or Connect
New Posts  All Forums:Forum Nav:

Downunder Theatre MKII - Page 9

post #241 of 283
Thread Starter 
The Mitsubishi I have can do fresh air, but I wanted something to run 24/7 and also to vent the hush box so went with the ERV. Uses the same amount of power (apparently) as a 75w light bulb
post #242 of 283
" I've not plugged it in yet so cannot comment on noise, that is more to do with the duct design IMvHO. It has a fan speed controller built in."

Can you get lined duct where you are? Look for a commercial heating supply. It is ducting that is 2" (5 cm) bigger per cross section dimension and has 1" (2.5 cm) rigid fiberglass sound insulation all around on the INSIDE of the duct. So a 6 x 8 duct would be 8 x 10 O.D., but still 6 x 8 on the inside. Use at least one 90 degree going into your room and one going out of your room. This should pretty much kill direct noise from the fan and most of the reflected sound (2 90's would be better). Also, if you could increase the duct size for at least the last 4 - 6 feet, that would slow down the air speed and oversize the duct grill to minimize the rushing sound. You are dealing with the same volume of air/minute, it is just travelling slower at the end, and therefore quieter.

It was suggest to me to do the supply from the ceiling (several ports, front and back) and return from the floor (from the front of a riser and up a column, for example).
post #243 of 283
Thread Starter 
Hi Jim,

Thanks for that. Yep, I am going to make my own ducts lined with 50mm of 48kg^m3 insulation. The plan is to:

1. 150mm x 150mm (effective) supply and return ducts (for both the AC and ERV)
2. The AC supply will dump into a large "box/plenum: above the screen with 2 bar diffuser vents
3. The ERV supply will come in, split into two and have boxes/grills in the soffit, at the front of the room
4. The AC return will be similar to the ERV supply, but at the back of the room
5. The ERV return will "dump" into the hush box with 2 lines running out of that, into the soffits and then 2 bar grills at the back of the room

.....too hard to get the returns down the bottom at the back of the room unfortunately.

Edit: the ducts will be made from 17mm ply, two layers with GG. Then waterproofing, then insulation, plastic membrane, insulation. So 318mm in total (square) with 150mm round PVC pipe in the ends to hook up the AC/ERV.
Edited by Elill - 12/15/13 at 1:04pm
post #244 of 283
That should to do it! smile.gif

So you aren't using any columns in your decor that you could use as a duct to suck air from the floor (if you are in the basement, this will help keep the room warmer as well (if you get any cold weather)) or have access to space outside the back wall. As you probably know the best circulation results from taking return air from the furthest point possible from the supply and not forgetting to mixing air top to bottom.

Nice table, by the way!
post #245 of 283
Thread Starter 
Originally Posted by just jim View Post

Nice table, by the way!

Thanks....Its sitting in a corner under a whole heap of stuff now.....the corners are "sharp" and with an 18 month old girl running around the two don't mix unfortunately.

Regarding the columns - these will probably be pretty large subs so no go there....waiting for Erskine Group to confirm all that (January with a bit of luck)
post #246 of 283
Thread Starter 
Last pre-Christmas delivery arrived this morning. This lot came from Bruynzeel, its excellent quality and cheaper than Bunnings. I am really impressed with the quality of the CD structural stuff - no voids on the edges and the faces are (a) in very good condition (b) very high quality for structural ply. The delivery guy helped me lift it all up into the garage too! high recommended, give Glen a call.

Here are the ceiling joists that will sit on top of the room-in-room frame:

post #247 of 283
Good to see Santa came early ... but bloody hell you've got a lot to do over the hols !! biggrin.gif

post #248 of 283
Peter M. Why not come to my place over the break, have some beers, watch some movies and discuss how busy poor Pete will be.

Sent from my SM-N9005 using Tapatalk
post #249 of 283
Elill I forgot to ask where are you getting your Beyma coaxial speakers from?
post #250 of 283
Thread Starter 
Originally Posted by chrapladm View Post

Elill I forgot to ask where are you getting your Beyma coaxial speakers from?

These guys:


I've not ordered yet, but the communication has been first class. Prices are really, really good too.....I was looking at a US based supplier, but its like paying freight to go round the world twice wink.gif
post #251 of 283
Thread Starter 
Originally Posted by Dingaling2004 View Post

Peter M. Why not come to my place over the break, have some beers, watch some movies and discuss how busy poor Pete will be.

Sent from my SM-N9005 using Tapatalk

Originally Posted by Peter M View Post

Good to see Santa came early ... but bloody hell you've got a lot to do over the hols !! biggrin.gif


Peter, Peter, Peter, you've got that all wrong it should be "... but bloody hell WE've got a lot to do over the hols !! biggrin.gif

Careful, I have both your phone numbers!

P.S. For the sake of being polite, both Greg and Peter (and others) have graciously offered to help
post #252 of 283
Thread Starter 
Originally Posted by Dingaling2004 View Post

discuss how busy poor Pete will be.

Oh yeah, and "poor" certainly is the right word, $12k has gone awfully quick......this soundproofing, fresh air, cooled room caper is expensive!.....that excludes the AC as well..... frown.gif
post #253 of 283
Can you PM me the price?

I know a dealer here in OZ and I can see if he will better the price. I usually order 18 Sound speakers from him. He uses Beyma also. And everytime I have order a 15" from him his price beats the online price at USSpeakers.com before shipping.
post #254 of 283
Thread Starter 
So for 6 8CX300ND's with 6 passive crossovers its 1169 Euro including freight. That's about A$1800 depending on rate.

Compared to US$400 each (speaker and crossover) plus freight!

They're a LOT cheaper than I was expecting, which is good, as I have had other blow outs. I was thinking of doing 2 ways, but its like $6,000 in drivers alone, plus extra amps, dsp channels etc.
post #255 of 283
Wow that is a great price. I was looking at getting a pair of 8XC20's or 10XC25's. I also would need the crossovers but that price is great for your coaxial. I will find out Monday what my local dealer can do. I hope he can match that or I am definitely going with them. I was also looking at possibly getting the Beyma SM110/N pair for my horned midbass in a 2way speaker build.

Do I just need to send them an email for pricing?

I don't speak French.biggrin.gif
post #256 of 283
Thread Starter 
Just email, I will PM you the guy's address/details. English is no problem.
post #257 of 283
Thread Starter 
A little update, finished the DD/GG for the "under floor" section today. With some luck I will start the ducts/HVAC tomorrow. I need to:

1. Move the AC, its pointing the wrong way
2. Install the ERV
3. Build the ducts/dead vents

The last point is causing me a lot of angst, I am just going to build them and with a lot of research and some luck it'll work ok. Going to be all "stiff" ducts (DIY as mentioned above somewhere) with the "elbows" to be made from 150mm (6") PVC pipe, which I'll then wrap up in insulation

P.S. Thing I have learnt so far:
(a) if drywall doesn't fit, beating the crap out of it is going to end in tears
(b) whenever dealing with drywall on a ceiling, wear glasses - getting dust in your eyes makes for a really unpleasant day's work

Oh yeah and I got 2 boxes of 1,000 decking screws (bungle head) from this joint, they're excellent quality and walk all over the crap you get from Bunnings - the square driver/head is good too:


I've often wondered how many screws a bloke should get from one box wink.gif
post #258 of 283
HI Elill, the screws in the link are actually called flat head. The little ribs on the underside of the head is a modification to help countersink the head in particle board or wood. They are not the bugle head used for Drywall screws and should not be used for Drywall. The bugle head is curved much like...well exactly like the end of a bugle. biggrin.gif

If you are finding the construction of the ducts daunting...I had mentioned the sheet metal ducts that come lined with 1" rigid glass insulation. This stuff is NOT the flimsy crap from the local building supply. You would need to source a commercial heating supply and you should be able to specify the weight of the galvanized metal it is made from. A heavy gauge will be very solid. It should be cheaper than building it out of plywood and the insulation is already permanently in place. You just assemble sections with "S" and "C" clips and tape. The corners are pre-lined as well. You are comparing 1/8" total metal to at least 1" total plywood, so it is significantly smaller. If you need to hang something off it, punch the screw hole with an awl instead of drilling. The metal is curved in by the awl and you will not be able to pull the screw out! The supplier would also have the canvas isolators to connect the machinery to the ducting without conducting the vibrations.

Good to see that our far superior Robertson (square) head screws are finally getting around. smile.gif All of our wood screws are Robertson, although most of them are now made of Taiwanesium, just north of you guys. South of our boarder, pretty much everything is the inferior Phillips (X) head. (a shameless plug for Canada! biggrin.gif)

...but sometimes beating the crap out of the DW just feels good...admit it! biggrin.gif

P.S. if an edge of the drywall is a little too tight...put a 2 or 3 foot piece of 2 x 4 along the edge and hit sharply with a hammer. This should distribute the force and keep the DW from breaking as it is finessed into place.
post #259 of 283
Thread Starter 
Hi Jim, many thanks for the comments.

I got those screws for the ply, I had planned on using them for the second layer of drywall too.....perhaps I should get some drywall screws for that

In terms of the duct work......its interesting, I rang several places about 3-4 weeks ago asking for quotes for sheet metal ducts and the price was either prohibitive or the time was way out there, hence the reason to DIY from ply.
post #260 of 283
Because of the shape of the taper on the wood screws, they would pull right through the Drywall. If you put a drywall screw in so that it is just below the surface and then take it out to look at the paper surface of the DW, you will see that the screw has pulled the paper in without tearing it. It is the strength of the paper that permits the screw to hold up the DW. Do the same with a wood screw...

Too bad about the metal. I guess with the volume of it being used in Toronto, the price is competitive...or is our plywood that much more expensive? The prices (I think it was you) mentioned for plywood seemed pretty cheap.
post #261 of 283
Thread Starter 
Started the ducts today, 2 nearly finished. Double skinned (mostly) ply, with GG in between. 150mm PVC pipe to connect to systems/ERV

One of these is the AC supply and the other is the ERV return. The other returns/supplies will be a little more complex. Next step is to cover insides with waterproofing.

post #262 of 283
Looking good Pete. But is that still a big pile of fyrchek in the background?

Sent from my SM-N9005 using Tapatalk
post #263 of 283
Thread Starter 
Big pile of everything! frown.gif
post #264 of 283
Thread Starter 
I am a few days behind on photos (plus having done nothing yesterday). Here is a shot of one of the ducts, lined with polyester insulation. The other shot is just another WIP of the ducts themselves.

Today I have put all bar 3 of the ceiling joists in (perhaps I'll get to it later if the cranky one permits me another hour), I say "in" they're cut and placed in place. Need to glue and screw. The the job I got done this morning which was a hurculean effort was getting the ERV/hush box return vent in. Its the biggest and heaviest. Has 2 sheets of 19mm ply in it, water proofing, two joists, and the lining. In other words is one very, very heavy MOFO. It took some physics of my forefathers, and possibly the Egyptians to get it in place, but its done now......had to take the PVC out of the end which was a pain, but shouldn't be too hard to get back in and nicely sealed.

Speaking of PVC, I got some nice large 150mm storm water "elbows" today, they have a real nice "bend" to them which will assist with air flow (not an acute 90 degrees, they "sweep").

Oh and I moved the internal AC unit (facing the wrong way) and put the EVR on a suspended "shelf" (the crate it came on hanging from joists with steel strap). Its fans are quite powerful, but have speed control. I am quite impressed thus far.
post #265 of 283
Can't wait to see some pics from inside the room Peter. Good progress on the ducts
post #266 of 283
Originally Posted by Elill View Post

Here is a shot of one of the ducts, lined with polyester insulation.
Is that rated for HVAC? (will fibers get loose)

What's your 10 year duct cleaning plan?
post #267 of 283
Thread Starter 
Originally Posted by BasementBob View Post

Is that rated for HVAC? (will fibers get loose)

What's your 10 year duct cleaning plan?

Yep, it is HVAC "rated"/designed for this purpose so no drama's there.

There is good access on the other side of the wall to the ducts if we need to get in for cleaning, but its unlikely according to the engineer.
post #268 of 283
SO are you done with the ceiling yet? Its been 12 days.biggrin.gif
post #269 of 283
Thread Starter 
Nah still plugging away with the HVAC. I'm back at work.....

Good progress today though, I hooked the AC supply up. The airflow is good.....well by my "hey that feels good on my hand test". It'll dump into another plenum above the screen with two registers in it.

All of the ducts are now up and in place with the exception of two little sections that are fiddly. With some luck, next weekend I'll have all of the HVAC work done.

- cables
- insulation
- ply
- gg
- drywall
post #270 of 283
When was the last time you had your hand calibrated?tongue.gif
New Posts  All Forums:Forum Nav:
  Return Home