## Calculate the First Sidewall Reflection and Panel Placement

The early reflected sound leaves the loudspeaker and then bounces once off the major boundaries in the room before reaching the ears of the listener. The speaker’s contribution to the early reflected sound is the frequency response at the off axis angles that represent the sound path from loudspeaker to boundary to listener.
The fittings and furnishings of the room at the locations of the reflections change the spectral content of this sound on its way to the listener because objects like acoustic panels, carpet, ceiling tiles are all frequency dependent absorbers.

You want the soundstage in your room to faithfully reproduce the soundscape encoded in your media. This means you want to hear spatial cues coming from your speakers — not from your room!
But early reflections from your room can overpower the spatial cues in your media. They throw off your imaging, destroy your soundstage and mask fine details like the sense of depth and width in a recording.

Naturally, the character of those first reflections has a huge influence on your total sound.
This means you can shape your sound with just a few acoustic panels at your first reflection points!

 Y : cm (distance from your ears in the listening position to your loudspeaker) X1 : cm (distance of the loudspeakers to the sidewall) X2 : cm (distance of the center of your head to the sidewall) D = cm ( the distance from the horizontal line between your ear and the wall to where you should place the center of the absorber panel. )

• Y is the distance from your ears in the listening position to the line your loudspeker create from side wall to side wall. This is all based on sidewall measurements with no diagonal distances.
• X1 is the distance of the loudspeakers to the sidewall (should be equal on both sides).
• X2 is the distance of the center of your head to the sidewall.

• D is the distance from the horizontal line between your ear and the wall to where you should place the center of the absorber panel. This places them at the optimal position so the width of the panel can absorb as many reflections as possible from both speakers.

Note that the ceiling reflection point will always be halfway between your ears and the tweeter if your tweeters are at ear height,
which they should be.

LISTENING-ROOM REFLECTIONS AND THE ENERGY-TIME CURVE

By reading this article you should get a good understanding of how important reflections are to what we hear and how to use ETC's to
analyze the reflections in your room.

Acoustic Treatment Setup in Your Listening Room or Studio

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