Why the PA Isn't Always Enough
By Stephen O. Frazier, Hearing Loss Support Specialist
Let anyone who has an ear listen to what the Spirit is saying to the churches.
(Rev. 2:29, NRSV)
The preaching and hearing of the gospel is central to the service in church but, for many
of the faithful, simply having an ear is not enough. Over one in ten Americans suffers
from a hearing loss and the incidence increase sharply with age - more than half of those
over seventy-five are affected.
Although many with hearing loss may still be able to communicate effectively in one-onone
conversations in quieter settings, hearing and understanding in public venues
(especially in large and reverberant churches) can be difficult to impossible. Hearing aids
and a good PA system help some but for many something more is needed.
If you hear, “I can't understand a thing he's saying,” it could be the listener has a hearing
loss sufficient to impair the ability to turn sounds into words. Simply turning up the
volume on the churches public address system (PA) is not going to solve the problem.
Louder is not necessarily better where the hard of hearing are concerned. Some basic
fundamentals of sound and sound processing problems sometimes unique to the hard of
hearing play key roles in understanding what's being heard.
Most people with hearing loss either have difficulty hearing higher pitched sounds or
can't hear them at all with the unaided ear. Vowels fall into the lower to mid range of
sounds typical of human speech while consonants fall into the upper range.
Consequently, a person who is hard of hearing will have difficulty discriminating
between such words as sill and till – particularly in a setting such as a place of worship, a
legislative chamber or someplace similar where the listener is some distance from the
person speaking and following the proceedings through sound from the typical public
Today's hearing aids compensate to a degree for the user's inability to hear high pitched
sounds by providing more amplification for those frequencies than the lower pitched
vowel sounds and are adjustable so that the amplification matches the user's hearing loss
at various frequencies as depicted in his or her audiogram. With hearing aids, in a one on
one situation, a hard of hearing person will usually be able to hear and understand what's
being said. If the speaker moves away, however, that understanding is impaired because
of factors the hearing aids cannot compensate for.
Typical directional microphones in hearing aids, intended to improve speech
understanding in noisy environments, have an effective hearing range of about six feet
(Etymotic Research, 2000a) so beyond that distance speech can become problematic due
to some fundamentals of sound and hearing . With the typical emphasis on pushing the
lower frequencies to make a PA system sound “good”, an engineer is actually making it
more difficult for the hard of hearing person to understand what's being broadcast by that
system by denying them the high frequencies.
Fundamentals of sound
One of the basic rules of sound engineering is the 6 dB rule of distance. Every time the
distance from the noise source is doubled, the sound pressure weakens and the level
decreases by 6 dB. Another rule, not of sound engineering but of people's perception of
sound, is the 10 dB rule. People generally perceive that the loudness of a sound doubles
every time the sound pressure level increases by 10 dB thus a sound at 60 dB will be
perceived as being twice as loud as one at 50 dB and at 70 dB would be heard as four
times as loud.
Signal strength by frequency
Another problem faced by those with hearing loss is the relative strength of sounds at
various frequencies. The amplitude of lower pitched sounds is greater than higher
pitched sounds and they will travel farther before they weaken to the point that they can't
be heard than will higher pitched sounds. As a result, as distance increases, the typical
hard of hearing person with high frequency hearing loss may still hear the lower
frequency vowel sounds but not higher frequency consonant sounds so critical to speech
understanding whether hearing aids are in use or not.
Speech to noise ratio
The speech to noise ratio plays an important role in speech comprehension and is
especially important to those with a hearing loss. It is, simply put, the difference between
the decibel level of the speaker and the level of background sound or noise. For those
with normal hearing a 10 dB difference is considered acceptable but for those with
hearing loss, it needs to be often as much as 20 dB or even 25 dB for adequate
comprehension of what the speaker is saying. This means background noise should not
exceed 55 dB for those with normal hearing to carry on a conversation without raising
their voices but may need to be as low as 40dB for a person with even a moderate
hearing loss to hear and understand a speaker whose voice measures 65 dB.
The speech to noise ratio comes into play in settings where the sound level of speech
goes down due to increased distance from the speaker but the background noise level
remains the same. As the distance from a loudspeaker increases but the background
noise level remains the same, a person with normal hearing may still hear and understand
the proceedings being broadcast by the loudspeakers but a hard of hearing person will
not. This situation is further complicated if there's considerable reverberation to contend
with. The ability of a hard of hearing listener with even just a mild to moderate hearing
loss to discern the words being said in strongly reverberant environment drops off much
more quickly than for a person with “normal” hearing. With the addition of background
noise, the drop off is even more significant (R. Harris & D. Swenson 1990).
The cocktail party effect
Further exacerbating the problem for the hearing impaired in a noisy environment is the
presence of voices other than the speaker. The ability to focus on one voice while
mentally blocking out others or to differentiate speech from background noise is known
as the "Cocktail Party Effect ." A very common problem affecting at least 20% of both
old and young people is this inability to focus their auditory attention on a particular
stimulus while filtering out a range of other stimuli just as a party goer can focus on a
single conversation in a noisy room. In that setting some will struggle to understand
conversation when there are multiple voices. Add hearing loss to the equation and they'll
understand little or nothing of what's being said.
Further, research documents that as people age they experience a decrease in their
cognitive ability and are found to particularly have reduced speech recognition abilities
when speech signals are altered or degraded in some way such as a strong Spanish accent
heard by a non-Spanish speaker (Gordon-Salant et al., 2008) and that they, like others
who are hard of hearing, could benefit from the slowing down of speech and increasing
Assistive listening systems
To address the speech perception problems people experience, even when a PA system is
used, the Americans with Disabilities Act (ADA) mandates the use of assistive listening
systems (ALS) in "each assembly area where audible communication is integral to the
use of the space" or "wherever audio amplification is used.” The sound signals delivered
by an ALS do not travel through acoustical space before arriving at a listener's ears but
are delivered directly via FM, infra-red or magnetic induction thus the sound received is
not weakened by distance or degraded by noise and reverberation during its transmission
thus improving the speech to noise ratio dramatically.
The ADA also requires that new assistive listening systems in public venues be hearing
aid compatible meaning their signal can be accessed without users removing their hearing
aids. All three currently available ALS technologies meet this requirement. FM and Infra
Red systems do so by incorporating a neckloop instead of a headset or ear buds with their
receiver. Users with telecoil equipped hearing aids access the sound by donning the
neckloop and turning on the telecoils in their hearing aids or cochlear implant.
For hearing loop systems, the loop transmits directly to the hearing aids and cochlear
implants via their t-coils and to other users via a receiver and headset or ear buds.
Because this allows users to keep their hearing aids in place (avoiding the possibility of
damage or loss), they are not required to borrow and then return a receiver and headset (if
fitted with t-coil equipped hearing aids) and provides sound customized to match the
unique frequency needs of each user, hearing loop systems have become the preferred
system of those with hearing loss.
ALS User Survey
A survey recently conducted by the Committee for Communication Access in New
Mexico, a nonprofit hearing loss advocacy group, has documented the preference of the
hard of hearing for hearing loop technology and the higher rate of use it receives over
systems requiring the use of a headset or ear buds.
The survey conducted using Survey Monkey and invitations to participate were sent to
over 2,000 known hard of hearing recipients in New Mexico and around the US. Nearly
350 individuals responded. All of them were not only hard of hearing, 98% had
addressed their hearing loss by getting hearing aids or a cochlear implant and 89%
reported having telecoils in their devices. 6% reported they did not have telcoils and
another 6 didn't know if they did.
When asked, "If you go to a theater, place of worship, meeting room or other venue that
has an assistive listening system where you must borrow a receiver and a headset, how
often do you borrow the equipment?", only 19% of respondents reported always
borrowing the equipment with 13% saying, "usually", 23% claiming "sometimes" and a
whopping 45% saying "never."
Hearing Loop advocates claim loop and telecoil technology is much preferred by the hard
of hearing since it allows users to access an ALS without the need to remove their
hearing aids and risk losing or damaging them. Users also express concerns over hygiene
with borrowed headsets or ear buds. Do these claims and concerns result in behavioral
changes when you transition from headsets to neckloops or to actual hearing loops in
place of FM or IR? According to data gathered in the CCAnm survey the answer is most
definately yes. When asked the same question as that noted earlier but with a neckloop
instead of a headset being part of the borrowed equipment, the "Never" response goes
down from 45% to 31% - a significant increase in equipment users.
Further confirmation was recorded when participants got to number 9 in the 10 question
survey. When asked," If you go to a venue that has a hearing loop, how often do you
listen to the proceedings using the telecoils in your hearing aids or cochlear implant?"
Among respondents who had telecoils and visited looped venues, 55% responded with
"always" and another 14% reported they "usually" turned on their t-coils - a resounding
two thirds! With another 11% saying they sometimes do, that left 8% reporting they
"never" and the remainder checking they don't have telecoils or they have no access to
hearing loops. 8% saying never use with loops campared to 45% with headsets
demonstrates an overwhelming preference for hearing loops over the ubiquitous but
largely unused FM or IR systems found in so many public venues in America.
If the purpose of a church's ALS is truly to make the service available to the most people
possible among those in their congregation with a hearing loss, then audio frequency
inducation loop systems (AFILS or hearing loops) are by far the most helpful to the most
people and the reason the Hearing Loss Association of America is encouraging churches
and other places to Get in the Hearing Loop.
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