Stereophonic spatial illusions are artificial. Stereophonic spatial illusions are artistic expressions like realism or impressionism, not like photography.
Stereo channel level and time differences created by microphones and mixing consoles are not natural spatial cues. Speakers are sound sources. Sound from left and right speakers is heard by both left and right ears. Natural spatial cues Head Related Transfer Function HRTF, Interaural Level Difference ILD, Interaural Time Difference ITD, and head motion locate speakers in three dimensional space.
Stereo channel level differences simulate natural head shadow ILD spatial cues at high frequencies. Natural ILD cues that locate speakers limit phantom stereophonic illusions to the directions between left and right speakers. Natural ILD cues that locate speakers reduce comb filter interference.
The head is too small to create head shadow ILD at low frequencies. Stereo channel level differences manipulate interference between speakers to simulate natural ITD phase shift at low frequencies. Natural ITD cues that locate speakers limit phantom stereophonic illusions to the directions between left and right speakers.
Natural spatial cues that locate the speakers limit phantom stereophonic illusions to the directions between left and right speakers. No stereo channel level or time differences can create phantom stereophonic illusions to the left of the left speaker or to the right of the right speaker or behind, above, or below the listener. All directions in three-dimensional space are compressed into the directions between left and right speakers.
Listeners hear three dimensions with left and right ears. Phantom stereophonic illusions can be heard between left and right speakers in front, behind, or above the listener. No phantom stereophonic illusions can be heard on the side between front and back speakers or between up and down speakers. Discrete surround sound is independent stereophonic illusions between left and right speakers in front, behind, or above the listener.
Stereophonic spatial illusions are produced at the listener’s ears, not in the listening room between the speakers.
When stereo channel levels R = 0 or L = 0 there is no interference between left and right speakers. Natural spatial cues locate one left or one right speaker.
When stereo channels are equal in level and time, L = R, the listener equal distance between left and right speakers hears a phantom center stereophonic illusion between left and right speakers. The phantom center stereophonic illusion between left and right speakers does not sound the same as one sound source between the speakers. Left and right speakers must not be too far apart to create a phantom center stereophonic illusion.
Stereo channel level differences R = 0, L= 0, and L = R are specific directions. Stereo channel levels L and R vary continuously and independently. Multiple phantom stereophonic illusions can be produced in different directions between left and right speakers simultaneously.
Stereo microphones are "in phase", the same polarity. Mixing consoles pan mono channels continuously from R = 0 through L = R to L = 0.
When stereo channels are equal in level and time, L = R, the listener significantly closer to one speaker hears a stereophonic illusion closer to the closer speaker. When stereo channels are equal in level, but stereo channel time differences are significant, the listener equal distance between speakers hears a phantom stereophonic illusion closer to the earlier speaker. Two speakers do not sound the same as one sound source.
Level difference cannot compensate for time difference. The stereo channel balance control cannot compenasate for the off-center listener. The stereo channel balance cannot be different for different listeners.
Stereo channel time differences create comb filter interference flange effects when stereo channels are summed to mono.
Speakers are uniquely directional. Musical instruments are uniquely directional. Interference between directional speakers does not reproduce the directionality of musical instruments.
Speakers produce sound. Sound from directional speakers reflects from or is absorbed by listening room surfaces and objects. Phantom stereophonic illusions are created at the listener’s ears, not in the listening room between the speakers. Phantom stereophonic illusions do not produce sound. Phantom stereophonic illusions do not produce sound that reflects from or is absorbed by listening room surfaces and objects.
Sound in the listening room only matters where the listener's are.
Short reflections directionally close to the speaker create comb filter interference. Long reflections directionally far from the speakers can enhance the speaker sound.
Listening room reflections of directional speaker sound come from all directions. Listening room reflections of directional speaker sound precede the recording venue reflections of musical instruments from the directions of speakers.
Real spatial cues heard in performance venues with electronically amplified singers and musical instruments locate the speakers in the performance venue, not the singers or musical instruments. Live recordings are made from feeds from the performance venue mixing console.
Electronic devices that provide identical and independent signal paths do not increase or decrease stereo channel level or time differences, so they do not change stereophonic spatial illusions. Different electronic devices that provide identical and independent signal paths do not sound spatially different. Amplifiers and speaker cables do not improve stereophonic soundstage.
Siegfried Linkwitz, Linkwitz Lab, "Stereo Recording and Rendering 101" https://www.linkwitzlab.com/Recording/AS_creation.htm
Fred G. Geil, "Experiments with Binaural Recording" dB Magazine, Volume 13 Number6 June 1979 pp 30-31, 34-35
Audiophile Heretic, July 24, 2026 Menu