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C

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Discussion Starter · #1 ·
Introduction...


After a year and a half in my house, I've finally started in my home theater and finally found the perfect name...

The Dark Knight Theater



It started out with just as just a cool name, but has slowly morphed into the theater's theme.


I'm putting the theater in my walkout basement, which has already been framed with 2x6's. The existing raw dimensions of the room are approximately 13'6" wide by 22'6" long by 10' high. Here is the basic floor plan:



This is an ongoing project.


Reference notes and links:

Model Theaters

ReedZone Theater: http://www.avsforum.com/avs-vb/showthread.php?t=735097
Farm House Cinema: http://www.avsforum.com/avs-vb/showthread.php?t=627306
Mr.Poindexter: http://www.avsforum.com/avs-vb/showthread.php?t=640853
Steve Jenkins: http://theater.stevejenkins.com/gallery/complete/
TK Theaters: http://www.tktheaters.com/gallery/tuscany/
BigJoeMoose's Theatre: http://www.avsforum.com/avs-vb/showthread.php?t=1018914
Big Mouth in DC: http://www.avsforum.com/avs-vb/showthread.php?t=683853
DE Theater: http://blog.audiovideointeriors.com/407roof/
Helene: Prototype System of Tomorrow: http://www.avsforum.com/avs-vb/showthread.php?t=908533
Cinema Kellogg: http://web.mac.com/donkellogg/Cinema_Kellogg/Chronicle/Chronicle.html
Sandmans Home Theater: http://www.avsforum.com/avs-vb/showthread.php?t=574704
Ted White's Theater: http://tedwhite.homestead.com/
Completed theaters: http://www.avsforum.com/avs-vb/showthread.php?t=1061114
Kirk's DE designed theater: http://home.comcast.net/~kirkk/Construction1.html
Anandtech Theater Blog: http://www.anandtech.com/weblog/default.aspx?bcategory=8
The Getaway: http://www.avsforum.com/avs-vb/showthread.php?t=1022589&page=1

Theater Setup

Overview: http://www.audioholics.com/education/acoustics-principles/haa-level-i-certification-training-course-overview
http://www.hometoys.com/news_detail.php?id=14914495


From Dennis Erskine

Subwoofers -

EQ will be required plus your room design should allow the ability to move and

relocated the subs during the calilbration process. Generally, you should avoid

having the drivers point directly into the seating locations. If you do, an 1"

of fiberglass board ( like OC703) can be placed in front of the sub's driver.

These drivers create HF artifacts as a result of their operation. These

artifacts can lead to subwoofer localization ... something you want to avoid.


Comb Filtering:

The audible impact of comb filtering is very unequal frequency response within

critical frequency ranges. The same sound from two different speakers will cross

paths, and, when they do, you'll have some frequencies cancelled (180 degrees

out of phase) and other frequencies augmented (in phase) plus all the variations

in between. These cancellations/augmentations will be inconsistent throughout

the room.


Isolation:

Reducing noise entering a space and reducing noise leaving that space to

adjoining rooms is NOT mutually exclusive, nor did I say that. My point is the

REAL reason sound isolation should be employed in dedicated rooms is to reduce

the noise floor IN the room. The fact those efforts assist in reducing noise

levels OUTSIDE the room should be considered a bonus. There are some differences

between the two efforts. First, a significant cause of high noise floors in a

room are a result of the noise brought into the room by the A/V installer or

home owner ... the equipment. Other in room sources of noise include HVAC noise.

The remainder is noise entering the room from the outside which needs to be

eliminated. Second, if the sound track is at 75dB in the room, and ambient noise

levels outside the room are at 35dB, you have a 40dB problem to solve. If the

ambient noise in the room (from outside sources) is 35dB, you have a 13dB

problem to solve. Don't get excited ... that sounds easi

er than it is and when we say 'noise floor' the metric is either NC or NR which

are weighted curves across a broad spectrum of frequencies.


The desired standard for noise transmission from inside a room to the adjoining

spaces is the theater should not increase the ambient noise level outside the

room by more than 3 dB SPL

Show me your...: http://www.avsforum.com/avs-vb/showthread.php?t=978755




Sound isolation:View Distance: http://myhometheater.homestead.com/viewingdistancecalculator.html

http://home1.gte.net/res18h39/thxscope.gif
http://home1.gte.net/res18h39/calculator.htm
THX recommends 36 degree viewing angle from back row (26 degree minimum) in regular theater.





Room Acoustics: http://www.silcom.com/~aludwig/Room_acoustics.html Room Modes: http://www.wsdg.com/resources/resour.php?SL=te&BL=5
http://www.remotecentral.com/cgi-bin/mboard/rc-custom/thread.cgi?4765
http://www.scribd.com/doc/6788280/Ho...ustical-Design
http://www.cinemasource.com/articles...des/modes.html
http://www.mcsquared.com/modecalc.htm
http://www.realtraps.com/modecalc.htm
http://www.holmacoustics.com/holmimpulse.php

Speaker locations for Audyssey DSX 10.1:
Channel 1: Left Main (placed 30 degrees to the left of the system centerline, at ear level)
Channel 2: (NEW) Left Height (placed 45 degrees to the left of the center line, and at a 45 degree up-angle relative to ear level)
Channel 3: (NEW) Left Wide (placed 60 degrees to the left of the center line, at ear level)
Channel 4: Left Surround (placed 120 degrees to the left of the system centerline, at or above ear level)
Channel 5: Center Front (placed on the system centerline, front of room, as close to ear level as practicable)
Channel 6: (NEW, Optional) Center Rear (placed on the system centerline, rear of room, at or above ear level)
Channel 7: Right Main (placed 30 degrees to the right of the system centerline, at ear level)
Channel 8: (NEW) Right Height (placed 45 degrees to the right of the center line, and at a 45 degree up angle relative to ear level)
Channel 9: (NEW) Right wide (placed 60 degrees to the right of the center line, at ear level)
Channel 10: Right surround (placed 120 degrees to the left of the system centerline, at or above ear level)
The “.2” Channels: Subwoofer 1 and 2 (positioned for best in-room bass response, but typically might be positioned in left/right front or left/right side locations)

Bass traps: http://www.peparsplace.com/Pg_23.htm
http://www.geocities.com/jonrisch/basstrap.htm
http://www.avsforum.com/avs-vb/showthread.php?t=1055475
http://www.avsforum.com/avs-vb/showthread.php?p=14578163#post14578163
http://www.avsforum.com/avs-vb/showthread.php?p=14581123#post14581123
How to place: http://www.realtraps.com/lf-noise.htm
Using a riser as a bass trap: http://www.avsforum.com/avs-vb/showthread.php?t=1103345
http://www.avsforum.com/avs-vb/showthread.php?t=859771
http://www.avsforum.com/avs-vb/showthread.php?t=1029689
http://www.avsforum.com/avs-vb/showthread.php?t=1068227
http://forums.musicplayer.com/ubbthreads.php/topics/2032618/Home_Theatre_Riser_other_Broad#Post2032618

Integra Firmware Updates: http://www.avsforum.com/avs-vb/showthread.php?t=1016297

Riser Height: http://www.avsforum.com/avs-vb/showthread.php?t=505237
Riser construction: http://www.audioholics.com/tweaks/do-it-yourself-diy-topics/multifunction-theater-seat-riser

TXH general specs for home theater:
http://www.cinemaequipmentsales.com/thx2.html

http://www.cinemaequipmentsales.com/athx1.html




Picture
  • 16:9 > =36 degree horizontal viewing angle from back row (26 degree min)
  • native HD capable
  • Screen luminance > = 16ft lamberts
  • THX certified, acoustically transparent screen
Sound
  • Mid-band reverberant field pink noise
  • No audible distortion playing program material at 115dBC
  • Background noise
  • At least four surround speakers, two side and two back
User Interface
  • Remote controls with a logical user interface
  • All basic functions available with a single key stroke
Measurement
  • Video performance measurements taken using Sencore CP5000 quality gear or better
  • Audio performance measurements taken using four microphone spatial/temporal RTA techniques with 1/12 octave resolution or better.
THX interview: http://www.avsforum.com/avs-vb/showthread.php?t=969252
theater color: http://www.cinemaquestinc.com/ive.htm

LightingFurnitureCable
  • projector- HDMI, 4 CAT5e (serial control, temp sensor, future expansion), Crestnet, 14/2 romex (from double-converting UPS through power inlet), RGB, VGA, composite, 2" conduit from rack with pull string.
  • CLS-CL6- 6 14/2 romex (ambiance cans, stage cans, sconces, trey rope light, step lighting, star ceiling), crestnet for control
  • riser- romex for future power recliners and touchpanel, 2 CAT5e for touchpanel, crestnet for touchpanel, RGB for touchpanel, speaker wire for future butt kickers, romex for step lighting, 2" conduit with pull string
  • front speakers- 5 speaker cables for LCRs and subs, 2 RG6 for future subs
  • back speakers- 5 speaker cables for rears and future rears and future subs, 2 RG6 for future subs
  • side speakers- 2 speaker cables for side surrounds, 2 RG6 for future subs
  • ceiling- conduit with pull string for star ceiling cables
  • Crestnet and CAT5e from outside thermostat to inside wall for temp sensor
  • Crestnet and CAT5e from outside thermostat to projector for temp sensor
  • If HDMI wallplate needed: http://www.avsforum.com/avs-vb/showthread.php?t=967079
ProjectorHVACDrywall Info
  • Ted White- "Generally first layer is horizontal, second vertical to stagger seams.
    • Found out later that this also helps with so that the coincidence resonance is different for each layer, which is a very good thing.
  • Start with 1 layer on ceiling, then 1 layer on wall. Then ceiling, then wall.
  • Screws on first layer can be shorter than second layer. Generally most people seem to get a screw that will sink 1" into stud . That's more than plenty." (1-1/2" for first layer, 2" for second layer)
  • You only need screws that are 1/2" longer than the thickness of the drywall if you are attaching it to 25-gauge resilient channel. (1-1/4" for first layer, 1-3/4" for second layer). Don't go too long or the screw may hit the wood, which would lower the efficiency of the clips and track.
  • hanging: http://archive2.avsforum.com/avs-vb/showthread.php?t=731185
  • https://72.52.223.187/xcart/product.php?productid=541&cat=93&page=1&js=n
  • http://www.drywallschool.com/protips.htm
WallsStage
  • Keep at least 1/4" away from walls.
  • Line with plastic and fill with dry sand if subwoofer is set on stage. Can save some time/money/effort by filling only the area under the sub with sand and the rest of the stage with insulation. If subwoofer is not set on stage, or if stage is on second or higher floors, can fill whole stage with insulation.
  • http://www.avsforum.com/avs-vb/showthread.php?t=1055475
RiserCIHIf I end up with the Panasonic PT-AE3000, I will not need a lens for CIH.

Masking
http://www.avsforum.com/avs-vb/showthread.php?t=941076
http://www.avsforum.com/avs-vb/showthread.php?t=1008446

Control

http://www.guifx.com/store/products/1077
www.crestron.com

Other

Install access door in soffit for sanitary sewer cleanout.
Mark floor at studs for easier drywall and furring strip insulation.
Fidelio velvet: http://www.bymichelle.com/fidelio.html

Theater intro: http://www.avsforum.com/avs-vb/showthread.php?t=1045823
http://www.avsforum.com/avs-vb/showthread.php?t=715166
http://www.avsforum.com/avs-vb/showthread.php?t=1049435

Star ceiling:
http://www.avsforum.com/avs-vb/showthread.php?t=911313
Other painted option: http://www.avsforum.com/avs-vb/showthread.php?t=1048747

Before and after pics:
http://www.avsforum.com/avs-vb/showthread.php?t=628588


How to take screen shots:
http://www.avsforum.com/avs-vb/showthread.php?t=1024326


How to take pan shots from Duositex:

"In order for automerge in Photoshop to "do its thing" it needs the images to

overlap by 40%. Or at least that's what it kept telling me. Eventually I simply

pasted one image on top of the other and used the warp feature of CS4 (not sure

if this was in CS3 or not...) to correct for the perspective in each image. Once

they lined up ok (and I do mean ok.. its not great) I used the "Auto-Blend

Layers" feature which, I have to say, worked fantastically on the first try. If

I had more images to work with, it all probably would've come out better, but

I'm pleased overall considering it was just two.


Sorry for the verbose breakdown....


P.S. I did no color correction.. I leave that to the owner to decide since I

wasn't present when he took the pictures to know if they're at all accurate."

Video Calibration:
http://www.curtpalme.com/forum/viewtopic.php?t=10457
http://www.avsforum.com/avs-vb/showthread.php?t=737550

Audio Calibration:
software: http://www.hometheatershack.com/roomeq/
Receiver has Audyssey, so will likely just use built-in software

Audyssey Calibration: http://www.avsforum.com/avs-vb/showthread.php?t=795421
http://www.cepro.com/article/audyssey_shows_calibration_kit_for_installer_program/K29
FAQ: http://www.avsforum.com/avs-vb/showthread.php?p=14456895#post14456895
http://www.electronichouse.com/article/audyssey_dynamic_eq_and_dynamic_volume/D1/

Popcorn popper:
http://www.avsforum.com/avs-vb/showthread.php?t=1063039
http://www.avsforum.com/avs-vb/showthread.php?p=14687615#post14687615

Audio sweep tones: http://www.dr-lex.be/software/testsounds.html




Steps to completion:
  1. Design room in AutoCAD (done);
  2. Notch existing furring strips on exterior wall (done);
  3. Install insulation in existing exterior walls and ceiling (done);
  4. Frame quasi staggered stud walls (done);
  5. Install back boxes for inwall speakers (sides and rears) (done);
  6. Install isolation clips and resilient channel in the ceiling (done);
  7. Frame soffit around existing utilities (done);
  8. Electric rough-in (contracted, done 5/25/09);
  9. Low-volt rough-in (almost done);
  10. Take thorough pictures of all wall and ceilings to document location of wires, cables, pipes, etc. (done 5/28/09);
  11. Seal boxes with putty pads (done 5/31/09);
  12. Install extra 2x2 blocking for drywall (done);
  13. Finish insulation installation (contracted, done 5/28/09);
  14. Hang doors (contracted, done 6/16/09);
  15. Install first layer of drywall on ceiling and walls (contracted, done 6/2/09);
  16. Install second layer of drywall ceiling and on walls placed horizontally using green glue and overlapping seems (contracted, done 6/2/09);
  17. Finish drywall (contracted, finished 6/10/09)
  18. Install screen wall with rolls of batte insulation behind it for bass traps and preconstruction brackets for LCR speakers and subs (contracted, done 7/2/09) ;
  19. Install false soffits (contracted, done 7/2/09);
  20. HVAC rough-in in theater (contracted, done 5/28/09);
  21. Install riser (contracted, done 7/2/09);
  22. Initial trimout of electric (contracted, done 7/3/09) and lv (done 7/3/09);
  23. Stuff false soffits with insulation for bass trapping (finished 7/29/09);
  24. Install stage (contracted, finished 8/1/09);
  25. Paint walls (contracted, finished 7/22/09);
  26. Have pad and carpet installed (contracted, done 7/31/09);
  27. Install threshold for doors' automatic bottom (did not need);
  28. Install fabric;
  29. Hardwood trim installation (crown, base molding) (contracted, base molding finished 7/18/09, crown finished 8/31/09);
  30. Final trimout (finished 8/29/09);
  31. Install seats (installed 8/1/09);
  32. Install screen, projector and speakers (finished 7/31/09);
  33. Program control system (GUI by 39 Cent Stamp finished 6/21/09, programming finished 4/18/11);
  34. Trimout rack;
  35. Install sound treatments (fabric wall panels);
  36. Install star ceiling (future);
  37. Enjoy (underway starting 7/31/09)!
Publicity:


Along with some other theaters here, my theater was in the Electronics House's Best DIY Theater issue:
http://www.electronichouse.com/artic...y_projects/diy


It was also in the January/February 2011 Electronic House:
http://www.electronichouse.com/artic...ghts_bat_cave/


I now have both of these articles framed and hung.


Here's the guy who did the GUI for my touchpanel- he's a great guy and I highly recommend him if you need any GUI work done:
http://guijaboard.com/wp/?p=108


I'd appreciate any comments or help!



Thanks!!

CJ
 
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C

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Discussion Starter · #2 ·
Equipment...

Sources

Game- Sony PS3

Media Server/Blu-Ray- Popcorn Hour C200 NMT

Cable- Scientific Atlanta 8300HD

CD Server- Arrakis DC6-1000


Display

Projector- Panasonic PT-AE3000U

Screen- 120" SMX 2.35:1 AT


Receiver- Integra DTR-8.8



Speakers

Front- 3 Triad Inwall Classic Gold LCR's

Sides- 2 Triad Inwall Gold Surrounds

Rear- 2 Triad Inwall Gold Satellites

Subs- 2 Triad THX Inwall Subs


Control- Crestron Pro2



Remote- Crestron TPMC-8x



UPS- MGE Pulsar EX RT 1000



Lighting- Crestron CLS-C6



Seating- Two rows of Berkline 13175's in IOVOOVOI configuration




Media Server-

The NMT is basically a media player that has hardware decoding for DVD's, BluRays, etc. There are several different brands. Most of them offer an ethernet jack and USB jack for playing video streamed over a network or from a USB hard drive. Some, like mine, have internal connectors for a hard drive. The newer ones have HDMI 1.3 outputs, supporting 1080p video and TrueHD audio (among others). Mine has component video, coaxial digital audio, optical digital audio, and analog audio outputs as well.


Here is a pic:



When it's first set up, the GUI is pretty basic. With a little work, you can get one like this:



It takes a bit of setup time, but once it's going, it's great. Here's a forum with more info: http://www.networkedmediatank.com
 
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C

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Discussion Starter · #3 ·
Framing/Insulation...


Many times the question is raised about what size room is best for acoustics. If you are building new construction and have the flexibility of making the room whatever size you want, then you can worry about not having any room dimension being a multiple of another (i.e., 20' long by 20' wide by 10' high). However, for the rest of us who are retrofitting space, it is fortunately not worth the time to modify the room. You can basically work with what you have and use sound treatments to help with any issues:
http://www.avsforum.com/avs-vb/showthread.php?t=793482


I'd love to do a room within a room construction, but the basement was framed during construction and there is not enough width in the room to do so. Since there is existing 2x6 studs, I decided to do quasi staggered-stud construction. I'm using 2x2's for the headers and staggering 2x4 studs between the existing 2x6's.


There is blocking about 8 feet up on the exterior wall. I was concerned that it was fireblocking. I talked to my builder and found out that it was just used at the seams of the outside OSB sheathing so that they would have something to nail to.


I'm just running regular pressure-treated 2x4 studs along the poured-in-place walls.


There are some existing utilities that were run under the ceiling, along one of the walls. I plan on framing a soffit around them to isolate them from the theater.


------------


I finished the main framing on 8/25/08


Here's the photosynth of the framed room. You will have to install some software from the main website. Unfortunately, it only works in Windows, but what else would you expect from Microsoft?!

http://photosynth.net/embed.aspx?cid=fd30afd5-220e-4979-b424-0b2777c9971e


Some regular pictures



This is the front wall, adjacent to where the screen is going to be placed.


 
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C

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Discussion Starter · #4 ·
Electric/Low Volt...
  1. Install the boxes for the receptacles, sconces and cans first.
    • The center of the receptacle boxes should be 12" high from the finished floor.
    • All walls over 24" long should have a receptacle, you can subtract the width of a doorway.
    • Receptacles should be spaced no greater than 12' apart along the wall.
    • The boxes for the sconces should be at whatever height you want the sconces. You could place them around 7' high so that nobody hits their heads, but can vary depending on ceiling height and aesthetics. I don't think that there is any code issues with height.
  2. Then, drill a 1" hole through the middle of the studs approximately 20" from the finished floor (code doesn't address this, it is just how it is normally done). You will have to go over the door, so go ahead and drill holes in those studs as well.
  3. For the receptacles, just start at a panel and run 12/2 Romex through the studs to each receptacle. Using 12/2 is slightly more costly, but it can support 15A or 20A receptacles.
    • Cut the wire off at the receptacle so that you will have at least 8 inches hanging out of the receptacle once it's pulled through.
    • Strip the wire so that the unstripped portion is between 1/4" and 1" into the receptacle box.
    • You need to staple the wire within 8 inches of the box.
    • When going vertically to go over the door, you will have to secure the wire a minimum of every 48 inches with a staple.
    • Start the run to the next receptacle from the last one and continue until you have run wire to all of the receptacles.
  4. Do the same thing for wiring each of the lighting zones as you did with the receptacles, except you only need 14/2 wire.
    • Start at the box for the dimmer and run it to the first lighting fixture.
    • Follow the same rules as the receptacles.
    • Where you run the wire along the joists (for the can lights against the screen and for the two lights over the seating), make sure that you secure the wire every 4'.
    • You can choose to use the same hole in the studs as you did for wiring the receptacle, which will save time but waste wire, or you can drill a new set of holes for the sconces.

These numbers are based off of the NEC 2008. Most places in the US go by this, but not all. Check with your local code enforcement agency to make sure these apply.


Finished the electric rough-in on 9/28/08:





Big had a great idea on how to hide receptacles:
http://www.avsforum.com/avs-vb/showp...9&postcount=16


If the plastic back box doesn't work for some reason, here's a place with a reasonably priced metal box:
http://www.hankselectric.net/detail.aspx?ID=402



I just read a great quote from John Dunlavy (via Chu Gai) regarding speaker cables and wanted to put it here, where I won't lose it! http://www.avsforum.com/avs-vb/showt...9#post16653309

Quote:

Recently a poster inaccurately quoted what I have said regarding extensive and carefully-controlled "blind and double-blind" listening tests that we at DAL have conducted over many years to determine if any "truly audible" differences exist between loudspeaker cables representing a wide range of pricing, size and design approaches.


From these comparisons, which encompassed a significant number of competent listeners and a wide range of audiophile amps and loudspeakers, the results we obtained led us to confidently conclude the following:


1) No audible differences existed between any of the cables assessed for lengths under 25 feet - if "stable" power amps and well-designed loudspeakers with reasonable input impedances were used.


2) When audible differences were substantiated they could be traced to:


a) "high-performance" power amps with excessive inverse-feedback and inherent stability problems that caused them to became unstable and oscillate at supersonic frequencies (creating audible distortion) when used with some low loss, high capacitance, low-impedance cables, and/or

b) a loudspeaker cable with a high series inductance and or a high series resistance, which sometimes caused an audible roll-off of high frequencies and/or a "dulling" of transient detail when used with a loudspeaker whose input impedance dropped below about 2 ohms over a reasonable range of frequencies, especially above about 10 kHz.


Beyond these special cases, no audible differences were ever substantiated between the most expensive, exotic-looking, widely-advertised loudspeaker cables and quality #12 AWG ZIP Cord having the same length.


The many listening comparisons we have made over the past 20-odd years between audiophile loudspeaker cables were carefully controlled according to proper scientific method and good engineering practices. Every reasonable effort was made to ensure that listening comparisons did not encompass spurious factors that might bias or skew results. A wide variety of music and test tones (impulses, tone-bursts, etc.) were used, along with a variety of audiophile loudspeakers and power amps. The amplifiers used varied in price from about $200 to over $10,000. The rooms used for critical listening comparisons were always acoustically well-damped, typically about 25 feet wide by 15 feet deep, with the loudspeakers placed along the long wall, about 10 feet from the listener and separated by an included angle of about 90 degrees. Listeners included DAL employees, salespersons of local audio stores, and numerous visiting audiophiles.


Among the approaches used in evaluating whether verifiable audible differences existed between different loudspeaker cables were:


1) pretending to switch cables but not doing so,

2) switching between cables but not letting the listener know which was being heard (blind and double-blind regimens),

3) switching between cables while keeping the listener informed as to which cable was

being used.


The results we have obtained consistently correlate very well with those published within

professional and trade journals by competent engineers who have performed similar tests and comparisons between cables. And, they have always correlated with those expected from the teachings of well-known transmission-line theory, network theory, etc. and predictions based upon the proper interpretation of a full set of lab-quality measurements.


There really are no relevant unknowns with respect to transmission-line theory and the measurement of meaningful cable performance parameters. The goofy beliefs and theories that need to be questioned are those often loudly annunciated by persons who pretend they possess competent knowledge and understanding of cable theory and measurement but lack the professional-level credentials and underpinnings to do so. The bottom line is very simple: if it can be heard, it can be identified, measured and quantified by well-known means within a well-equipped laboratory manned by personnel possessing appropriate professional credentials. (Those who believe otherwise are doomed to be victims of those who pursue the design and sale of products based upon pseudo science and nonsensical advertising claims.)


Sadly, the allure of expensive, "high-tech appearing" loudspeaker cables can be traced to an industry typically missing qualified electrical engineering personnel but brimming with personnel who excel at composing "great-sounding advertising prose" containing claims for technology and performance that are virtually baseless. (A sad commentary regarding a very large and profitable industry!)


But, the advertisements of some cable manufacturers do contain what are purported to be measured comparisons between different cables, including ZIP Cord, which is portrayed to exhibit only about 3% efficiency at 60 Hz. However, common sense reveals that such a low efficiency would cause a typical "AC extension cord" to turn "white hot" if connected to an ordinary toaster. Hmmm!


Another advertisement compares loudspeaker cables according to their Joule rating - but a Joule is merely a watt-second, used as a unit of energy-storage when comparing batteries or some capacitors. Hmmm! Thus, such graphs portray totally meaningless information that is not only false but also misleading and downright silly from an engineering point-of-view. When asked why they do not publish meaningful measured performance specifications for their cables, such as loss Vs frequency into typical loudspeaker load impedances, series resistance, parallel capacitance, series inductance, frequency dispersiveness, etc., representatives of most large cable companies usually reply that such performance attributes are meaningless. Hmmm!


I have recently asked five very competent Professors of Electrical Engineering at prominent

universities their opinion of audiophile loudspeaker cable design and advertising. The language of their replies would probably not be permitted even here on the INTERNET. Needless to say, they share the feelings of all competent and informed electrical engineers that the advertising claims and specifications for audiophile loudspeaker cables are without substance and cannot be verified by theory, measurements nor proven by competent blind listening comparisons. The same conclusions have been stated in a few magazine articles and peer-reviewed audio journal papers by authors possessing credible academic and technical backgrounds.


Thus, the question arises as to why any competent manufacturer would not at least attempt to design loudspeaker cables with measurable electrical properties that represent the teachings of network/transmission-line theory and the fruits of good engineering practice? For example, at very high audio and low radio frequencies, cables with a relatively long length can best be characterized by applying "transmission-line theory", while at lower frequencies it is easier (and probably more accurate) to design and analyze cables by using "network theory".


For example, using the teachings of transmission-line, the "optimum cable" would be one whose "characteristic impedance" was equal to the average impedance of the load. However, while this solution somewhat applies to loudspeaker cables, it results in a cable whose relatively large capacitance and low inductance might cause some "high-performance" (but frequently unstable) power-amps to oscillate - usually at super-sonic frequencies, detectable as audible distortion on transients, etc. (This is the reason that some expensive audiophile loudspeaker cables incorporate an expensive, hi-tech looking box at the loudspeaker end of the cable which houses a simple inexpensive resistor and capacitor, often called a "Zobel Network". Hmmm!


Recognizing what frequently are shortcomings of the "ideal cable" designed according to

transmission-line theory, competent engineers apply the teachings of "network theory" to design loudspeaker cables with lengths less than about 25 feet. In this case, an ideal loudspeaker cable becomes one whose series resistance, series inductance and parallel capacitance are all minimal. The combination of these properties insures the lowest loss across the audio spectrum while minimizing the probability of amplifier instability. Such a cable might be one with very large diameter, low resistance wires, separated by a distance that minimizes capacitance without increasing inductance beyond an amount that would alter high-frequency performance.


Achieving either of these design properties and goals can be accomplished without incurring a high engineering and manufacture costs that might lead to high retail prices - such as those currently being charged for some exotic, hi-tech looking cables with questionable performance properties. So, why not design, manufacture and competitively market loudspeaker cables based upon advertising that articulates their meaningful design parameters and competently measured electrical specifications - rather than the flooby-dust, buzzard-salve and gobbledygook specs presently found in too many cable advertisements? Are most cable manufacturers afraid to advertise meaningful performance

parameters, such as the resistance, inductance, resistance, propagation-factor, etc, for their cables.

(Can most cable manufacturers even measure them?) Hmmm!


So, the best present advise is very simple: CAVEAT EMPTOR (let the buyer beware)!



Best of listening,



John Dunlavy
 
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Discussion Starter · #5 ·
Drywall...


So, why do we care about sound isolation?

To quote DE:


( http://www.avsforum.com/avs-vb/showpost.php?p=17318270&postcount=32

Sound isolation really begins with your defining what you want to achieve ... and then usually backing off that requirement to meet budgetary constraints.


There are two sides to this coin. The outside in and inside out views. The inside out perspective is the more common: "I want to listen to my stuff loud and not raise the ire of spouse, children, neighbors and environmentalists". The outside in perspective says you want to listen to the entire dynamic range of a recording (22dB SPL to 105dbSPL at the listening position) without clipping, distortion, or permanent hearing loss.


Let's look at both of these and use, as a starting point, the value of 35 dBSPL as the typical ambient noise level in a quiet suburban home. Also the recommended best practice which says the objective is you do not want to raise the noise level in an adjacent space more than 3dB (a doubling of loudness).


So from the inside out view, if your ambient noise level is 35dB, we add 3dB to that and say our goal is 37dB. Taking the top of the dynamic range of 105dB and substracting 37dB from that, we come up with 68dB. In the simpliest form, your isolation efforts need to reduce sound transmission through the walls/floor/ceiling by 68dB. Again, in its most simple form, you're looking for an STC of 68dB. That's pretty substantial. [NOTE: STC is a poor metric in this case since STC only considers the 1/3 octaves centered at 125Hz through 4000Hz and further is a single weighted number representing that entire range. But, for simplicity's sake, it's what we have for now.]


The ouside in view, says we have an ambient noise floor of 35dB, the softest sound recorded on a sound track is 22dB. You need to achieve a >13dB reduction in ambient noise inside the room. By comparison, that looks pretty easy to do until you start to consider noise being transmitted into the room by HVAC system, equipment fans, projector fans, etc. When we look to certification bodies ... THX for example ... the concern is less on noise sources you can control (dishwasher, children bouncing balls off the floor above) and more directed to environmental noises you cannot control (airplanes, traffic, trains, etc.). These noises by the way are loud by comparison to ambient and therefore the >13dB number is very minimal. OK, so what happens if you don't get the noise floor in the room to
 
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Discussion Starter · #6 ·
Soffits and Columns...

I have enclose the existing utilities in a soffit. I've hung the soffit from RSIC clips and will be using double drywall and green glue to isolate it from the theater.



I plan on building false soffits in which to run the new HVAC, electrical, low-volt wiring, and can lights.


The false soffits will also act as bass traps. I plan on stuffing them with insulation and using rigid insulation on the outsides to hold everything in. They will be faced with fabric.


--------

7/2/09





-------

7/30/09


 
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Discussion Starter · #7 ·
HVAC...


No clue what to do with HVAC. Hopefully I'll figure it out before I'm done!


I will probably run flex duct for the HVAC and tap into the existing lines outside of the theater for the time being. Once I finish the basement, I'll change them over to the new system.


One good rule of thumb was suggested by Dennis Erskine in another thread- size the volume of the air (cfm) supplied according to the room size and heat generated, but size the system so that the velocity of air is less than 250 feet per minute (fpm) at the register.


Here's some more info (provided too late late for me, but I hope it helps someone else):


Dennis posted some more design info on HVAC systems:


"You'll want two supplies (typically in the front of the room, high mounted) and two returns (high mounted) in the back of the room. You do not want air flow directly on any seating location. You do not want a velocity of more than 250 FPM through any vent (diffusor). You want the HVAC system to maintain a temperature of 70 degrees F with an outdoor temperature range of -30 to 100 degrees F and to maintain a relative humidity of not less than 25% nor greater than 50%. You want six air exhanges per hour and 15 CFM of fresh air per person."

http://www.avsforum.com/avs-vb/showt...6#post16857696



Use Hart and Cooley 821 light commerical diffuser for the supplies (DE?). Use linear diffusers (Ted White).


-----------------------

Edit- I've hired a contractor to finish the basement, and that will include some portions of the theater including running the AC vents to the theater (but not routing them all the way through). I started another thread with my questions regarding the air return location.


Here's a drawing of my proposed layout:



And the thread discussing how to hide the return:
http://www.avsforum.com/avs-vb/showt...1#post16463130


Info on why I went with central air rather than minisplit:


Quote:Originally Posted by broconne
The wall thing makes a lot of sense. It just seems like there are a lot of benefits to the mini-split system. You don't have to worry about noise traveling through the ducts. Theater can get hot with people and equipment - makes sense for it to have its one mini-split zone.


Originally Posted by broconne
The wall thing makes a lot of sense. It just seems like there are a lot of benefits to the mini-split system. You don't have to worry about noise traveling through the ducts. Theater can get hot with people and equipment - makes sense for it to have its one mini-split zone.


There are a lot of benefits to the minisplit system. I have 50+ feet of flex duct between the HVAC unit and the theater and the basement is on a separate system from the rest of the house, so noise isolation is covered. The only downside to doing it like I did is that it is not on a separate zone (I may correct this later). In the end, it wasn't worth the extra $$ (to me) to have a separate AC system for the theater.


Also, with a minisplit, you still need a way for air exchange. Normally I'm guessing that this would be done with the space under a regular interior door. However, this is not good for sound isolation. I guess a dead vent would be an acceptable way.


Some more info on HVAC:
http://www.avsforum.com/avs-vb/showthread.php?t=808024
http://www.avsforum.com/avs-vb/showt...5#post16100715
http://hvac-talk.com/vbb/showpost.ph...0&postcount=10


Some help from the experts on my specific wants and needs:
http://hvac-talk.com/vbb/showthread.php?t=294992


CJ
 
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Discussion Starter · #8 ·
Walls...


Can hang panels using the rotofast panel anchors:
http://www.rotofast.com/instructions_snap_on.htm


Terry Montlick on fabric wall coverings:


I am all for fabric walls. They work great and look great. I design rooms with them all the time.


But unfortunately, Anchorage is not a very acoustically transparent fabric in the Guilford line -- not all GOM fabrics are equal. It is not as bad as Guilford Carrara, which has poor acoustical transparency. From our own lab tests, Anchorage reflects 4.5 dB at 4 kHz and almost 6 dB at 8 kHz. Carrara, the worst of the Guilford line, reflects more the 6 dB at 4 kHz and close to 10 dB at 8 kHz. For reference, GOM FR701, the standard for acoustical panels, reflects around 1 dB at 4 kHz and around 1.5 at 8 kHz. This is one reason that professional acoustic panel makers stick to the FR701 line.


The result of lower acoustical transparency is that more area is needed to get the equivalent amount of absorption. Not as much sound gets through to the porous absorber (fiberglass, acoustic cotton, etc.) to be absorbed. Your absorbing walls will still work, but just not as effectively for the area you are devoting to them.


BTW, for those of you without your own acoustics labs, the "blow-through" test is an amazingly accurate indicator of acoustical transparency, given its low tech and informal nature. You just put your lips together and blow, as Lauren Bacall famously said in "To Have and Have Not."
If the fabric is easy to blow through, it is very probably extremely acoustically transparent. And if you don't know what easy and harder to blow through feel like, just order some swatches of the 3 Guilford fabrics I mentioned above. This will provide you with a little test kit for informal evaluation of other fabrics.


Here is some more great information on fabrics from Terry:


Have a look at Guilford Wilshire 2735. Its acoustical transparency is excellent, as good IMO to be used as speaker grill cloth. Very close behind is Guilford Lido 2858. In the "next tier," marginal for use as speaker grill cloth but still excellent for covering wide band absorbers (and not extremely burlap-looking), are Guilford's Bailey 2299 and Spinel 3582, Acoustimac DMD fabric, and C.F. Stinson Galaxy.
 
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Discussion Starter · #10 ·
Flooring...


Base board should be installed 3/8" from the floor. You can also install it after the carpet has been layed, but make sure that the flooring people install the tack strips in the correct location for the future installation of base board.
 
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Discussion Starter · #11 ·
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Discussion Starter · #12 ·
Lighting...


I'm using the Crestron CLS-C6 for the lighting control. This is very similar to the Lutron Grafik Eye GRX-4506 and supports 6 zones.


Zone 1- Can lights

Zone 2- Stage can lights

Zone 3- Sconces

Zone 4- Rope light in tray ceiling

Zone 5- Rope light for steps and runner

Zone 6- Star ceiling


 
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Discussion Starter · #13 ·
Stage...


The stage will be built to a similar design as Ruben's (SMX). It will begin approximately 18 inches from the front wall so that there is room to install super-chunk bass traps behind it. The screen wall will be built on top of the stage so that I can have part of it on hinges and be able to access the space behind the screen wall.


Originally Posted by Dennis Erskine
The sand filled stage is a functional portion of a good home theater which, fortunately, can be disguised as something architectural and belonging in the room (such as stage, for example). First, the stage must be constructed AFTER the drywall is installed. Second, when it is built, it should not come into contact with any of the walls (and idealy be isolated from the floor or that great sound conductor called a concrete slab). Here's what it does:
1. the subs are anchored to the stage. For optimal subwoofer performance, the sub must be anchored to something of considerably more mass than the sub itself.
2. The dry play sand provides the mass; but, it is not a solid mass that would allow vibrations from the sub (and the other main speakers) to pass through on their merry way to the rest of the house...the sand is an absorber reducing (rather dramatically) the amount of kinetic energy entering the structure.
3. Because the kinetic energy is not being transferred to the structure, your walls do not become occasional speakers injecting distortion artifacts into the room.

[At the lower frequencies, the vibration enters the structure...within the home their a lots of walls of different sizes, shapes and mass. Each of this has a resonance frequency. When that resonance frequency is equal to or a harmonic of the frequency being produced by your sub, that wall becomes a speaker...and, a surprisingly loud one at that.]

Here's another POV. You're spending a bunch of money on your gear (and many times a few grand on your subwoofer). For $300 to $500 are you willing to bet it (the stage) won't help.

Until you've heard truly smooth bass response and the sound in a well calibrated room, you cannot imagine what you're giving up...and, I've a demo room for just that purpose.



--------

7/21/09



-------

7/30/09



 
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Discussion Starter · #14 ·
Riser...


floor to bottom of screen:

Front row eye height is 42". This will be 1/3 of the way up the screen. The screen is a 2.35:1 screen, 120" wide, so the height of the screen is 51.06". 1/3 of that is 17.02". This means that the bottom of the screen is 42" - 17.02" = 24.98", say 25" from the floor.


Height of seated front row viewer's top of head:

The seated height of the front row viewer's eye is 42" and the top of head is approximately 46" in a Berkline 090.


Height of rear row viewer's eye:

Do not take an assumed riser height for this number. Instead, unless you are using different seating, it should be the same as for the front row viewer's eye height, 42".


The rest of the dimensions are from the scaled CAD drawing that I made of the room.


calculator:
http://www.theater-calc.com/




The riser will be constructed with 3 layers of plywood- 3/4", 1/2", 3/4", for a total thickness of 2". This leaves 14" for the side height, which will have to be made from ripped 2x16's. Or, I could place it on spacers and use 2x12's.


Make sure that the riser is deep enough so that there is a walking path, even with the seats fully reclined. This way, if someone has to leave from the second row, everyone else doesn't have to get up so that they can get through.


I may end up stuffing the riser with insulation and putting in vents to use it as a bass absorber.

------


I found an article on the net on riser construction that Dennis Erskine did for a, now defunct, theater building magazine. If no one has an issue with it, I'm going to post them below.









Please note- instead of felt between the layers of plywood, it is now recommended to use Green Glue instead.


Also, it is now recommended to space the outside joists 32" wide and the rest of them 16" on-center. However, to do this, you should be sure to use 3 layers of OSB/plywood so that there is no flexing. http://www.avsforum.com/avs-vb/showt...6#post16655766


Another note- since the article, it has become the practice to decouple the riser (and stage) whenever possible. This is done by simply keeping the riser from touching the walls rather than fastening it to them. This gives you the flexibility of adding tactile transducers without having to worry about the vibrations traveling through the walls, and also helps with the general sound insulation.
http://www.avsforum.com/avs-vb/showthread.php?t=1193579


-----

5/22/09-

Here's the riser that they built. They did not nail the top so that I can run the wiring and add insulation before putting on the top. I plan to also cut out areas around the sides and back to use it as a broadband bass trap.



------

6/25/09


Here's a picture of the notches that I cut out from the riser the other night, until 2:00 am.



-----------

7/1/09





The framers are here today to work on the theater. They are framing the screen wall, soffits, columns, and stage. They will also be finishing up the riser. The riser and stage are being placed on two layers of 30 lb. roofing felt, framed up with 2x12's, then a layer of 1/2" OSB glued and nailed to the framework, a layer of Green Glue, and finally a layer of 3/4" tongue and groove OSB screwed down to the frame. I'm stuffing both with insulation (don't have time for sand in the stage). The riser will be carpeted, and the stage will be done with dark-stained red oak hardwoods.


---------

7/8/09



-------
 
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Discussion Starter · #15 ·
Furniture/Trimout/Misc....


If I decide to ceiling-mount the projector rather than placing it in the soffit as planned now, Dennis came up with a good way of doing it:


"You do not want the projector coupled to the floor joists. The image will bounce around everytime someone walks on the floor above. So ...


Once your ceiling is finished, take some 3/4" mdf, you'll need to cut the MDF so that it will be (a) centered on the room center line to look good; and, (b) so that it will span two of your HAT channels. Use a router to put a nice finished edge on the MDF. Prime the MDF. Mount the MDF to the ceiling using appropriate screws into the channel. Counter sink the screws and fill the holes with filler. How many screws? Divide the weight of the projector (and mount) by 15. That will tell you how many screws. Use liquid nails on the back of the MDF, BTW to firmly attach the MDF to the ceiling. Paint to match the ceiling. Install projector bracket and projector."


The only change that I would make is that I would probably use a piece of wood rather than MDF.


--------------

Audio and video calibration. This audio list was shamelessly copied from Will1383 ( http://www.avsforum.com/avs-vb/showthread.php?p=14982321#post14982321 )

SoftwareTest Tones, DVD's

DIY panels:

http://remixmag.com/mag/remix_diy_acoustics/
http://remixmag.com/images/DIYAcoustic_diagrams.pdf
http://www.decware.com/paper39.htm
http://www.angelfire.com/sports/RCcars/acousticpanel.htm
http://geekwithfamily.com/2006/09/22/audiophile/how-to-build-jon-rischs-diy-acoustic-panels/
http://www.geocities.com/jonrisch/a1.htm
http://www.pmerecords.com/Diffusor.cfm


Projector setup:
http://www.avsforum.com/avs-vb/showthread.php?t=1162970
http://www.avsforum.com/avs-vb/showthread.php?p=16092540#post16092540
http://www.avsforum.com/avs-vb/showthread.php?p=16320068&highlight=serial#post16320068
http://www.avsforum.com/avs-vb/showthread.php?p=16275233#post16275233
http://www.avsforum.com/avs-vb/showthread.php?p=16748016#post16748016
http://www.avsforum.com/avs-vb/showthread.php?p=16308072#post16308072
http://www.avsforum.com/avs-vb/showthread.php?p=16356434#post16356434
http://www.avsforum.com/avs-vb/showthread.php?p=16358765#post16358765
http://www.avsforum.com/avs-vb/showthread.php?p=16373343#post16373343
http://www.avsforum.com/avs-vb/showthread.php?p=16516265#post16516265


The touchpanel GUI was created by a very nice and talented forum member, 39 Cent Stamp. I cannot thank him enough for all the help he has given this graphically challenged individual (me)!


Main Page



Audio Source Selection



Tuner



Video Source Selection



PS3



CATV



Favorites



Features



Lighting



39 Cent Stamp also has a blog and would enjoy any comments regarding the GUI posted either on this thread or his blog:
http://guijaboard.com/
 
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Discussion Starter · #16 ·
Finished Product...


Well, it's never truly finished, but I'd call this substantially complete!




And when it was finally done, a few (or more) drinks were raised in its honor



I was also fortunate enough to have it featured in the January 2011 print edition of Electronic House and in Electronic House's DIY Theater Showcase: http://www.electronichouse.com/artic...y_projects/diy
 
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BIGmouthinDC

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#18 ·
The tray ceiling design looks just a bit small in proportion to the overall room size. Are you hiding some ducts?


If you can make the lowered part of the ceiling smaller the room will look a bit bigger.


What are your plans for the windows? Seating?
 
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#19 ·

Quote:
Originally Posted by BIGmouthinDC /forum/post/14176816

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Click to expand...
I don't care who you are, that's funny right there.
 
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Discussion Starter · #20 ·

Quote:
Originally Posted by BIGmouthinDC /forum/post/14176833


The tray ceiling design looks just a bit small in proportion to the overall room size. Are you hiding some ducts?


If you can make the lowered part of the ceiling smaller the room will look a bit bigger.


What are your plans for the windows? Seating?
Click to expand...

There are existing utilities that run under the ceiling, along the bottom wall in the picture. The soffit along that wall has to be that big to enclose them, which means that it has to be that wide on the other side to be balanced. The soffits along the front and rear of the room can be changed, but will have to be large enough to enclose the future HVAC ductwork. Right now, the size is more schematic than calculated.


I'm going to make plugs for the windows, using plywood as a base and using a combination of foam and mass-loaded vinyl for the plug portion. They will be covered with fabric to match the walls and decorative hand holds.


Haven't really made any decisions on the seating as yet. My wife wants me to move the leather sectional down to the theater so that she can get new furniture for the family room. I want leather recliners. Her idea will probably be the interim solution.

Quote:
Originally Posted by BIGmouthinDC /forum/post/14176816

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Click to expand...

LOL- it may be a while until you can edit that post!


Thanks,

CJ
 
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