# troubleshooting new ext cab



## SkyFire_ca (Jul 16, 2007)

hey guys... just got done building a new extension cab, 1x12. made with fir ply (yuck, but less $$) and built really solid. Glued all sides and braced internally, (no exterior screws) convertible back, inset and angled baffle with "bluesbreaker" style top fascia. so yeah, not too bad aside from the junky wood.
problem I'm having is that I'm getting a horrible fuzz to the tone. I'm using an eminence red white and blues speaker that hasn't been used in a while, but worked fine when last it was tested (one of my combo's, about a year ago, tops). It sounds to me like a dead speaker (crud...) but I'm not sure... before I go pulling speakers from one of my other amps, any other ideas? If I had another loose speaker, I'd have already answered my own question I'm sure...

also, anyone think of a reason that Fir would be bad to build with?
thanks in advance...


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## mrmatt1972 (Apr 3, 2008)

I can't help you with the fuzz problem, but I think you're right to suspect the speaker. Fir is more expensive than particle board, but not as rigid as birch. If you want top quality you go for the hardest one, if you want cheap, you go for the cheapest. Also, fir tends to have a lot of voids.


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## washburned (Oct 13, 2006)

Possibility if you have rear mounted the speaker and the opening is too small the edge of the cone could be rubbing on the edge of the opening-happened to me years ago when I built one of my early cabs.


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## SkyFire_ca (Jul 16, 2007)

well, the circle was cut by jigsaw... so it's possible, it's not perfectly square... it's also rear mounted... though, it seems far enough back to not cause a problem... I'm going to have to pull a speaker to test thoroughly, when I do I'll true-up the hole some and check that first... thanks guys, tonnes of help


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## tbellisario (Apr 14, 2010)

Does the buzz seem to be on all registers from low "E" and up and at all volume levels? You could have an unevenly torqued speaker frame from a wood or glue joint void. Its unlikely the speaker if you know it is good from another amp. I would remove the speaker and run some wood glue around all of the wood joints and hopefully you will fill any easy to fix void from the assembly process. If you did not use wood screws some times the bracing will pull away during the glue curing and create air voids, this is why you should always use wood screws to hold the wood together while the glue sets. If the void is internal to the wood there is not much you can do.
If when you cut the wood you see any voids on the edge of the cutting, try to fill those as well.


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## SkyFire_ca (Jul 16, 2007)

are you suggesting that the speaker frame may be twisting because the baffle isn't "square" or true... that's definitely possible.
I tested a few things last night... tried the speaker in another cab, beatup old pressboard thing... unfortunately, the hole in the baffle wasn't sufficient to front load it with, and rear mounted it sounded the same as the other cab. I also tried front mounting it to my new cab. that worked a little better. I still have some "fizz" on the upper end of gainy sounds, but that may be the amp or speaker just not handling it well.
I suspect that the problems all revolve around the baffle. I'll have to check if it's true and try to widen the hole a little, true it up to round...


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## tbellisario (Apr 14, 2010)

From what you describe in your last post "sounded the same as the other cab" I would suspect the speaker or the amp.


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