Flat Pack Speaker Boxes now available at TRB CNC

Waveguide LRThere are many places to purchase speaker boxes for your amateur home or automobile speaker project. Now there is one more. Live in or near the Portland Oregon area? You can now order and pickup directly here in town. If you’re not too far away I’ll even deliver.






TRB CNC makes hobbyist speakBoth-speaker-with-veneeroer enclosures and custom CNC signs, art projects and prototype parts in wood, plastic, soft metals or foam. Send me a drawing and I cut the parts. CNC is a very accurate way to cut wood, plastic or other materials that can be cut with a carbide bit. I’m focusing on speaker enclosures because that’s what I know best but I’m open to new ideas.

IMG_20130521_092307_447Building a Dipole kit? Need a custom baffle? This is the place to ask. I can layout and cut single or double sided baffles in MDF, high quality plywood or solid hardwood. By stacking hardwood planks together we can cut deep shapes into the baffle including waveguides, rear driver mounting roundover to reduce diffraction effects, dado corners for increased surface area, miter joints for seamless corners, even lock miter joints.

IMGP2755Is your project not so fancy and you just need a baffle with accurately place holes cut to exact dimension? Just ask. Send me a picture with measurement and I can usually cut to order in one day.

Speaker Flat Pack Assembly tips

So, you bought a flat pack speaker box and want to know the best way to assemble it, or maybe it has gaps at the seams and you want to know why.

Since these parts are all cut on a CNC machine there is a possibility they may have tabs on the edges of some of the pieces. These tabs can sometime interfere with the joints of the enclosure making it appear as if the parts are not cut square. First thing you should do when you unpack the kit is brush all parts with a stiff brush paying careful attention to the inside corners of the dado cutout. Sawdust build up in this area can prevent the enclosure from fitting tightly and squarely.

Second is to check the inside ends of all rabbets. When the machine cuts it sometimes leaves tiny bits of uncut material at the inside of the corners. These, being on the assembly edge of the box, can also prevent a tight, square fit when assembling the box. I use a box cutter or razor knife to trim any excess material that might be left over on the inside of the dado cuts. Third, thoroughly clean all parts again with a stiff brush. I found a dry dish brush works very well for this. You want to remove any and all loose material but you don’t want to change the shape of the parts at all. The machine is very accurate at cutting the part out but sometimes it pack dust tightly into corners making square assembly difficult.Begin by laying out and identifying the parts.

  • Front and Back are 11 ½” x 7 ½.
  • Sides have rabbets cut around the outside edges
  • Top and bottom are different sizes with Top being the smaller nearly square piece. Continue reading

Custom Flat Pack Speaker Enclosures

After several discussions on various speaker building forums I’ve decided to offer flat pack speaker enclosures as an ongoing service. As my first offering I’ve designed a simple unfinished enclosure that can be quickly scaled to any volume with minimum effort. The enclosures will be made mostly from Plywood and MDF. The first group will be simple unfinished MDF flat pack enclosures just like those being offered at Parts Express. The biggest difference being that I can beat their price, mine ship faster and I offer custom driver openings. I can also offer custom baffles for waveguides, routing for flush mounted drivers, routing for rear mounted drivers, woofer waveguides (rear mounted woofer or midrange), round-over or chamfering inside or outside,  and any other custom driver mounting option at reasonable rates. My initial boxes will be very similar to PE boxes in terms of simplicity. But, rather than assemble the enclosure around the sides as they do, my enclosures assemble around the back.

The back of the enclosure is a flat piece with a dado cut around the outside. The sides, top and bottom then assemble against the back to form the enclosure. Adding more complex joints is very easy using this technique and makes it much easier to produce a custom enclosure size since all parts are relative to the back dimensions except box depth. I can now offer custom sized unfinished enclosures in any volume up to about 8 cubic feet without having to charge for extra setup time. The client can calculate the dimensions based on my design. From there I can edit the part sizes, cut the enclosure parts and ship them off to the customer. Below is a short video showing the basic design used in construction. Continue reading

New Signage

While I don’t have a store front I still need some advertising. First ITRBCNC Door Sign found a piece of Hickory and made a nice simple easy to read door sign, but it lacks luster and flair. TRBCNC Door Sign-Hickory



So, I found this awesome piece of zebra wood and carved me up little more decorative a sign for my shop door. Sign created in Vectric Cut2D and carved using two bits. A CMT 60° 1/2″ laser signmaking bit and a Whiteside 3/16″x3/4″ downcut spiral  bit to cut tabs and separate it from the stock.

First project

This is my first project. You have to start somewhere, right?

It’s nothing complicated, just a simple baffle for a Linkwitz Lab XL521 open back loudspeaker project. Apparently this is a kit being assembled by the customer. They are touted as the best sounding loudspeaker made. But I’ve heard that before…


Linkwitz Lab LX521 Customer built speaker kit.

Continue reading

CNC CRP-2448 Auto Gantry Square

I finally got my new CRP-2448 CNC machine up and running. I’ve managed to cut several things quite successfully, none of them Speaker related. But, since I’ve solved a few crucial issues I though I’d share what I’ve learned here. Eventually I’ll set up a CNC blog for these articles but for now they are here.

First, I purchased the proximity sensor kit from cncrouterparts and it works fine. However, I did need to change the auto square code under the “Ref All Home” button. It comes with code to home each axis individually starting with Z, then X then Y then A. I found it works better using the refcombination(x) code rather than the default Z-X-Y-A so I changed the code under the button to:

DoButton( 24 )
DoButton( 22 )
Refcombination(10) Continue reading

SIGGMA AC54W Build from scratch

Greetings fellow speaker builders and web wanderers. This article chronicles my ongoing development as a speaker builder and covers my second high quality speaker project. The AC54W features an Aurum Cantus AC-!30MKII mid woofer and a custom tweeter waveguide. The waveguide enhances the overall quality and power handling by increasing the acoustic output of the tweeter over a very wide range. This waveguide operates from about 13Khz down to 800hz and produces a significant increase in output over most of that range. This allows a crossover slope that reduces the power applied to the driver allowing it to cross much lower at much higher power with much less distortion. More details as we proceed.

The build begins with an enclosure design. At the time I designed this I was limited to a table saw, router and drill press for enclosure construction so the enclosure has no fancy curves. box design
Baffle size ended up 11″Wide by 13″High by 12″Deep rather than the dimensions in the image, ignore the measurement markers on the image above. But the placement is accurate. it’s a simple design with placement dictated mostly by waveguide shape more than anything else. The waveguide dominates the baffle due to it’s enormous size. Continue reading

Demystifying Phase in speaker systems

When I first began fiddling with speakers I felt like I was out sick the day phase was explained. It seemed everybody understood this mysterious effect except me. I understood that filters made phase changes and even that a speaker alone had some phase but exactly what phase is, eluded me. It wasn’t until my ego got in the way that I realized I couldn’t bluff my way past it any more. I had to at least try to understand this mysterious effect called “Phase” if I was going to be able converse with the crowd who did understand it, so I began reading. I was immediately relieved to hear how complex it really is and that I didn’t understand it because it couldn’t be understood. It’s simply too complex. More reading led me to realize the “too complex” attitude was a copout from someone who didn’t really understand phase. So I kept reading. Now I despise articles that present large squiggles of math as “proof” that “a butterworth filter has no phase” and hearing such things only confused me further. Turns out there is more misunderstanding about this innoccuous relationship than fact, even from some reputable places. Many years have passed since I began my search for understanding and in all that time only one thing remains constant. It was so close to me I missed it. In fact I missed it because it is so simple. In reality it’s the phase relationships that are complex, probably the most complex relationship in reality. But in the end it comes to this: phase is a measurement of time. It’s really that simple. It can be expressed in minutes, seconds, hours, years, even centuries, or it can be expressed in degress, radians, milliseconds or microseconds but they all represent the same thing, time. Phase is a measurement of time. More specifically, loudspeaker phase is a measurement of the arrival time of the individual harmonic components of a sound. Continue reading