boxy sounding cabinet

[frosty55]

Any advice for getting a good sound from a 2x12 guitar cab.
Having built it myself, loaded it with a celestion Vintage 30 and a celestion G12-H, the sound i get is quite" boxy".
Cab is driven by a Marshall JCM200 TSL100 valve amp and i use a Gibson Les Paul. Do the speakers need "playing in"?
Certainly dont get as much top end to the sound that i used to from my 4x12 bwith celestion V30s in.

[corworld]

More details please. Open or closed back? Parallel or series wired? A picture would help.

[frosty55]

drivers are 8 ohm, wired in paralell. Cab is sealed back.

[corworld]

This is outside the scope of this forum but the internal dimensions of a sealed cab are critical to the end sound. If your design was a new one, this may be part of the problem. Adding a port or making it a semi-open back could help but that may not be the sound you're after.

Also, check that the speakers are in phase. + and - wires going to the same terminals. That would serious mess up the sound.

[Wakculloch]

Experimenting with different absorbent linings may help. Boxy sound can be symptomatic of reflections off the cabinet back wall coming through the cone.

[mac1amps]

Also be aware of the fact that closed back cabs, which are known for more "punch" (low end), are also known to reduce "brilliance" vs. open back.