SOUND 2 PREMIUM Electronic ear new generation


NEW SOUND 2 numeric electronic ear
Logo de la marque Hasler

Function :

SOUND 2 PREMIUM is a numeric electronic ear new generation.
Sound 2 PREMIUM is a digital ball mill level indicator able to sense precisely the noise level of the ball mill. This sound system has been imagined & created by HASLER Group.

SOUND 2 PREMIUM is a unique advanced electro-acoustic transducer able to evaluate and show on display the filling level of ball mills. Compared to other basics ears available on the market, SOUND 2 PREMIUM shows you the data you have to pilot for more productivity and integrates one of the most accurate measurements and high perfomance algorithms of the market.

The operating noise defines the filling ratio of the ball mill: full mill makes soft & dull sounds or empty mill diffuses loud & high sounds of ball mills.

SOUND 2 PREMIUM is a plug & play digital ball mill level indicator able to sense precisely the noise level of the ball mill. The 2 major advantages of a digital signal compared to an analogue signal are :
Higher precision in measuring, analysing and processing the signal in real time from the microphone.
DSPs simplify filters as they allow predictable and highly repeatable results (characteristic of digital circuits, as opposed to analogue circuits).

Sound 2 PREMIUM is composed of a microphone and a front panel display integrating a software with advanced control algorithms. Sound 2 PREMIUM is robust and has been developped to meet constraints in cement applications:
● The head of the microphone is 4-5 cm in the rear, and is protected by a fine grid covered by a thin plastic film at the level of the foam coat.
● The microphone is insulated from the interfering noises existing in the plant.
● The front panel display is composed of a watertight cover able to prevent the entrance of dust, which would disturb the response of the electronic ear.

Key benefits

  • High performance to increase productivity of ball mills
  • Numeric data treatment : high precision & process of the signal
  • Analogic data output (0/4...20 mA)
  • Control system able to confirm transmission of DSP data
  • Integrates a cross talk system (see details next page)
  • Customized information front panel display (eg: filling level)
  • Plug & play system & stock available
  • Helps to reduce power consumption per ton of the product
  • Helps to reduce wear of grinding media and lining
  • Over 35 years of experience on electronic ears : product durability & reliability
  • Designed for dusty environment

Key features

  • Numeric signal for sound acquisition & processing
  • LCD screen (HMI)
  • Automatic calibration
  • Read & Host communication (remote control)
  • Host Prot. configuration & diagnosis
  • Adaptation according to the material to be crushed
  • Compatible with previous electronic ear Sound 1
  • IP65 metal body
  • Multi-language interface


The SOUND 2 PREMIUM is configurable by the communication via various protocols, and also allows the data transmission of
measurement :
• Modbus TCP (RJ45 Ethernet)
• Modbus RTU (RS422)
• Profibus DP (RS485)


The heart of the electronic ear SOUND 2 PREMIUM is digital & provides accurate measurement.
This system includes an autocalibration function to ease commisionning. The digital outputs are configurable by the user.

The filling level can be displayed on the LCD screen.
This solution enables you to filter precisely the sound of the ball mill to gain accuracy.
The digital outputs are configurable by the user

Configuration & soft maintenance

  • Maintenance can be performed by

  • The calibration parameters can be stored on SD card

  • Restitution of parameters by SD card


  • Sound 2 PREMIUM compensates the interference noise from adjacent mills.
  • In the example on the right side, a portion of the output of the wiretap No. 1 is used to offset the interference of the mill Wiretap No. 2 and vice versa.
  • The crosstalk copensation is adjustable between 0-17%.
  • 0 to 6 V signal - independent of the configuration of the monitor - is used to correct the indication of the other ear. This signal is called CT OUT, an abreviation for «Cross  Talk OUTput.»
  • Sound 2 PREMIUM is compatible with Sound 1.


SOUND 2 PREMIUM microphone can be installed «plug & play» on ball mills.
This mill control system consists in a very sensitive microphone installed close to at the mill inlet, at the grinding ball impact point and as close as possible to the mill shell. The foam of the numeric electronic ear must nearly touch the mill shell.



Technical specifications

  • Adjustable gain from 0 dB to 45 dB
  • Operating frequency span : 300 Hz to 4500 Hz
  • Voltage output : 0 ... 10 V on minimum 1 kΩ
  • Current output : 0/4 ... 20 mA on a maximum load of 600 Ω
  • Humidity : According to DIN40040 class F 95% at 25°C non-condensing
  • EMI rating: ±2 kV on the signal, ±4 kV on the 220 VAC power supply
  • Case size : Width 256 mm, height 270 mm, depth 118 mm
  • Protection grade : IP65
  • Weight : 2900g.

Power supply

  • 88 VAC until 264 VAC. Frequency : from 47 Hz to 63 Hz


According to IEC 654-1

  • Operating :  -10°C to + 50°C
  • Storage : -30°C to +70°C

Relays contacts

  • Max. switching current : 2 A, AC
  • Max. switching voltage : 24 VDC, 250VAC
  • Max. switching power : 125 VA (48 VA)



  • General Electrical Emissions: EN50081-2
  • General Electrical Immunity: EN50082-2
  • Electrical safety: EN61010-1

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