Thứ Tư, 8 tháng 2, 2012

Center Stage screens

Center Stage screens

Do you realize if it weren't for Edison we'd be watching TV by candlelight?Al Boliska

Retractable electric

- The world's only retractable with fabric velvet borders.
- Patented stealth tab tensioning.
- Popularly used in front of standard TVs.
- Black backing layer, standard.
- Gen4, RF-only or 4-wire, motor options.
- Premium, extruded aluminum case.
- Integrated 1-piece install rail, wall or ceiling mount.

Fixed frame (NEW - curved screens!)

- Premium, 3.3" x 1.6" heavy duty, elliptical contour extruded frame.
- Wrapped in premium Fidelio black velvet,
the world's darkest.
- Easy grommet / O-ringscreen installation for lifetime 360° tension.
- Integrated 1 or 2-piece install rail with included bubble level and mounting hardware.
- CH (scope to 16:9) and CW (16:9 to scope) fixed masking panels now available in both Fidelio velvet and Millibel AT.


We fully support those who enjoy either the challenge, creativity, or value in making their own screens.  Click here for DIY resources: instructions, test results, recommendations, and links to some of our favorite DIY sites.

Center Stage XD 

After three years of development, the new Center Stage XD is the overall best performing acoustically transparent screen available at any price.  We tripled the hole density, raised the gain a little, improved the audio by +0.5dB, and reduced the minimum seating and speaker distances. No other acoustically transparent screen fabric on the market offers as high a gain (1.2), balanced with such a high level of acoustical transparency (1.5dB average attenuation above 8kHz), fine texture (1,500+ holes per square inch) and price.  The perforated vinyls can get higher gain but ruin the audio, require an EQ and have such visually unacceptable hole patterns that A.T. screens often suffer a terrible reputation.  Woven screens typically keep the audio in tact, but have lower gains and/or visually intrusive 2 x 2 thread patterns.  When video AND audio performance are considered, the new Center Stage XD material is the best performer, anywhere.


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.

Center Channel Best Practice

On this page we'll collect published advice, specific to best practice with the center channel.  It is the most important channel after all...
Here's an article Vertical vs. Horizontal Center Speaker Designs we wrote for one of our favorite AV sites,  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.  The woven vinyl fabrics have much smaller holes than perforated 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 XD screen fabric is 1.5 dB from 8k-20kHz, adding the black backing will increase this attenuation less than one more decibel.
Center Stage XD
black backing
Average 2k-20kHz, dBA-0.7-0.3
Average 10k-20kHz, dBA-2.3-0.3
Average 16k-20kHz, dBA-2.0-0.5
Average 19k-20kHz, dBA-1.3-0.6
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)


In the beginning there was nothing. God said, 'Let there be light!' And there was light! There was still nothing, but you could see it a whole lot better.Ellen DeGeneres


No matter how bad a movie this guy makes, you'll see it exactly as he intended it.  Center Stage XD screens are used in mastering studios and university virtual reality labs across the US and Europe.  Our fabric has been tested to have nearly undetectable color shift.  It's performance of x=.002, y=.004 (red +/-0.0%, green +/-0.0%, blue -2.9%) with a downloadSencore OTC-1000 using a NASA Calibrated White Reflectance Standard as the reference means that its neutral white color makes for a reference quality projection material.  CenterStageXDColorTesting.pdf (Rev. 8/09, 77.3k)

Worry no moiré

When two patterns are superimposed on one another, a moiré patterning effect can be created depending on the relationship of the projector's fixed panel pattern and that of the holes in the acoustically transparent screen.  One goal for an acoustically transparent screens is to have a high enough ratio of holes per pixel for interference not to occur.  Woven fabric screens are inherently superior to perforated vinyl screens in this respect, especially due to the Center Stage XD having over 1500 holes per square inch. For extra measure, our fixed frame screens are always cut at a 10 to 20 degree tilt with respect to the roll, eliminating the possibility of moiré with any projector at any size for resolutions up to 4K.


Center Stage XD is a woven fabric and while it is nearly the smoothest texture woven material available, it is not a sheet of vinyl.  For acoustic reasons, this is an advantage, but if you're going to sit 8 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.  Request a sample; you'll be impressed.

Screen, speaker setup

Screen  A good target for your screen width would yield a viewing angle of up to approximately 40 degrees, the THX recommended maximum.  You should consider smaller if you watch plenty of 16:9 content, standard definition resolution, or prefer a brighter, punchier image with smoother motion.  Target perhaps 35 degrees.  You could consider larger if you watch mostly film (e.g. 2.35 ratio) content, high definition resolution, have no ambient light, and prefer a more immersive experience.  We generally don't recommend larger screens than about 45 degree viewing angle unless you've had prior experiences and know you'll enjoy it.
For a 40 degree viewing angle, the ratio between the seating distance and screen width is 1.37.  For example, if you know you are going to sit 12.5 feet from the screen, the screen width you would target would be (12.5x12) / 1.37 = 109.5, so you may consider our 110 inch wide screen size, although we would generally advise to round down to the 105 inch wide size for better image fidelity.  For a 35 degree viewing angle the seating distance to screen width ratio is 1.59.
Speakers  If you have a very large screen and a narrow spacing between your left and right speakers you can get all three behind the screen.  The advantages of this include better concealment (e.g. high WAF factor), and the minimal sonic effect that the screen imparts will be identical across your (hopefully) identical front speakers.  The cinema certainly has all their front speakers behind the screen, but keep in mind they are very wide (e.g. 2.35, or "scope" ratio), always "high definition" film or 4K (which can support very wide viewing angles), and the side fill speakers are often installed starting fairly close to the screen.¹
THX guidelines for a dubbing stage are for the narrow end of our recommended range (22.5 degrees from center - 45 degree L/R spread), whereas the home theater guidelines are toward the wider end (30 degrees from center 60 degree L/R spread).  If your setup is destined to better adhere to THX and Dolbyhome theater guidelines, then your left and right front speakers are likely to be outside the screen.  If only the center channel is behind the screen, the high frequency attenuation isn't as noticeable on voices and instruments with high frequency content are more often mixed into the left and right channels.  Pay attention to where the speakers should be not only for on-screen sounds, but also with off-screen effects and keeping a smooth transition to your side speakers. 
Experiment with aggressive toe in for the left and right speakers.  Try aiming the left speaker toward the right-most seat and likewise with the right speaker.  It will likely improve off-center imaging and reduce the smearing effect from sidewall reflections.  You can angle any of the speakers that are behind the Center Stage screen without issue due to the screen's acoustical transparency.
You can place the speakers up to approximately two inches from the screen surface, as long as you don't have ports with high velocity airflow.  The deeper the bass that the speakers behind the screen are reproducing, the more you space you should give between them and the screen.  You can place a subwoofer behind the screen as long as it is spaced at least 12 inches away and no ports are directed at the screen.