Center Stage audio performance

 Acoustically transparent (AT) projection screens are now uniquely able to maintain the quality of your projected image and rid your home theater of the acoustic distortion that a television or fixed frame screen would impose. AT screens do not acoustically reflect, refract, or otherwise smear the imaging of your speakers. The majority of your sound comes from the center channel, and with an acoustically transparent screen the sound will come from behind the image, not from the floor or ceiling. You no longer have to be limited to the traditional horizontal MTM center speaker, and can alleviate the comb filtering (horizontal lobing) across your seating positions caused by having the same frequencies reproduced by multiple horizontal drivers. An easy fix is that you could turn your speaker vertically for improved frequency response performance across your theater, or even better, you could use a center channel that is identical to your left and right speakers.

Think vertically

Here's an article Vertical vs. Horizontal Center Speaker Designs we wrote for one of our favorite AV sites, www.audioholics.com:  Vertical vs Horizontal Center Speaker Designs

Frequency response of an Infinity IRS Epsilon center channel (-3dB at 45 kHz) with a Cary SLAM-100 tube amp (-3dB at 100 kHz), with just the speaker, and adding the Center Stage screen fabric and with the black backing layer.  The response was 1/6 octave smoothed to better reflect audibility, and the measurement used frequency sweeping to alleviate Doppler distortion and reduce test uncertainty.  The screen was eight inches in front of the speaker and the calibrated Behringer ECM8000 microphone was placed 39 inches from the speaker.  The results show excellent acoustic neutrality, as the fabrics do not create audible comb filtering and benignly attenuate towards the top frequencies.

Nothing, even air, is truly acoustically transparent.  More precisely, an AT screen is acoustically translucent, and the trick is to behave as neutrally as possible.  For example, any fabric with holes will comb filter to a measureable degree, but in order for it not to have an audible effect the lobing needs to be as closely spaced as possible (our hearing will average frequency/special response) and at the highest frequencies.  This is done by having the holes as small and closely spaced as possible, while maintaining an openness factor of around five percent.  The woven vinyl fabrics have much smaller holes than microperfed vinyl screens, thereby minimizing and shifting the comb filtering to high enough frequencies as to not need equalizer correction, although we argue that you can't compensate for audible comb filtering through equalization because its effects are complex and change with position.  This is why you want to avoid the main mistake of horizontally-aligned similar drivers in your center channel and the highly audible comb filtering in the critical midrange frequencies or resorting to EQ.

What is the real world result from placing your speakers behind a Center Stage screen?  If only your center channel is behind the screen, you will need to increase the volume of the center channel one to two decibels.  If you have all three front speakers behind the screen, you will only need to trim your surround channels one to two decibels to match your slightly attenuated front soundstage.  The qualitative effects of having a fabric in front of your speakers is that you will notice that brighter recordings are tamed down a little, with a slight loss of sparkle and air, because the attenuation is higher in the top octave.  While the average attenuation of the Center Stage screen fabric is two decibels from 8k-20kHz, adding the black backing will increase this attenuation around one more decibel.

Audio testing

Here is our audio testing where we confirmed that similarly woven acoustically transparent screen fabrics that are approximately five percent open have practically identical acoustic performance: CenterStageAudioTesting.pdf (211k)

And here is our testing of the acoustical transparency of the screen material with a speaker firing through the screen at different angles.  We confirmed that our screen is acoustically inert enough to allow you to angle your speakers as you need for their radiation patterns, room surfaces, seating locations and general preferences: CenterStageSpeakerAngleTests.pdf (145k)

Center Stage video performance

Color

No matter how bad a movie this guy makes, you'll see it exactly as he intended it.  Center Stage screen fabric has been tested to have nearly undetectable color shift.  It's performance of x=.000, y=.005 with a PhotoResearch PR-650 using a PhotoResearch Calibrated White Reflectance Standard as the reference means that its neutral white color makes for a reference quality projection material.

Worry no moiré

When two patterns are superimposed on one another, a moiré patterning effect can be created depending on the relationship of the two patterns.  Generally speaking, the goal for a screen with texture is to either behave randomly, or have a high enough ratio of holes per pixel for interference not to occur.  Woven fabric screens with randomized thread patterns should not moiré at any image size (e.g. Screen Research).  Woven fabric screens with symmetrical weaving, including all of the fabrics listed in the nearby chart, require a bit more thought in their application, although they are all superior to perforated vinyl screens.

Even though Center Stage screen material is a patterned weave, we are the only screen company that eliminates the possibility of moiré by manufacturing every screen with its fabric cut at an 15 degree angle with respect to the roll.  In addition to eliminating the chance for your projector (or your next one) to create moiré patterns with the screen, cutting the screen fabric with the threads at an angle reduces pixelation, screen door effect, and smoothes out the image texture with no loss in resolution or contrast.  Center Stage screens are guaranteed to be moiré-free, without having to resort to randomized thread patterns which have been shown to cause cross-pixel light interaction and reduce ANSI contrast.

If you are buying bulk Center Stage screen material to make your own DIY fixed frame screen, you should definitely tilt your cut piece 15 degrees for 1080p images under 120" in width.  Even if your image is larger or your pixel densities are otherwise not that high, you should confirm that you'll be OK with a sample first, and consider the benefits in image smoothness comes from tilting your cut.  We can even do the precision cutting for you (+/- 0.1 inch), which typically only costs an additional $35 to $45.

Borders

We've experimented with all kinds of paints and fabrics, and nothing gives you the light absorptive power of black velvet fabric.  While painted trims are the common solution and help the screen lay flatter, our black velvet fabric is so dark that you may need to put a piece of masking tape on the screen to see where the overscan pixels are.  Even ultra-flat black paints look grey in comparison to our black velvet fabric we sourced from Switzerland.  We have new techniques and patent pending tension features that allow the velvet borders to roll up flat with the screen material, giving you a very flat image surface and the sharp-edged, high- contrast image "pop" that only the best fixed frame screens can offer.  No other retractable projection screen in the world uses fabric velvet borders or comes even close to the image edge and contrast that our new design offers. The upper right photo shows with ambient light the difference in color between a painted border from a major screen company and the Center Stage velvet trim.  What does this do to your image when the lights are turned out?  The lower right photo shows the results in a darkened room with a projected white image and four pixels of overscan.  Note how the velvet soaks up the overscan, which gives your image a sharper, better defined border with improved dynamics.

Translucence

How light reflective are the surfaces behind your screen?  If your paint colors are any lighter than a medium tone, or if you have windows, pictures, or reflective speakers, then you first want to try to tame the reflection.  Dark paint is cheap and improves your contrast.  Window shades pay for themselves and keep your neighbors from seeing you play with your Wii.  If you have a TV behind the screen, your speakers are reflective or you otherwise just can't easily treat the reflective surfaces, then I guess you're boned.  Or, you can order the black backing option, which is over twice as acoustically transparent (you'd lose an average less than one dB) and effectively cancels the light transmittance through the screen.  The black backing material does not improve the contrast of your image unless you have significant reflections from behind your screen.  If you think this may be an issue for your installation, tell us to send you samples of both the screen and black backing fabrics.

Texture

Center Stage is a woven fabric, and not a perfectly smooth sheet of vinyl.  For acoustic reasons, this is an advantage, but if you're going to sit 10 feet or closer and tend to watch the pixels instead of the movie, you may have sharp enough vision to make out the texture of the fabric.  As a standard feature on our retractable screens we cut the screen material at a 15 degree tilt, or angle.  The result of biasing the thread direction is that the texture on the screen surface is diffused.  This biased screen texture eliminates the chance of moiré, reduces screen door effect, and smoothes your image.

Control options

Standard RF motors  Our standard RF motors come with two of these wall-mountable RF controls.  You don't have to aim the remotes at the screen, and the motors are quiet and reliable.  The limitation is that you cannot tie these motors into your universal remote or automation system.  Even universal remotes that have RF capability only use RF to transmit their codes.  We're not aware of any remotes that can learn RF signals.  These motors are included in the base electric screen prices.

Premium Somfy® ILT motors  For those of you who need to have the screen tied into a universal remote or automation system, or are interested in a faster, quieter option, we offer the premium Somfy ILT motor.  These motors come with a short control cable attached with a 4P4C (telephone handset, commonly but incorrectly known as a RJ9, RJ10 or RJ22) connector on the end.  Our standard solution is to plug that control cable into the splitter and then connect things like the IR receiver and/or a wall switch.   You'll likely need us to include these, so let's explain your options in more detail.  The prices and part numbers are in a table on the store page "Somfy Motor Accessories."

4-Connector splitter  This handy device not only splits one control cable into three more 4P4C connectors, but also has connections for dry contact control (open/ close) or 5Vdc input (a 12Vdc trigger will work using a relay into the dry contact terminals).  If you aren't just connecting a wall switch, this is the economical hardwired control option.

IR receiver  If you want to control the screen using infrared commands, you'll first need this IR receiver.  This receiver can be mounted within line of sight to your transmitter using a nifty little screw. 

ILT wall switch  A nice hardwired control option is this wall switch.  Besides being the obvious, on the back are connectors for dry contact control (open/ close) or 5Vdc trigger input (a 12Vdc trigger will work with a series resistor), and a limits programming switch.  The wall switch simply connects to the Somfy motor's control cable with the 4P4C connector.

IR remote  If you already have an IR file for a Somfy motor that you can drop into your universal remote, you won't need to buy this fugly remote.  Or, you can also buy it, program/ teach your universal remote, and then return it to us for full credit.

RF receiver  Plug the control cable into this and voilá - you almost have the ability to control the screen with an RF signal.  What more do you need?  Read on.

RF remote  Somfy's Telis RF remotes are available in three colors, black (e.g. "Lounge"), silver, and white (e.g. "Pure").  They're a bit large and expensive, but come with a nifty little hanging knob.  While the picture doesn't show it, the white remote's hanging knob is white.

Screen features, options

Here is a comprehensive guide to what features you can get through various levels of our customized offerings. For each feature, a revelatory picture will display when you float your mouse over the description.

	Screen fabric	Screen w/ no case	The Full Monty
Center Stage fabric	Standard	Standard	Standard
Precision cut	Optional	Standard	Standard
15 degree angled fabric	Optional	Standard	Standard
Stitched, deep black Swiss fabric velvet borders: 2" sides/ top, 1.75" visible on the bottom	Optional	Standard	Standard
Integrated weight bar, rolled in 4" velvet	-	Standard	Standard
Black backing material, 2nd layer	Optional	Standard	Standard
1.5" VelcroTM backing, to adhere to fixed framing	Optional	-	-
Custom 2.75" extruded aluminum roller tube, profiled, to maximize stiffness for zero sag	-	Standard	Standard
Metal L-brackets	-	Standard	-
Patent pending stealth tab tensioning	-	Standard	Standard
120v/60Hz or 230v/50Hz quiet motor with preprogrammed custom limits	-	Standard	Standard
Foamed roller tube	-	Standard	Standard
2 wall-mountable RF remote controls	-	Standard	Standard
3-prong 120v cord, 118" black or 96" grey,          No-plug 220v cord, black	-	Standard	Standard
3-prong 120v flat-plug 96" cord, black or white	-	Optional	Optional
Extruded aluminum case standard finishes: black or white satin	-	-	Standard
Extruded aluminum case upgrade finishes: natural brushed, black pearl blue 5-coat gloss, or custom finishes	-	-	Optional
Integrated 1-piece install rail, wall or ceiling mount	-	-	Standard
Machined aluminum end caps, fully color matched	-	-	Standard
1-year parts and labor warranty	-	Standard	Standard
30-day satisfaction full-credit guarantee - includes orig. shipping	Standard	Standard	Standard
1-year full-credit upgrade option	Standard	Standard	Standard
A little extra love	Standard	Standard	Standard
Price range	$140 - $800	$858 - $2150	$1158 - $2835

Screen, speaker setup

Here is a (hopefully) helpful guide on building your own fixed frame screen.  It's not rocket surgery and nearly anyone can get a top-performing fixed frame screen for much, much less than currently available manufactured options.  DIYFixedFrame.pdf (Rev. 5/11/08, 848k)

Both sides of the Center Stage screen material are the same, however we inspect the inside of the roll to ensure that there are no blemishes.

Here is a recommended viewing angle calculator: Viewing Distance Calculator

Here is a recommended source for black velvet: Black Plush Triple Velvet

Curved screens  There is no acoustical or brightness benefit to building a curved screen with Center Stage screen material.  The only benefits are elimination of pincushion distortion from your anamorphic lens and the general coolness of the screen look.  Here's a good build thread on a curved screen.  The only thing we'd add is that you don't need 50 clamps - you can just use the concave part from the MDF that you cut the convex from and a few clamps.  If you do have 50 clamps, you're a stud.  If you don't have any clamps, try cutting the curved frame sections from a couple 2x6s.

We believe about half of what you're hearing is the room itself, so best practice would dictate that half your audio budget go to acoustically treating your room.  While vertically aligning your front speakers on the same horizontal plane, spacing them from reflection points, and losing the coffee table are free, an investment in room absorption panels, Green Glue and other sound isolation products pays off generously.  Your exploding robots will sound better, and others nearby will no doubt appreciate hearing less sound leakage.  Go to Sound Isolation Store to buy Green Glue and other supplies.

¹Dolby and THX cinema speaker layouts