A Blues Junior-Sized Extension Speaker

This is my Blues Junior-sized extension speaker. It's the same width and height as a Blues Junior, but the depth at the top is the same as the depth at the bottom of a Blues Junior, so that a Blues Junior sits on top of it neatly, with no overhang.

The handle is recessed, so that a Blues Junior stacked on top of the speaker doesn't rock. The recessed area around the handle is wider, so it's easy to grab. The Tolex extends under the handle.

The cabinet is loaded with an Eminence Cannabis Rex, which has great bass response and clean smoothness. Right now, the back is fully open, but I intend to partially close it. I'm going to take frequency response readings with different-sized panels so I can see the effect that the panels have on overall response.

I made the cab with 3/4 inch void-free birch plywood, with 1/2 inch ply for the baffle board  and face panels. I thought the Tolex covering would be difficult, but it only took a couple of hours to cut the vinyl and glue it up. The contact cement is pretty stinky, though. The corners aren't perfect, but they're pretty darn good for a first try. I copied the Fender pattern of using four pieces of fabric.

Here's how the speaker looks with a Blues Junior stacked on top. I tried to make everything identical, for a "factory" look. The half-inch roundover, the size of the face panels, the location of the baffle screws, etc. Eminence supplied the "Eminence Inside" plate with the Cannabis Rex.

I got the Tolex and the grille cloth from MojoTone, and a yard of each was more than enough. The speaker came from Parts Express.

I used T-nuts on the baffle board instead of the wood screws that Parts Express provided. The front of the baffle board is framed with strips of 1/4 inch plywood so that the grille cloth stands off the baffle board and won't buzz or slap on the low notes.

Since Eminence rates the Cannabis Rex for either open or closed-back use, I may pick up some more lows when I partially baffle the back. The C.Rex is louder than the stock Blues Junior speaker, but doesn't sound noticeably louder because it's so smooth. I had to check it with a sound level meter to be sure.

The C.Rex alone is 3dB louder than the stock speaker. The two together are 4-5dB louder than the stock speaker alone. You can hear the difference, but if you're being buried by a loud drummer, this isn't going to make enough of a difference to get you heard.

This particular Blues Junior is a late 2001 cream board model, and I've equipped it with my presence control mod. It does a pretty decent job of helping you cut through the mix.

Here's another look at the stack, with my Formicaster alongside. It's kinda cool having the controls right up there at hip level.

The sound of the two speakers together is impressive. The C.Rex really complements the stock speaker, which according to Eminence's replacement chart, is a Legend 125, or something very close to it. If you were playing this rig in a lounge, you could send your bassist home--there's lots of clean bottom end.

If you like bass and clean headroom, I wouldn't hesitate to recommend the Cannabis Rex as a replacement for the stock speaker. For lead rock guitar, you'd probably want something brighter and more aggressive.

 

 

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