Page 28 - Fall_DTF

Perception of Benin Beams

A series of simulator tests was also conducted by the Iapan the average increase in annoyance due to rattle was equivalent
Aerospace Exploration Agency (IAXA; Naka, 2013) to to an increase in exterior boom PL of 4 dB, confirming the
evaluate loudness and annoyance ratings of N-waves with headphone test rattle penalty of 3-9 dB.

different amplitudes and rise times, using both indoor and _ . _ .

‘d fi t_ Th ‘ ‘ I t d 1 dn Vibration studies were also conducted in the IER (Carr and
0“ cor Con gum mm‘ 2 l _ as S ev_a “a e O“ _ ass Davies, 2015; Rathsarn and Klos, 2016; Rathsarn et al., 2018)
and annoyance and found that indoor ratings were higher _ _ . . .
than outdoor mm‘ s fora Wm 10“ dness level using vibration isolators on the test chair legs and shakers

g g ‘ attached to the seat bottom. For vibration levels near the high
Human Response to lndoarBaams end of what is predicted to occur in buildings (Klos, 2016),
hi recent years, sonic boom subjective research has shifted vibration penalties up to 10 dB were observed, indicating
to exploring perception of booms experienced indoors. that vibration also plays a role in the indoor perception of
Initial studies in NASA’s IER simulator found that boom sonic booms.
“rude and rise time Persist as important factors for Startle is another possible factor in the human response
an indoor response (Rathsarn et al., 2012; Loubeau et al., . . . .
_ _ _ to sonic booms. Earphone studies examined startle in
2013a). Overall, the longer rise tunes of low booms result in _ _ _ . .
decreased annoyance conjunction with annoyance and loudness for impulsive
‘ sounds (Marshall and Davies, 2011, 2012) and found that
To assess the feasibility of utilizing a subscale flight startle ratings were strongly correlated with annoyance due
demonstrator, a comparison of indoor annoyance to sonic to the abruptness of the initial shock and resulting high-
booms predicted for subscale and full-scale supersonic frequency energy. Subjective judgments of startle were
aircraft (which have different low-frequency energy, even for compared to physiological responses using measured skin
the same overall loudness value) was conducted (Loubeau, conductance, heart rate, and electrical activity of three
et al., 2013b; Loubeau, 2014). The test used shaped, low- neck muscles. Although subject-to-subject and day-to-day
amplitude booms for four classes of aircraft size from variabilityin the physiological responses were observed, their
subscale demonstrator to full-sized airliner. For a given association with startle was rare, and it was concluded that low
outdoor PL, the annoyance to subscale aircraft booms was booms are below the threshold of consistent startle responses.
not significantly different from that for full-scale aircraft Cammunflysmdies
booms. This confirmed that outdoor PL can be used to . . . .
Data relating the response of communities to low-amplitude
evaluate supersonic aircraft designs regardless of size. These . . .
sonic booms are needed by the international regulatory
results show evidence that human response to booms from . th d .d .f . I d fl. ht
b ale demonstrator are relevant to a full-size aircraft agencies so all can ea e ‘ supersonic over“ ‘g
a 5“ Sc will be permitted. If so, the regulators will need to establish
and help justify plans for use of a subscale demonstrator . . . . .
f _ d_ h 1 1_ _ d low-boom criteria for certification of supersonic overland
or community stu ies. However, t e resu ts were unite to aircraft The“ decisions will need to be based on bum sing1e_
isolaled booms with no fame‘ event and cumulative impacts Community testing protocols
A series of tests was conducted to investigate the human are under development to gather these response data.
response to rattle and to combined boom and rattle (Loubeau Historically, noise dose-response testing for transportation
et al., 2013c). Using binaural recordings of rattle played back sources and for military installations with impulsive noises
over headphones, the study found differences inannoyance such as booms, artillery, and blast noise has related the
between rattle sounds for the same PL. Rattle sounds from percentage of community members highly annoyed by the
structural elements such as windows, walls, and doors were noise to cumulative metrics such as day-night level (DNL).
judged more annoying than rattle from smaller objects, and In 2011, a NASA Community study was Conducted of the
the study confirmed the presence of elevated annoyance response of 100 Edwards Air Force Base (EAFB) Caufomia
indoors when rattle is Present‘ residents to sonic booms The waveforms and sonic boom
Rattle studies conducted in NASA’s IER facility using a more perception and response (WSPR) program was designed
realistic sonic boom playback and indoor environment to test and demonstrate the applicability and effectiveness
(Rathsam et al., 2015; Loubeau, 2018) found that rattle of techniques to gather data relating the human subjective
increased indoor annoyance. Window rattle sounds response to multiple low-amplitude sonic booms, i.n essence
reproduced for avariety of window types demonstrated that a dose-response test. It included a range of sonic booms from
as 1 AI:i:iuI:lr:I Tbday 1 hiizois