January 23, 2022
Description
I wanted some low-profile ceiling speakers for my 7.2.4 home cinema system, which should be angled at 45 degrees down from the ceiling to best adhere to the recommended Atmos speaker placement. Not being able to find and suitable for my taste and space, I designed these. Based on Dayton RS100-8 full range driver (90-20.000hz) they are rated at 30W RMS and 60W max, with 85 dB/W@1m. They should be able to deliver > 95dB SPL @ 3m.
After printing, the cases were sanded using a random orbit sander with 80 & 150 grit sandpaper. After layer-lines were smoothed out, a spray filler were used to coat the outside. After drying, they were sanded with 450 grit sandpaper by hand, getting a smooth surface and rounded corners.
3-4 layers of matte black spray-paint were then used to get a nice matte finish. EVA gasket material were used between case and terminals, and case and screws for the mounting plate to ensure an air-tight cabinet.
These are intended to be mounted through 30mm Rockfon ceiling plates, some adjustments are needed if you can not access the backside of the ceiling. A differen design for the "plate" should be enough.
Frequency response were measured using REW with a minidsp Umik-1 calibrated microphone, an onboard soundcard ,cheap cables and a "Nobsound NS-04G Pro" stereo 2x50W amplifier (TPA3116 based).
Sound is a bit tinny, caused by too much treble and low frequency output compared to the mid-range. After applying a software equalizer the frequency response is flat from ~90 to 18khz, as can be seen in the second plot. With equalizer applied they sound great. A good home cinema receiver with speaker calibration should be able to do the same.
Materials used:
License:
Creative Commons - Attribution - Non-Commercial - Share Alike
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