it's hard not to worry!I just don't have enough money coming in right now to do much!
Congratulations - that'll be a great desk when it's restored. I used to record on one of those in the 1980's and remember it sounded tremendous. I'm looking forward to seeing your photos and designs. ATB John.I have an exciting and slightly inconvenient delivery arriving tomorrow; A very much in need of TLC Trident 80C console.
Hey John, Yes it was hard to resist for the price I got it (about 10% of current market value) and I'm lucky in that an ex trident engineer lives just down the road from me, I teach his kids, he used to build these things so he's excited to help me restore it. I've also got a DDA AMR24 basically in mint condition, which is another huge desk, bigger than the Trident actually, so my control room is going to be more like a storage container for a while :D I'm either going to end up using both, putting one in the tracking room once it's built, or selling one. I'll use the DDA for doing work and repair the Trident as and when, then I intend to play with both for a good while before making a decision. Thanks for the encouragement and interest in my project! PaulGood to hear about your progress Paul.It's truly terrifying how quickly building burns cash - despite being an optimist it's hard not to worry!I just don't have enough money coming in right now to do much!Congratulations - that'll be a great desk when it's restored. I used to record on one of those in the 1980's and remember it sounded tremendous. I'm looking forward to seeing your photos and designs. ATB John.I have an exciting and slightly inconvenient delivery arriving tomorrow; A very much in need of TLC Trident 80C console.
That's a great desk as well, I know some people rate them along side the very best.I've also got a DDA AMR24 . . .
That is fortunate! When I had my (infinitely more modest) Soundcraft desk restored a few years ago, the engineer who did the job had worked for Soundcraft in the early 80's. He was slightly dewy-eyed when he saw mine and said that, in all probability, he'd assembled the desk 35 years earlier. Sounds like you are accumulating an embarrassment of riches Paul! ATB JS.. . . I'm lucky in that an ex trident engineer lives just down the road from me.
Hi guys,
I'm just playing around with a space saving concept here. Has anyone thought/done this before?
After much thought about hangers, I've come to the conclusion that as well as them having a slight, loose membrane effect, the main way in which they work is through redirection. The waves of all frequencies hits the hangers, the highs and high mids are absorbed by the insulation, any frequencies which the insulation does not absorb are reflected off of the angled panel, attenuated and away from the listener into more hangers/absorption. Any lows that creep around the hanging panels find themselves at the rear of the hangers where they are absorbed in more insulation; then, they either pass through the walls/ceiling or reflect back through the labyrinth highly attenuated. That is my theory anyway.
There's 3 main ways I've seen of doing hangers/waveguide absorbers. There's the way most common on here using homasote, there's the Philip Newell way of using heavy particle board with deadsheets, then there's the John Brandt way of using non hanging waveguides, rigidly attached to the framing with the insulation stuffed between the panels.
All three have their pros and cons in my opinion.
But, what about condensing the amount of space these waveguides often take up? and relying on the deflective properties of dense rigid waveguides to deflect all unwanted reflections to the rear of the room?
I've drawn an incredibly rough diagram of what I mean; the side walls have lots of narrow, rigidly fixed waveguides at an angle of ~40 degrees (this angle would vary depending on the room, speaker angle) with insulation stuffed in between, then this can be concealed with fabric. This version only takes up 90mm (the width of 4x2s) but produces an incredibly wide and long sweet spot.
If you were to ray trace this room, you will see that all of the rays that do not get absorbed will be deflected by the many narrow waveguide panels, either they will ping pong around between the waveguides passing through the absorption each time, or they will be deflected completely away from the listening position to the back of the room where they can be absorbed more efficiently, or diffused. This is really combining the concepts of RFZ and NE but in a fraction of the space, since the side walls do not need to be very thick at all.
This would mean that the energy is largely left in the room so that it doesn't feel overly dead, but a wider sweet spot can be produced than a typical RFZ room.
What do you think? Will this work?
Paul
Random thoughts:- The 'Sawtooth' concept pops up now and then. You can see some examples on Newell's website.
They are usually big areas of slanted wall though. I don't know if they have HF absorption on the surface or not.
The BBC CID system didn't have HF absorption. I used simple angled plasterboard with a foot of fibre behind in a recent venue refurb. No flutter, no loss of HF and MF energy, and great VLF absorption.
90mm treatment will not address Width Modes and non resonant LF reflections.
The 'Sweet Spot' for stereo can only exist in a small area unless radically different types of loudspeaker are used.
Indeed many to most Pro speakers have HF Wave guiding.
Auralex Space Couplers placed under fibre treatments, e.g. clouds, seemed to increase LF dramatically, up to 45% in the 125 Octave if I remember rightly.
Dan, thanks for your thoughts... I should have said RFZ instead of sweet spot, or even ray free zone... A couple of ways to deal with modal resonances, the first being the walls are lossy enough to act as membranes and so the low end goes out into the surrounding areas around the control room - not ideal for everyone I’ll admit but for me it’s not an issue in my design. Secondly the walls could be made thicker, indeed my first concept of this was with 350mm thick walls and the wave guides were about 2’ wide once angled. This is more similar to the NE concept. I thought I’d try to push it to try and get it as thin as possible, and as simple As possible. Option 1 of using lossy walls is probably the only feasible way of doing it, with very rigid wave guides. Effectively, the idea is to have many, many “soffit wings” instead of just the one pair at the front of the room, but this concept could be used as well as the traditional RFZ soffit wings, for example to increase the reflection free area. It would be useful for rooms where more than 1 critical listening area is desired. PaulRandom thoughts:- The 'Sawtooth' concept pops up now and then. You can see some examples on Newell's website. They are usually big areas of slanted wall though. I don't know if they have HF absorption on the surface or not. The BBC CID system didn't have HF absorption. I used simple angled plasterboard with a foot of fibre behind in a recent venue refurb. No flutter, no loss of HF and MF energy, and great VLF absorption. 90mm treatment will not address Width Modes and non resonant LF reflections. The 'Sweet Spot' for stereo can only exist in a small area unless radically different types of loudspeaker are used. Indeed many to most Pro speakers have HF Wave guiding. Auralex Space Couplers placed under fibre treatments, e.g. clouds, seemed to increase LF dramatically, up to 45% in the 125 Octave if I remember rightly.
It is an interesting idea. It would make most sense with more omnidirectional loudspeakers.
I wonder what are the pros and cons of such tiny reflectors versus the huge ones used by Newell and others.
Would the room feedback to human noises be HF only, a bit odd?
Wasn't there a sawtooth in the MHOA?
Design concept 1
Did some more research on sawtooth designs, there's a couple of threads on gearslutz (such as this one: https://www.gearslutz.com/board/studio- ... esign.html ) as well as a section in Newell's book - thanks to DanDan for pointing this out.
Now I know these designs are not anything new - back in the 70s, studio designer Wolfgang Jensen used such an approach in his rooms. From what I can ascertain, they seem to work very well and are in many ways similar to the non-environment concept - the main difference being that the Jensen rooms are not as highly absorptive, the sawtooth panels are reflective one side and filled with insulation behind.
I am having a hard time finding fault with the design... it seems that such a design would work even better for reflection control than a typical RFZ style room. The only potential difference I can think of is the focus on a diffused return of energy from the rear found in RFZ style rooms. But, a Jensen style room seems to kick the butt of an RFZ for wide reflection control in the ray region.
Here's a diagram of how a Jensen style design approach could work in my space:
I horizontally ray traced the extremes of each change of angle for each surface on one side of the room, the grey shaded area shows where the rays combine with the white area showing the reflection free zone (at least in the frequency range of concern)
I first drew the room, then marked the listening position, then spaced the speakers with the desired toe in and distance from the listener. Then I drew the side walls angled at 6 degrees either side and then divided them up every 2' and drew the diagonal panels of the sawtooth.
The reflections from the saw tooth side walls hit the rear wall where they can either be absorbed and/or diffused. I have drawn in some slatted poly traps in the rear corners and an air transparent fractal diffuser in the centre of the main wall. The angled sawtooth panels could either be completely solid or could be slatted as well to provide more/less reflectivity, depending on what was desired.
What do you guys think of this concept?
Paul
Just an update to my previous post, in reality it would probably look more like this...
I'm thinking BAD panels to front the angled reflective parts of the sawtooth side walls would be a nice option.
The walls could either be concealed behind fabric so the sawtooth is hidden and appear to be just "normal" walls, or just left exposed which might look quite cool.
Here is a link about CID rooms, prototyped by the BBC for anyone interested in a similar concept http://downloads.bbc.co.uk/rd/pubs/reports/1995-04.pdf
Paul
Here' some basic 3D images of this concept...
Is anyone out there? :shock: :lol:
This place has gone awfully quiet during lockdown, I hope everyone is well and safe...
Paul
So I just thought I'd mention on my thread that the improvements to Gregwor's TL calculator implemented in version 2.05 really make a huge difference to previous calculations!
A somewhat depressing difference. I thought I was going to be getting decent isolation all the way down to 20hz but looks like this is near impossible using timber frames.
So, anyone who has previously used an earlier version of the calculator may want to re-evaluate their design using the newer version found here:
https://docs.google.com/spreadsheets/d/ ... 1543869474
Paul
Hello there Paul,
I'm still clinging to the perch thanks! I've been concentrating on my build for the last few weeks and it's coming along steadily.This place has gone awfully quiet during lockdown, I hope everyone is well and safe...
Dead right! I ran my numbers again and it persuaded me that I should increase the gap between my leaves. Best wishes to all & stay safe.I just thought I'd mention on my thread that the improvements to Gregwor's TL calculator . . . really make a huge difference to previous calculations!
Thanks John, glad to hear things are progressing for you, that's great news. Yes regarding the MSM calculations... it's a pain in the butt, care to share what your TL graph looks like? Or is it on your thread already? I am contemplating building the rest of the studio with concrete blocks now, seems to be the only way to get decent low frequency isolation in any case. Or perhaps I will just have to settle for compromised isolation below 40hz. PaulHello there Paul,I'm still clinging to the perch thanks! I've been concentrating on my build for the last few weeks and it's coming along steadily.This place has gone awfully quiet during lockdown, I hope everyone is well and safe...Dead right! I ran my numbers again and it persuaded me that I should increase the gap between my leaves. Best wishes to all & stay safe.I just thought I'd mention on my thread that the improvements to Gregwor's TL calculator . . . really make a huge difference to previous calculations!
Hello again Paul,
No, I never have posted a T/L graph and I haven't updated my thread recently either, but when I used the calculator recently it offered these results assuming an inter-leaf cavity of 200mm (as originally intended). Increasing the gap to 300mm improves low end isolation slightly, but there's still an uptick in sub bass frequencies and the curve doesn't flatten out until the gap is 400mm (!). However, I don't know how the fact that most of my outer leaf is actually single tier brick will affect this. I based the calculation on the least dense materials in the outer leaf (12mm cement board and 18mm OSB) because the overall isolation can only be as good as this. Additionally, because three of the outer leaf walls are formed of bricks, this will impact on the efficiency of the MSM system, which are known to work best when the mass of both leaves are the same. Looks like I'll never be able to play 5 string bass through an Ampeg stack in there! ATB JS.care to share what your TL graph looks like? Or is it on your thread already?