Although Public Adress systems and Voice Evacuation systems have almost become standard components of the technical installation in public buildings and facilities, the performance of these systems has not always been given a lot of attention. This is now gradually changing. After all, what good is a sound system if the messages are hardly intelligible? Codes and standards worldwide are setting minimum requirements on speech intelligibility, usually defined in terms of the Speech Transmission Index (STI).

The purpose of Bedrock Optimizer is simple:


Bedrock optimizer schematic presentation

Bedrock Optimizer uses proprietary optimization algorithms developed by Embedded Acoustics, the inventors of STIPA and co-developers of the Speech Transmission Index. Making use of strategically placed sense microphones, which form part of the permanent installation, in combination with the Bedrock DSP500 hardware, the following analysis is carried out:

  • The level and spectral composition of the background noise is continuously monitored. As these measures slowly change over time (for instance, as a space becomes more crowded), the PA settings are adjusted.
  • Special, proprietary algorithms make use of any message (or even background music) played through the sound system as an ad-hoc test signal. A spectro-temporal analysis is carried out, based on the fine structure of the ad-hoc test signal as well as the modulation spectrum.
  • EQ settings, gain, compression and even delay are gradually adjusted, independently for each zone or channel. The adjustments are such, that the Speech Transmission Index (or any other measures that can be mapped to the Common Intelligibility Scale) is guaranteed to be optimized.
  • The operator/installer sets predetermined boundaries on the degree to which Bedrock Optimizer is allowed to tweak settings. In other words: the envelope within which Bedrock Optimizer has “free reign” can be pre-determined. 

Bedrock Optimizer is based on the BSP64 platform. It interfaces through analog line IO (8×8 channels) and Cobranet. It can be configured through an embedded webserver, and can be customized to work with the control logic of any sound system or PLC, through a dedicated Gbit LAN interface. 

In addition to PA the gradual optimization and adjustment described above, Bedrock Optimizer also offers the following functionality:

  • Install-time optimization with synthetic test signals. After installation, it will take a while before Bedrock Optimizer has collected enough statistical data for the optimization engine. This process is speeded up significantly by running an install-time optimization protocol which uses synthetic test signals. This is an easy process; it takes place just once, as soon as the installation is done (or whenever major changes to the PA system are applied).
  • Multi-channel STIPA measurements. In addition to the measurement algorithms used for optimization, Bedrock Optimizer also contains a multi-channel STI measuring instrument fully compliant to IEC 60268-16 4th ed. (2011).
  • Logging and reporting. Bedrock Optimizer can be configured to continuously log all adjustments, activities and predicted intelligibility scores. This will provide owners/caretakers with a wealth of data about their sound system, which can be used for maintenance purposes or to establish audit trails.
  • Manual signal processing settings. In addition to the automatic adjustments done by Bedrock Optimizer, all signal processing of the Bedrock DSP500 are available. This means that Bedrock Optimizer eliminates the need for any additional delay lines, compressors, equalizers, etc.

 Please contact us if you would like more information.