Double Garage Studio Design - Melbourne, Australia (7/10)

Thanks for the reply Scott. My UK search for triple grips brought up a load of stuff about hair products! haha I'm sure there'll be an alternative. My Dad is a civil engineer at the council so is going to get advice for me from the structural department, should help put my mind at ease.

adamthedrummerboy wrote:

Thanks for the reply Scott. My UK search for triple grips brought up a load of stuff about hair products! haha I'm sure there'll be an alternative. My Dad is a civil engineer at the council so is going to get advice for me from the structural department, should help put my mind at ease.

Too funny. I don't have much need for hair products these days. Yeah, there'll be a different name for the same thing. Let me know what you find out about the joists. Scott

It's alive..!!! So...lots has happened. North (Door) and South (Window) walls have all got 1 layer of 16mm mdf on them, East and west walls have 2 layers each and ceiling has one layer of plywood. Ventillation fan installed on resilient mount. Plus there is some flexi-vent going in in stages. Next... 1. Plaster to go on North and South walls, and ceiling. 2. Feature panelling to go on East wall 3. West wall is going to be a full bass trap... I am planning to use more dense (~25 kg/m^3) panels in the frame and fluffy stuff in the gap. Also, where to put the split-system AC unit...? I am thinking of mounting it central to the West wall (rear bass trap wall)...which means I'll need to ensure the frame is adequate there. The alternative is to put it on the North wall next to the doorway firing across the room. Thoughts??

Ventillation fan installed on resilient mount.

How do you know that mount will actaully isolate it? What frequency is that mount tuned to? What load does that rubber need in order to provide the correct resilience, and what deflection is that supposed to produce? To me, it does not look like that mount is going to isolate that fan... Also, it seems that you are putting your fan inside the room??? That isn't correct: the fan should be as far away as possible from the room, optimally at the very end of the outlet duct.

Also, where to put the split-system AC unit...? I am thinking of mounting it central to the West wall (rear bass trap wall)...which means I'll need to ensure the frame is adequate there. The alternative is to put it on the North wall next to the doorway firing across the room. Thoughts??

But you already have your inner-leaf and outer-leaf walls in place, don't you? So how are you going to get the pipe bundle through correctly? It can't just go straight across the gap!!! That would create a major flanking path... Just like your electrical power feed, there has to be a long section of pipe inside the cavity, running parallel to the wall faces, between the point where it goes through the inner-leaf and the point where it goes through the outer leaf. How are you planning to do that with your walls already in place? - Stuart -

Soundman2020 wrote:

How do you know that mount will actaully isolate it? What frequency is that mount tuned to? What load does that rubber need in order to provide the correct resilience, and what deflection is that supposed to produce?

:shock: I've got no idea! Could you point me towards any resources to help out...Google has not been kind to me on that front. The rubber is neoprene purchased from here... http://www.clarkrubber.com.au/strip-neo ... -50mm.html

Soundman2020 wrote:

Also, it seems that you are putting your fan inside the room??? That isn't correct: the fan should be as far away as possible from the room, optimally at the very end of the outlet duct.

The fan is positioned outside the room...above the outer leaf, inside the roof cavity...and at the end of the outlet duct. It is as far away as I could get it within the constraints of the building...short of doing some major works. The fan will connect to a roof mushroom via a short run of flexiduct.

Soundman2020 wrote:

But you already have your inner-leaf and outer-leaf walls in place, don't you? So how are you going to get the pipe bundle through correctly? It can't just go straight across the gap!!! That would create a major flanking path... Just like your electrical power feed, there has to be a long section of pipe inside the cavity, running parallel to the wall faces, between the point where it goes through the inner-leaf and the point where it goes through the outer leaf. How are you planning to do that with your walls already in place?

Yes...something else I didn't consider too well. For electrical, there is still access between the walls at the door way as I haven't covered that over just yet. I was thinking I could use flexible conduit...sealed and stuffed with some fibreglass insulation at the ends, to run cables from the outside leaf to the inside leaf. I was going to punch in at a point on one side of the door and run over the door and into the room on the other side, making only one penetration point into the room on the north wall (wall opposite the window). Then use exposed conduit to run the wiring around inside the room. Is that a good solution? I'll need to talk to my AC guy about the requirements for the split system...but I could potentially do something similar in that same area. I'm just not sure on the do's and don'ts with the AC connections between the head unit and the compressor. Any advice there also would be appreciated. Do you think placing on the west wall (rear wall from a mix perspective) would be the best position? It would help to keep the room symmetrical. Thanks for the looking. Scott

I've got no idea! Could you point me towards any resources to help out...Google has not been kind to me on that front. The rubber is neoprene purchased from here...

You'll need to know the Shore scale and hardness of that rubber in order to figure it out. I could make some educated guesses, but it would be best if you contact hte manufacturer and ask them directly: What is the Shore hardness of that specific rubber, and which Shore scale that is measured on. Also ask them what the optimal static deflection is for maximum vibration isolation. As I said, I can estimate those, but accurate numbers would be better. I would hope it is something like Shore A 40 or less.

The fan is positioned outside the room...above the outer leaf, inside the roof cavity...a

Ahh! OK. :thu: All is good... :)

For electrical, there is still access between the walls at the door way as I haven't covered that over just yet. I was thinking I could use flexible conduit...sealed and stuffed with some fibreglass insulation at the ends,

The best way for maximum isolation is to do it like this: Cut a small section out of the middle of the conduit, and wrap the gap with your Neoprene. Hold it in place with zip-ties. Seal the seam where the rubber joins itself. After the wireing has been pulled through, poke fiberglass insulation down each end of the conduit, and cap it with caulk.

I was going to make only one penetration point into the room on the north wall (wall opposite the window) and use external conduit to run the wiring around the room.

:yahoo: :D :thu: Or do it like this inside the room: http://www.calcentron.com/Pages/fram-tr ... aceway.htm http://www.export.legrand.com/EN/dlp-wa ... ng_95.html

I'm just not sure on the do's and don'ts with the AC connections between the head unit and the compressor. Any advice there also would be appreciated.

There's a bundle of stuff that connects the two units. Usually there are two copper pipes (one to carry the cold coolant to the indoor unit, the other to return the warm coolant to the compressor unit), and an electrical cable that also carries the control signals, plus the condensate drain hose. The copper piping is semi-flexible: it can be bent to a certain extent with a wide radius bend, and if you wall has a decent air gap then there should be enough space to bend it where it comes through the inner-leaf so that it runs parallel to the leaf surface. Then run it across a distance of at least one stud bay inside the cavity, more if possible, bend it again to take it out through the outer leaf. The electrical cable can follow the two copper cables here. Another possibility is to make a "loop" out of that bundle inside the wall cavity. That's fine for the two pipes and the cable, but not for the condensate drain hose. That one has a special requirement: it must always be on an incline, downhill from the indoor unit. The condensate runs away by gravity alone, so there can be no uphill sections in that (unless you also want to invest in a condensate pump...). As long as you do things with the above in mind, and no straight-across penetrations, then you should be OK.

Do you think placing on the west wall (rear wall from a mix perspective) would be the best position? It would help to keep the room symmetrical.

For a control room, the middle of the rear wall is a good location. For a live room, it doesn't really matter. - Stuart -

Awesome - thanks again Stuart. I'll get those rolling in the next week or so. I found this company - Gelmec - and was thinking of using a gel mat to isolate the fan... http://gelmec.com/ They have product SN-15 under: products/sheet materials/ gel anti vibration mat, that seems to fit the bill. They even have data! That seems hard to come by for a lot of products. Anyways...plastering is done. :yahoo:

So I've been busy... Plaster done...and painted. Concrete floor painted. Paling wall done. This will be my front wall - so I thought a feature wall was apt. Covers for the front corner traps...done. There's no insulation in there yet...I'll wait to do a base level reading in REW when I get the window and door done. I'm wired and ready for my electrician to connect everything up. I have 2 double power points on the side walls and a 4 outlet on the front wall, plus a central 4 spot LED light, and a controller for the ventilation fan (the grey box). This is the rear wall frame that will be ALL bass trap / absorption ALL the time. As mentioned in an earlier post, there will be fluffy fibreglass in the gap and higher density panels at the front between the studs. I will cover this with material of some sort...somehow...!? The air conditioner head unit will be mounted central on this frame. Getting there. Next: Speaker stands. Laminate glass on the internal side of the window...then door...and AC...then to testing :yahoo: But first...Merry Christmas. :lol:

Inspiring build! Looking good so far 8) Merry Christmas everybody :)

Ok so, two questions: 1. In Rod's book he says to put fibreglass insulation in between the double glazing. Is is a big deal if I don't get all 4 surfaces with insulation? I can get the two sides...but the top and bottom... I'm hoping to get a glazier out this coming week to put some 12mm laminate glass in. 2. Door handles/levers. What's the deal? I'm most likely going with just the one beefed up door. I could do a heavy duty roller latch...but how do I make that a secure door? I was looking at lockable lever handles...but then I have to cut through the whole door. What's the go? Electrician should be in on Monday to get me wired for sound...and lights etc. AC guy next week. Also...I made these. And I was thinking of making something like this... So close to the end I can smell it!

he says to put fibreglass insulation in between the double glazing. Is is a big deal if I don't get all 4 surfaces with insulation? I can get the two sides...but the top and bottom...

Think of it this way: That space is a large resonant cavity... without insulation, there is no damping... :) What are those shiny white surfaces top and bottom?

I was looking at lockable lever handles...but then I have to cut through the whole door. What's the go?

Electro magnetic latches... :) That's one way to do it. Some are just surface mount, others need a through-hole, some fit in a pocket on the edge of the door, or embedded in the frame. Or you could put an ordinary mechanical surface-mounted latch. Or if you really have to, you could drill through to have a typical latch set on your exterior door, as long as you do it carefully and choose a latch that has plenty of mass to it, with a good, heavy sealing plate on both sides.

Also...I made these.

Nice! Solid wood? Also, I'm assuming you made them the correct height so that the ACOUSTIC AXIS or your speakers will end up at 1-2m above the floor? I'd also suggest putting some Sorbothane pads under your speakers, carefully sized to decouple them as well as possible.

And I was thinking of making something like this...

"Ladies and gentlemen, welcome aboard. Please fasten your seat-belts, pay attention to the 'No Smoking' sign, and place your tray table and seat back in the upright position.... " :) :thu: - Stuart -

Soundman2020 wrote:

Think of it this way: That space is a large resonant cavity... without insulation, there is no damping... :)

Yeah, I thought you'd say that...so I worked it out. I wrapped some fibreglass insulation in calico. And I had 12mm laminated glass installed.

Soundman2020 wrote:

What are those shiny white surfaces top and bottom?

We call that paint... :shot:

Soundman2020 wrote:

Nice! Solid wood? Also, I'm assuming you made them the correct height so that the ACOUSTIC AXIS or your speakers will end up at 1-2m above the floor? I'd also suggest putting some Sorbothane pads under your speakers, carefully sized to decouple them as well as possible.

Yes, solid wood (MDF core, clad in reclaimed hardwood), and yes, at the right height. Question: When you say, 'carefully sized'; how does one do that? The dimensions of my speakers are; H:323mm W:305 D:222 Weight 5.5kg Also, I have power on now... My door is in progress... And...I made this... I have to get the switchboard upgraded before I can get my AC installed, so a couple of weeks before that can happen...sigh! Going to start testing once the door is finished.

I started doing some testing...with this set-up The mic is at the 38% mark and 1.2m high. I've got some proper sorbothane feet for the speakers on their way. I measured the room empty then with super chunks in then with the back wall loaded up. I used the lower density stuff for these. This has the lower density stuff capped off with higher density (approx 25 kg/m^3) Here's a link to the MDAT file https://drive.google.com/a/aquinas.vic. ... sp=sharing It seems I seem to have a large problem at 50Hz... :shock: Questions: Am I doing the test right? (see top pic) How does one deal with 50Hz Any thoughts on the data so far? How does one deal with 50Hz anyways. Next is to make some panels for the walls - first points of reflection.

Here's a link to the MDAT file

I downloaded that and took a look, but the data does not seem to be very useful, since you did the tests at a very, very low level. According to the data, all your tests were done at around 50 dB. It needs to be 85 dB. You need to re-calibate REW correctly, using a proper hand-held sound level meter, then repeat all of those tests. - Stuart -

Thanks again for taking the time Stuart. Well - take two - I calibrated this time :oops: The last tests were run at around 95dB...I just didn't do the calibrate thing. Anyways...here's the new measurements. https://drive.google.com/a/aquinas.vic. ... sp=sharing There seems to be some weird stuff going on below 60Hz :shock: The levels increased after I added the corner bass traps...!? The empty room shows a non-symmetrical bass response...but the room is symmetrical..except for the ventilation vent at the front of the room. Anyway, that disappears, and there is a big boost at 50Hz after adding treatment. What the..!? I'm guessing a hard backed cloud will be happening as part of the treatment. I have a 2.4 x 1.2m panel of 50mm Bradford Ultratel http://bradfordinsulation.com.au/~/medi ... sheet.ashx I was thinking of using for that...at around a 20 degree angle (low end toward the wall).

there is a big boost at 50Hz after adding treatment. What the..!?

... It looks like you tripped over the cable and broke it!! That is a pure, perfect 50 Hz tone that never dies away, nor even decreases slightly. It is constant level, forever. You can see all the odd-order harmonics, crystal clear, at 150 Hz, 250 Hz, 350 Hz, 450 Hz... All doing the same thing: carrying on flat, forever.... You live in Australia, where the power mains is 50 Hz... Do the math ... 2+2 = Mains Hum! (And serious). I'm surprised you didn't hear that! 50 Hz mains hum at 90 dB should be deafening!

The last tests were run at around 95dB...I just didn't do the calibrate thing.

Even allowing for the loud mains hum, your actual test levels are still only around 70 dB. I think your sound level meter is broken. Can you get hold of another one, one that is known to be accurate, and use that to calibrate REW? Are you SURE you are using it properly? Is it set to C and slow? Do you have it at the correct location, distance and angle when you take the readings? So unfortunately, we still don't have usable baseline data! First you need to find the source of that mains hum and eliminate it, then re-calibrate REW and your system to produce 80 dB at each speaker individually, which means there will automatically be 86 dB with both speakers running. - Stuart -

Soundman2020 wrote:

there is a big boost at 50Hz after adding treatment. What the..!?

... It looks like you tripped over the cable and broke it!!

Sigh. The mic was faulty. I didn't actually listen through the mic directly myself...but when I did :shock: ...there it was...50Hz all the way. So I'm waiting impatiently for a replacement at present. Anyhoo...some progress pics. I designed a wall panel frame that looks like this... And, when I found out the hanger I wanted to use cost $18 each...I designed an adaption of the design using off-cuts, that looks like this: So the frame hangs on it like this...I. am. a. genius! I've been working some ray tracing on grid paper and doing some pre-emptive placement of the panels...of course it all comes out for testing. AC goes in this week... :yahoo: Question: Is an angled hard backed cloud inevitable in this sized space (L:5300 W:4400 H:2300mm)...or do I wait and see what the tests reveal?

AC in...testing and treatment under way. Here's the REW data...v3.0 - New mic and I think I got the calibration thing right... :horse: https://drive.google.com/a/aquinas.vic. ... sp=sharing Next two panels will be an angled cloud over the desk/listening position as well as a cloud just in front of the couch at the rear wall. I'm looking for input here: I have a 2400 x 1200 x 50mm panel of Bradford Ultratel fibreglass insulation that I was planning on fixing to a 16mm panel of MDF for a hard backed cloud. My thinking is to angle it about 20 degrees and have it be over the desk area...starting about 200mm from the front (facing) wall. Yes? No? Maybe? Or could it just be put flat to the ceiling?? The room is sounding pretty good so far - there is a small flutter echo that I think the clouds will deal with - I had the smaller one up in place just to listen and it seemed to deal really well with what I was hearing at the back of the room. Stuart, I'd be real curious to hear your analysis of the REW data. I think this really is getting to the finish line... :shock:

Well it's getting pretty exciting here at studio build central.... :yahoo: Hardbacked cloud is in - 18mm MDF back with Bradford Ultratel 50mm fibreglass insulation on the front. I put 3.5 of the 70mm Soundscreen batts up on top as well. 2 of 5 I'm hoping to fit into the space. Mirrors the layout on the opposite wall A little sign I found at a 2nd hand shop. So....whatdayathink? Looks alright? Not bad for a rank amateur IMO! 8) It sounds awesome so far. I had a listen to a range of different tracks yesterday, and the left right imaging as well as the sound stage are both really clear. The bass seems OK, but I still reckon there could be some improvement to be had in that area. The MDAT file is here - it's got a load of tests in it - all Left / Right / L&R. https://drive.google.com/a/aquinas.vic. ... sp=sharing Question: I've got a couple of big dips that I'd love some advice about. How does one deal with such things? Are they significant enough to worry about? I think I've dealt with all of the first point reflection for both the mix position and for the couch. Plus the test results seem to show a reasonably smooth response throughout...but I'm no expert (still working that learning curve)...Stuart...what say you?

You are getting quite a nice improvement there! The rear wall had a major effect on that, and it is coming along pretty well. What are the final dimensions of your room (inner leaf hard surfaces? The modal response (empty room) doesn't seem to fit the original dimensions you gave... Also, what are the final positions of your speakers and mix position? (in relation to the front wall, side walls, and height)?

The bass seems OK, but I still reckon there could be some improvement to be had in that area.

Yup. True. It can be better. Some of what you are seeing seems to be SBIR, so it might be a good time to do some tweaking of your listening position and speaker positions. First, try moving your mix position a bit, forwards and backwards, to see if there is a better (smoother bass response) location in the general vicinity of where you have it now. Then try moving the speakers a bit further apart / closer together, while making to corresponding adjustments in the angles. You should be able to get a bit of improvement there. However, it also looks like you have issues with the side walls: you might need more bass trapping on those. I would use the wall/ceiling corner for that. Your cloud could also be angled a bit less, and moved a bit closer to the mix position (a bit further away from the front wall). For example, try it with an angle of about 15°, and maybe 25cm from the front wall, then again at 50cm from the front wall. Tweaks like that can often get you unexpected results. Also, what speakers are those? How do you have the rear panel controls set right now? There's one more piece of magic that we can do when you have finished with everything else... PM me about that... :) - Stuart -

Right... I moved speakers around and listening position....then I moved the cloud forward...and I'm getting a much better room response..I think. Room Dimensions (hard surfaces) W:4435mm L:536mm H:2290mm (height varies a lot across the room...this an approx average) The speakers are currently 1200mm from the side walls and 700 mm from the front wall, with the mix position about 1700mm from the front wall. Question: My speakers are further apart than I am from them...I think I've read that this is bad? I'm around 1450mm from each speaker while they are around 1850mm apart. When I moved them closer together, the bass response got way bumpier than at this distance. When I listen to music the separation seems reeeeally good, vocals are dead centre and the sound stage is excellent. In fact, I think it's really showing me the limitations of these speakers - Mackie MR5's. Speaking of which...here's the settings on the back of the Mackies I put an LED strip on the back of the cloud to show off my feature wall. Here are some pics of the side treatment... I think I'm about done. Just gotta finish the guitar gallery and a couple bits of trim. Then it's time to rock \m/, I've added some REW measurements for the geeks out there... 8) ...I know..it takes one to know one... :roll: https://drive.google.com/open?id=0B1XmY ... 2lOUDcybGM

Regarding Speaer distance - Mike Stavrou summed it up best for me. He (RE: "Mixing with your mind") spoke about the sound "Ribbon" Imagine a long plank that you can put your speakers on. You sit in your listening position and have two people push and pull the speakers in and out to find the best spot. If they are too close then the sound "bulges" in the centre, if they are too far apart, then the middle sounds weak and the stereo effect is too pronounced. I've seen the "Equilateral triangle" diagrams as well, but the "sound ribbon" makes sense to me and can be proven by actually doing it. If you can't move the speaker positions, you may find moving the chair back and forth may create the same effect. I would suggest experimenting and then marking out the "best" chair position. Hope this is of some help

Imagine a long plank that you can put your speakers on. You sit in your listening position and have two people push and pull the speakers in and out to find the best spot.

Then again, you could just calculate the best position, based on room dimensions, speaker Q, treatment, and SBIR... Which was done way back, several pages ago ...

If they are too close then the sound "bulges" in the centre, if they are too far apart, then the middle sounds weak and the stereo effect is too pronounced

Not if you calculate correctly, and toe them in correctly to keep the acoustic axis intercept in the right location. Contrary to popular belief, there is not just one fixed position that works, nor one fixed angle. There's a fairly broad range of distances and angles that are usable. They key is to minimize SBIR by setting up the speakers in the best relationship to the front and rear walls, with correct treatment, locate the mix position correctly, then test with REW and tweak as needed, according to the actual acoustic response of the room, rather than based on internet myths and old wives' tales...

I've seen the "Equilateral triangle" diagrams as well,

The concept of that triangle is basically correct, but the way they are drawn in most texts (and copied all over the internet, out of ignorance) is usually wrong. It's fine for people who have had their ears surgically relocated into their eyeballs, but for the rest of us with our ears still located in the same position where the good Lord put them originally, the typical "equilateral triangle" is wrong.

you may find moving the chair back and forth may create the same effect.

That would not be a good idea if you do it more than a couple of inches, since the mix position location is fixed initially based on the minimal modal response position in the room, in most cases. And since the majority of home studios are built inside small rooms, moving your chair back is going to put your ears in the central null of the room, as well as reducing the round-trip distance to the rear wall, likely putting the reverberant field timing inside the Haas time, thus messing up your psycho-acoustic ability to determine directionality even more. - Stuart -