BTE Releases AEQ4 Parametric Equalizer

Targeted at desktop and embedded professional audio applications, the PEQ4 algorithm is designed to enable “quality-conscious third-parties to incorporate the highly revered High-End Outboard EQ sound into their products, ” according to BTE Audio.

In earliest parametric equalizer units, all filter bands are connected in parallel rather than in series-cascade as in conventional parametric equalizers. The parallel architecture has a distinctive musicality due to different phase behavior and smoother interaction between adjacent bands. In order to achieve symmetrical curves for boost and attenuation, filter bands are placed in feedback paths during attenuation. While trivial to implement in the analog domain, implementation of these feedback paths in the digital domain is rather involved due to the resulting delay-free feedback loops which are considered as uncomputable in classical digital signal processing theory. The PEQ4 Algorithm is designed to simulate the latest version of “first generation” units in the digital domain with its meticulously designed topology which inherently has the ability to authentically emulate delay-free feedback loops.

Features

• Supports sampling frequencies up to 384 kHz.
  
• Clickless parameter update.
  
• Topology optimized for low latency, low noise and high dynamic range.
  
• Supports both 32 bit (single precision) and 64 bit (double precision) floating-point processing.
  
• Upsampling algorithm which is automatically enabled at sampling frequencies below 88.2 kHz.
  
• Implemented in C++: portable to any platform that is supported by a C++ compiler.

Specifications
Five overlapping bands with the following specifications:

• Low Frequency Shelving/Peaking: Selectable filter type: Shelving or Peaking. Center Frequency is continuously variable from 8Hz to 800Hz. Quality Factor(Q) is continuously variable from 0.38 to 4.72 in Peaking mode. The amount of boost or attenuation is continuously variable from –12 dB to 12 dB.
  
• Low Mid Frequency Peaking: Center Frequency is continuously variable from 8Hz to 800Hz. Quality Factor(Q) is continuously variable from 0.38 to 4.72. The amount of boost or attenuation is continuously variable from –12 dB to 12 dB.
  
• Mid Frequency Peaking: Center Frequency is continuously variable from 80Hz to 8kHz. Quality Factor(Q) is continuously variable from 0.38 to 4.72. The amount of boost or attenuation is continuously variable from –12 dB to 12 dB.
  
• High Mid Frequency Peaking: Center Frequency is continuously variable from 120Hz to 25.6kHz. Quality Factor(Q) is continuously variable from 0.38 to 4.72. The amount of boost or attenuation is continuously variable from –12 dB to 12 dB.
  
• High Frequency Shelving/Peaking: Selectable filter type: Shelving or Peaking. Center Frequency is continuously variable from 120Hz to 25.6kHz. Quality Factor(Q) is continuously variable from 0.38 to 4.72 in Peaking mode. The amount of boost or attenuation is continuously variable from –12 dB to 12 dB.

Applications

• Software Plug-ins
  
• Digital Audio Workstations
  
• Digital Mixing Consoles
  
• Hardware Effect Processors

PEQ4 Demo
In order to demo the PEQ4 Algorithm, BTE Audio has integrated it into a VST Plug-in.The demo requires a WIBU Systems CodeMeter Stick and it is only available to well-established audio hardware and software manufacturers.

For more info, check out http://www.bteaudio.com.