Introduction: Mark I Super Psyllium Passivia Speakers
Inspired by the multitude of speaker designs on instructables, what better way to enter the Art of Sound fray than to make YAS (Yet Another Speaker)! We are regular people here at Regularity Audio Labs, and had these wonderful empty containers scattered about the house. A tube enclosure speaker came to mind with the enclosure driving the design. Design: Find an inexpensive full range shielded speaker to fit a bottom cutout, retain the screw-on lid as an access hatch, and add feet so the speakers wouldn't roll around. The speaker drivers are 3", full range, magnetically shielded, rated at 30 watts/8 ohms and could probably substitute as the mains in a low powered multimedia setup, or a small desktop monitor system. The driver spec sheet recommended a 2L sealed enclosure. The containers are 1.9L, close enough!
Step 1: Parts and Tools
The speaker drivers ($12/each), back connectors, spikey feet, speaker wire, and poly stuffing were purchased online. All the rest locally sourced.
2 - 1.9L plastic fiber containers from big box store (regularity is good, ask Jamie Lee!)
2 - 3" magnetically shielded full range speakers(30 watts/8ohms) (speakers came with gaskets)
4- speaker connectors (2 black, 2 red)
8 - slip on connectors for the terminals
8 - pairs of fasteners to attach speakers to enclosures
4 - spikey feet
8 - #4 lead fishing weight eggs
Dremel Tool with router attachment OR Xacto knife for cutting driver opening
Drill with assortment of drill bits. You'll need a 3/8" bit for the spikey feet.
Soldering iron and solder (if you break off a speaker terminal like I did)
Needle nose plier
18" long thin hardwood dowel
Tape measure to calculate enclosure circumference and calculate 60 degree foot spacing
Ruler with mm scale
sandpaper & safety razor to smooth: cuts, sharp edges, and drill hole burrs
Step 2: Mark and Cut Speaker Cutout, Drill Speaker Mounting Holes
This is by far the hardest step. The drivers require a 71mm circular cutout. Center the supplied gasket, tape in place, and mark the cutout with a permanent marker. The bottom plastic is tough. I don't like freehand cuts with a razor knife. My Dremel with router attachment cut a fairly decent hole. In order to accurately drill the speaker mounting holes, drop the speaker into the cutout, center and secure with tape, then drill through the speaker flange holes from the top into the container enclosure below. Just be careful and don't slip and damage the speaker cone or surround. The speaker is secured with hex head metric machine screws (#4/.70) with a pronged mounting nut installed backwards. When mounting the speaker later, a long hardwood dowel allows you to hold the nut in place while tightening the screw.
Step 3: Locate Spikey Feet and Add Weights
The spikey feet come in a set of 4, 2 for each speaker. They require a 3/8" drilled hole. Note the feet and internal hardware must clear the back of the installed speaker driver unit. The feet are mounted 60 degrees apart. Measure the circumference of the cylinder with a tape measure, divide by six, and measure and mark half of the result on each side of the centerline (the container label has a centerline). I ultimately mounted the feet with the nubby ends facing out, to minimize surface scratches. Due to the weight of the driver units, the speakers are front heavy and flop forward. To counteract this, I added 4 lead fishing weights in a duct tape "package" taped to the back of the speaker.
Step 4: Attach External Connectors and Make Internal Cables
The container lid makes a great removeable access hatch and mounting panel for the external speaker wire connectors. For the internal cables, use a 40cm length of speaker wire, strip ends, attach slide-on connectors and crimp. This cable stays inside the enclosure and connects the front speaker driver to the back cap. Note, the slide-on connectors for the speaker drivers are much narrower than for the back connectors.
Step 5: Mount Speakers in Enclosures
Pre-attach the internal cables to the speaker drivers before mounting the units in the enclosures. This minimizes the need to work in tight place! Remember to use the wood dowel (Step 2) to hold the backing nut whie tightening the machine screw with the Allen key.
Step 6: Sound
The speakers have a very clear, bright, detailed sound loud enough for a small room. Bass is decent too. I used a 100 WPC amp for the sound demo. The shielded drivers allow placement next to CRT's for those who still own them.
Participated in the
Art of Sound Contest