Guitar Speaker Cabinet Build

Background

A couple of months ago I picked up a used Blackstar HT-5H (5 watt hybrid guitar amp head) on Ebay dirt cheap for a friend of mine. I needed a cabinet to pair it with and after looking at prices for a while, I decided I may as well build my own since I had a whole sheet of leftover cabinetry grade plywood in my basement. Thus the project began.

I have a few photos to show you of the project. Unfortunately I didn’t take many progress photos as the build progressed. Most of these are from after the construction is pretty well done. I have never built a speaker cabinet before and I wasn’t expecting this to turn out well enough to make it into a guide. Lucky me, it turned out much better than expected!

So I’ll insert some photos here and make a few notes about what I did.

Materials

Here is a basic list of materials I used.

  • One 4’x8’x3/4″ sheet of oak faced cabinetry grade plywood
  • One 2’x4’x3/4″ sheet of oak faced cabinetry grade plywood
  • One 4’x4″x3/4″ solid red oak trim board
  • Various screws
  • Wood glue
  • 3M Water-based Contact Cement
  • Black Tolex
  • Plastic Corners
  • A handle
  • Rubber feet
  • Speaker (12″ Warehouse Guitar Speakers Veteran 30 16 Ohm 60 Watt.)
  • 18 AWG speaker wire
  • 3/8″ Techflex
  • Various heatshrink tubing
  • Stain (Minwax Special Walnut)
  • Varnish (Pratt & Lambert Satin Varnish)
  • Black Paint (Pratt & Lambert Accolade interior flat acrylic – base 3 with 6 ounces of black tint)

I’ve probably missed a few things but that’s all I can think of for now.

Here is a list of tools used in this project.

  • Table saw
  • Circular saw
  • Jig saw
  • Scroll Saw
  • Palm router
  • Drill
  • Drill Press
  • Dremel
  • Belt / Spindle Sander
  • Files
  • Scrapers
  • Screwdrivers
  • Hammers
  • Hand Saws
  • Dovetail Template Block
  • Brushes
  • Rollers
  • Rolling pin (stop laughing)
  • Staple Gun
  • Clamps
  • More types of sandpaper than I care to mention.

And so on. Again, I’m sure I missed a few things. That’s the majority of what went into this project. The other major factor was a hell of a lot of time. I work full time and do computer work on the side so I was limited to what little free time I had. This project took about two months from start to finish. If I were working on it full time I’d say two weeks would be a good estimate of build time. One of the most time consuming factors is waiting for varnish to dry. The paint dries fast since it’s water based.

Design Notes

We started off by taking some measurements of the head itself. The Blackstar HT-5H is about 9 inches deep, 17-1/2 inches wide and 8 inches tall. Our goal was to build a cab that was roomy enough to get good sound out of the selected speaker and be a good fit for the head. We ended up with a 21 in wide by 21 inch tall cab. The front has a little slant to it so the top was 13 inches deep and the bottom was 15 inches deep. We also opted for a 2/3 covered open back design, meaning the back is 2/3 closed by wood panels and 1/3 open. Guitar cabs are thankfully pretty forgiving of these parameters unlike hi-def audio applications so we didn’t have to be too precise.

Photos

Stained and ready for tolex

This is the cabinet after it’s been stained and varnished. We joined oak faced cabinetry grade plywood using hand cut dovetail joints, wood glue, and wood screws. I filled the holes with Timbermate putty and sanded it all smooth after routing rounded edges on the cabinet. The face boards are solid red oak.

stained and ready for tolex

Here is one more view from the other side. The dark stripes inside are caulk I used to seal the joints entirely.

Front view

Here is the face of the cabinet. We’ve applied black tolex from Mojotone to the sides. We’ve also added black plastic corner caps like Marshalls have. I think I would do the caps a little different the next time. They didn’t fit the best due to the size of their radius and the slant on the cab. Metal corners would have worked better. We stretched an inexpensive grill cloth from Mojotone into place on the baffle. That was a real pain to get straight and took longer than expected.

side view

A side view of the cab. It’s a little dirty, but still looking good.

handle

This is the faux leather dog bone style handle we went with. These are really designed for Fender combo amps. It caused me a bit of grief later. I ended up having to modify the amp head by adding feet extensions to it so it would clear the handle correctly. The Blackstar head has very tiny feet.

face plate

This is the custom nameplate with model number I had etched for this.

rear speaker view

This is a rear view. We used a Warehouse Guitar Speaker 12″ 16 Ohm 60 watt Veteran 30 speaker. It’s a clone of the Celestion Vintage 30 with slightly scooped mids. The black paint is Pratt and Lambert Accolade. The stuff covers great is one coat. It’s expensive though if you don’t happen to work for the paint store, which I do.

rear speaker view 2

Here is a better view of the speaker. I custom made the cable as well.

cabling 2

This is a closeup of the cable. I used 18 AWG speaker wire. I twisted a pair of them together for the positive pole and another for the negative pole and then reverse twisted those pairs together. I then covered them with 3/8 inch techflex jacketing and some heatshrink tubing at the ends.

back panels

These are the back panels. They’ve just been varnished with Pratt & Lambert Satin Varnish. I really like how it flows and looks. I varnished the whole cabinet with a total of three coats, sanding between coats with 1000 grit wet or dry automotive paper. Once the final coat was on I lightly buffed it with 2000 grit paper to smooth it out.

full amp

This is the finished product. Not a bad match in my opinion. I have yet to modify the legs on the head in these photos so it’s sitting askew.

full amp 2

Here is a side view. I polished it up with Armor All so it looks better now.

amp back

Here is the finished back. Notice the ridiculously heavy speaker cable. I made this out of Mogami 12 AWG cable with a super thick shell and Switchcraft oversized plugs. I still had to grind out the plug openings a bit to make the cable fit them. I could likely push at least 500 watts though this cable. I’m pushing 5 watts with the Blackstar. Call me the king of overkill.

locking jack

This is the Neutrik locking 1/4 inch jack. Also notice the plate I had made up so you know exactly what wattage and impedance the cab is. I hate it when manufacturers don’t label these things clearly.

Cover 1

Here are the custom covers we made up. It’s been ages since I sewed anything. My mother on the other hand, has started making everything from quilts to pocket books for people. So of course she decided to volunteer for this project. We went to the Fabric Warehouse in Waynesboro and bought some perforated vinyl at a great price. Thanks Denise!

I had my doubts about my mother’s abilities with this material. Unfortunately, I was correct to be worried. She did the best she could but she’s never worked with this type of vinyl before and her seams aren’t the best to begin with. They look okay from afar but up close they show some issues.

Cover 2

The head cover isn’t too bad. She got the seams pretty straight and the proportions weren’t bad.

Cover 3

The cabinet was a different story. There was a lot more material to handle and it kept moving on her during the actual sewing. As you can see she has issues with the proportions and her seams weren’t so good here. There is some puckering as well. This is after we attempted to fix it once. We may make another attempt but now that the sides are sewn it may be impossible to fix without ripping it all apart. She said it about drove her crazy working with it so it might be a while before any fixes are considered. I may have to try my hand at sewing it myself. I’m not looking forward to it though.

Conclusion

That wraps it up for now. We may build another one of these in the future with a straight face and make a mini stack out of it. This will do for now though. It’s sounds decent for an amateur cab with a low dollar head on it.

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4 responses to “Guitar Speaker Cabinet Build

  1. Thanks for posting. The Veteran 30 is a little dark sounding with this amp for my taste, but the guy that will be using it runs a lot of effects and his sound ends up bright and over saturated. I’m hoping that darker tone will help even out his treble spikes.

  2. You may be able to use a heat gun on your vinyl cover to take out some of the wrinkles–leaving the cover on as you sweep the gun, at a distance, over the surface. Of course, if you get in a hurry you could end up making a trash can liner. However, I think with a test run on a scrap piece and a little patience you could improve the fit. I dig your effort though–I like the results.

    I especially like the limited use of Tolex–I prefer bare wood for its beauty and natural breathing–one unencumbered by a synthetic covering.

    • Thanks for you input. I did consider a heat gun for this, but the top and bottom seams are just straight cut against the wood, not wrapped. I was afraid the tolex would shrink back from the wood when it cooled if I used a heat gun. It if were completely wrapped on all sides a heat gun would have been great. It came out pretty clean regardless. The tolex is nicely stretched and tight. My main problem was the adhesive. I had never worked with waterborne contact cement before. It takes forever to dry to its tacky state.

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