#1
I was running some random brand, standard sized 4x12 that I put Vintage 30's in for about a year. I just recently got my hands on a Marshall MF400 Cab which is a Baltic-Birch, oversized 4x12, with Celestion G12K-100's. Its a much better cab than the one I was using, and since V30's are a big part of my tone, I swapped out the G12K's for the V30's. But when it was all said and done, I ended up losing a lot of bottom end by switching cabs and I have no idea why. Same speakers, same amp (Peavey 6505+), and the cab is the size of an oversized Mesa cab. I should be rolling my bass knob back because of all the bass I should be having. Now I have to turn the bass on my parametric EQ up to get some bass out of this cab, which I'd rather not have to do.

Any ideas why this is happening? Could I have possibly installed the speakers wrong?
Gear:
-Mesa Dual Rectifier (3 Channel) with KT88 and KT66 Tubes
-Peavey 6505+
-Roland JC120
-Ibanez Tone Blaster TBX150H
-Mesa 4x12 Straight Cab
-Marshall 1960BV
-Gibson Les Paul Custom
-Gibson Flying V
-Line 6 M13
#2
There are some formulas for calculating cab dimensions that are considered when making a cab. Perhaps Marshall had those particular speakers in there for a reason?
#3
Quote by xXBansheeXx
I was running some random brand, standard sized 4x12 that I put Vintage 30's in for about a year. I just recently got my hands on a Marshall MF400 Cab which is a Baltic-Birch, oversized 4x12, with Celestion G12K-100's. Its a much better cab than the one I was using, and since V30's are a big part of my tone, I swapped out the G12K's for the V30's. But when it was all said and done, I ended up losing a lot of bottom end by switching cabs and I have no idea why. Same speakers, same amp (Peavey 6505+), and the cab is the size of an oversized Mesa cab. I should be rolling my bass knob back because of all the bass I should be having. Now I have to turn the bass on my parametric EQ up to get some bass out of this cab, which I'd rather not have to do.

Any ideas why this is happening? Could I have possibly installed the speakers wrong?


Because you went to a larger cab. The larger the enclosure the more power you will need to make louder bass, this applies to almost anything related to bass. When you increase the size of the enclosure you do improve the frequency response; however you will in turn need more power to get the same volume levels of bass. Bass is relative to sound pressure, the more air you can move from your cab the louder the bass will be, increase the size of the enclosure and you successfully increase the amount of air required to move to produce your bass frequency. I hope this gibberish makes some sense I typed it while on the phone.
#4
Well V30s are not that bassy (I personally compared my V30s to about 4 different speakers) the V30s had less bass then any of them in the same cab.
I would say go back to the G12k, see how that sounds, and if it doesn't work go back to the cab with the V30s.
Sometimes a cab that should be bassy has no bass, and cabs that seem like they should have no bass have tons, just like the one guy said, dimensions can change so much!