Activeforever Bellman and Symfon Maxi Personal Amplifier User Manual
Bellman® Audio Maxi is a revolutionary communication aid
that uses digital state-of-the-art technology to bring out
speech and music in diffi cult listening situations. Maxi is
developed especially for people who prefer an easy-to-use
device with large tactile controls and clear indications. Maxi
is intuitively user-friendly a
nd has superior sound quality.
Outstanding
sound. Maxi delivers the clear and crisp
dig
ital sound that you deserve. It fully exploits the advan-
tages of digital technology t
o clarify speech and reduce
anno
ying background noise and feedback - all to give you
an outstanding sound quality. Thanks to a unique micr
o
-
phone suspension, Maxi’s ultra-sensitive microphone is
eff ectively protected from handling noise. This guarantees
hours of comfortable and noise-free listening.
Easy to handle. Bellman Audio Maxi has been designed
with
simplicit
y and usability in mind. The unique design
makes Maxi practically intuitive to use. All common func-
tions can be accessed using a single push on a button and
there are no complicated menus to get lost in. Unparal-
leled ergonomics combined with high contrast colouring,
large tactile buttons and soft grip materials, makes Maxi
the ideal companion for hearing impaired people that de-
mand fl exibility, quality and ease of use.
Maxi
Digital communication aid
www.ActiveForever.com
Technical specifications
Dimensions
Weight
Battery type
Battery life
Ext. mic./Aux in connector
MicroSet
TM
/headphones conn.
Volume control
Tone control
Power switch
Mic and T-mode
Ext. mic / Aux in accessories
MicroSet
TM
accessory
R/L-channel balance setting
Maximum volume setting
Dynamic compressor
Dynamic noise reduction
Feedback cancellation
Digital signal processing
Acoustic specifications
Output level with BE9122
Ref. test gain
Output level
with BE9125
Ref. test gain
Electrical specifications
Output power
Distortion
SNR
Frequency response
Aux in sensitivity (max input lvl.)
140 x 45 x 27 mm (L x W x T)
133 g (including batteries)
Two ”AA”-size alkaline cells
Up to 150 h
2.5 mm stereo telejack
3.5 mm stereo telejack
9 steps (5 dB/step)
5 pre-set steps, push-buttons
on-off toggle button
Separate mode select buttons
Automatically selects Aux in or
ext. mic. when plugged in
Automatically selects MicroSet™
accessory
when plugged in
0-20 dB programmable attenua
-
tion (in steps of 5 dB)
0-21 dB programmable attenua
-
tion (in steps of 3 dB)
10 channels
Dynamic gain range: 0-35 dB
Compression: 3:1
Expansion: 1:1.5
Attack time: 25 ms
Release time: 250 ms
10 channels Adaptive frequency
domain noise reduction
Adaptive time domain feedback
cancellation
19.948 kHz sampling frequency
16-bit resolution in stereo
IEC 118-0
117.67 dB @ 1 kHz (SPL90)
119.52 dB (HF Ave. SPL90)
29.21 dB (SPL70)
134.85 dB @ 1 kHz (SPL90)
130.89 dB (HF Ave. SPL90)
38.9 dB (SPL70)
125 mW/channel (@ 16 Ohm load)
0.559 % THD
82 dB
40 Hz – 10 kHz
Tone, high: +10dB@3.15 kHz
-6dB@250Hz Tone, mid: flat
Tone, low: -10dB@3.15 kHz
No bass boost
+6 dBV
Features
Digital signal processing
Omni-directional electret condenser microphone
Telecoil pickup for inductive loops
10 channel dynamic range compressor
10 channel dynamic noise suppression
Adaptive feed-back manager
Intuitive user interface
▪ LED lightbar for excellent readability
▪ 9 step volume control (5 dB/step)
▪ 5 step tone control
▪ Mic and T-mode indicator
▪ Low battery warning indicator
Auxiliary stereo signal input (2.5 mm telejack)
Headphones stereo output (3.5 mm telejack)
Push-To-Listen mode (Int. mic and Aux in mixed)
Soft-mute when switching between signal sources
Advanced settings
▪ L/R channel balance control (5 dB/step)
▪ Maximum volume control (3 dB/step)
▪ T-coil selector lock (on/off)
Requires no individual fitting
Powered by two AA-size alkaline batteries
Transparent belt clip
Noise cancellation
Noise cancellation operates in frequency-domain and uses ten channels to continuously analyse and attenuate stationary noise.
The noise cancellation dynamically adjusts the gain for each frequency band to give an optimal dynamic range, thus suppressing noise
without affecting speech or other interesting information.
Noise is suppressed with 5 dB without sacrificing resolution or intro
-
ducing sound artefacts, which increases the listening comfort.
Dynamic range compression
The dynamic range compressor operates in the frequency-domain
and is implemented as 10 channels, logarithmically.
Each channel has individual attack/decay, expansion, compression
and saturation distance parameters, which have been trimmed to
reduce microphone noise, emphasise speech or other interesting
information and still offer a natural sound.
The personal amplifier should not need individual fitting nor user
selectable programs, which means that the parameter settings have
been preset from factory.
Feedback cancellation
The feedback cancellation operates in the time-domain by continuously analysing the signal to detect pure tone within a certain fre
-
quency range, since they may indicate a build-up of feedback.
The adaptive algorithm estimates the feedback potential (path) of
the amplifier and can accurately (in magnitude and phase) eliminate
the feedback cause even before the whistling occurs.
The algorithm reacts quickly to any change in the feedback path caused by moving. Feedback cancellation works for different posi
-
tions of the headphones (near the amplifier as well as away from it).
The feedback cancellation provides the user with 10 dB additional
gain, which is beneficial when using open type headphones (or other
open fitting transducers).
Battery level supervision
The supervision of the battery voltage level is continuously operating in the background, making one measurement every 10th second.
The result of the measurement is presented to the user by means of
the Low Battery indicator (Amber LED).
The battery supervision indicates a Battery Low condition when the
estimated remaining battery time is around 10 hours.
When the battery is almost depleted the battery supervision shuts
down the amplifier in an controlled manner, to avoid unpleasant
sounds or malfunction due to abrupt power loss. The amplifier noti
fies the user about this action by three quick consecutive flashes of
the Low Battery indicator before it shuts down.
Frequency response/tone control
BE2020_008DAS_001_EN © Bellman & Symfon AB 2008
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