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I completed a couple of Dolby Atmos speakers in past couple of weeks. These are front upward firing Atmos speakers that reflect the sound of the ceiling creating surround effect from the ceiling. Drivers used Peerless TC9FD18-08

Initially when I tested the Atmos speakers, I was disappoint as I could not hear much effect. Then one day I was playing the Eagles farewell concert in DTS and my Denon automatically set the surround to DTS-Neural X. The makes the Atmos speaker playing all the time and with vocal and I can hear the singers voice from the ceiling. But the reflected sound was in front of my seating position. Because the singing and music is continuous, it makes it easy to find the optimum position where the sound is reflected. The position is a couple of feet in front of my couch. My Atmos speaker is design with a 30 degree angle and obviously that is not optimum for my seating position. So I raised the back of the Atmos speaker up and that shifted the sound further away from the Tv back to my seating position. The difference is night and day, and now the Atmos speakers effect is awesome. Now the ceiling is like a big speaker. So now settled with a 40 degree angle and they are just awesome.

When I design the Atmos speaker, I use calculated the sound reflection based on the speaker height, ceiling height and the listening position and 30 degree seems optimum. But it then out that the angle is wrong and the speaker need 40 degree for optimum performance. I think I know my mistake. The picture below is how I come up with 30 degree angle. The red line is the sound from center axis, and the yellow line represent the sound that is is 15 degree off center. I thought that is good enough as sound is disperse out at all angle. I am thinking of building another box with 40 degree angle and deeper depth so that the lower drivers won't get blocked.

Anyway, below are some photos of the speakers.





The design...

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