John Sayers' Design Forum

John Sayers' Recording Studio Design Forum

A World of Experience
Click Here for Information on John's Services
It is currently Mon Dec 16, 2019 7:24 am

All times are UTC + 10 hours




Post new topic Reply to topic  [ 99 posts ]  Go to page 1, 2, 3, 4, 5 ... 7  Next
Author Message
PostPosted: Sun Jan 11, 2009 4:11 am 
Offline
User avatar

Joined: Wed Dec 06, 2006 6:22 pm
Posts: 144
Location: Berlin, Germany
Allrighta,

I recovered some links and want to share my thoughts...
Back to my room. Start with calculations:
area: 17 m² = 183 sf
volume: 50 m³ = 1765 cf
refresh rate/h 11

to calculate cfm use: refresh rate * volume / 60

that makes ~324 cfm
in SI Units:
550m³/h -> 9,2m³/m -> 0,1533m³/s

to calculate air velocity I used
this
or
this
-> 960 fpm @ 20cm / 7.87" (314cm² / 0.338 foot²)
-> 480 fpm @ 28cm / 11.13" (628cm² / 0.676 foot²)
-> 240 fpm @ 40cm / 15.75" (1256cm² / 1.352 foot²)
This is what i get with the different diameters/cross-sections in my ventilation plan.
Of course this is calculated for max needs but I don't expect that I really need 11
refreshs per hour and I don't know what kind of pressure (static or back, i have no clue)
the silencers and ducts will add to the system.

But my "conclusion" is that the fan I selected (see below) should be capable to handle
the needs...shouldn't it :?

Fan:
Helios RR 200 A
820m³/h (free air movement)
380PA max pressure
in my case: 550m³/h @ max ~ 170 PA

Now that i know these figures I can figure out some problems with my silencers and the
ventilation plan.

FIRST:
About exchange chambers:
Rod's answer on Philper's post:
"You don't need fans on both the inlet and return - either one will work
fine - but part of what makes the system work is that the chamber becomes
pressurized - and that along with the slight negative in the room of interest
causes air to flow."


and

"That is the reason that ducted air conditioning system have return air ducts -
basically - what goes in - has to come back -
in huge commercial systems sometimes - we might do 100% fresh air to a space -
but then that means we need 100% exhaust to balance it out........
But it is impossible to do 100% exhaust and thingk that you could ever draw all
of that air through cracks under doors, etc......... and even if you could - that
doesn't create enough negative pressure in the room to steal it from another room
with NO free air in it."


-> Now, my understanding of this is:
It's ok to have 1 fan sucking air out of the room IF there is the possibility to
get the same amount of fresh air back! If, let's say, there's a window in the room
from where fresh air should be pulled in, make sure that the opening at least matches
the size or is capable to deliver 100% of that what has been taken from the rec room
without any problems, resistance, whatever.
And if the window is closed don't expect the fan to do it's job properly...

btw Dan Fitzpatrick did this in his studio, too -> look here
or directly in his thread starting here.

SECOND:
Inlet/Outlet size, silencer details:
Rod's description -click here-
Rod's post on TomM's drawing 1 post later:
"If you size the outlet the same as the inlet you will not acheive the
2nd goal (2. slow down the velocity with the intent of quieting the
ruch of air into the room.) - the velocity will step up to exactly
the same as it was before"


and another good description from Rod -click here-


-> note to me: think about WHERE velocity change is important.
my Fresh air supply (notes 'bout what I have to change and what is ok):
- general velocity change of 1/2
- inlet (in control room) cross-section is ~628cm² (according to 2x diameter of fan (20cm->314cm²)).
- I should adjust the interior of the silencer to the same crossectional size (not double the size).
- outlet of this silencer should be same as inlet
- short flex duct
- inlet of "silencer to recording room" same size
! now another velocity change to 1/2 !
- interior double that size
- outlet (rec room) according to interior size -> meaning to me -> double the size of silencer's inlet

upper silencer will be hung from ceiling with isolation hangers and will only have direct contact to
ctrl room wall. silencer to recording room will be mounted to framing of rec room and won't have any
contact to concrete or ctrl room wall.
details:::(no changes made yet)
Attachment:
fresh-in-01.jpg

Attachment:
fresh-in-02.1.jpg


Exhausted air:
- it is important to lower the velocity from the point on entering the silencer respectively it is
important NOT TO CHANGE VELOCITY at this point
- ergo double the inlet's cross-section (so they are the same size as the interior -> change from 314cm²
to 628cm²)
- take care of abrupt change in cross-sectional area (see notes below) -> redesign outlets
! velocity change !
- outlet will stay the size it is right now (314cm² -> because of the fan's diameter 20cm -> 314cm²)
- each silencer's outlet will have a Flex Duct
- to bring the 2 Flex Ducts together I'll need another "box".
- interior is the same size as the 2 inlets
! velocity change !
- outlet same size as 1 inlet
- short Flex Duct
- connects to standard round aluminium duct (240cm long, diameter 20cm)
- inline fan
- short duct ~40cm through brickwall

silencers will be direct mounted to the framing except "the box" which will be hung from the
ceiling with isolation hangers
details:::(no changes made yet)
Attachment:
exhausted-01.jpg

Attachment:
exhausted-02.jpg


further useful informations:

"Avoiding abrupt changes in duct cross-sectional area"
good link from AVare: Apr26, 2008
quote taken from HVAC Acoustic Fundamentals, page 76 (PDF-File!)

-> personal note: redesign silencer's inlets and outlets evtl look for products


About Flex Duct:
Same PDF-File as mentioned above, page 40:
"Flex duct is a very good sound attenuator, but it also allows a significant
amount of duct breakout (see Duct Breakout Sound Path, page 44). For this
reason, it is a good idea to limit flex duct to no more than 5 ft. (1.5 m)."


This confirms what I've read from Rod and several others not to use Flex Duct
on long runs. But it's ok to use it for short interconnections.

-> note to me: interconnections will be fine with Flex Duct. :)


still unanswered:
- will I run into (acoustical) problems with my fresh-air supply plan?
- will silencers and short flex ducts cause any high pressure problems that
the fan can't handle?
- should I just quit the plan on having ventilation? I mean...I just can open
the doors?


more to come...

Regards,
Carsten


You do not have the required permissions to view the files attached to this post.


Report this post
Top
 Profile  
 
PostPosted: Fri Apr 03, 2009 2:49 am 
Offline
User avatar

Joined: Wed Dec 06, 2006 6:22 pm
Posts: 144
Location: Berlin, Germany
hello all,

three weeks ago my wood arrived.
tomorrow will bring me gypsum and insulation.

and here are some shots :)

more soon...
Attachment:
K640_IMG_7475.JPG

Attachment:
K640_IMG_7468.JPG

Attachment:
K640_IMG_7522.JPG

Attachment:
K640_IMG_7568.JPG


You do not have the required permissions to view the files attached to this post.


Report this post
Top
 Profile  
 
PostPosted: Fri Apr 03, 2009 7:24 am 
Offline
Senior Member
User avatar

Joined: Thu Jan 04, 2007 6:37 pm
Posts: 883
Location: Regional Victoria, Aus
are you worried that your room is not Symmetrical?
[edit] sorry just saw that it's the live room.
my bad

_________________
inkspotproductions
www.bantamstudio.info


Report this post
Top
 Profile  
 
PostPosted: Tue Sep 01, 2009 10:43 pm 
Offline
User avatar

Joined: Wed Dec 06, 2006 6:22 pm
Posts: 144
Location: Berlin, Germany
well ladys and gents,

I'm still alive and have to say:

building a studio IS PITA!

but I guess you all know what I'm talking 'bout.

anyways.
I'm glad that I did...ouch...sorry... do it.

Since middle of march I'm working nearly every damn day from early to late and now I think
the end is coming nearer.
Sorry for no posts or pics of my work so far but I absolutely had no time to post anything.
I guess and hope that in a few days I can slow down with the work and relax a little.

Don't want to leave without a few piccis.
some impressions of my work hope - you like.

cheers and greetings,
carsten

Attachment:
2of4doors.JPG

Attachment:
doorframehinge-detail.JPG

Attachment:
doordetail-no1.JPG

Attachment:
doordetail-no2.JPG


You do not have the required permissions to view the files attached to this post.


Report this post
Top
 Profile  
 
PostPosted: Tue Sep 01, 2009 11:10 pm 
Offline
Senior Member
User avatar

Joined: Sat Mar 29, 2003 12:26 am
Posts: 2073
Location: Netherlands
Wow, they look sharp!
Could you tell more about your hinges and the door? Is it custom made?
We need detail, DETAILS you here me! :yahoo:


Report this post
Top
 Profile  
 
PostPosted: Tue Sep 01, 2009 11:49 pm 
Offline
User avatar

Joined: Wed Dec 06, 2006 6:22 pm
Posts: 144
Location: Berlin, Germany
:)

they are...

I made the doors by myself.
3 layers MDF (19mm - 16mm - 16mm)
where the hinges are i glued hardwood - beechwood - trapezes (dovetails) in (pics are
@ home. I'll post em later)
4th and 5th layers are only MDF-stripes 'round 10cm wide

Attachment:
gluing 4th layer.JPG


the hinges are made by Simonswerk. (VX7729/120 - 120kg load capacity)
I shot em on the bay for nothing (10 axial-radil slidebearing hinges: 4,50€ (not the piece...
for all!!!)
and the reiceiver-elements cost me 10,-€/piece

you can simply adjust everything with these hinges. I'm really glad I bought these!
can't imagine what had happened as I hung the 1st door without these.
the door was too far left, too high and too near...omg :shock:
but hey :D you got your superduperspcial looper....turn a few screws here and there
and after 15 min the door fitted precisely.

sorry for being a little short right now. but I'm in the middle of sawing and gluing the 5th
layer :)

cheers,
carsten

here are a few more pics:

Attachment:
receiver element.JPG

Attachment:
hinge and door 1.JPG

Attachment:
hinge and door 2.JPG


You do not have the required permissions to view the files attached to this post.


Report this post
Top
 Profile  
 
PostPosted: Thu Sep 03, 2009 1:17 am 
Offline
User avatar

Joined: Wed Dec 06, 2006 6:22 pm
Posts: 144
Location: Berlin, Germany
howdy!

here are some pics of my door leaf construction.
the main leaf consists of 3 leaves of MDF (19mm/16mm/16mm - as mentioned above).
I chose 19mm for the first leaf because my beechwood dovetail is 28mm thick and due to my hinges
size it was best to place the beechwood with a distance of 7mm from the top of the door leaf. So
all screws can be screwed straight into the dovetail. Next reason was that the next MDF leaf
(16mm) only had to be sawed with my festool plunge cut saw and just the 1st leaf had to be routed.
I layed both MDF plates on the table adjusted the dovetail took the routing guides fixed 'em
and sawed straight through both plates. now I had one plate cut and the other one was marked so
that routing was pretty simple.
Attachment:
detail-02.JPG


after routing I put the 3rd leaf on it and drilled a bunch of holes for the screws through the plates.
time to glue the beast.

glueing was a bit tricky. i did it with a putty so the glue was more like a film not like
sausages on wood...
you have to be fast. i mean FAST. my girlfriend helped me but we were too slow i guess.
a few spots were already dried as we put them together.

for the next door leaves i chose to glue only 2 leaves per time instead of all three. and that
was a good decision. glueing was far better and way faster (although i did it alone...).

darn... the screwing and glueing pics are @home.

anyway.

more to come in short.

cheers,
carsten

Attachment:
detail-03.JPG

Attachment:
detail-01.JPG

Attachment:
topview.JPG


You do not have the required permissions to view the files attached to this post.


Report this post
Top
 Profile  
 
PostPosted: Thu Sep 03, 2009 5:26 pm 
Offline
Senior Member
User avatar

Joined: Sat Mar 29, 2003 12:26 am
Posts: 2073
Location: Netherlands
ah, now I get it. Those pictures say it all. Nice work!


Report this post
Top
 Profile  
 
PostPosted: Thu Sep 17, 2009 10:55 pm 
Offline

Joined: Mon Jun 08, 2009 6:09 am
Posts: 113
Location: South West of France
Grear job on the door Carsten! One question for you - you obviously research what you do A LOT so I'm interested in picking your brain :shock:
You felt the need to fit dovetail insets in your MDF door. I understand that you did it because MDF is quite weak on the edges. You have 5 screws per hinge going in the door, and I assume that you fitted 3 hinges in the door. If we don't count the bottom hinge as the pull is mostly from the top, we have 10 screws which for a door of 100kg is a pull of 10kg/screw.
If they were big enough and long enough, do you still think that the pull would be too much or did you do that to play safe? I'm only asking because my door are made of 4 sheets of 25mm MDF, ie. total thickness of 100mm, ie. a weight per door of... 150kg :mrgreen:


Report this post
Top
 Profile  
 
PostPosted: Fri Sep 18, 2009 12:24 am 
Offline
User avatar

Joined: Wed Dec 06, 2006 6:22 pm
Posts: 144
Location: Berlin, Germany
thanks TheFrenchVoice.

yeah. indeed. researched A LOT and now my brain feels like irish stew.

paul woodlock used hard wood inserts in his doors.
Ro used plywood.
and I thought: that's too easy ;)
a dovetail is a very strong joint and since I knew my doors will be heavy (of course not as heavy
as yours) I decided for the dovetail to be "a little more" on the safe side.
I use only two hinges. their total load capacity is 120kg (I guess per hinge). my doors are roughly 90kg.
the screws are the recommended 5mm x 60mm.
I haven't built anything like that before so I had to rely on what the manufacturer wrote in
their construction papers.
I guess the manufactures always calculate the capacitys with some headroom and so did I.
my doors are overkill anyway. I use double doors. (my build has 2 leaves with only 2 layers of gypsum)

I don't really understand your question (sorry...):
Quote:
If they were big enough and long enough, do you still think that the pull would be too much or did you do that to play safe?

did what to play safe?
using 5 screws/hinge?

I think as long as I use what a hinge manufacturer recommends I can't be wrong. and I don't
really think that chosing longer and stronger screws would maximize any kind of load capacity...

hmm...don't know if this answer was helpful... :roll:

greetings,
carsten


Report this post
Top
 Profile  
 
PostPosted: Fri Sep 18, 2009 1:04 am 
Offline

Joined: Mon Jun 08, 2009 6:09 am
Posts: 113
Location: South West of France
Cheers Carsten - I used to be carpenter many many moons ago so I know all about dovetail - but not mechanical properties of MDF as MDF didn't exist back then!

My question was if you put those insets to play it safe, or because you thought that the five screws per hinge going in the door were not grabbing the MDF enough and that the door would free itself from those screws and fall off?

Bigger and longer screws would have a stronger grab, but not sure if grab would be enough, hence my question!

BTW when stating maximum loads, hinge manufacturers usually mean for three hinges per door, two on top spaced by around 10cm and 1 at bottom (for maximum load carrying capacity) - for technical specs on hi-load hinges click here - those specs apply to all hi-load hinges, not only those of this brand, so this is quite handy!


Report this post
Top
 Profile  
 
PostPosted: Fri Sep 18, 2009 2:23 am 
Offline
User avatar

Joined: Wed Dec 06, 2006 6:22 pm
Posts: 144
Location: Berlin, Germany
now I got it.
I did it because of both :)
I'm not a carpenter but have a little experience in working with wood so I knew by some experience and of course by
reading that MDF isn't that strong on the edges. so I did it as some people here and on other boards suggested.

Quote:
BTW when stating maximum loads, hinge manufacturers usually mean for three hinges per door,

doh...for short my heart stopped beating...you think two hinges aren't strong enough?

c.


Report this post
Top
 Profile  
 
PostPosted: Fri Sep 18, 2009 4:15 am 
Offline

Joined: Mon Jun 08, 2009 6:09 am
Posts: 113
Location: South West of France
LOL Carsten don't worry too much, it's bad for your arteries. It just means that your two hinges will wear much faster (if they're rated at 120kg load @ 3 hinges as it's almost always the case for hi-load - best is to check with the manufacturer). Also remember that if you use a door closer then you should apply the adjusted door weight (and not actual door weight) for the total load. So, if your door is 90kg and you have a regular door closer the adjusted weight is about 120kg, bang on the rating of your hinges... if they are 3 of them (again, check that I'm not talking baloney!)

If you choose to fit a third hinge then I'd say, forget inserting a dovetail inset, just do a rebate in your door and use extra long quality screws to fix the hinge to your door (the way it's shown in the pdf file I attached the link of in my previous post, ie. two hinges on top one at the bottom). That'll give you added piece of mind that your door won't fall off on a customer. Which is not nice. Especially for them.


Report this post
Top
 Profile  
 
PostPosted: Tue Sep 22, 2009 6:56 pm 
Offline
User avatar

Joined: Wed Dec 06, 2006 6:22 pm
Posts: 144
Location: Berlin, Germany
hey TheFrenchVoice,

I just got an answer from the manufacturer of my hinges and he says:
Quote:
...der Belastungwert ist immer eine Referenzangabe für den Einsatz von 2 Bändern an einer Tür 1 x 2m.

in english:
load capacity is always a reference data for the use of 2 hinges on a door 1 x 2m :)

my arteries can relax and my customers can come...

greetings,
carsten


Report this post
Top
 Profile  
 
PostPosted: Tue Sep 22, 2009 7:35 pm 
Offline

Joined: Mon Jun 08, 2009 6:09 am
Posts: 113
Location: South West of France
Carsten, sometimes in life we get lucky. That was one of this times for you! Having said that not a lot of work would have been involved fitting a third hinge, but it's always good to know that you're safe the way it is isn't it?


Report this post
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 99 posts ]  Go to page 1, 2, 3, 4, 5 ... 7  Next

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 14 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group