Why Use an Acoustically Transparent Screen? |
With virtually no loss of sound quality, it allows a center channel speaker
to be positioned directly behind the screen, the optimal location for full
range audio performance. When installing a home theatre system, the proper
set up for the sound system ensures the highest quality results. The
ideal position for the main speaker is behind the screen on the same
level as the right and left speakers. This maintains:
- Quality sound localization for the dialogues
and overall sound effects
- Movie Theatre quality that is true to the
original sound mixing engineering
- The ability to use identical speakers due to
space restrictions and avoids interference with other objects on the
floor or ceiling.
Figures 1 & 2 and Table 1 show the third-octave
band insertion loss results in detail from 100 through 20,000 Hz. and
summarizes the average and maximum screen insertion loss (IL) for each
screen sample, as well as the band in which the maximum IL occurred.
These results are valid for third-octave bands between 100 and 20,000
Hz.
Acoustically Transparent AT1200/AT Grey Test
Procedure
Testing of the AT1200/AT Grey acoustically
transparent material was performed by engineers at Auralex Acoustics in
Indianapolis, IN in November of 2005. A Klipsch loudspeaker was
positioned in a semi-anechoic test room such that it simulated a
center-channel configuration in a typical theater setup. An Earthworks
omni-directional microphone was placed 24" from the loudspeaker.
Wideband (20-20,000 Hz) pink noise was played through the loudspeaker
using the Goldline Audio Toolkit DVD. The third-octave band levels were
measured with the TerraSonde Audio Toolbox 3 analyzer using Real-Time
Analysis (RTA) module.1 The overall noise level was set such that the
signal-to-noise in the test room was at least 25 dB in all bands of
concern. A 30-second average of the sound level was measured and saved
with no screen sample in place.
Using the temporary screen framing apparatus
provided by Draper, the screen samples were placed between the
loudspeaker and the microphone. The wideband pink noise signal was
played again through the loudspeaker and the third-octave band levels
were measured and saved for each screen sample. Nominal screen sample
size was 64" wide by 36" high. The distance from microphone to screen
sample surface was ~18". (Note: Different screen-to-loudspeaker and/or
screen-to-microphone distances yielded no significant changes in the
measured results.)
1 Microphone and analyzer were calibrated to 94
dB(SPL) at 1 kHz. Levels were measured from 25-20,000 Hz, but only the
bands of concern for transmissibility are reported, i.e., 100-20,000 Hz.
Photo 1: Special lighting effects
show the silhouette of the front and center channel speakers hidden
behind the AT Grey projection screen.
Photo 2: Draper 119" HDTV Onyx with
AT Grey viewing surface and a Vel-Tex® covered frame. Photography:
©Scott Arthur, Weaverville, NC. Design/Installation: Scott Varn, Harmony
Interiors, Asheville, NC.
About Draper Acoustically
Transparent AT1200 & AT Grey
Draper's acoustically transparent (AT) viewing
surface is the most innovative and versatile acoustically transparent
front projection screen material available. With virtually no loss of
sound quality, it allows a center channel speaker to be positioned
directly behind the screen, the optimal location for full range audio
performance. With over 76,000 microscopic openings per square foot, both
the AT1200 and AT Grey have the sound transmission characteristics of
high quality speaker grille cloth, with less than 6% light loss. Both of
Draper's acoustically transparent screen materials allow audio and video
to interact seamlessly, creating the ultimate home theatre experience.
