The Bee

The Bee


Designer:
Nick D

Project Category:
Portable Speakers

Project Level:
Intermediate

Project Time:
8-20 Hours

Project Cost:
$500 – $1,000

Project Description:
This is a 200 watt, semi-portable boombox designed to have a great sound and reach high volumes.

Design Goals:
All-in-one system that can be moved around if needed, not battery powered. Must have +/- 3db and get very loud. Tuned to below 50 hz. Size and weight were not huge concerns. Must be made with a natural pine.

Driver Selection:
(2) Dayton Audio RS225-8 8″ Reference Woofer (295-356)
(2) Dayton Audio RST28F-4 1-1/8″ Reference Series Fabric Dome Tweeter 4 Ohm (275-141)

Enclosure Design:
(i will attach a photo of the plans i made in AutoCAD) I used a program called WinISD to design the enclosure. I split the box into 2 equal enclosures for the 8″ drivers, each enclosure is 0.83 cubic feet with a 1.5″ diameter, 5.5″ long port tube, this should theoretically let each driver reach 45hz (at -3db), although i do not have a calibrated microphone to check

Enclosure Assembly:
The person this was for asked that i make it with a pine from a local sawmill. Since pine is so light, i was worried about the box resonating. So the walls of the box are 1/2″ pine and 1/4″ MDF glued together, the front baffle is 1/2″ Pine and 1/2″ MDF glued. The rear baffle is simply a piece of painted 1/2″ MDF screwed on so i can access the inside in the future if needed. For the best look i personally selected each pine board with a lot of character in the grain. The 2 enclosures are separated by a 1/2″ MDF partition, and i had to make an enclosure within the enclosure to seal off the amp (the plans dont show this). All seams are sealed up with silicone. I added a brace above each of the 8″ drivers and one centered in the back to screw the back panel to. Once the box is together i had it clear coated by a friend to protect it, bring out the grain, and give it a nice gloss finish

Crossover Design:
I used a free program called VituixCAD to design the crossover network, rather then explain the entire thing i will simply attach an image of the crossover diagram.

Tips & Tricks:
On the back panel i used that black metal panel to attach the power to and RCA, these are great because they give a professional look and are easy to attach electronics to, but you need to seal this thing up from the inside or it will let air escape and resonate like crazy, i used a pvc pipe cut in half (so like a half circle)

Conclusion:
The speaker came out great, it has a great sound, a great low end, and can get extremely loud. It technically is portable with the carry handle and all but it is very large and also weighs like 50-60 lbs so thats why i say “semi” portable. i originally planned to make a cloth grille for the front that was removable to protect the speakers if needed but i never got it done.

About the Designer:
Im more of a woodworker then anything else and I have made a few speakers in the past but this one was my first major speaker project where i designed the entire enclosure and crossover network.

Project Parts List:

Lepai LP1601S 200W Class D Stereo Amplifier with Bluetooth and Power Supply
Dayton Audio PMPC-8.2 8.2uF 250V Precision Audio Capacitor
Dayton Audio PMPC-15 15uF 250V Precision Audio Capacitor
Dayton Audio 0.27mH 18 AWG Perfect Layer Inductor Crossover Coil
Dayton Audio 1.5mH 18 AWG Perfect Layer Inductor Crossover Coil
Dayton Audio DNR-5.6 5.6 Ohm 10W Precision Audio Grade Resistor
Parts Express Gold RCA Jack Solder Type with Nut Pair
IEC AC Power Jack Chassis Mount with Switch and Fuse Holder
Littelfuse 6.3A GDC Type 5 x 20mm Slo-Blo Fuse 5 Pcs.
Penn-Elcom D0946K Blank Dish Black 4″ x 4-3/8″
Penn-Elcom H1008 Black Leather-Look Strap Handle 8.57″ Long
Penn-Elcom C1824K Metal Cabinet Corner Black 2 Leg

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