Formica's Audio / HT room... the construction

[formica]

Ok, after talking about it for months as I planned out the concept, I

have finally reached the stage of starting construction. The

intention of this thread is to cover both the design and construction

of the room.

For those expecting a no compromise room... you will be disappointed as

this is a renovation rather than a new construction. The room

will consist of several recuperated rooms in the basement of my 1950's

urban home. Space is at a premium as well as ceiling

height.

The first drawing here consists of the existing spaces I have to work with.

Anyone who has built a similar room (there are actually quite a few on

here, but Picky's comes to mind) will know how much planning goes into

choosing which compromises work best for you.and getting everything as

good as you can make it.

Given my post will be lengthy... I'm going to divide it up into multiple smaller posts over the few days.

I'm open to all comments... as you never know what you missed, BUT note that I have started the work.

I hope someone finds this interesting

ROb

BASEMENT - Existing.pdf

[formica]

Part 1: Room layout and Main Channel Placement:

I will be using Heritage all the way around for my room, with Klipschorn mains and Heresy effects.

Klipschorns... what is there to be said about placement... they go in

the front corners, right? As wide a wall as possible,

right?

Well I ran into quite a few compromises right from the start..

I live in an older home with only a 6'6" basement... with the main

supporting columns and beam (which runs under the joists) dividing my

basement down the centre at 13'. The columns are at about 12' c/c

and there is only 5'11" under the beam.

Given the existing rooms I want to conserve, I can widen the room to a

maximum of 16' and have the beam run within my space at about 3' from

one side wall. The depth OTOH is pretty flexible. As some

can see from the drawing, the column will acoustically interfere with

the right channel for anyone sitting in the right rear position.

Rotating my room to face the other axis isn't really possible if I want

two rows of seats. That would also cause the only seats to

be in the resonant peak up against the back wall.

I've done the calculations to eliminate the column... and the resulting

beam would be to large to install under the joists. Replacing the

entire beam and column to lie within the joists would be quite labour

intensive including temporarily supporting the home on two floors for

over 22'. In other words, a lot of costs that wouldn't be recoverable

when I do sell the home.

I did not consider the option of using Cornwalls as mains given that I

actually have some but was surprised at the improvement khorns had in a

compromised (13' wide upstairs) room versus them. So surprised... that

I kept both pairs in the same room for several months in case I was

mistaken. Khorns simply had sharper and cleaner (less thumpy)

bass with a better transition between bass and mids.

I saw two remaining options...

1) consider focusing the Khorns by building a

double angling the front wall to fit the Khorns 13' apart but place the

sweat spot at 8' to 10' back (a sort of built-in false corner which I

posted in another thread).

2) or widen the room to a true 16' and live with the column (5"x3") for the rear seat.

I've opted to keep it simple and optimize for the front seats where

I'll be > 95% of the time. I will be leaving the steel

structure exposed, for a somewhat industrial look... which should match

well my recycled pine look floor.

I know it's a compromise... but it's a question of balancing the

options (cost, space, usage, etc...) If any of you

come over, I promise to sit in that rear right seat... []

ROb

BASEMENT - Proposed.pdf

[formica]

Part 2: Furniture layout:

Ok, although this will serve as a dedicated music / HT room... I don't

live in a modern sprawling suburban home. In my 1950's urban

home, space is limited... so dedicating this much footage is difficult

to do, and this room will continue to be used for family

gatherings.

Although not weekly, I do need to have a flexible furniture plan that I

can rearrange and be able to fit a long table. This rules out a

fixed raised platform for the rear seats, as well as an equipment rack

in the middle of the room.

With only 16' width across the front, I will probably also slide

furniture around depending on whether I'm watching a movie or listening

to music. Viewing movies at the 8' to 9' theoretical acoustic

sweet spot is a little to close for my taste (I'm aiming 10' to

11'). It's not as complicated as it sounds; I currently do the

same thing in my upstairs living room.

This also allows me to turn all the furniture towards each other (in

typical living room fashion) in case we are entertaining friends rather

than looking at the screen.

I'm considering two recliners up front, and recycle an existing sofa out back.

ROb

[formica]

Part 3: Centre Channel:

Given my room isn't overly tall, I was faced with having to find a

shorter than a typical heritage centre in order to retain a reasonably

tall screen. When I say "typical", I'm referring to the Belle, LaScala,

and Cornwall.

I'm aiming a 40" screen and a 30" tall centre or less.

I could use a heresy (which I currently have), a Cornwall on it's side

(ie: a vertical Cornwall II) or build a custom unit in the lines of the

Cornscala. The way I figure it, a Cornwall would be very wide

(see subwoofer design below) and the Heresy is a little wimpy.

OTOH, the Cornscala would be the best match sound wise, and building my

own cabinet would give me the most flexibility.

I did a couple of quick calculations, and I'm pretty sure I can keep it

under 28" high and slightly narrower than that... but it would be as

deep as a LaScala (using the same K400). I may lower the Cornwall

bass bin tuning just a bit... and flatten it's thumpy response as I

don't want it's bass to overpower the mains. With ±24" inch depth

I found it would protrude a bit too much into the room... so I looked

into partially encasing it. I don't want it fully flush either as

I'd like to maintain the "design" polar response of the mid horn. The

proposed design will create a somewhat circular speaker placement up

front.

Initially I will continue to use the Heresy, and will build the CCCS

(Centre Channel Corn-Scala) only once everything is up and running.

[DrWho]

wow, talk about a few dilemas [] FWIW, I think that pdf of your

proposed layout is the best way to go. The only modification I would

suggest is in regards to your IB subwoofers...you really are going to

want to mount them in a vent facing each other so as to reduce

"cabinet" vibrations. That or you're going to need to do some insane

bracing. I would also suggest not having that cubby hole which is going

to resonate at a certain frequency. Eyeballing the dimensions it looks

to be around 55Hz which will be in a range excited by the woofers. I

suppose with that center channel in there it becomes less of a concern

(more like a 150Hz resonance). I just don't like the idea of your

center channel cabinet affecting the sound of your subs...who knows,

maybe I'm over thinking the issue []

So are these heresy surrounds going to be hanging from the cieling?

With a 6' roof you're gonna have to duck around them when moving around.

(btw, are you sure with the dimensions? that seems mega mega short to me)

[picky]

Rob: I like what I see in your plan, but I have to agree with Dr.Who: Loose the cubby. It'll only become a haven for standing waves and buzzing.

Also, the cut into the next room (towards the bathroom) to gain the 16' width scares me because the ceiling will have to drop so low to get beneath that beam. That whole area could become a "bass haven". Removing that wall is also what reveals the pole in the first place. Can you compromise and build a complete wall along that surface with a door in it to get to the bathroom and other areas and then keep the main room 12' 6" wide instead? Heck, that is still 2 feet wider than my room and your room is much deeper than mine, thereby giving you more room to work with and you'll still have your 2 rows of seats. My room is 10-1/2 feet wide and I have 2 RF-7s and a 78" screen along the front wall. They fit perfectly in that tight space. I would think you'd have room for the two KH's and your 40 inch screen with the 12-1/2 foot width. Leaving that right wall straight removes a lot of problems.

[formica]

Glad you two guys dropped in... [] this may clarify some items (the drawing is partially to blame... [])...

Part 4: Subwoofer design and placement:

I like bass. The music I love has plenty of it and movies always have

their share of effects. From the start, I planned to have a no

compromise subwoofer for my room. The only way I could accomplish

this and remain in budget while fitting it into my space, was building

an Infinite Baffle.

I won't go into the theory of those (as many of you already know what's

involved) but that is the reason for the storage room behind my main

screen wall. I've purchased 6 AE IB15's even though the space

will only provide ±5 times VAS as I can increase the volume to more

than 10 times VAS by leaving the door open to the other adjacent

room. This will also provide an interesting experiment in seeing

if there is a measurable difference between the 5 and >10 x VAS.

Although bass isn't "supposed" to be directional... I opted for a

symmetrical front installation to avoid any risk of localization due to

any harmonics and imperfections. Given the middle spot is already taken

by the centre channel, I require two manifolds to keep thing

symmetrical. Again I'm limited to 30" height maximum and a

relatively narrow space (16' wide room - 48" Khorn mouth x 2 - 30"

centre = 2'9" each side) to fit them.

Ok, here I've tried several different concepts and have come up with the following compromise.

Mike, you brought up several good points, which concerned me too...

particularly on the difficulty in bracing such a large beast... and the

risk of it resonating. My actual IB manifold shop drawings

(which I'm attaching with this post) are much more complex than what

was initially drawn onto my floor plan. I decided to separate the

centre recess from the two manifolds... which allows internal bracing

at ± 18" c/c. I will also be lining all the plywood panels with

MDF and bracing the exterior with some pine stripping (not all drawn

in). The centre recess will simply be braced with 2x3's.

By placing the drivers tight against the semi-encased centre, it will

provide bass coupling (+3db), provide a non-obstructed space at the

rear, and I can still have some mechanical force cancellations for the

opposing drivers in my heavily braced manifold. Using two

separate manifolds pushed the subs to far out into the Khorn's mouths

if I wanted to recess the centre. In theory, each manifold

should still be within coupling distance with the mains at 80Hz... as

well.

The design has 4 drivers stacked over each other in each manifold...

with space for 8 drivers total, Some may notice that two stacked

15" won't fit into a 30" tall manifold... and they won't... but I will

reduce the height of the opening to match the centre. It will

still be more than large enough to act as an IB.

Part 5: Rear effect loudspeakers:

Nothing special in this department... Heresy I 's for all

four. Sides may be wall mounted... but rears will be on custom

stands. You are right about ceiling mounting being dangerously

low. I'm even worried about the projector itself...

The rear-effects would have to be moved out of the way when we have

family over but can stay put for friend gatherings. At the

moment, my processor only does 5.1... so I won't be using them all, but

I will eventually upgrade it.

ROb

PS: one of the items i haven't decided on is equipement placement...

that's why there are the three options. I'm leaning towards #1...

more to come...

IB15 manifold - with centre - r3.pdf

[DrWho]

so you going with 6 or 8 woofers? do the pictures show 8? if not, then I'm reading it wrong []

Btw, I like equipment location 2 a lot more for two reasons. First,

location 1 is on an outside wall where you will be more prone to water

damage (if it were to ever occur). Second, location 2 allows for rear

panel access through the closet. I know the IB's are back there so

you'll have to put a door on the back of the rack, but it would make

your life so much easier on so many levels. It also brings your

electronics closer to your main speakers, which cuts down on costs and

possible signal degredation. The only downside is that you might see

the lights off to the side when watching a movie...but a tinted glass

door would work wonders.

And do you have WinISD? If not, I can drop you some screenshots of how

the drivers model up. We're talking +-1dB with some pretty drastic

changes in the rear volume so you should be fine. In fact, the smallest

acceptable volume per driver would be around 10 cubic feet, but ideally

would be 20. 5x and 10x the VAS comes to 80 and 160 cubic feet per

driver respectively. With 6 drivers you're looking at 118dB with 200

watts! [H] (max at 80Hz limited by cone excursion at 10Hz...with room

gain that should easily be 118dB at 12Hz).

[michael hurd]

You must have missed where he said he purchased 6, but there will be room for 8 in total, if he feels the need to "upgrade" in the future.... muhahahaha. []

[formica]

Also, the cut into the next room (towards the

bathroom) to gain the 16' width scares me because the ceiling will have

to drop so low to get beneath that beam.

The existing ceiling (including the bathroom nook) simply has the beam

boxed in below the finished 6'6" height. I agree that boxing-in

that whole area would make it look uncomfortably low. I'm

actually planning on lightening up it's "visual mass" even

further by leaving it exposed on one side. It'll be very

"industrial loft" in styling... but you'll have to trust me on this

one. []

I'm still trying to work out my final ceiling plan layout... for

both lighting as well as I'd like to have it partially black.

My room is 10-1/2 feet wide and I have 2 RF-7s and

a 78" screen along the front wall. They fit perfectly in that tight

space. I would think you'd have room for the two KH's and your 40 inch

screen with the 12-1/2 foot width. Leaving that right wall straight

removes a lot of problems.

That was similar to my initial idea... to just extend the room

the 12'6" width... and then partially angle the screen wall so that the

Khorns would be focused at 8 to 10' back. Cornerhorns are

trickier to place given their fixed 45-degree angle... as a 13'

wall places my sweet spot 6'6" from the screen. That created a

number of other challenges in construction, imaging, as well as

modifying the horns' theoretical mouth.

BTW, that was the most difficult compromise I had to take.

Neither was perfect... and it'll be impossible to compare. In the

front seats, I'm pretty convinced the 16' room will rule...[]

ROb

[formica]

Part 6: Equipment rack:

Here is one item I'm not really decided on yet... but I'll have to be making a decision soon.

The electrical work is right around the corner, as I finishing

demolition and don't have a lot of rough carpentry to do. I will also

be rewiring a significant portion of my basement in general, given I've

stripped my walls and ceiling. It'll give me the opportunity to

uniform'ize what's been done by previous owners during several

renovations.

Btw, I like equipment location 2 a lot more for two

reasons. First, location 1 is on an outside wall where you will be more

prone to water damage (if it were to ever occur). Second, location 2

allows for rear panel access through the closet.

There are positives and negative for both those spots...

Location 1 is actually directly below my existing electrical panel on

wall... and building a larger multi piece cabinet around it, would give

it visual purpose. In other words, something has to go in that spot...

media or equipment. I would have to make the equipment rack

mobile so I could slide it forward to get to it's innards but hooking

up would be more tedious.. This spot would have the shortest runs

to the projector.

Location 2, like you mentioned, would provide a good rear access... but

the equipment would be installed very high on the wall (above a Khorn,

next to the screen). Loading CDs and DVDs would require a good stretch.

The rack could be built independently from the wall for vibrations. It

could also include several rear facing spaces for equipment I intended

on installing in adjacent rooms... like the IB's power amp and it's EQ.

This spot would have the shortest runs to the main speakers but

technically would not allow for a TT (even though I'm not into vinyl).

Part 7: Projector and screen:

As I posted in a thread in the HT forum, I'm totally new to

projectors... but I have narrowed down several features I'd like. I

would like a ceiling mounted unit so that I can leave it in place

regardless of the furniture as well as possibly build a hush box for

it... exhausting into the next room.

I originally wanted to have a constant height projection... (40" x

variable width) but I have since learned that I'd require a motorized

zoom, which unfortunately surpasses my PJ budget (1600$ or

less). I will have to live with 16:9 format.

For the screen, I'm simply going the painted wall initially... and I'll

see later down the road. I'm not keen on the "acoustically

transparent" screens as they degrade both the image and sound..

So my current layout with the centre below will work with either a

purchased or DIY screen.

Right now I'm considering the Panasonic AE700 or the Sanyo Z3 because

of their vertical shift lens and 720p capabilities, but nothing is set

in stone...

I'm still open to recommendations.

Still more to come... including some pictures eventually.

ROb

[psg]

Hi Rob,

This is a long thread, so I'll just say what comes to mind now. But I'll be following this as it unfolds!

Your room will rock! I think 16' will likely be enough, but if

you want I can push my KHorns in 2 feet to see what they sound

like. I agree that you'll want to move your seating to the single

sweet spot for stereo music when you are alone. But that's not a

big deal.

I don't know the first thing about infinite baffles so can't comment about that. Sounds like it will shake the house!

One of the things I love about my own setup is the rear access to the

equipment rack, even if I have to stretch over a couch to insert a DVD

or CD. So that's the option I'd go for. However, I have

gotten used to NOT having equipement lights in front of the

room. Having gear up front looks cool but it's distracting

when watching a movie, especially dark scenes.

I have wall-mounted my center Heresy with a simple but effective design

and will be posting a thread when I can get pictures (I broke my

digital camera last winter). You'll want to see that, I'm use.

[sfogg]

Rob,

May be too late for this but...

Getting into the bass design....

What are your proposed crossover points with the K'Horns? Does your pre-pro/receiver offer the option of stereo subwoofers.

Bass is more or less non-directional below around 80hz *but* there are other components to the perception of bass then just gross localization.

Stereo bass down to around 40hz is perceivable with the difference in perception being in the envelopment/spaciousness of the bass vs. an 'in the head' feeling of mono bass.

Mono bass reproduced from the centerline of the room from the perception point of view is about as bad as it gets. You get equal energy and no interaural time differences in the bass.

However... if you are say crossing the K'Horns at 40hz so that material below 40hz goes to the IB and the IB also receives the LFE channel then this likely isn't a big deal since you still have stereo bass response down to about 40hz with the K'Horns.

If you are planning on crossing the K'Horns higher up then it becomes more and more of an issue. If you don't have the ability for L/R stereo subs in your processor/crossover then it may not be worth considering too.

"I've purchased 6 AE IB15's even though the space will only provide ±5 times VAS as I can increase the volume to more than 10 times VAS by leaving the door open to the other adjacent room. "

Costs more but you can also cut the VAS of the drivers in half by compounding loading them. Basically double the number of drivers ($$$$) and mount them front to back (reversed phase) with an airtight spacer between them.

Couple other things to consider....

A) Riser for the back row? Gives better site lines both to the screen and for audio.

If your walls are open consider running additional wiring to each row of seating for bassshakers/buttkickers at a later date. Even with extremely potent subwoofers these can be a lot of fun and add to the experience for not terrible money.

C) I don't know how easy wiring will be at a later date by try to plan ahead. If you can run conduit that is great to be able to pull cables easy later on.... esp. for the projector in case you ever move from component to DVI or HDMI...etc...etc. Make sure you run a male/female (female end at projector) 1/8" mono cable to the projector. You may want to do some IR relay and you will need that cable. One the same note be sure to run at least a three conductor cable to the front of them for a IR receiver if you decide to do IR relay with equipment at the back of the room, in a closer, external to the room...etc...etc. Even with equipment in the room IR relay is really nice to be sure macros work seamlessly.

D) Consider running a composite cable and a two wire cable to either a fairly nearby wall location or to up near the front of the room to feed a small external LCD display. This can be used for the OSD of your equipment without having to turn on the projector or having the display appear on the projected image which is really distracting IMO. A 7" $100 unit of ebay will work perfectly fine for this.

E) If you are planning on building a hush box for the projector and are able to do it completely seal it to the ceiling and run intake/outlet air ducts in the ceiling to take/exhaust the air completely outside of your room. This will make it even quieter and also prevent it from heating the room. I do this in my setup and it is great.

F) Lighting.... nothing makes the experience like pressing 'Play' on the remote and having the house lighting automatically dim down to movie level. In my setup if you hit 'Pause' the lights dim up somewhat... hit stop and the house lights come up to full brightness over 60 seconds time. For simple setups PCS SceneMaster dimmers work extremely well. They are controlled over X10 so there is no need to run additional control cables. Each dimmer is around $80 and the IR to X10 controller you will need is around $30. You also need an additional box to program the scenes in the dimmers which I think is about $20. Multiple controllers can have their scenes overlap such that sending a single command will dim each controller to different lighting levels and they can also have their fader times set differently as well. This can be added at a later date as long as you already have the lighting/sconces and such you want and installed on their own switches as desired for later control.

Good luck and have fun.

Shawn

[formica]

This is a long thread

I put a lot of planning into it and I also tend to get wordy sometimes...

Your room will rock! I think 16' will likely be

enough, but if you want I can push my KHorns in 2 feet to see what they

sound like. I agree that you'll want to move your seating to the

single sweet spot for stereo music when you are alone.

Actually your email comparing your LaScala's on your long (18') versus

short (11'?) wall, both focused toward you, help weigh my opinion to

the 16' version. If you get a chance to bump those Khorns in a

couple of feet, I'd be interested in your perceived difference.

What are your proposed crossover points with the

K'Horns? Does your pre-pro/receiver offer the option of stereo

subwoofers.

My current preamp has a fixed THX 80Hz x-over and it doesn't do stereo

subs but I would like to upgrade it after I'm done and enjoyed a couple

of movies.

I do use the mains full range, and they roll of naturally (40Hz sounds

about right). I probably would cross them over around that 40Hz

if I had the bass management, like you proposed.

Couple other things to consider....

A lot of good points... I'll definitely try running as much empty

conduit as possible... as well as some "pull boxes". I'll try to

draw some of those, and post it in case I miss something. I

had not thought of the LCD... but definitely practical and has a "cool"

factor to boot.

Most of you guys seem to lean toward the option of having the equipment

up front with rear access. Any other options I missed,

remembering that the rear sofa is removable and the stair is only

separated by a railing?

Although I haven't talked to the 5'2" missus about it, I'm sure she'd

wonder in dismay to why I placed the DVD player above my

Klipschorns. [] I somehow don't think that's what Mike

meant with his "It's all about compromise" tag line... []

Still more to come... including acoustic treatment and acoustic insulation...

Rob

[sfogg]

There are pre-pros that let you cross at 40hz so that is an option.

"Most of you guys seem to lean toward the option of having the equipment

up front with rear access. "

I'd get it out of the sight lines in the front of the room. It of

course looks more impressive at first with racks of gear up front but

all the LEDs and everything else just end up being a distraction when

the lights are all down. Most want the front of the room as

dark/noreflective as possible to make the screen 'pop' with the

projector on.

Equipment in the rear of the room should work fine and still give very

easy access for loading CD/DVDs etc..etc. All my equipment isn't even

in my room and I ended up loving it that way. It had me concerned at

first but it worked out fine. If you do consider going that route put a

wall jack in somewhere in the room with at least a video cable and a

couple of audio cables. That way if you want to temporarily plug

something in inside the room you can do so. I have that in my back wall

and it is useful for when I'm going acoustic testing down in the

theater.

Shawn

[psg]

This is a long thread

I put a lot of planning into it and I also tend to get wordy sometimes...

It's all good!

quote user="psg"]Your room will rock! I think 16' will likely be

enough, but if you want I can push my KHorns in 2 feet to see what they

sound like. I agree that you'll want to move your seating to the

single sweet spot for stereo music when you are alone.

Actually your email comparing your LaScala's on your long (18') versus

short (11'?) wall, both focused toward you, help weigh my opinion to

the 16' version. If you get a chance to bump those Khorns in a

couple of feet, I'd be interested in your perceived difference.

I'll do that...

What are your proposed crossover points with the

K'Horns? Does your pre-pro/receiver offer the option of stereo

subwoofers.

My current preamp has a fixed THX 80Hz x-over and it doesn't do stereo

subs but I would like to upgrade it after I'm done and enjoyed a couple

of movies.

I do use the mains full range, and they roll of naturally (40Hz sounds

about right). I probably would cross them over around that 40Hz

if I had the bass management, like you proposed.

I tend to set the KHorns to large and the sub at L+R/40Hz for stereo

music, just in case the KHorns are missing anything. I don't set

them to small for movies either.

Most of you guys seem to lean toward the option of having the equipment

up front with rear access. Any other options I missed,

remembering that the rear sofa is removable and the stair is only

separated by a railing?

Although I haven't talked to the 5'2" missus about it, I'm sure she'd

wonder in dismay to why I placed the DVD player above my

Klipschorns. [] I somehow don't think that's what Mike

meant with his "It's all about compromise" tag line... []

I like rear access, but not having fear upfront. Too many lit

displays. But it's all about compromises and you'll love your

read access !

[formica]

Part 8: Acoustical treatment:

Given space limitations, the room dimensions aren't very flexible... so

the room acoustics are somewhat dictated to me. The only wall I

can really move is the screen wall by several inches either way.

I don't have access to EASE to accurately simulate my room... and given

the number bump outs and openings (including an open stair at the

rear), it's very difficult to accurately predict using standard

formulae.

I have done very approximate room calculations by hand...

without noticing any major problems. It won't be an ideal golden

ratio room, but it shouldn't be horrid either. I've decided to

build it, and then measure it's energy-time curves using a software

(probably ETF) before deciding on which treatments are required.

Without a doubt, foam by mail has me intrigued.

I'm a little concerned on the effect of the "hardness" of most of my

surfaces. Finishes will be standard gypsum for both walls and

ceiling and the flooring will be a laminated product (see acoustical

insulation section for actual compositions). I'm figuring I could

work that with some furnishings, curtains, and throw rugs if need

be.

My subwoofer will also be EQ'd using those measurements using the Behringer BFD...

next up: acoustical isolation...

ROb

[formica]

I didn't get around to typing my next instalment but i thought i'd

start posting some pictures this first batch are the before:

This picture dates from before 1999... when I was using the room as a

pool room. Looking into the bathroom nook towards the existing

utility room...

[formica]

Fireplace and stair (circa 2001)... I'm still working out a plan for those...

[formica]

Another from about 2001.. using as a ping-pong room... looking

into the bathroom nook, towards the wood covered wall which will be

demolished.