Smart Acoustic SIEM250 In Ear Monitoring System (655~679 MHz)

Smart Acoustic


This system operates in the 655~679 MHz frequency range which is good for most areas. To learn which frequencies will operate in your area please use the ACMA Channel Finder at

The SIEM250 is easy to setup and great sounding all inclusive wireless in ear monitoring solution from Smart Acoustic. With each SIEM250 you get 1 x Transmitter, 1 x SRC250 Bodypack, an Earphone set with replacement gommets, 1 x Antenna and Power Adaptor all contained within a road worthy metal travel case. Running on the UC UHF band with a frequency range of 655 – 679MHz, linking your Transmitter and SRC250 Receiver together is a quick process. Simply match the Channel number on both units and you are good to go. Either Mono or Stereo in ear mixes can be created on your mixing console to send to your SIEM250 systems XLR inputs. The LCD display on the Transmitter will then show you the level of the signal entering the unit so you can adjust the Input Level control on the face of the SIEM250. If the signal needs to be reduced further, there is a handy -12dB pad switch on the rear of the Transmitter.

You can also monitor the signal being sent to a body pack with the SIEM250’s headphone output. The lightweight and durable poly carbonate SRC250 Bodypack Receiver that comes with your SIEM250 system can be mounted to your belt or to a guitar strap. It is powered by 2 x AA batteries and has >5 hours operating time. On the easy to read LCD display of an SRC250 you can monitor in real time the RF connection strength to the Transmitter and the level of signal being sent to the SRC250. You can also monitor the Battery life in the unit and can quickly adjust your output level with its volume control. The SRC250 also allows you to set discrete EQ specifically for that receiver with 2 different modes. Extra SRC250’s can even be added to a SIEM250 system to receive the same mix signal. The SIEM250 Transmitter can be rack mounted in a 1RU space with the included Rack Ears.

Warranty: 12 Months

  • Wireless In Ear Monitoring System
  • 120 Frequency channels
  • Comes with Transmitter, SRC250 Receiver, In Ear phones and Carry Case


  • Band: UC
  • Frequency Range: 655- 679MHz
  • Transmitter Output Level: 10dBm
  • Operating Range Under Typical Conditions: 50m
  • (Note: Actual range depends on RF signal absorption, reflection and interference)
  • Audio Frequency Response (+ / - 3dB): 60Hz - 16KHz
  • Total Harmonic Distortion (+ / - 30KHz deviation [1KHz tone]): <1%
  • Dynamic Range: >90dB A-weighted
  • Operating Temperature Range: -10° to +50°c
  • (Note: Battery characteristics may affect range)


  • Max Audio Input Level: +6dBV
  • Gain Adjustment Range: 40dB
  • Input Impedance: 6.8K ohm
  • Dimensions: 44mm x 212mm x 160mm
  • Weight: 900 grams
  • Power Requirements: 12 - 18 V DC at 300mA - supplied by external power supply
  • XLR Input: Impedance balanced (Pin 1 - ground - cable shield / Pin 2 - Hot / Pin 3 - Cold)


  • Audio Input Level: 100mW
  • Sensitivity: -94dBm for 30dB SINAD, typical
  • Image Rejection: >55dB
  • Dimensions: 90mm x 64mm x 23mm
  • Weight: 100 grams without batteries
  • Power Requirements: 2 x AA batteries (alkaline or rechargeable)
  • Battery Life: >5 Hours



Order weight is calculated on whichever of the dead (actual) or volumetric weight is the greatest. As of 10/9/21 capped $8.80 to $16.50 for up to 20kg to most areas. For orders under $50 options are Standard Postage $8.80 or Express Shipping for $16.50. Orders over $1,000 ship for free. Express Shipping covers one delivery attempt so please provide an address where someone is available to sign for courier delivery between 9am and 5pm weekdays. You can instruct us to ask the courier to leave your parcel unattended in a safe place, although please be aware that if anything happens to the parcel, neither us nor the courier company can be held responsible. Work addresses are a great delivery option. If using a work address please include the business' name.

* for some larger items does not apply to Australian remote island locations, some mainland remote locations (outside Darwin NT and Perth WA metro areas) or outside Australia. If unsure if you are entitled to capped shipping it is best to contact us prior to placing order.