Activeforever Bellman and Symfon Maxi Personal Amplifier - Manual (Page 2)

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: [email protected] kHz
-6dB@250Hz Tone, mid: flat
Tone, low: [email protected] 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 chan-
nels to continuously analyse and attenuate stationary noise.
The noise cancellation dynamically adjusts the gain for each frequen-
cy 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 continu-
ously 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 operat-
ing 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_008D
AS_001_EN
© B
ellman & S
ymf
on AB 2008