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

[formica]

Here is another shot of the rear of the equipment rack, with the doors

open. Power cables will run down on the right hand side and audio

on the other.

Above the doors at the top of the rack (facing the closet side) there

is room for my sub's pro power amp (it's 2R high but could easily fit a

3R one) Below the doors there is also has a closet facing shelf

which has enough room to fit a standard PC.

I'll probably be using several shelves for software, as I don't own that much audio equipment... but thought I'd plan ahead.

[formica]

Have you had a chance to fire up the projector yet?

Give it a quick once over if you get a chance to make sure everything

is OK with it... just in case.

Yup I did the weekend I brought it home... and the image looks

fantastic. I'm glad I pushed it back to be able to maximize the

2.35:1 image. Unfortunately (or maybe I should say fortunately) I

don't have any audio equipment setup in the room... so my testing was

image only... and much less addictive. I still managed to put one

hour onto the bulb.

I don't know if I had mentioned it in the other thread, but having seen

the AE900U's reduced SDE in the store really convinced me it was worth

the hassle.

More pics... here is the window panel in. (white screw caps will be painted to match)

[formica]

Building a woofer hole-plug for my IB manifold since I have 6 drivers

but 8 holes. I changed my design several times... and now regret

not having bought the 8 originally.

[formica]

I threw a party, and many woofers showed up... but some just didn't belong...

[formica]

Maybe they could try again when they grow up... (that's a Heresy K22 woofer next to the IB15's)

[formica]

This is what the manifold looks like with the drivers installed. The

manifold was designed with the rear drivers' baskets facing inwards to

create a more compact design... as well as display some of the

engineering that went into them.

I will eventually put grills on them... but I'm pretty pleased with the final appearance.

[formica]

Here is a closeup of one manifold with three drivers. For those

with keen eyes, you will notice I haven't wired them up yet, as I'm

missing some hardware. Therefore, no comments to how they sound

yet...

That's all for now... i can't wait to get this thing running...

ROb

[DrWho]

"which" IB15's are those?

[sfogg]

Glad you are happy with the AE900. It does through a great image and the smooth look from the Smoothscreen is very nice.

"he manifold was designed with the rear drivers' baskets facing inwards to create a more compact design... as well as display some of the engineering that went into them."

Probably too late now but for v2 consider doing push-pull with the drivers... one facing in, one facing out. It is claimed to reduce distortion caused by the suspension/spider of the driver itself. M&K uses that in some of their subs (and mains) for example.

BTW.... do you sleep?? That room is looking great and is just going to shock you when you get it finished!

Shawn

[formica]

"which" IB15's are those?

These are actually the first series using left over Lambda parts like

the phase plugs and heavy poly cones (ie: phase plug = no vent

hole). I don't know how they compare to the later versions... but

their T/S remained pretty unchanged.

consider doing push-pull with the drivers... one

facing in, one facing out. It is claimed to reduce distortion caused by

the suspension/spider of the driver itself. M&K uses that in some

of their subs (and mains) for example.

It's doable, but I'm unsure if the benefits would justify the

costs? In other words, I agree that doubling my drivers to 12

units in push-pull layout will reduce distortion, but so would using

the twelve units conventionally (reducing their excursion by

half). In conventional subs, the push pull setup also benefits

from smaller enclosure requirements (about half) and therefore less EQ

but this is less of a concern with an IB.

Wouldn't mind throwing in a rotary sub though... []

BTW.... do you sleep??

Actually not enough, but that is another story... [^o)]

ROb

PS: I'll be up and running as soon as i can get someone to help

haul a pair of Klipschorns into the room... and a little hook up time.

[gaspr]

Fantastic job on the home theatre Rob. Really awesome and

inspiring. Lots of great ideas here. Can't wait for you to

describe what it sounds like. If you crank it, I could

probably hear it from here!!

Thanks for sharing with us.

Garth

[formica]

A quick update the equipment is in!

Yup, moved and plugged it all in, as well as ran a couple of quick SPL

checks. With all that, and my hectic life, I haven't gotten to

watch my first movie yet, but I did run a couple of 2 channel CDs.

Soundstage seem quite a bit better... but the room is a little

live. Sub moves some serious air... but it also vibrates the

entire home and my new Rattle Riddled Room (RRRR). Soundproofing

seems almost useless given the possible intensity. I was

concerned that there would be less tactile feel on the concrete section

of the subfloor... but that won't be a problem.

Unfortunately at louder volumes, it'll also shake the projector so I'll

have to explore a different mounting method so that'll be less affected

by ceiling vibrations. Other than that, the next major steps now

are... watch a movie, chase down the 5,000 rattles, make new

interconnects of proper length, and get some furniture.

Later..

ROb's RRR

[Guest " "]

looking good...better get it done before the candles, mirrors, dry plant arrangments, empty shaby-sheek storage units, glass bead trays, etc show up.

[DrWho]

shaking the whole house...lol

So how is your current projector mounted?

[formica]

better get it done before the candles,

mirrors, dry plant arrangments, empty shaby-sheek storage units, glass

bead trays, etc show up.

Believe it or not, I'm the actual "decorator" of the house... so I've

got a pretty good reign there. Mirrors BTW are out (as well as

glass vases)... they make too much of a mess when the fall off. [8-|]

shaking the whole house...lol

Gave Tool's new album "10,000 Days" a quick spin before heading out to

work today and the IB / Khorns were loafing along at 119db (C

weighed, slow). The rattles were pretty unnoticeable at that

volume. [] I haven't scanned it with Speclab yet... but

it's a bit compressed... I'm guessing pretty strong 40 to 80Hz content,

with a little stretching down to 20Hz.

OTOH, the bassy start to Massive Attack's Angel is problematic for

rattles since there is very little content other than the bass to drown

out the vibrations. Pot lights and the door separating the back

wave seem to be noisiest.

So how is your current projector mounted?

Because I moved the projector back a couple of feet, it's support

partially leans on the ceiling with resilient channels, which I'm

guessing is the source of the vibration. I'll have to open the

ceiling up and attach to the actual joists. Unfortunately the

hush box I couldn't use, is rigidly attached to the structure and acts

as a cross brace to boot...

Later...

ROb

[sfogg]

"It's doable, but I'm unsure if the benefits would justify the

costs? In other words, I agree that doubling my drivers to 12

units in push-pull layout will reduce distortion, but so would using

the twelve units conventionally (reducing their excursion by

half). In conventional subs, the push pull setup also benefits

from smaller enclosure requirements (about half) and therefore less EQ

but this is less of a concern with an IB."

I didn't mean adding any additional drivers. I mean out of each pair of woofers flip one of them so it was firing into the room from the other side of the cone and of course invert the polarity to it.

M&K does this with some of their woofers and they claim it reduces distortion from the woofers themselves. The mechanical distortion of the surrounds/spider becomes out of phase between the two drivers (one pushing, one pulling) so it cancels each other.

Shawn

[DrWho]

It's probably too late for this, but have you considered decoupling your motorboards from the actual wall? With it coupled you would really need to build that entire front wall like a huge speaker cabinet.

[formica]

I didn't mean adding any additional drivers. I mean

out of each pair of woofers flip one of them so it was firing into the

room from the other side of the cone and of course invert the polarity

to it.

I misunderstood it as a clamshell (isobarik / push-pull) layout.

Right now, I do have 4 of the 6 drivers physically inverted (with the

correctly inverted

polarities)... And I'm looking to see if I can't find 2 more so

that I can have a symmetrical 8 total (4 per channel would also give me

4ohms versus 12ohms now).

It's probably too late for this, but have you

considered decoupling your motorboards from the actual wall? With it

coupled you would really need to build that entire front wall like a

huge speaker cabinet.

It's not too late as I actually thought about that...

I don't remember what page it's on but the manifold is bolted to the

concrete floor rather than the wall. The wall itself is entirely

covered in glued-n-screwed oriented strand board on the backside... as

well as both corners on the front side. I'm willing to admit that

the trim work isn't entirely decoupled though... but I doubt it's

capable of transmitting that kind of vibration.

Gave Tool's new album "10,000 Days" a quick spin

before heading out to work today and the IB / Khorns were loafing

along at 119db (C weighed, slow). The rattles were pretty

unnoticeable at that volume. [] I haven't scanned it with

Speclab yet... but it's a bit compressed... I'm guessing pretty strong

40 to 80Hz content, with a little stretching down to 20Hz.

A quick scan of the album in Spec lab showed the bulk of it's bass

content is actually in the 50Hz to 100Hz region but it does extend casually down to

20Hz. BTW, the 119db was more of a test as it is VERY loud (even

with a compressed recording)...

I gave Breakbeat Era a quick spin this morning... a much more

dynamic sounding album with strong bass content down to about

10Hz. It did provide a much better feeling of the capability of

the Khorn / IB combo... which both still seemed to loaf along

regardless of the volume. Excursion was visible... but very

reasonable.

So far... IB's do live up to their hype... [8-|]

More to come...

ROb

[formica]

Ok, I haven't updated this thread in a while either... but I have had a

chance finish connecting everything and making some repairs, but I

still haven't started on the decorating or the calibration.

Calibration will be a little tricky since my desktop is upstairs and I

no longer have access to a laptop. I did run the typical built in

test tones in the processor and DVD but it just provides a general

level calibration. I'm not sure if I trust the processor, as it

seems a little hot on music but I'll see more once I get a PC plugged

into the line level inputs. I'm also looking at getting a DVD

image calibration tool like AVIA or the like. Any

recommendations?

For now, I turned off the "sharpen" tool in the OPPO DVD player because

it seemed to pixelate the edges of the text. I remember reading

something about that, but can't find it now.

After quite a few movies and even more albums I am very pleased

overall, even before the calibration. The video image

is great, the khorns sound much happier now (imaging is quite a bit

better on a wider wall), and the subwoofer really is a step above

anything I've played with.

Unfortunately at louder volumes, it'll also shake

the projector so I'll have to explore a different mounting method so

that'll be less affected by ceiling vibrations.

Ok, I've opened up the ceiling and remounted the unit. The

mounting looks just as neat, but it is now directly attached to the

joints. It makes a big difference, but I can still get the unit

to vibrate certain syth bass at high enough volumes. But then

again, I can get the structure to vibrate too... because I can:

shaking the whole house...lol

With some more testing... would you believe it's not the IB, but mostly

the Khorns? Their corners are braced, sheathed both sides in

oriented strand board, glued, screwed, and mostly attached to the

floor. I think the weak point lies in their connection to the

joists at the top. I tried to minimize those connections during

construction (trying to create a weak link) but a link all the

same. I know I'm asking for a lot... but got to aim high.

OTOH, the bassy start to Massive Attack's Angel

is problematic for rattles since there is very little content other

than the bass to drown out the vibrations. Pot lights and the

door separating the back wave seem to be noisiest.

Started addressing the light fixtures... it's pretty time consuming and

annoying. I found that keeping the bass playing helps to track

down the problems... but just gets a little repetitive. I haven't

yet attacked the door in a major way, just applied some weather

striping for now.

I also finished a floor repair, paint touch ups, installing my power

centre, etc... it doesn't look dramatically different but the

details are falling into place. I'll try to get some more

pictures soon...

I'll also have to start researching the furniture thing too...

I'm thinking a love seat flanked by two singles and recycling my

existing sofa out back.

ROb

[picky]

Rob: I'm sorry to hear that rattles are giving you so many fits. I know Dr. Who made a great suggestion in that the motor boards of manifold should be decoupled from the wall (and the room) but, I would guess that's not an option at this point. You must somehow be hitting the structure's resonant frequency to make the whole house shake as it is.

Although, I realize that your issues in the room are not funny, there is a similar, amusing story that occurred years ago to inventor, Nikola Tesla. At one point, he had his laboratory on the third floor of a New York office building on the South end of 5th Avenue. One day, he wanted to perform an experiment on a new, large oscillator he had invented. He broke through the ceiling of his lab and secured the oscillator to the iron beam of the building. As he began sweeping the oscillator using various frequencies, bricks began to fall to the sidewalk below and windows began to shatter. The affect was not so apparent to Tesla who was in close proximity to the epicenter of the now quaking building. However, when he looked out of his window, he noticed a crowd of police officers on the ground below, motioning for him to come down immediately! Tesla had apparently discovered the structure's resonant frequency and he was virtually shaking the building apart. I certainly hope you have better luck. -Glenn