A World of Experience
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That makes sense to me now. I never extended the baffles within the box on my design. I will incorporate that into my design.Okay, I checked out my notes here. I messed with it and leaving a total of 1" of MDF on the baffles overlapping one another through the path (1/2" on the end of each baffle) here is it:
Thanks for the detailed explanation of the reasons why, and yup, I get it now and am on board. I will flatten out my baffle walls and bring down the speakers to ear level again.First, your speakers are too high up, and they are angled down.
The manufacturer says that the speaker was designed so the acoustic axis is dead center of the 3" mid driver which is where I have it. There is a small tweeter above the mid driver as well.Second, you seem to have the acoustic axis of your speakers drawn in the wrong place: it looks like you have it centered on the tweeter, but that isn't correct. Check with your speaker manufacturer to find out where the real acoustic axis is for your specific speaker.
Thanks again for the detailed explanation. I haven't seen documentation that the speaker MUST be on its side, but the manufacturer has definitely built the speaker so that it is intended to be on it's side. My guess is because when the speaker is on its side, the tweeter is directly above the mid driver, and only the bass driver is off to the side, so given the explanation you provided, orienting the speaker vertically might have the same issues as you are suggesting I have while orienting it sideways, but with the more directional high frequencies. Either way, I will likely reach out to them to get a definitive answer.Third, you have your speakers laying on their sides, which is not such a good idea (unless the specific speaker you are using is designed to ONLY be used like that).
Roger. Moving them.Then you have your computer monitors and secondary speakers in the wrong place! Move them.
If you are willing to share, I would love to see your design to see if I can incorporate it. Thanks!Desks have a very negative effect on room acoustics. I have developed a design you could use if you want, for a low impact desk that doesn't have too much negative effect on room acoustics.
Will do. And as Greg suggested, I'm doing some investigation into ray tracing in Sketchup to get the best angle.Use whatever surfaces you can at the front of the room to force the early reflections away from the mix position, towards the rear of the room where they can be attenuated. Angle those wings accordingly, with hard, solid, rigid, massive surfaces in the center regions, and do the top and bottom regions similar to the soffits themselves, with bass trapping.
Reading back, I may have misinterpreted the comment below to mean that I didn't need to anchor the base plate of the soffit to the floor...Ummmm.... why won't the sole plate be anchored to the floor?
If I did misinterpret that, I'll go back and figure out a way to anchor it in my design. Either via getting the thermal camera to figure out where I can put anchors in, or gluing down if I can't bolt it given the radiant heating.Quote:
If the soffit structure just needs to be affixed to the walls firmly, but doesn't need to be bolted to the floor, then I can lay the floor now underneath and build the soffit on top post reno.It depends on how you design it, but I normally have a sole plate that rests on the slab across the front of the soffit, and the floor butts up against that. Then there's trim on the soffit that covers the floor/soffit junction.
Thanks for the info!Try to find legrand: it's the best.... just not cheap.
Thanks Greg! This is very helpful.Here it is. Here is a diagram showing how based off of something such as your joist spacing, you can determine 2 of your silencer box dimensions.
Basically just make the desk as small as possible, maybe angle the top of it a bit to prevent reflections from bouncing off of the desk into your ears. Also, cut as much material out of the sides and back of the desk as you can and put insulation in those holes. You can use a perforated material to cover it up if you'd like. Put as much of the equipment down low in the front of the desk as possible. Other than that, customize it for YOUR needs and YOUR room. Personally, I hate having my hands up high so my plan is to have a low drawer type spot for my keyboard and mouse. I'll also embed my screens into my desk. I don't mind looking down at my screens and this will also keep my view into my ISO room nice and open. The top of my desk where there is no need for a hard surface to hold things like drinks, it will be either perforated or just fabric covered insulation. Basically making the desk as "invisible" acoustically as possible.If you are willing to share, I would love to see your design to see if I can incorporate it. Thanks!
Construction grade glue (think PL Premium) is pretty insane stuff. It will literally rip the wood apart as you try to remove it from the concrete. For anything other than walls that have door frames in them, you're probably safe with this glue. If you're renting a thermal camera, it won't hurt to throw some anchors in here and there.If I did misinterpret that, I'll go back and figure out a way to anchor it in my design. Either via getting the thermal camera to figure out where I can put anchors in, or gluing down if I can't bolt it given the radiant heating.
Here's an image showing the effect of increasing or decreasing your cross sectional area. As you can see, even doubling the cross sectional area doesn't yield amazing results. The bigger the difference, that greater the insertion loss!1) If I am unable to achieve 2x the cross sectional area of my register in any of my designs, is there a way to design around this? I'm thinking maybe Greg's suggestion of making the silencer boxes longer with more impedance mismatches could help compensate. Is this a thing? Or is there a requirement that the impedance mismatch must be at least 2x to have any effect?
Whichever way you can fit them. It's best to fit them in between your inner and outer leaf so that they aren't eating into your inner leaf space, but if your inner leaf box has to be inside your inner leaf, no problem. The biggest compromise is that they typically end up fitting into a tri corner that will then hinder your bass trapping.2) If I am able to fit the boxes behind my baffles on the ceiling (haven't had a chance to model this in sketchup yet, but it will be my first task when I get home tonight), should those boxes be incorporated into my inner leaf, i.e. drywalled around them as if they were soffits? Or should I build my inner leaf and then punch a hole through it and mount the silencer boxes inside the inner leaf?
I can tell you from personal experience that the difference from having 1 silencer box to 2 on a run is crazy. I would NEVER suggest using a single box after hearing the difference. The bigger the box, the better. It makes sense if you think about it. The further the sound has to travel through a large box, the more insulation there is. The quieter it gets.4) If #3 is an option, how would I calculate how much I would potentially lose in isolation from only having 2 vs 4 silencer boxes?
Just like soffit wings! Ray trace it. Like soffit wings, it needs to have a hard backing (think at least 3/4" OSB) and having insulation below the OSB will help. In theory if it is angled correctly, it could just be a hard surface, but it's not really acting as a baffle extension so much as just absorbing and reflecting sound towards the back of your room. Therefore you'd be crazy to not have insulation on the bottom side of it. Filling above the cloud with insulation is a great place for insulation too. Make sure you place your lights in a position so that they won't reflect off of your screens or windows into your eyes.5) I know I am going to have to build a cloud at some point, but I honestly haven't spent much time at all thinking about this. Can you suggest some good resources that I could use to get up to speed on what I need to consider in a cloud design? I'd like to get to a rough size and position pretty quickly so I can finalize where my track lights need to go. Or is this just the same concept as the baffle wings, deflect reflections from the speaker to the back of the room?
Thanks Greg!For anything other than walls that have door frames in them, you're probably safe with this glue. If you're renting a thermal camera, it won't hurt to throw some anchors in here and there.
Whoa, if I'm reading that right, having 2x the cross sectional area impedance change only gives you about half a db in TL?Here's an image showing the effect of increasing or decreasing your cross sectional area.
Is the difference from having 2 silencer boxes on a run, vs having 1 that is as long as the two separate boxes combined significant as well?I can tell you from personal experience that the difference from having 1 silencer box to 2 on a run is crazy
OK, I took my first punt at ray tracing in Sketchup. Here's what I did. First I ray traced without any soffit wings to see where my problem areas would be... I came up with this: (arrows showing the rays that came close to my listening pos, x showing approximately where I would need to extend my wings to) Then, I tried to extend the wings such that they covered the intersection of those rays, but I believe the new wing angle introduced a new problem ray... so I shortened the wall (increased the angle of the wall) as much as I could to capture the first problem rays, but still deflect the new problem ray... this is what I netted out with. Question I have is, how do I know when I've cleared enough room around my listening position? ... and if what I have there isn't adequite, I'm a little unsure of how to remedy it... Would love to hear your thoughts.Use the search feature on the forum to look up ray tracing. It's very very important that you do ray tracing in SketchUp to ensure your design works perfectly.
... or you could try changing the angle of the soffits themselves, and the position of the speakers within the soffits...Then, I tried to extend the wings such that they covered the intersection of those rays, but I believe the new wing angle introduced a new problem ray...
How big is your console/desk? When you are seated normally at your desk, mixing in typical fashion, how far do you need to lean/move left or right of the center-line, for normal mixing? Measure that, and add about 6" or so each way for good measure. Ditto for how far forward/backward you might lean or move over the desk while mixing? For most home studios, that will like be a circle or ellipse of maybe two or three feet in diameter, which actually isn't so easy to achieve. For a large console in a large room, it could be a dozen feet each way, which is REALLY hard to achieve...Question I have is, how do I know when I've cleared enough room around my listening position?
The ITU recommends a listening area minimum of around 0.7m radius, but as Stuart said you should try to get your RFZ to extend as wide as your console/work station and as far back as you think you'll need while working.Bhudie wrote:Thanks Greg!For anything other than walls that have door frames in them, you're probably safe with this glue. If you're renting a thermal camera, it won't hurt to throw some anchors in here and there.
Whoa, if I'm reading that right, having 2x the cross sectional area impedance change only gives you about half a db in TL?Here's an image showing the effect of increasing or decreasing your cross sectional area.
If that's correct does that mean that unless you can get much more multiples on the cross sectional area, the majority of the attenuation comes from the turns inside the silencer box?
And if that's correct, am I right to assume just making way longer boxes is a better use of my efforts than trying to wrestle with getting big impedance changes given my lack of usable space?
Same question said a different way...Is the difference from having 2 silencer boxes on a run, vs having 1 that is as long as the two separate boxes combined significant as well?I can tell you from personal experience that the difference from having 1 silencer box to 2 on a run is crazy
OK, I took my first punt at ray tracing in Sketchup. Here's what I did. First I ray traced without any soffit wings to see where my problem areas would be... I came up with this: (arrows showing the rays that came close to my listening pos, x showing approximately where I would need to extend my wings to) Then, I tried to extend the wings such that they covered the intersection of those rays, but I believe the new wing angle introduced a new problem ray... so I shortened the wall (increased the angle of the wall) as much as I could to capture the first problem rays, but still deflect the new problem ray... this is what I netted out with. Question I have is, how do I know when I've cleared enough room around my listening position? ... and if what I have there isn't adequite, I'm a little unsure of how to remedy it... Would love to hear your thoughts.Use the search feature on the forum to look up ray tracing. It's very very important that you do ray tracing in SketchUp to ensure your design works perfectly.
Thanks,
Aaron
If I can use a system like this on my East wall where outer leaf is an exterior wall, then I could get my registers in the front and back of the room and have enough isolation from my silencers to still make this all work. I've mocked up roughly what I mean here, to see if it is plausible. I would love some feedback on this possibility.There's one other way of doing it: Since the issue is partly about noise being picked up by the duct that passes through the cavity, that can be eliminated by NOT using a duct to pass through the cavity! Instead, use a massive extension of the silencer box to pass through the cavity. So for example, you would build your silencer box on the outside of the outer leaf using plywood, then create a "duct" out of the same plywood that goes completely through both leaves and terminates in the register, on the other side of both leaves. That plywood "duct" would still need to be broken in the middle (to prevent sound flanking along it) by simply sawing all the way through it, then wrapping the gap with thick rubber (EPDM, Neoprene or Sorbathane) to seal the gap and make up the missing mass.
Yes.... but it depends on how fast the flow was before and after the change. It it is still low after the change, then there probably won't be any turbulence issue. For example, if the velocity was 50 fpm before and 100 fpm after, then I would not be worried., but if it was 250 before and 500 after, then yes, you'd have a problem.I imagine that the problem with half of the cross sectional area is that the air speed would get too fast, and then you would need to have enough space for the turbulence to settle before air entered the room otherwise you would create noise at the register. So questions:
1) Is this assumption correct?
A smaller silencer box will increase the static pressure, and probably won't provide the transmission loss you need. The general rule in HVAC is that the return run should have a large cross sectional area than the supply run, or at the very least, the same.2) If so, can I utilize a smaller silencer box for the return air because the air speed won't pick up until it leaves the room, and I would have a long run of joist space to let that air settle before it hits the second silencer on the outer leaf?
What's on the other side of that wall? You only show one silencer box on the outer leaf, but nothing about the silencer box on the inner leaf, nor what joins them....If I can use a system like this on my East wall where outer leaf is an exterior wall, then I could get my registers in the front and back of the room and have enough isolation from my silencers to still make this all work. I've mocked up roughly what I mean here, to see if it is plausible. I would love some feedback on this possibility.
I'm wondering if I can do a combination now... running my small silencer boxes for the return on each leaf, 6 runs of them... 3 along each side of the room (6x36" cross sectional area = 216"... I know that's not the right number, but I was thinking I could get away with 5 changes per hour instead of 6, in which case this would be large enough of a cross sectional area, and a low enough velocity), and have them vent out on the east wall. I spoke with my contractor and he doesn't think the large boxes on the East Wall (the wall with my supply boxes in my previous post) will fly with the inspector due to setback requirements. Instead I could utilize the pool room next door for the supply boxes on both leaves as you suggested... bumping out my outer leaf wall to accommodate the larger boxes. This would put my supply register in the front right corner of the room, but I could duct it to the front central bottom of my baffle, and then have multiple return registers on the ceiling in the rear of the room.Filling your joist cavities decreases the gap in your MSM system, but for many of us, there's no other choice. I haven't done the math to see if this is feasible, but with that in mind, did you ever consider running 2 or 3 sets of your long joist cavity style silencers down each side of your room? One side being supply, the other being return. You could have your outer leaf silencers mounted on the outside of your room (like the supply silencer in your recent picture). They could have 2 or 3 sleeves on them that would connect to the inner leaf silencers (these would be the long skinny joist cavity style).
With silencer boxes, it is 100% okay!Also, cutting that many openings for registers in my double layers of drywall seems mental...
What about putting the silencer boxes on the front side of the building? You could hide them with a nice design so no one would really be able to tell what they are.I spoke with my contractor and he doesn't think the large boxes on the East Wall (the wall with my supply boxes in my previous post) will fly with the inspector due to setback requirements.
Well....I feel like this works for HVAC, but I can't help but think it might not work well for preserving my isolation ...
Drilling one single 1/2" hole through your leaf is already mental! ... if it isn't done correctly, with excellent seals and enough mass to get back to the right situation. That's why you need silencer boxes on every penetration...Also, cutting that many openings for registers in my double layers of drywall seems mental...
OK, first off Greg, thanks for asking this question... looks like somewhere along the line I got turned around and doubled my cross sectional requirements for my silencer boxes. In copying my calculations below I realized that 6 runs of these return silencer boxes is more than enough cross sectional area... In fact I only need 4 runs.1. Are you doing forced air or a ductless minisplit? Can you share any HVAC calculations you've done?
Unfortunately not, that'll be the family TV room, and there's going to be a built in media center right across that wall. However, with my current design, I don't think I'll need to do that, as I will have the supply register vented to the front bottom of my speaker baffle wall, and have the 4 return registers in the ceiling in the rear of my room. Am I missing something?2. What is the room opposite of your pool mechanical room being used for? Can you sacrifice a corner of it (up high or a side wall corner) for a silencer box? The reason I suggest this is because it would allow you to easily have supply and return on opposite sides of your room!
I wasn't planning on doing an inside out ceiling. I read that you recommended it above. I'm guessing the main benefit is the extra few inches of effective ceiling height? I am wondering if I'm better off not doing that and using the 6 inches of the inner leaf ceiling joists as spring, since I'm now eating up a lot of space for the silencer boxes.3. Are you doing an inside out ceiling?
This is a no go as far as the wife approval factor... That wall faces our pool, and she's just not having it. But unless I am missing something, I think using the pool equipment room works doesn't it?What about putting the silencer boxes on the front side of the building? You could hide them with a nice design so no one would really be able to tell what they are.
A few things:Are you doing forced air or a ductless minisplit?
Do inside out.I wasn't planning on doing an inside out ceiling. I read that you recommended it above. I'm guessing the main benefit is the extra few inches of effective ceiling height? I am wondering if I'm better off not doing that and using the 6 inches of the inner leaf ceiling joists as spring, since I'm now eating up a lot of space for the silencer boxes.