Lateral Sound Reflections

Published On: June 28, 2024Tags: , , , , ,

Watch out! Strong lateral reflections can hurt!

The text is presented below to supplement the original from ASC Founder and TubeTrap inventor Art Noxon, Acoustical PE. This week’s discussion focuses on a well-known nemesis: early side wall reflections. Enjoy!

Lateral Reflections…

…are very significant in the listening experience. We have 2 ears, which allows us to be very perceptive of incoming lateral sound. In HiFi, sidewall reflections are known to change the stereo imaging effect. The rule of thumb is to weaken or eliminate these early lateral reflections.

The most commonly understood lateral reflection is the sidewall reflection. It occurs at ear level on the side wall about half way between speaker and listener location. Right speaker is reflected into right ear.


There are two other lateral reflections that are just as important as the side wall reflection. Upper corner and lower corner sidewall reflections arrive a few milliseconds after the wall reflection.


An 80 dB direct is followed by 3 side wall reflections within 8 ms, well inside the sound fusion time window.

…continued next week!

For help with the…

SoundPlank Placement

  • Enlist a (helpful) helper
  • Obtain a small mirror
  • Round-up a roll of blue painter’s tape
  • Sit in your ‘sweet spot’ chair
  • Have the helper move the mirror along the wall
  • Mark the wall with the tape at the location (on each side) where you see the tweeter from your listening seat
  • Place the control device centered on the mark, covering about 65% of the wall height (e.g, use a 5′ tall absorber on an 8′ tall wall)

Consider installing SoundPlanks to balance the frequency and reflections in your listening room.


Latest Newsletters!

Go to Top