6th order bandpass loudspeaker: Building a Knock off Panaray 502 B Bose loudspeaker

Last year I built a pair of the Panaray 402 loudspeakers and they sound great but needed the lower end to be matched so they sound a bit more full range. So adding the woofer enclosure will provide that earth shaking deep bass we all want in our music. I had wanted to build this subwoofer box last year when I was making these (https://www.instructables.com/Speaker-Build/ ) a pair of Bose 402 style speakers, as I knew I was gong to need the low end frequencies.

I had a 12 inch Mackie subwoofer sitting around in my speaker collection and I also had the MDF sheet of wood for this build, from a project I did last year.

With lows down to 50Hz at a heart stopping 90 SPL (sound pressure level) and at 8 Ohms, I should be able to put about 400 Watts after the active crossover to limit anything over 155Hz.

Because this speaker is a 6th order bandpass loudspeaker, it will not create the 20 Hz to 45 Hz audio range, but the increase in the loudness in the 50 Hz - 140 Hz will be good for live performance music or small venues.

Frequency Response : 50 Hz - 140 Hz

Frequency Range : 45 Hz - 160 Hz

Nominal Dispersion : Omni-directional below 200 Hz

Loudspeaker EQ Required

Overload Protection 7-ampre AGC

Long-Term Power Handling: 400 W

Sensitivity (SPL / 1 W @ 1 m): ~ 90 dB SPL

Nominal Impedance 8 Ω 

Table saw

Jig saw

Router, hand held

Drill, cordless

Drill bits, various sizes

Wood glue, for ports

Wood Bar clamps,(the more the better!) 12 inch x4, 18 inch x2 and 36 inch x2

Soldering iron and solder

Circle compass

Paint (I used White to match the other speakers I built)

Paint brush

Wood screws

Screw driver

One sheet of 3/4 inch MDF (4 by 8 Feet)

Tube of industrial wood glue, for the box

Caulking gun for above adhesive

A 12 inch subwoofer (I had a used 12 inch Mackie subwoofer, 8 Ohm that is used for this project)

Fuse holder

Quarter Jack input plug

Plastic terminal plate

Inductor 6.0 mH

14 AWG speaker wire

Cabinet Handle, spring loaded

I drew out a quick drawing of all the dimensions and use this to make a cut list. Using a specification sheet I also checked that I had a good understanding of how the box and ports lined up with the speaker internal to the box.

Take your time and write out a cut list and quantity required. It is well worth the time and makes life easier!

Take your time, and measure serval times to get all the proper cuts. I labeled my pieces as I cut them and this allowed me to check as I went. For example I cut two of the same 15.5 inch by 14 inch, they were labeled TOP and BOTTOM in pencil on the sheet of wood.

The ports were glued and used to mark the cuts required for the ports. Placing them in the right location and using the inside of the port to trace the opening required. I drill a hole large enough for my jig saw blade and cut the ports out.

You want to make sure to round the edges of the ports with a router and a half inch round over. This will help the port sound better and eliminate a whistle sound when air moves in and out of the port.

After a fit check I started to glue all of the ports, mounting them to the front sheet of MDF. Next the sides and the top and bottom, the sheet that requires the large hole for the subwoofer I made by centering the woofer and traced, then I took a compass and drew a circle the correct size for the speaker to sit snug... the out side circle is to make sure you do not hit any of the walls as you finish the build.

I use claps to hold all panels of the wood as the wood glue dries.

Since this box will experience lots of vibrations, I then go back after the glue has dried and drill pilot holes for 2 inch screws on all glued corners, spaced out about 6 to 9 inches, to enforce the structure of the box.

I wired up the speaker after mounting the woofer. An inductor was placed in series with the woofer to help block high frequencies from damaging the speaker. I also added a fuse after the speaker terminal. This will help protect the woofer if there is damage to the amplifier.

I used the same paint I had from the other speaker build and painted the entire cabinet. I added the spring loaded handle as when it is not in use the handle sit tight in the holder. The fuse and quarter inch speaker jack was labeled on the connection plate.

It was AMAZING!!! The bass that is generated out of this box was definitely not what I was expecting, it was better. The low frequencies do not do well in a recording in a video, but the response was extremely good. I powered it up with a 200 Watt amplifier and and let the bass drop. The woofer box matched nicely with the knockoff 402 speakers I built back in May of 2020. Not wanting to drive my neighbors crazy I reduced the sound levels and continued my sound check with many different types of music and the low frequencies definitely could be heard and blended well with the other speakers. I will add a video when i do an out door concert and can try and provide an audio recording that may show just how amazing a 12 inch woofer in the right box can be enough to thump deep lows and provide depth to any music.