The soundstage is a psychoacoustic phenomenon that refers to the listener's perception of the spatial locations of sound sources, including their width, depth, and height, as reproduced by speakers. This perception is highly subjective and can be influenced by numerous factors, including the recording, playback equipment, room acoustics, and the listener's hearing abilities.
Measuring Soundstage with Speakers
While psychoacoustic phenomena like the soundstage are inherently subjective, this does not mean they are unmeasurable. The challenge lies in determining which measurements correlate with the subjective experience of soundstage. Traditional measurements in audio testing, such as frequency response, harmonic distortion, and signal-to-noise ratio, provide insights into a component's fidelity but do not directly address spatial characteristics.
Potential Approaches
- Binaural and Spatial Measurements: One way to capture the soundstage could involve binaural recordings and playback techniques that use microphones placed in the ears of a dummy head to capture the spatial characteristics of sound. This method can preserve spatial cues crucial for spatial hearing. Applying this to speakers would require a standardized recording and playback setup that accurately reflects these spatial cues.
- Cross-talk Cancellation and HRTF: Measurements considering the Head-Related Transfer Function (HRTF), which describes how an ear receives a sound from a point in space, could potentially correlate with soundstage perception. Techniques like cross-talk cancellation, which involves processing audio signals to reduce or eliminate the audio signal interferences that can blur spatial cues through speakers, might offer measurable parameters correlating with perceived soundstage quality.
- Harmonic Distortion and Timbre: Certain subjective qualities, such as "warmth" or "layered imaging," have been associated with specific harmonic distortion profiles. While directly correlating these with soundstage might be challenging, it suggests that the complex interactions between harmonic content, timbre, and spatial cues through speakers could contribute to the perception of depth and spatial positioning. Analyzing the harmonic distortion spectrum in a way that considers its impact on perceived spatiality could provide insights.
Finding a direct or correlated measurement for soundstage among speakers underscores the broader challenge of quantifying subjective audio experiences. Although no direct measurement currently exists that can fully account for the perceived soundstage, exploring the relationships between existing measurements and spatial perception could be enlightening. Combining traditional audio metrics with advanced psychoacoustic models and spatial audio analysis techniques could bridge the gap between objective measurements and subjective experiences, offering a more comprehensive understanding of how speakers influence the perceived soundstage.