1. About the limits of human hearing
When the channel separation of the speaker amplifier is low, there will be a certain amount of crosstalk between the left and right channels, which may affect the stereo effect. However, once the channel separation is higher than a certain value, it is difficult or even impossible for the human ear to perceive. For current amplifier production, it is usually not difficult to achieve qualified channel separation. Generally, when doing power amplifiers or some master-slave active speakers, the channel separation is defined. In short, at the current industry level, in many cases, the channel separation is in the category of weak or even imperceptible. One of the reasons that I rarely test in past evaluations is that I have limited time and give priority to testing important parameters. I usually don’t have time and energy to test for data tests that are not strong or unperceptible. (lazy)
2. For the amp or the headphone system channel separation is very delicate
If a friend who has read my article from the beginning, or someone who has a deeper understanding of the reproduction of the sound and the difference between the sound of the speaker and the headphone playback should understand. In order to gain a deeper understanding of the problem itself, I will simply repeat it here. We often say that the width of the sound field and the width of the vocal/instrument image are commonly referred to as the perceptual sound source width (ASW) in psychoacoustics. The width of the sound field can be expressed by the angle θ formed by the straight line a and the straight line b. This was originally an important indicator to measure the quality of the concert hall. It was first introduced into the field of household HiFi by Dr. Floyd Toole. Through decades of research, Dr. Floyd Toole and Dr. Sean Olive have found that ASW is related to IACC (Binaural Auditory Cross-Correlation Function) and LF (Early Lateral Acoustic Energy Ratio). Generally speaking, the smaller the IACC and the larger the θ, the wider the sound we hear when playing a piece of music. The larger the LF, the wider the ASW.