Audio Calibration

Anthem Room Correction (ARC) System - Part 1


Introduction to the Anthem Room Correction ARC System - Part I

Among the numerous room correction systems (automatically adjusts speaker delay, frequency response, and loudness, with respect to the listening position) I have tested, the Anthem ARC currently stands out as the best for consumers. This section outlines the product's distinctive competencies. To keep things simple I am going to use the term AVR exclusively. The Pre/Pro is an AVR without a power amp although the absence of the power amp may allow the Pre/Pro designer the space to extend performance. For example the number of DSP chips (programmable and application specific) may be increased.


  • Anthem Room Correction (ARC)
  • Software Version 3.01, Calibrated USB Microphone, Microphone Stand
  • ARC is included in all Anthem and Anthem Statement AVRs (A/V Receivers) and Pre/Pros (A/V Processors)
  • Note: The PC Software and microphone are included with all Anthem AVRs and Pre/Pros down to the $1,000 MRX 300 AVR.
  • Subwoofer version called PBK is $100 (not tested). PBK works on most Paradigm subwoofers. Look at the Paradigm website for subwoofers that have a USB port for PBK equalization.
  • PBK subwoofers are not required for Anthem AVRs and Pre/Pros which have the same subwoofer correction algorithms. Multiple subwoofer deployments may benefit with PBK and ARC (not tested).
  • Anthem
  • Paradigm
  • SECRETS Tags: anthem, system, audio

Room correction occurs in three steps:

  1. Measure the room's response to test stimuli sent to the speaker
  2. Fit the digital filter coefficients for room correction
  3. Perform room correction in real-time with a digital signal processor in the AVR.

Step 2 heavily influences the quality of outcomes. Not surprisingly, these algorithms often consume 90% of the development time of the best products.

Computing the model's coefficients has typically fallen to a DSP chip on board the AVR. The DSP is designed for real-time signal processing, making it ideal for the signal processing aspect of this application (Step 3). The DSP, however, falls short when tasked with off-line computations (Step 2). To circumvent this issue, room-correction algorithms are often deliberately simplified, thereby sacrificing the quality of the model's parameters for the sake of compute speed.

A PC is better suited to calculate the model's coefficients. The filter computations are completed on your computer from files of measurement data. This is a huge advantage over systems that use the DSP chip inside the AVR. As algorithms are improved all that is required is a software update. Moving to a PC provides another advantage; namely, the PC display is the user interface. The AVR's on-screen display cannot provide 1% of the information and cannot store data from previous runs to compare differences.

For example, the PC can display the Anthem ARC frequency response data (before and after correction). Numerous customization options may be available on an advanced room correction system. As the options are changed in the configuration panel the post equalization frequency response graph also changes to show the effect. Navigating complex options on a GUI from the AVR to the TV screen becomes impossible and how a change affected the final acoustical response of the system is impossible to determine.