Thank you, Duke. Yes, when it comes to acoustics, there is so much more than frequency x amplitude. When you get the balance of these correct as well as phasing, reduction of comb filtering, reduced smearing, reduced multiple harmonics, and improved decay times along with linearity left to right and front to back, your spatial queues are more audible, overall resolution increases, and just more of everything on the recordings becomes audible.
I showed a prototype of a diffuser/absorber for use over a flatscreen TV. I immediately started receiving negative comments like “it’s a solution looking for problems”, and that TV reflections cannot be heard due to the angle and distance from speakers, and so on. So I instead of trying to explain to people that wouldn’t likely believe me anyway, I asked ChatGTP and posted it in the group. I posted it exactly without any editing. I was then banned from the group by the moderator claiming my response was offensive to members. Here below was the exact response I shared with them. I share it hear hoping people that read this will better understand acoustics.
ChatGPT, what happens to sound waves and reflections when a flatscreen TV is positioned between floor standing speakers on a wall or stand mounted, and would there be benefits to adding a diffuser/absorber panel over the TV like the one shown in the photos I took of the Ortvik piece and uploaded (uploaded these to ChatGPT)?
The following is a condensed simple version of what it said. I have the highly technical version too that includes mathematical formulas on comb filtering.
From ChatGPT
A large flat-screen TV between speakers acts like an acoustic mirror right in the most critical part of the soundstage. From a technical and factual standpoint, here’s what’s happening:
• Specular reflections (mirror-like reflections): The glass surface reflects mid and high frequencies almost perfectly back toward the listener, creating strong early reflections within a few milliseconds.
• Comb filtering: The reflected sound combines with the direct sound, causing peaks and nulls (typically 500 Hz–5 kHz), which leads to tonal coloration and loss of accuracy.
• Center image degradation: These reflections interfere with phase coherence between left and right channels, resulting in a diffuse, oversized, and unfocused phantom center.
• Temporal smearing: Early reflections blur transients and reduce clarity, making the system sound slower and less precise.
• Edge diffraction: The physical edges of the TV create additional secondary reflections, further degrading imaging and adding subtle harshness.
• Haas Effect: this is a critical element in perceived sound and spatial queues that is seriously affected by hard reflections in numerous negative ways.
The Haas effect (or precedence effect) is a psychoacoustic phenomenon where the brain perceives two identical sounds as a single sound if they arrive within 5–40 ms of each other, with the first sound determining the perceived direction. It is used in audio to create stereo width and in sound reinforcement to localize sound to a stage.
Now, placing a diffuser/absorber hybrid panel (like the one shown) over the TV addresses these issues very effectively:
• Breaks up reflections: The uneven surface scatters sound in multiple directions instead of reflecting it straight back, eliminating strong early reflections.
• Reduces comb filtering: By dispersing and weakening reflections, interference patterns are minimized, resulting in smoother frequency response.
• Improves imaging precision: With fewer coherent reflections, the center image becomes tighter, more focused, and more stable.
• Absorbs excess energy: The PET backing absorbs mid/high frequencies, lowering the overall reflection level and improving clarity.
• Enhances transient response: With less time-smearing, attacks are cleaner and decay is more natural.
• Maintains liveliness: Unlike pure absorption, this hybrid approach preserves some spatial energy, so the room still sounds open and natural rather than overly dead.
Bottom line: the TV introduces one of the most damaging reflection points in a high-end system, and covering it with a properly designed hybrid panel converts a major acoustic liability into a controlled, beneficial surface—resulting in sharper imaging, better tonal accuracy, and improved overall realism.
