Room Correction Requirement Definition for WiiM

[Dako]

Dear WiiM Team,

First and foremost, thank you for your continuous efforts in pushing the boundaries of high-fidelity audio. Your commitment to innovation has not gone unnoticed. As an enthusiast of your products—and someone who values accurate and pleasing sound reproduction—I would like to provide some structured feedback and requirements for how your Room Correction (RC) system could evolve.

I have noticed that there are many different threads in the forum asking for various Room Correction features. My goal here is to consolidate all these requests into one forum thread. This will simplify the conversation and help guide the development.

1. Introduction and Acknowledgements​

Room correction is an essential tool in modern audio systems, mitigating the acoustic issues introduced by the listening environment. Your current RC solution is promising, and the consistent updates demonstrate your dedication to improving user experience. The purpose of this document is to outline a set of requirements that build on the solid foundation you have created, further enhancing the performance and flexibility of your Room Correction features.

2. A Brief History of Room Correction​

From early analog equalizers to today’s advanced digital signal processing, room correction has come a long way. Dr. Floyd E. Toole’s pioneering research at Harman International provided key insights into how listeners perceive sound in real rooms. His work revealed that:

• Multiple Measurement Points: A single “sweet spot” measurement might not reflect the average listener experience, hence the need for multiple measurement locations.
• Smooth In-Room Response Over On-Axis Perfection: Aiming for a smooth, natural in-room response often yields better results than forcing a ruler-flat on-axis frequency response.
• Reflections & Modal Behavior: Low-frequency room modes and reflective surfaces have a significant impact on perceived bass and imaging. Controlling these aspects leads to more accurate and enjoyable sound reproduction.
• Listener Preference Curves: Many listeners prefer a slight low-frequency lift (“house curve”), demonstrating that subjective preference can differ from purely neutral targets.

Building on these principles, we can refine the feature set for a more flexible and user-friendly Room Correction system.

3. Proposed Requirement Definition​

Below is a list of key requirements that will help shape the next iteration of WiiM’s Room Correction tool. Some are adapted from existing reference systems (e.g., Lyngdorf) and user wishes, while others draw on the established science from Dr. Floyd Toole’s research.

3.1 Separate Measurements for Each Channel​

1. Individual Left/Right/Subwoofer Measurements
   • Current State: Only left and right channels are measured together or in a simplified manner.
   • Requirement: Conduct separate measurements for each channel (Left, Right, and Subwoofer). This will facilitate more accurate calibration and phase alignment among channels.

3.2 Multiple Measurement Positions​

1. Multi-Point Measurements
   • Current State: Only one measurement is available to define the correction filter.
   • Requirement: Allow for multiple measurement points in the listening area. The user must have the ability to specify the Main Listening Position (MLP) as a primary reference, with additional measurements around the MLP to optimize correction across a broader seating region.

3.3 Microphone Calibration​

1. Uploadable Microphone Calibration File
   • Current State: Users cannot load a calibration file for their measurement microphone.
   • Requirement: Provide functionality for uploading a microphone calibration file (e.g., .txt, .cal) to compensate for the unique frequency response of different mics. This ensures more consistent and standardized measurement accuracy.

3.4 Time Alignment (Impulse & Distance Settings)​

1. Time Alignment to MLP
   • Current State: Time alignment is only available between the WiiM device and speakers/sub, not specifically from the MLP.
   • Requirement: Implement a precise method for time alignment either through:
     • Impulse Response Measurements—letting the system automatically detect correct delays, or
     • Manual Distance Entry—allowing users to specify each speaker/subwoofer distance from the MLP.
       This ensures coherent arrival times of sound to the listener.

3.5 Separation Between Room Correction Filters and Parametric EQ​

1. Non-PEQ Implementation of Room Correction
   • Current State: The RC filter appears to be stored as a PEQ, limiting users who want to make further manual EQ adjustments.
   • Requirement: Provide a dedicated RC filter layer that operates independently from the user’s parametric EQ (PEQ). Users should be able to apply minor tweaks or “house curves” on top of the existing RC filter without overwriting or undoing the correction data.

3.6 Additional Recommendations and Enhancements​

1. Save & Recall Profiles
   • Permit saving multiple profiles (e.g., one for multi-seat listening, one for the single-seat MLP). This is especially helpful for comparing different correction philosophies or calibrations for different speaker setups.

4. Conclusion and Gratitude​

I appreciate WiiM’s dedication to improving the audio experience through ongoing software updates. By incorporating these requirements—rooted in acoustic research and practical user feedback—you can create a better Room Correction system that may rivals the industry’s leading solutions. Dr. Floyd E. Toole’s findings have taught us that truly satisfying sound reproduction results from a balanced approach to measurements andpsychoacoustics. We believe that by adopting these guidelines, WiiM can continue to innovate and set new standards in room correction technology.

Thank you for your consideration. Please add more to this thread if I missed anything.

 

[EddNog]

Would be good to have full L/R room correction when using the Bass Management, too.

-Ed