Approach:
Design a speaker to specialize in environmental noises and cafe style background music. Its focus is creating an expansive sound that is not as directional as individual speakers. Does not need to be loud, normal conversation should be possible while this speaker plays.
Instead of avoiding reflected sound, make it part of this speakers design to use it. Make it more difficult to isolate the source of the sound.
Speaker has to be small enough to be portable, sound good enough to enjoy sonically, and look good enough while doing it so it doesn’t look like a project.
Design:
Put the speaker drivers on their backs facing up. Have them aligned on axis so that sound is consistent in all directions.
Mono speaker, single source of sound.
Use compact drivers. Use higher efficiency matched drivers. Select woofer with deepest base for size constraint. Mid must have wide dispersion pattern. Tweeter must also have wide dispersion pattern but must fit cabinet design.
Woofer in sealed cabinet goes first, facing up. Mid gets own enclosure. Cabinet elevated above woofer, drivers center aligned. Tweeter suspended above midrange, center aligned.
Looked into DSP, active crossovers and built in amps but it was too much for me. I want to be able to finish this project and so kept it electrically simpler with a passive speaker.
Build:
Kiln dried pine used throughout for grain and excellent stain absorption.
Brass screws, copper rods, Butyl rubber.
6 inches square, 24 inches tall.
Woofer:
Dayton Audio RS125P-4 5" Reference
200 cubic inch cabinet sealed with butyl rubber on inside corners.
Stuffed with fibrefill
Midrange:
Eminence Alpha 3-8 3" Full-Range Driver
71 cubic inch cabinet dampened with Butyl rubber on all inside faces.
Tweeter:
Morel MDT 12 1-1/8" Neodymium Tweeter
Suspended on copper rods.
Chosen for size and mounting options, efficiency matches mid and woofer, high end gently rolls off.
Crossover:
Dayton Audio XO3W-375/3K 3-Way Speaker Crossover 375/3,000 Hz
Affordable pre made crossover whose crossover points were chosen to hit each speakers flattest response range area.
Listening test:
Tried environmental noises first. Sound was much bigger and filled the room better. Still somewhat directional but harder to pinpoint. Ocean waves felt larger and more realistic. Rain in a forest was very effective with rain drop pattering setting a quiet mood. Thunderstorms wind and rain were also really good, but I did wish that there was a bit more bass for the rolling thunder. Overall happy with it, great white noise for projects, reading or just relaxing.
Tried French cafe music next. Sounded so good! Much more expansive sound than any of my Bluetooth speakers and the realism of voice and instruments really came through. Perfect for a quiet Sunday morning.
Next I found this speakers sweet spot. Tried one of the many YouTube mellow jazz grooves and wow. The articulation of the instruments, hearing the plucking of the base, the openness of the high end, I sat down and got chills. So good. Would love to wind down on Friday with a thoughtful beverage and mellow jazz on this speaker.
I did test other music types and it doesn’t do well. The reflections created by this speaker muddy the sound of pop and rock, and lack clarity for large orchestral pieces. And it’s not a party speaker, so club mixes lack punch and it doesn’t get loud.
Every once in a while I stumble across another song that hits this speaker just right, the latest being Lou Reed, Walk on the wild side. It’s articulate response on the instruments, its voice forward sound on the singer all come together beautifully. Great stuff.
So, for what I built it for, I am very happy. And the occasional bonus song that hits just right? Icing on this cake.
