Problem with my homemade 4x12

[fanticidaldream]

About a year ago, against the advice of just about everyone on the internet, I decided to build my own 4x12 cab. For a while it worked great, outshined my other cab and sounded precisely the way I hoped it would. Recently, after bringing it to and from a gig for the first time, it began making this awful crackling noise.
One thing I did notice about the noise is that it is not universal. Certain frequencies do not cause the crackling, while others do. For this reason I'm fairly certain it's not a blown speaker but I've never encountered this problem before.
http://youtu.be/1_25Vg7yoeY
That is a short video demonstrating my problem. (shot on an iPhone - ignore the terrible compression if you can)
I'd like to add that I did isolate the issue through the usual process of elimination. The blame lies solely on the cab. And although I don't have pictures of it I checked the wiring out and everything seems solid.
Any help is greatly appreciated,
Bill

[lkrasner]

Not sure exactly what your setup is in terms of speaker impedance and connections, but can you try to isolate 1 speaker? I use a 1/4" jack with short leads with quick connectors on it. Then you can disconnect speakers from each other and plug into each to find the bad one. If you don't find anything, it's most likely something in your wiring.

[PRR]

> Certain frequencies do not cause the crackling, while others do. For this reason I'm fairly certain it's not a blown speaker

Certainly could be a blown speaker.

Agree with krasner's advice to try each speaker alone.

[P Batty]

I once had a speaker where a piece of wire was under the dust cap, glued in place during construction. When it finally broke loose from the glue  it sounded similar to what you describe. I almost went nuts tying to figure it out.  A foreign object between the cone and the cage could do it as well. You'll definitely have to check each speaker seperately, preferably in a 1-12" baffle. Or the cabinet may have a brace that is loose.

[Jim Coash]

I would suggest you have a warped voice coil in at least one speaker.  That would be due to amplifier clipping.  You either need more efficient speakers (E/V), a bigger amp (at least twice the RMS power) or learn to live with Clint Eastwood's advice. "A Man's got to know his limitations".  Jim