modifications to this design

Hey guys, I was checking out he SAE pics in the other thread and the 5th pic down which is a long horizontal studio with studio room on left and control on right is almost identical to what I want to do with my garage. But I have a question. Below is the pic from that thread. The bedroom I currently make music in is a nightmare for bottom end and low mids. It basically a small square bedroom with plaster walls and ceiling and floor boards. When I eventually get around to my garage project I definitely want to create a control room with decent bottom end, however the proposed control room will also suffer from being small, approx 4 x 4 meters and approx 2.4 high. So my question is, what changes would need to be made, if in fact it needs changing, to this design in order to achieve decent bottom end/low mids. Is this current design supposed to be for larger room dimensions therefore meaning that some changes would need to be made to accommodate smaller room dimensions? Same goes for the studio recording space on the left. The main difference between what I want to do and this design is: 1) I will have a window where there is currently a sliding door. 2) There will be a door ( 2 doors) to go from the control room to studio between the wall and proposed window. 3)I will not be having the external door to the studio where it is on the design, it will be where the bottom "slot resonator wall" arrow is pointing. Below is a quick drawing I did just to show the door locations. So I guess in a nutshell what im asking is, should you stick to the above SAE design completely regardless of room dimensions? I am so frustrated with trying to get the bottom end of my mixes right that at this stage I dont care about anything else! I would gladly swap for a room with terrible mids and highs but good bottom end! thanks, hope everyone is well,

forgot, what about the ceiling for this design? Being that what I intend to build will be small, from what ive read, a more "absorbing" type ceiling would be the way go?

When I eventually get around to my garage project I definitely want to create a control room with decent bottom end, however the proposed control room will also suffer from being small, approx 4 x 4 meters and approx 2.4 high. So my question is, what changes would need to be made,

First, don't make it square! Square rooms, or rooms where there is a direct mathematical relationship between the dimensions, are bad acoustically, since that means that our modal issues will occur right on top of each other in the audio spectrum, at the same frequency, or at one octave intervals. So make the room non-square. In fact, look into the subject of room ratios, and use one of the many good ratios for your room.

what changes would need to be made, if in fact it needs changing, to this design in order to achieve decent bottom end/low mids.

That's a function of the actual size of each individual room, and the ratio, and the treatment. Small rooms need more treatment.

Is this current design supposed to be for larger room dimensions therefore meaning that some changes would need to be made to accommodate smaller room dimensions? Same goes for the studio recording space on the left.

You can scale that up and down, yes, and that will keep the room ratios the same, but it does mean that the actual response moves up and down the musical scale in different ways. In general, the smaller you make the room, the worse it gets. But 4m long by 2.5m high by (xx m) wide is still reasonable. That can work, for a control room.

The main difference between what I want to do and this design is: 1) I will have a window where there is currently a sliding door.

No problem with that: In fact, it should improve isolation, since windows can be sealed much better than doors can.

2) There will be a door ( 2 doors) to go from the control room to studio between the wall and proposed window.

No problem there either. As long as you build those doors suitable for good isolation.

3)I will not be having the external door to the studio where it is on the design, it will be where the bottom "slot resonator wall" arrow is pointing. Below is a quick drawing I did just to show the door locations.

Keep your doors out of the room corners! Corners is where you need to have your bass trapping, so move the doors along the wall a bit, to leave enough room for the traps in the corners.

So I guess in a nutshell what im asking is, should you stick to the above SAE design completely regardless of room dimensions?

That's just a rough design that John did as an example of how rooms could be laid out in a typical garage. You'll need to adapt it to your own specific case, both in terms of isolation and in terms of treatment. Every room is different, and they all need their own specific treatment, based on the design, the size, the materials, and even the workmanship.

I am so frustrated with trying to get the bottom end of my mixes right that at this stage I dont care about anything else! I would gladly swap for a room with terrible mids and highs but good bottom end!

:) I hear ya! Ben there, done that... :) But the solution is to have BOTH good low-end response AND ALSO good mids and highs. If low end accuracy is an issue for you, then I would seriously consider flush mounting ("soffit mounting") your speakers. That will most definitely tighten up your bass response considerably, and even extend the reach of your speakers down a bit lower, if done correctly. But that's only half the story: you still need to treat the room accordingly, and here the rule is very simple: Small room = lots of bass trapping. Smaller room = even more bass trapping. Tiny room = insane amounts of bass trapping.

forgot, what about the ceiling for this design? Being that what I intend to build will be small, from what ive read, a more "absorbing" type ceiling would be the way go?

Very likely, yes, but that also depends on the rest of the design. All parts of the room work together, in harmony, to provide the overall response. But in general, yes, a "soft" ceiling is a good idea, paired with a "hard" floor. - Stuart - It would help to

Hey Stuart, thanks for the reply. Regarding your advice on not making it square, does this mean that even if the side walls are going to have saw tooth slot resonators fitted to them, the actual wall itself (behind the resonator) would still need to be angled? Looking at Johns drawing it seems to be ok to build a square room as long as the elimination of squareness is employed in the acoustic treatment design. Am I understanding this right? Are they also slot resonators at the back wall of the control room in Johns drawing? It says "cloth front". Also, ive just realized, the actual "studio" room seems to be square, albeit with panel absorbers but does this mean that non parallel walls are more important in the "mix" room than the recording space? Or is it due to the fact the there's a fair amount of absorption design in the studio room that it doesnt matter about the walls being square? Given the small room dimensions we have discussed, what thickness off the wall would the resonator need to be? Both at its greatest depth point and smallest depth point. Perhaps minimum size suggestions would be better! thanks again!

Regarding your advice on not making it square, does this mean that even if the side walls are going to have saw tooth slot resonators fitted to them, the actual wall itself (behind the resonator) would still need to be angled?

Right. For acoustic purposes, it is the solid, hard, massive boundaries of the room that matter: the actual inner-leaf walls. Anything acoustic treatment that you put on those walls is not considered, since it has little to no effect on low frequencies, and it is the lows that are the problem: modal issues are practically always below about 200 Hz, and what waves that long "see" is just the hard boundary of the room.

Looking at Johns drawing it seems to be ok to build a square room

It doesn't look square to me! It's a lot longer than it is wide... The height is not known, but assuming a "standard" 8 feet (2.4m), it won't be square in that direction either. If I had to guess, I'd say it looks like maybe 4m long by 3m wide by 2.4 high. Definitely not square.

as long as the elimination of squareness is employed in the acoustic treatment design.

The acoustic treatment does not affect the things that actually stops the sound waves getting out of the room: the walls, floor and ceiling. That's what the sound waves "see", and what causes them to stay in the room. Treatment on the walls/ceiling is for damping and diffusing the waves, but does not actually prevent them from getting out. All calculations regarding the room ratio, volume, area and basic calculations are taken from the hard boundary surfaces. The surfaces of the individual acoustic treatment devices in the room is only considered for calculating how they affect the sound field locally, not the overall modal response of the room.

Are they also slot resonators at the back wall of the control room in Johns drawing? It says "cloth front".

Those are bass traps, not slot walls. Basically just huge bundles of very thick absorption, such as mineral wool or fiberglass, with acoustic cloth on the front to hide them from view: The are not very pretty! :) The cloth is only there for aesthetics: it does nothing at all acoustically. It is called "acoustic cloth" because it is acoustically transparent: it lets sound right through without affecting it at all.

Also, ive just realized, the actual "studio" room seems to be square,

Maybe it is just the aspect ratio of your monitor that makes it look square? In reality, it isn't: The distance from the front wall (where the sliding glass doors are) to the back wall (the thicker line, marked "slot resonator wall) is clearly greater than the distance across the room, between the inner-leaf side walls (the thick lines behind the "panel absorbers" on one side and the "high frequency absorbers" on the other). Try printing it out on paper, and measuring it: your printer should print it with the correct aspect ratio, even if your monitor is squishing it up. I very much doubt that John would build a square room anyway. He might try to fit a studio into a square space, but I'm sure he would do something to make it non-square first.

but does this mean that non parallel walls are more important in the "mix" room than the recording space?

Both live rooms and control rooms can be built with parallel walls, or with non-parallel walls. It's just a matter of designing them correctly, with suitable treatment. The number one reason for making walls non-parallel is to eliminate flutter echo between those walls, but since flutter echo is a mid- to high frequency problem, it can easily be dealt with using absorption and/or diffusion, just as John is doing across the "studio" room. In the other direction, he has angled the glass sliding door, so that breaks up the parallelism between those two walls. The second biggest reason for angling the side walls of a control room, is to create an RFZ design (Reflection Free Zone), which is a very good thing to do. John's angled side walls accomplish that, to a certain extent, but he doesn't seem to be aiming for a full RFZ design with that room.

Or is it due to the fact the there's a fair amount of absorption design in the studio room that it doesnt matter about the walls being square?

Once again, I don't seem the room as square. It is longer than it is wide, so it cannot be square. But to answer your question: no, absorption cannot compensate adequately for a square room. If the room is square, the modes will occur at the same frequencies in both directions. Even worse is a cube: then the modes occur at the same frequencies in all three directions. That's the entire point of choosing a good room ratio: ensure that the modes are spread out evenly across the spectrum, not too close to each other, and also not too far away. Take a look at some of the room ratio / modal response calculators linked from the forum, and you'll see what the issue is with squares and cubes. Of course, those calculators only really apply to rectangular rooms, not rooms with severely splayed walls, but so far the rooms you are talking about all seem to be rectangular, so the calculators will work just fine.

Given the small room dimensions we have discussed, what thickness off the wall would the resonator need to be? Both at its greatest depth point and smallest depth point. Perhaps minimum size suggestions would be better!

Slot resonators are tuned systems: they are basically a series of Helmholtz resonators sharing a common cavity. So they should be tuned as needed by each individual room. The dimensions of the slots, and the slats, and the depth of the air cavity are all factors in the equations for tuning the wall, so you can adjust any of those to get the range of treatment that the room needs. Changing the depth of the cavity across the width of the wall (as John does in that diagram above) gives you are more broadband response, covering a wider range of frequencies (defined by the deepest and shallowest depths), but with a lower Q. So it isn't possible to give you a max and min depth without knowing what range the room needs treating, and also the width and depth of the slots, and the width of the slats. - Stuart -

Hey Stuart, my apologies, I wasnt detailed enough. What I was trying to say regarding Johns control room is that the inner leaf walls seem to be parallel, I used the term "square" incorrectly. So as you have already pointed out, to avoid flutter echoes which are mainly mid and highs, the angled slot resonator takes care of this problem (regardless of the parallel relationship of the walls behind the slots). but what you are also saying is that such a design isnt very good for Low frequencies because the lows have enough energy to pass through the angled "slot walls" hit the hard surface behind them, then come back and reinforcing itself (standing waves) due to the other hard parallel wall on the opposite side? So if this is the case, what sort of angle do the inner leaf side walls need to be, does even the smallest amount of angle help? It would suck if it needs a fair amount of angle cause then you would lose room space. Stuart, can you point me in the direction of correct slot wall design/construction? I have googled but most I have found are just a single large cavity stuffed with insulation with timber slats across the face. I notice in your reply regarding slot walls you mention the spacing between slats AND each slot depth, so im assuming a proper slot wall contains many slot chambers? Or am I interpreting this wrongly? thanks again!

I found the slot wall design on Johns "manual" page, looks like I was just misunderstanding what you meant. :oops:

but what you are also saying is that such a design isnt very good for Low frequencies because the lows have enough energy to pass through the angled "slot walls" hit the hard surface behind them,

Not really, no: it's a great design! :) Low frequency sound travels through ALL treatment in the room, not just the slot walls. Sound basically ignores any object whose dimensions are smaller than its wavelength: it just "wraps" around the object and carries on, as thought it were not there. And since we are talking about waves that are tens of feet long in the low end of the spectrum, pretty much all objects are smaller than that. So the low frequency sound doesn't even "see" things like acoustic treatment "doodads" on the walls": But it still does see the wall behind them, since the wall is a solid, rigid, hard, reflective barrier. So low frequencies go right through pretty much any acoustic device, to one extent or another. That's why it is so difficult to treat low frequencies in a room: the treatment has to be BIG to have any effect at all, since the waves themselves are big. So it is the room boundary that defines the modal response of the room, not so much the treatment. That's why you should always use the dimensions of the room to the surface of the inner-leaf walls when calculating room ratios and modal response, regardless of the treatment that is in there. Yes, they waves do lose some energy getting through the slats, and they do diffract and refract and do other strange things on their way through and back again, but the effect is small.

hit the hard surface behind them, then come back and reinforcing itself (standing waves) due to the other hard parallel wall on the opposite side?

Weeeellll.. sort of! Standing waves are a function of the room itself, based entirely on the dimensions of the room. So from that point of view, yes, a standing wave is formed when the frequency of that wave is such that the wavelength exactly matches one of the dimensions of the room (or actually, when the half-wave matches the dimension). Those are called "axial" modes, because they occur along the three "axes" of the room: length, with, height, appearing to "bounce" backwards and forwards between the parallel walls. But there are also two other types of modes in a room: tangential modes and oblique modes. Those are also standing waves that form in the room. Tangential modes happen when a wave takes a path around the room that hits FOUR surfaces then comes back to the starting point in phase with itself, and oblique modes happen when a wave takes a path that involves all SIX surfaces of the room. So modal response can get pretty complex.

So if this is the case, what sort of angle do the inner leaf side walls need to be, does even the smallest amount of angle help

The angles on the slots do nothing at all for low frequency sounds, since they basically just ignore them: low frequencies are non-directional. Low frequencies propagate somewhat like a balloon expanding outwards with the speaker at the center of the balloon. High frequencies, however, are another thing entirely: they act more like rays shooting out in straight lines from the speaker, and they are focused in a cone, like a spotlight beam, coming from the acoustic center of the speaker: the higher the frequency, the tighter the beam. They act like a stream of rubber balls that bounce off the surfaces that they hit, at the equal but opposite angle (like a billiard ball bouncing off the cushion of a billiards table). So high frequencies will, indeed bounce right off the slats and come back at your head, which is not good. So yes, you do need to angle things to keep those "reflections" away from your ears, or alternatively, put an deep, thick acoustic absorber at the points where things could bounce back at you. You can angle the actual inner leaf itself, and if you do that then you are following the basic concept behind the RFZ philosophy of room design: creating a Reflection Free Zone around the mix position. Or if you have slot walls or any other type of "hard" treatment at the first reflection points, then you can angle those, instead of the inner-leaf wall.

It would suck if it needs a fair amount of angle cause then you would lose room space.

Yep! :) That's the problem: If you have to angle (or "splay") the side walls, that does indeed eat up a lot of space. Fortunately, you don't need to angle the entire side wall: just the front part, between you and the speaker. So you'll see lots of room designs here on the forum that do that: the front half or third of the side walls are angled inwards towards the front, to create that reflection free zone. And if you combine that with properly soffit-mounted speakers, you can go a long, long way to massively improving the room acosutics, before you even think about putting treatment in it. The complete RFZ concept is an excellent design philosophy for studios, and seems to be the current favorite

Stuart, can you point me in the direction of correct slot wall design/construction? I have googled but most I have found are just a single large cavity stuffed with insulation with timber slats across the face..

Yep! That's about it! OK, it's actually a bit more complicated than that, since the size and spacing of the slats is important, and so is the depth of the cavity behind them. These are tuned devices that absorb specific frequencies. You "tune" them to the frequencies that need absorbing in the room, based on the predicted or measured properties of the room. Since the air trapped in each slot resonates at a specific frequency, it also absorbs that frequency, taking energy out of the room at that frequency, which is what you want. So you have to tune them to the right frequencies! You don't want to be removing energy at the wrong frequency... There are calculators that you can use to figure out what frequency any specific combination of slot depth, slat width, slot height, and cavity depth is tuned to. There are several linked right here on the forum.

I notice in your reply regarding slot walls you mention the spacing between slats AND each slot depth, so im assuming a proper slot wall contains many slot chambers? Or am I interpreting this wrongly?

Ideally, yes. This is where things get a bit fuzzy, though: If you look at the equation for calculating the resonance of each slot there is no factor that deals with the width or height of the cavity behind it! :shock: It turns in out that, mathematically, the ONLY thing that matters about the cavity, is the depth. In effect, each slot only "sees" the depth behind it, and doesn't care about the rest of the cavity. So you don't really need to put dividers behind the slats to separate the cavities from each other In reality, though, it isn't that clear cut: adjacent slots do interact to a certain extent, so the overall effect of a slot wall is that it acts as a broadband absorber that is tuned to the range between the highest and lowest tuned frequencies, rather than a set of individually tuned absorbers. If you look at the absorption graph, it is like a broad curve, rather than a series of sharp peaks. If you want sharp peaks, then you can indeed put dividers between adjacent slots, but mostly you want broader, general absorption tuned to specific areas, so you can also group together several slots and put dividers between the groups. But just to complicate things more, there is an issue called "percent perforation": If the total amount of "holes" in the sot wall is less than about 5% or 10% of the front surface of the slot wall, then it acts more like a series of individual resonators, and no dividers are required. but once you the percent perforation gets up to about 15% or 20%, the slot wall acts more like a broadband absorber, tuned to the mean center frequency of the individual slots. And once you get to even higher percentages, say around 30% or so, it acts more like a bunch of insulation with of wood in front.... And then there's the issue of diffusion: Since a slot wall is a series of surfaces broken up by "wells", it also acts as a diffuser for higher frequencies. Then there is edge diffraction: Sound waves diffract around sharp edges, so that's what the do when the hit the corners of the slats, to a certain extent. Then there is reflection: A slot wall is mostly just a large flat reflective panel, so it reflects a lot of highs. Then there is absorption: at low frequencies (below the range that you can tune it to), sound mostly ignores the slats anyway, and just "sees" the insulation behind, in the cavity. So it acts somewhat like a low efficiency bass trap, too. So yeah, it's a sort of complex device! Absorber-diffuser-difractor-refelctor-tuned resonator-bass trap, all in one! :shock: Which makes it a VERY useful thing to have in your room, if designed right. But if you stick with John's designs, you get a pretty decent broad-band absorber that will work for most home studios. John already did the math, and his design will cover the majority of cases for typical small home studios. You can refine parts of it if you find you need to treat more specific things. - Stuart -

cool, I think I may have confused you again though! :oops: My questions regarding "how much of an angle is needed" isnt in relation to the slot wall angle, but the wall BEHIND it, the actual thick grey line wall in Johns drawing which I assume represents the inner leaf (thick blue line representing outer leaf). The thick grey line walls seem to be parallel but what you are saying is that it is THESE very walls that will determine modal ringing, etc, in the room because the bottom end doesnt "see" the acoustic treatment? This is why I was asking what sort of an angle the side walls would need to have in order to improve the rooms low end acoustics. Is it worth the loss of space in the end? I really like this design and will use it as the basis for my rooms, I will also reference the room drawing John has on his slot wall construction page from his manual. Thanks for the prompt replies Stuart. Im learning a lot.

but the wall BEHIND it, the actual thick grey line wall in Johns drawing which I assume represents the inner leaf (thick blue line representing outer leaf).

Right. Those are the inner-leaf walls.

The thick grey line walls seem to be parallel but what you are saying is that it is THESE very walls that will determine modal ringing, etc, in the room because the bottom end doesnt "see" the acoustic treatment?

Correct.

This is why I was asking what sort of an angle the side walls would need to have in order to improve the rooms low end acoustics. Is it worth the loss of space in the end?

Well, you CAN angle those walls too, if you want, and in an RFZ design that normally is done, for the same reasons as above, and especially if slot walls will not be part of the treatment. BUT! Splaying your walls does not get rid of the modes. There will still be modal ringing going on, since there are ALWAYS several different manners in which the room itself can resonate, or put in more understandable terms: There are always paths around a room that sound waves can take, in order to arrive back at their starting point, in phase with themselves. So splaying walls does not make them modes go away: it just moves them to a different frequency. And since the room is no longer rectangular, you can't use the simple "modal calculators" or "room ratio calculators" to figure out where the modes will be. Those calculators only work for rectangular rooms with parallel walls. As soon as you angle a wall, all modes associated with that wall will be moved slightly, both in position and frequency. In reality, there are three different types of modes: axial (occur between two parallel surfaces), tangential (occur between any four surfaces), and oblique modes (occur between all room surfaces). By splaying a wall, you do in fact "get rid of" the axial modes that were associated with it, but they didn't magically disappear: they simply became tangential modes at a slightly different frequency. So they are still there, just much harder to predict now. For real-world purposes, provided that the splay angle is not too great, you actually can still use the simple calculators, and the results won't be far off. To do that, you use the average dimension of that angled wall. So for example if you splay the left and right walls so they are 9 feet apart at the front and ten feet apart at the back, then you would use 9'6" as the dimension in your calculations. The results won't be accurate, of course, bit "close enough for government work" as the saying goes... :)

Thanks for the prompt replies Stuart. Im learning a lot.

That's what we're here for! :) If you'd like to delve into all this theory a bit more, to get a more complete understanding, then I'd suggest that you buy "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics). It's not as technical as you might think from the title, and walks you through the subject from basic to advanced without going into crazy sophisticated mathematics: it keeps it all to simple high-school math for the most part, and the explanations and diagrams are very clear, and very useful. - Stuart -

Hey Stuart, ive been thinking about what you said regarding the slot walls and low end. Particularly where the inner leaf walls are parallel. Has anyone ever put something fairly dense (or mass heavy) like stacked stone for example on the wall face within the actual slot wall behind the insulation? So from within the room the layers would be, slats, cloth, insulation, stone, plaster wall (that the stone is glued to). My thought behind it is, instead of letting the low end hit the flat plaster behind the insulation in the slot wall, why not let it hit something dense or mass heavy and in the case of stacked stone is diffusive as well due to its constant varying dimensions. Would something like this help? Obviously the cost would increase significantly but im just curious! Off topic: Is there anywhere I can find details on how to attach down lights to an inside out ceiling? I had a look at Johns recording manual but didnt see anything, unless i missed it. In order to let the heat from the light escape out of the ceiling cavity I was thinking to build little upside down U shape wooden boxes, the light itself would be fixed to one opening of the " U " and the other end would be left open, the " U box" would also keep the insulation from actually coming into contact with the light. The "air out" end of the box would be slightly shorter in legnth so that it would remain unseen and covered by the ceilings finishing cloth. thanks,

My thought behind it is, instead of letting the low end hit the flat plaster behind the insulation in the slot wall, why not let it hit something dense or mass heavy and in the case of stacked stone is diffusive as well due to its constant varying dimensions.

What would be the purpose of the stone? Is that just to increase the isolation of the room? If that's the idea, then yes, it would, provided that the entire inner-leaf was done like that. The mass of the stone certainly would increase the isolation. On the other hand, if the purpose of the stone is as acoustic treatment, I'm not sure what the idea behind that is. Sound will be reflected by drywall almost as well as by stone: there's very little difference in that, if the inner-leaf wall is built solidly enough. And even though some studios do use stone-faced walls for other purposes, I can't see what benefit there would be to doing that inside a Helmholtz resonator. It is basically just a resonant cavity inside there, so I don't see that the diffusive / reflective properties of the stone would provide any benefit for that.

Off topic: Is there anywhere I can find details on how to attach down lights to an inside out ceiling? I had a look at Johns recording manual but didnt see anything, unless i missed it. In order to let the heat from the light escape out of the ceiling cavity I was thinking to build little upside down U shape wooden boxes, the light itself would be fixed to one opening of the " U " and the other end would be left open, the " U box" would also keep the insulation from actually coming into contact with the light. The "air out" end of the box would be slightly shorter in legnth so that it would remain unseen and covered by the ceilings finishing cloth.

There are several designs on the forum for light boxes. If you do a search I'm sure you'll find plenty of ideas that you can adapt to your room. These days many people seem to opting for LED lights, which produce very little heat at all, and really don't need much ventilation. Another option is to build a ceiling cloud, and install the lights in that: that can look very neat, and there are quite a few examples of that on the forum too. - Stuart -

I thought that maybe the stone would diffuse the low end due to the low end not really "seeing" the slats, insulation, etc within the slot wall. I thought that it would be better than having two completely flat parallel plaster surfaces behind the slot wall. Just a silly thought I guess! I'll just shut up now! My ceilings are really low so hanging lights or clouds is no option, but what about wall lights? my rooms are only 3.2 by 3.6. Maybe 3 or 4 wall lights in each room will do the trick? Im not sure about the differences in light dispersion between ceiling lights and wall lights, time to visit a lighting store!

I thought that maybe the stone would diffuse the low end due to the low end not really "seeing" the slats, insulation, etc within the slot wall. I thought that it would be better than having two completely flat parallel plaster surfaces behind the slot wall. Just a silly thought I guess! I'll just shut up now!

Not silly at all! The only "silly" thought is the one you DON'T express: You might just come up with something that nobody else thought of! And it it doesn't pan out, at last you learned something new. In this particular case, stone diffuses higher frequencies much better than lower frequencies, for a simple reason: Sound waves are only affected by things that are bigger than their own wavelength. So the short wavelengths of high frequency sound are affected by the variations in the stone surface, since the waves are comparable in size: a a few inches. But low frequency waves, with wavelengths of tens of feet, don't even notice very large objects in the room, much less the difference in depth between one stone brick and the next. In general, you can think of high frequency sound acting like rays or "rubber bullets", that move in straight lines and bounce off at sharp angles if they hit something their own size, while low frequency waves are much more like a balloon that just expands out into the room in all directions at ones. Mids are somewhere in between. When you think of sound in these terms, it easier to visualize what is probably going on as the waves interact with the room. At least, I find it easier. - Stuart -

Thanks again Stu. I have decided to get one light for each room (one light that has 3 halogens mounted on an arm), I will build a box into the cavity that will house the light, I'll make it so half of the light sticks out beneath the ceiling height line so I can turn the lights where I need them. I went and checked out LED downlights today and almost had a heart attack when I saw the price! At least this way I only need to build 2 ceiling boxes instead of 8! Hey, I have been researching fresh air system designs but I can only find designs of the baffle boxes. I want to check out details on the whole design, fans, motors, the whole lot. Or is it just the air in and air out boxes and thats its? Surely theres gotta be fans involved yeah? I intend on installing 2 split systems (one in each room ) for cooling and heating but am wanting to educate myself on fresh air design. Due to the fact that part of my room was done over a year and a half ago (before discovering this forum) I dont think I can access the areas I need to successfully put in a fresh air system, having said that, my two rooms are small and they both have doors leading in and out so I can open them periodically if need be. thanks again!!!

I went and checked out LED downlights today and almost had a heart attack when I saw the price!

:) Yep, the ain't cheap! Prices are coming down, but still not reasonable...

I want to check out details on the whole design, fans, motors, the whole lot. Or is it just the air in and air out boxes and thats its? Surely theres gotta be fans involved yeah?

Oh yeah! There's a lot more to it than just silencer boxes! You do need fans, for sure. There are several types. You need to choose one that provides the amount of airflow (CFM) that YOUR room needs, at the lowest speed possible, and for the static pressure in YOUR system. So you first need to do the math to find those numbers, then based on that choose the right fan, and the right duct, and the right registers, and the right size for the silencer boxes...

but am wanting to educate myself on fresh air design.

There's a section on Rod's book that deals with that. It covers the basics, and should be enough to get you on the right track for figuring out the numbers.

I dont think I can access the areas I need to successfully put in a fresh air system,

You probably can: but it might imply some "renovation": taking bits out, doing it right, then putting them back in again... Probably not really an issue that you "can't" do it, but more of "I really, REALLY don't want to do that!!! Please!!!"... ! :!: :D

my two rooms are small and they both have doors leading in and out so I can open them periodically if need be.

That's a common misconception: opening the door does nothing. Your room is sealed pretty much air-tight, so even if the door is open, there's no reason for the air to move. Air needs a reason to move. Normally in a typical house there is enough leakage through the structure itself, and through windows, that opening the door is enough to cause air to move, albeit slowly. But in a studio, there is no other path for air to take. So any air that comes on the open door has no place to go: there's no other path for the stale air to take to leave the room, allowing the fresh air in. So nothing happens: You still have a room full of stale air. You need to give the air a reason to move: fans, ducts, silencers.... :) - Stuart -

madmuso wrote:

I intend on installing 2 split systems (one in each room ) for cooling and heating but am wanting to educate myself on fresh air design.

Hey madmuso, I'm about to install two Daiken split systems in my studio that also do air exchange. They go by the name of Ururu Sarara (i think!). I haven't got them running yet, but I know John has mentioned them elsewhere on the site as a combined solution to HVAC. At around $1500 each (plus installation) they ain't cheap, but it was the best solution for me with two rooms of around 25 square meters of floor area each.

I was wondering about your HVAC plans, Steve, since you don't show that anywhere... Silencer boxes, ducts, fans, things... :?: :?: :?: - Stuart -