Download Let`s keep things natural

Let’s keep
things natural
Reaching New Heights
in Signal Fidelity and
Speech Understanding
Oticon Agil Let’s keep things natural
Life around us is rich with possibilities,
sensations and action. We are drawn to them
naturally, eager to participate in our surroundings and to engage with others.
When listening in a complex environment
with many different sound sources, our cognitive system automatically tries to separate
them. Once they are isolated, we can then apply our attention to the specific sound stream
we’re most interested in and set competing
sounds aside. We cannot
selectively attend to the source that we find
most interesting until we organize every
sound source in our environment.
Speech is composed of intricate, precisely
timed acoustic events and any manipulation
of that signal runs the risk of compromising
this richly embedded waveform. Our users
need full access to all of the details of the
spoken word.
Preserving signal fidelity is essential.
Doing so gives the brain access to every bit of
information it needs to organize the world of
sound, select the sound stream that is most
intriguing and follow it over time.
Making sounds loud enough to hear and
applying processing to provide the fullest
access to the most important parts of the
signal must be accomplished with the utmost
of care. Overly aggressive, overly manipulative signal processing can easily corrupt the
natural intricacies of the speech signal. The
details of how you amplify the speech signal
make all the difference.
We say Let’s keep things natural!
Providing full access to the
sounds of life is the key to
helping those with hearing loss
Oticon Agil Let’s keep things natural
It’s not just about audibility, it’s about
creating order out of acoustic chaos
The brain’s natural 3-step process
of understanding speech
Hearing care is not just about making sounds audible. Increasing speech intelligibility depends
on so much more. Amplifying sounds while preserving not only the dynamics of the signal but
also as many as possible of the fine temporal structures and subtle acoustic cues is essential in
modern hearing care; hence the focus in Oticon’s research and development.
The brain is wired to absorb all of the sensory information around us and to organise it into
meaningful percepts. It untangles and separates different sound sources - such as one voice
from another; sounds coming from the kitchen versus sounds coming from the TV in the next
room; traffic noise versus playground noise, etc. The more accurately and naturally the information can be presented, the easier it becomes for the brain to create order out of the apparent
acoustic chaos of a soundscape.
Auditory input is extremely complex: rapidly-changing acoustic events can contain everything
from intricate timing cues, harmonics and loudness information to a phenomenal amount of
information embedded in the frequency spectrum. The purpose of modern hearing care is to
help the brain restore order to what seems like chaos, using whatever sources of information
are available, including: visual cues, situational cues and acoustic information such as spatial
cues and speech characteristics.
Organize, Select & Follow
Nature has endowed the auditory system with an ability to interpret sounds in a three-step
process. First, it organises the soundscape, an ability that is fundamental to speech understanding. This accomplished, the brain can then select the signal of greatest interest - such as
human speech - while suppressing (but not eliminating) other sounds in the environment. It
will then follow that signal over time.
The higher the signal fidelity the more relevant the information becomes, allowing the brain to
organise, select and follow a particular sound source, such as a conversation in a noisy restaurant. And since each and every acoustic cue is meaningful and indeed synergistic, people with
hearing loss must concentrate and work hard just to keep up.
If the signal is distorted; if acoustic components are missing, unclear, inaudible or degraded,
the listener will be forced to spend more energy on organising sound sources and resolving
ambiguities in an already difficult listening situation. But when the information is natural and
complete, the human brain effortlessly creates meaning out of acoustic chaos.
Organize
Select
Follow
In a soundscape, the auditory
system relies on spatial cues
and other acoustic information in order to make sense
of the many environmental
sounds. The brain organises
various streams of sounds as
identifiable percepts.
When a soundscape is organised, the brain is able to select
a particular sound source and
ignore intrusive background
noise. This ability is crucial; as
well as allowing us to direct
our attention to a particular
person it enables us to switch
our attention from one person
to another; something we
always do when interacting in
a group.
When listening, the auditory system instinctively
tunes into the individual
characteristics of the voice in
focus – i.e. level changes and
stress patterns. The higher
the fidelity and the better
preserved the natural dynamics of the speech signal are,
the easier it becomes to follow
speech and ignore competing
sounds. Any energy saved can
then be channelled into other
cognitive processes such as
reflecting, remembering and
responding.
Oticon Agil Let’s keep things natural
Casual conversation isn’t
meant to be exhausting
When considering what it takes to communicate in complex listening environments, sensorineural hearing loss can
be regarded as a loss of one’s ability
to organise sound in great detail. The
frequency, loudness and temporal distortions that characterise sensorineural
hearing loss can rob people of their
ability to distinguish one sound from
another.
Since even the smallest acoustic event
can be vital it is important to preserve
the entire acoustic event. Making speech
and other sounds audible is not enough;
if the auditory system fails to provide a
clear enough signal (high fidelity) the
brain will be forced to expend more energy
on unravelling the acoustic message than
actually listening. This reduces its capacity
to memorise, recall and respond to incoming
messages, which in turn leads to misunderstandings, frustration, and exhaustion. Only
with access to the entire acoustic event can
the brain perform to perfection.
Understanding releases precious energy
People with hearing loss must concentrate
harder in order to keep up. Exactly how much
energy this requires depends on the fidelity
of the signal being received from the peripheral auditory system. The more distorted
or degraded the signal is, the more energy
will be required to organise the soundscape,
segregate sound sources and resolve ambiguities in what already amounts to a difficult
listening situation.
Being able to automatically decode enough
of the speech signal to instantly recognise
what is being said gives listeners the freedom to channel their energy into performing
deeper level processing: to delve into the real
meaning of a conversation, to interpret and
respond, and to commit what was said to
memory. To this end Oticon has developed
a unique approach that involves preserving
signal fidelity for maximum speech understanding and minimum listening effort.
Oticon Agil Let’s keep things natural
Technology to support how
the brain works
Oticon’s new RISE II platform represents a
significant leap in processing power and
intelligence. Twice as fast as its predecessor,
this platform promises more efficient signal
processing than ever.
RISE II has facilitated three new audiological
concepts in Oticon Agil: Speech Guard, Spatial
Sound 2.0 and Connect [+]. These concepts
are designed to preserve naturally occurring speech and spatial cues while enriching
sound quality to such an extent that precious
energy can be conserved on listening.
Concept
Spatial Sound 2.0
Spatial Sound 2.0 maintains embedded
acoustic cues such as inter-aural level differences (ILD), which the brain uses to
organise the soundscape and select certain sound sources. Situations do exist in
which the preservation of natural acoustic
cues may not be enough to ensure optimal
speech understanding. For example, when
the Signal-to-Noise Ratio (SNR) is worse in
one ear, Spatial Noise Management helps the
auditory system focus on the side with the
most favourable SNR.
Technology
• 10kHz Bandwidth
• RITE Technology
• Open Ear Fitting
• Binaural Processing
• Spatial Noise Management
Speech Guard represents a revolutionary approach to signal processing. It maintains the
dynamic characteristics of speech and other
sound sources as much as possible using a
new signal processing strategy. It maps the
full range of the speech signal into the user’s
remaining dynamic range, ensuring audibility while preserving the subtle modulation
and temporal details of the speech signal. By
making sounds easier for the brain to decipher, Speech Guard makes it easier for the
listener to follow a certain speaker over time.
Connect [+] Power Bass and Music Widening are based on cutting edge technologies
designed to enhance the perception of bass
or low frequencies while adding a perception
of depth and spatiality to music. Connect [+]
significantly enriches the ConnectLine listening experience.
Benefits
Spatial Sound 2.0 helps the brain organise sounds by preserving naturally occurring spatial cues. When SNRs differ significantly between left and right ears, Spatial
Noise Management steps in to improve
intelligibility and listening comfort.
The energy of
understanding
Speech Guard
Connect [+]
• Floating Linear Gain
• Power Bass
• Music Widening
Speech Guard preserves vital speech
cues to enhance signal clarity and fidelity.
This helps to reduce listening effort and
enhance speech understanding.
Connect [+] delivers a richer, more natural listening experience by reproducing
the bass at a normal level and by recreating the natural depth and spatiality in the
streamed signal.
Speech understanding and listening effort are improved thus freeing
up the cognitive system to concurrently undertake other important
tasks such as remembering, reflecting and responding to what is being
said.
Spatial Sound 2.0
Oticon Agil Let’s keep things natural
Spatial Sound 2.0 organises the sound
environment and maximises intelligibility
Although we are rarely aware of the
spatial attributes of sound, the brain constantly uses spatial information to organise and select the most interesting signals.
Hearing instruments can compromise our
ability to access and use spatial information. For people to understand speech,
access to spatial cues in any soundscape is
vital. It improves not only their ability to
hear but also their ability to understand
speech in quiet and in difficult listening
situations.
Spatial Sound as a concept comprises four
components: binaural processing; extended
bandwidth; RITE; and Open Ear fittings.
These components help to preserve interaural level differences (ILD) as these are vital
to organising and deciphering various sound
sources in the listener’s environment.
Spatial Sound
In difficult listening situations, Spatial
Sound 2.0 adds a fifth component, Spatial
Noise Management, that helps the listener to
direct attention to whichever side of the head
offers the best SNR. It enhances the ear with
the best SNR to give the brain a richer signal
and to make listening easier.
the signal to maximise the audibility of the
better ear while suppressing the poorer signal side. Spatial Noise Management supports
the brain in its efforts to select sounds of
interest. In this case, selecting the ear with
the more robust signal makes speech more
accessible and listening easier.
When Spatial Noise Management is deemed
desirable, a series of adjustments are made to
Spatial Noise Management
Spatial Sound in Oticon Agil preserves
any inter-aural level differences created
by the head-shadow-effect (also referred
to as spatial cues), and supports the
natural process of organising various
sound sources, as illustrated in this
kitchen environment.
The ability to organise sound is crucial to
making sense of one’s surroundings and
to understanding speech. Spatial Sound
comprises four components: extended
bandwidth, open ear fittings, RITE
technology and binaural processing. All
four components contribute to preserving
important spatial cues.
The coffee machine on the user’s right side (bold
red waves) is producing excessive noise. Spatial
Noise Management detects the dramatic change
in SNR between the right and left ears via wireless binaural processing.
Spatial Noise Management applies noise management on the right ear to attenuate the noise
signal and, depending on the situation, adds gain
in the ear with the better SNR to enhance the
speech signal.
Speech Guard
Oticon Agil Let’s keep things natural
Speech Guard preserves signal fidelity
and the important details of speech
A
By fully preserving speech and spatial cues, and by greatly enhancing transparency, Speech
Guard takes sound quality to ever greater heights. Naturally, the more the amplified signal
resembles the original speech signal, the better the listener’s perception of it will be.
A) The sound picture of someone with
normal hearing. He/She is able to access
the full range of loudness, frequency and
spatial cues and receive all the important
details of speech.
Speech is dynamic, with levels that change over time. Amplitude changes represent an important natural cue that enables us to distinguish one person talking from another. For the most
part these changes occur within a predictable range and in a predictable pattern. In complex
sound environments however, other sounds can enter the picture. These sounds will affect the
behaviour of the signal, making it jump up and down in more unpredictable time patterns.
In order to protect the listener from such potentially dramatic changes in signal levels, compression strategies employed in conventional hearing instruments are designed to increase audibility of soft sounds and reduce the intensity of loud sounds - often at the expense of sound
quality. In fact, many subtle details of the original speech signal can be obscured by traditional
compression.
B
Floating Linear Gain
The new principle of Floating Linear Gain in Speech Guard helps to preserve the dynamic
details of speech across environments, resulting in audible but, importantly, natural speech
sounds. Providing a clear and natural signal reduces listening effort and increases the listener’s
ability to follow conversations. When signals are unclear, distorted or contain audible artefacts
from compression, the brain is forced to draw on additional resources to make sense of speech
or other sound signals.
Depending on changes in signal level, Speech Guard sets the appropriate linear gain level for
optimal amplification at each moment in time for a particular listening environment. For steady
sounds the linear gain is slowly updated. For sounds that are too soft or too loud, Speech Guard
responds rapidly with fast compression just for an instant, to quickly arrive at the appropriate
linear gain window for the new sound. This is the basic principle of Speech Guard.
B) Sound picture of someone with a hearing loss. Only loud sounds are audible and
the limited access to speech and spatial
cues means important details of conversation are missed without amplification.
C
C) With conventional compression systems, audibility and listening comfort are
achieved by making soft sounds louder
and loud sounds softer but not without
distorting the sound picture.
Speech Guard helps people to focus on the acoustic event that caused the signal level to
change, and not on artefacts created by conventional compression systems. This is achieved
through rapid response to level changes. This ensures that any changes to the gain do not affect the natural temporal characteristics of the acoustic event.
Also, when rapidly-changing sounds such as a dog barking or dishes clattering threaten to interrupt the speech signal, the system instantaneously responds. Such intrusions are amplified
at their natural level without being allowed to affect the ongoing level of the speech signal.
D
D) Oticon Agil preserves the most
informative elements of sounds such as
speech patterns and presents them distortion free within the listener’s reduced
dynamic range.
Principle for new Speech Guard
Illustration of floating linear gain
Speech Guard in principle
When the sound scene is steady with small
dynamic changes, the gain is linear and amplification will adapt slowly to changes in the
input level. For sounds that are too soft or too
loud, Oticon Agil responds rapidly with fast
compression just for an instant, to quickly
return to an appropriate linear gain window.
This ensures that speech and spatial cues are
amplified in a more natural and consistent
way across different soundscapes, which is
the basic principle of Floating Linear Gain.
Speech Guard in action
Participating in conversation requires an ability to follow speech over time. This means being able to focus on the person while ignoring
competing sounds, be it sudden loud sounds
(transients) or more stable background
noise. Speech is dynamic; its level changes
over time. Amplitude changes are important
natural cues that make it easier to differentiate one voice from another, making the job of
following conversation easier.
This unprocessed speech envelope with
a transient shows a waveform with a 6 dB
modulation depth and no distortion in the
signal. The transient is a short peak (50 ms)
of 80 dB.
With Floating Linear Gain the output signal
preserves the 6 dB modulation depth and
the distortion-free quality. The transient is
kept at a loud yet comfortable level where it
does not distract the wearer unnecessarily.
The Floating Linear Gain reacts so quickly
when handling the transient that the ongoing
signal is perceived as intact.
With a conventional compression system
the modulation depth is reduced and the envelope waveform is corrupted. When handling
the transient the compressor attacks too
slowly, making the transient very loud and
annoying. It also releases too slowly, which
makes the ensuing speech signal sound distorted and, in the worst case, inaudible.
Floating Linear Gain in Oticon Agil
Floating Linear Gain in Oticon Agil
Original signal
An Example of Floating Linear Gain Window
Unprocessed speech
dB
transient
Output
Octicon Agil
Floating Linear Gain
Insertion Gain
ns
fe
r
fu
nc
tio
n
Linear
tu
ra
l
tra
Conventional HI
Conventional compression system
Na
Speech Guard
Oticon Agil Let’s keep things natural
window
Input
Input level 67 dB with
500 Hz pure tone, 5
Hz modulated speech
envelope.
Connect [+] enriches the ConnectLine
listening experience
There are many sounds in life beyond faceto-face speech to which hearing instrument
users desire full access. People often complain that listening to the TV, radio or music
via their hearing instruments is not particularly enjoyable. But when sound is delivered
directly from the sound source to the hearing instruments, the listening experience
becomes far more pleasurable. This is what
Oticon Connect-Line is designed to do.
ConnectLine TV and ConnectLine Phone solutions deliver sound signals from TVs, mobile
and landline phones directly to hearing
instruments via the Oticon Streamer, with excellent SNR. Oticon Agil takes direct wireless
streaming of sounds to entirely new heights
with the introduction of two highly innovative signal processing advances: PowerBass
and Music Widening.
Power Bass
Music encompasses a wide range of frequencies as well as dynamic variations. Thus, the
more access people can gain to these frequencies and dynamic changes, the greater
the joy of listening will be. When streaming
sound to open or vented hearing instruments, low frequency (bass) content tends
to leak out of the ear canal, which limits the
potential bass output of the streamed signal.
The bass content is further limited by conventional compression strategies, as these
cannot react fast enough to dynamic changes
of the low frequencies without distorting the
signal.
Power Bass enables intelligent provision of
optimal low frequency amplification. Zerodelay processing ensures no signal distortion.
With PowerBass not only is the bass content
PowerBass
of the signal optimally increased; the perception of bass is enhanced using low frequency
overtones.
Music Widening
The perception of spatiality that is embedded in sound also contributes to its naturalness, depth and fidelity. Sound emitted in
an enclosed space such as a concert hall is a
product of sounds coming directly from the
original sources combined with sounds being
reflected from various surfaces in the room.
Our binaural hearing system utilises any
inter-aural timing and level differences
detected in reflected sounds to gain a perception of the size of the room, our own location
within it, and to externalise sounds that are
heard. When sound is streamed directly from
0
In a real listening situation the sound perceived by the user is a combination of sounds
emanating directly from people talking (blue
waves) and reflections from the room itself
(light blue waves). These reflections provide
a real sense of spatial awareness and lend
sought-after depth to the acoustic signal.
Virtual Reflection
0
PowerBass ON
PowerBass OFF
PowerBass OFF
Level relative to maximum (dB)
PowerBass ON
−20
−40
The effect of music widening is here illustrated by showing a real acoustic situation,
where a person is situated in a living room
enjoying music played from a hifi-system.
In this real situation, the sounds perceived
by the user is a combination of sounds coming directly from the speakers (blue waves)
and the reflections from the walls of the
room (red waves). It is these reflections
that account for the perception of spaciousness and depth to the acoustic sound.
−20
−60
100
1000
10000
Frequency (Hz)
When there is headroom available the Power Bass
algorithm enhances the low frequency (LF) signals
by adding LF gain (indicated in blue). This is particularly desired in open/vented fittings where LF
will leak back out through the vent in streaming
situations.
−80
100
1000
Music Widening adds the perception of
depth and spaciousness to streamed
sound
Virtual Reflection
−40
−60
−80
the source to the hearing instruments, such
perceptions can be affected and sounds may
seem to originate from inside one’s head.
Oticon Agil’s Music Widening feature helps
to restore a perception of space and depth by
creating virtual sound sources from virtual
room reflections. This feature offers a more
complete and natural music experience.
Music Widening
Power Bass gives a natural harmonic balance to streamed sound by enabling better low
frequency reproduction. In does so in two ways.
Level relative to maximum (dB)
Connect [+]
Oticon Agil Let’s keep things natural
10000
Frequency (Hz)
The Music Widening algorithm in Oticon
Agil is based on the creation of virtual reflections in the processing of the streamed
signal to give the user the perception of
a ‘virtual’ room. This virtual effect will be
present regardless of where the person
listening to the streamed music is located.
When no headroom is available, adding gain to the
low frequency signal is no longer an option. Using
the principal of missing fundamentals Power Bass
then generates low frequency harmonics to create
a high level low frequency tone (indicated in blue).
In doing so, it achieves the goal of enhancing the
perception of bass.
Virtual Source
Oticon Agil Let’s keep things natural
Oticon Agil gives users
the energy of understanding
Oticon Agil is the latest step in our journey
to give users the means to spend less energy
on listening and understanding and more on
actively participating in life. We call it the
energy of understanding.
To us, the ability to enjoy life means being
able to live it without limitations. And, like
you, that is what we work towards achieving
for people with hearing loss. That’s what we
mean by People First.
Our insights into how our hearing system
and brain works allow us to develop products
to support the natural auditory system and
are the inspiration for our innovation. And
through this, we develop solutions that bring
people even closer to the world around them.
It’s about empowering people and giving
them the ability to live life to its fullest.
People First
People First is our promise
to empower people
to communicate freely,
interact naturally and
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participate actively
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