Wall Reflections pt. 2
Last installment, we discussed the sonic effects of floor and ceiling reflections. Now we move on to the all-familiar side wall bounces and learn how they affect the listening experience.
Courtesy of ASC founder and President, Art Noxon, Acoustical Engineer.
Enjoy!
Last installment, we discussed the sonic effects of floor and ceiling reflections. Now we move on to the all-familiar side wall bounces and learn how they affect the listening experience.
Courtesy of ASC founder and President, Art Noxon, Acoustical Engineer.
Enjoy!
| The hifi footprint is located between two side walls. The speakers continue to deliver the two direct signals, one LL from the left speaker into the left ear and the other right speaker into the right ear RR. Left alone we’d have the same sound stage that we’d get if there was only the hifi footprint. |  |
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| Instead, we have the hifi footprint set up between a set of parallel walls. In addition to the two direct signals, LL and RR, we have the two “first reflection point” reflections, LLL and RRR. Left speaker off Left wall into Left ear and visa versa on the right. It is the all too familiar early side wall reflection |  |
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| The left speaker bouncing off the left wall into the left ear causes the apparent position of the left speaker to move towards the left wall, and the right towards the right wall. This is the same as if we placed the speakers too far apart and didn’t have any walls. The resulting sound stage is dimmed or weakens in the middle and become more present in the space between each speaker and the nearby wall. |  |
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| There is also a Front Wall reflection. Large boxy cabinets do not play the front wall but the more modern omni style cabinets that are rounded and narrow near the top and do play or illuminate the front walls about as well as the side walls Just as side wall reflections move each speaker image towards each side wall, front wall reflections move each speaker image closer towards the front wall, which moves the whole image towards the front wall. This is similar to how the ceiling bounce of each speaker raises the whole soundstage up. |  |
| The last wall is the rear wall. If the rear wall reflection would act like the other wall reflections, it should drag the image towards the rear wall, moving it closer to the listener, opposite to the front wall bounce. However, unlike the other bounces, the rear wall bounce travels a lot further once the direct passes the listener, instead of a few feet as before, it travels 12 to 14’ further. That means the reflection is weaker and much more time delayed. In addition, we human listeners have fixed ear pinna which is great for collecting sound from what is in front or to the side of us but not good at collecting information from behind us. Rear wall reflections do not impact imaging unless they are within a few feet to the ear.
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