Marshall 1966 2x12 unnaturally woofy sounding.

That elusive piece of the overall equation, so many options and so little time to test them all — Celestion, Fane, Eminence, Jensen, JbL, Utah, Ceramic, Alnico, 1x12, 2x12, 4x12, 2x10, 4x10, 1x15, 2x15, 4x15, 1x18 and I'm sure there are even more!

Marshall 1966 2x12 unnaturally woofy sounding.

Postby sitka_spruce on Mon Dec 01, 2014 2:14 pm

I'm having this issue with one of my 1966As in that it's heavy on the lows and not the lowest of lows but a bit up. I have two similar cabs except for the handles and they're not nearly as woofy. I replaced the backboard of it and the issue remained. I made it 1/3 open and it's even woofier still.

I'm thinking it could be something about the baffle of it. An 'A' or slant model as it may be, the baffle is technically a one piece jobbie. But a one piece w. bits of board screwed into its sides at 90*, for it to fit snuggly with the angled front of the cab, to make it look like a baby 1960A from the outside.
Image

Not sure you can tell from this image
Image but looking closely top right and bottom left you'll actually see the plies of these 'book-end' boards fitted to the baffle. As such I could imagine the joints of those to be not quite so solid and I could also see the baffle letting some air through at these points.

Having said that I'm open to suggestions. The cab in question has the expected 1960 tube style handles and may not be quite so air tight there either, but running the cab as partially open back I can't see why that would make such a huge difference with not so much pressure build-up.

Cheers!
Last edited by sitka_spruce on Tue Dec 02, 2014 10:08 am, edited 2 times in total.
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby PeterS on Mon Dec 01, 2014 11:41 pm

Do both cabs have the same speakers?
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby sitka_spruce on Tue Dec 02, 2014 10:07 am

PeterS wrote:Do both cabs have the same speakers?

Thanx mate!

There are even three of them in my possession. Doesn't matter what speakers I put into this one though. It has seen various Weber's Celestionesque speakers + their California and Thames... Currently it's loaded with and Eminence Delta and a Fane Elite 12, which are both PA speakers. And I made it 1/3 open amongst other things to cut back on low end - and it's even boomier open than closed (?).

Note that it's not boomy in the lowest of lows. Down there it's pretty tight. It's a bit further up but not so far into the meaty frequencies of 400Hz and beyond.
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby OldSchoolDave on Tue Dec 02, 2014 12:34 pm

sitka_spruce wrote:Doesn't matter what speakers I put into this one though.

And I made it 1/3 open amongst other things to cut back on low end - and it's even boomier open than closed (?).


That's very unusual behavior :? . Something seems to be resonating at certain frequencies. Makes one wonder if there's a void somewhere in the plywood (although your pics appear to show the good stuff).

What about those handles? Could those be the culprit?

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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby sitka_spruce on Tue Dec 02, 2014 2:39 pm

OldSchoolDave wrote:
sitka_spruce wrote:Doesn't matter what speakers I put into this one though.

And I made it 1/3 open amongst other things to cut back on low end - and it's even boomier open than closed (?).


That's very unusual behavior :? . Something seems to be resonating at certain frequencies. Makes one wonder if there's a void somewhere in the plywood (although your pics appear to show the good stuff).

What about those handles? Could those be the culprit?

Dave

Cheers, mate! Those pics are unfortunately not of my cab but an identical one, save for the handles. I tried to pad it internally but to no avail. No visual voids or irregularities from what I can tell.
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby OldSchoolDave on Tue Dec 02, 2014 11:40 pm

sitka_spruce wrote:I tried to pad it internally but to no avail. No visual voids or irregularities from what I can tell.


What about the feet? Could this cab be coupling with the floor somehow? Are they the same as your other cab(s)?

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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby sitka_spruce on Wed Dec 03, 2014 8:50 pm

OldSchoolDave wrote:
sitka_spruce wrote:I tried to pad it internally but to no avail. No visual voids or irregularities from what I can tell.


What about the feet? Could this cab be coupling with the floor somehow? Are they the same as your other cab(s)?

Dave
Seem I may have miss read your comment on the handles: I suppose I could try to do something about those to make them more air tight but at least one of them has to be made removable or you couldn't unscrew the speaker on that side. I tried to replace both w. all metal handles but on one side it's really up against the speaker so I had to go with plastic there to make it fit.

Good point about the feet. These are the stock tapered plastic ones, same as the other ones. Then they're rather worn from having been pushed around by previous owner(s). I tried to fit them with felt scratch protective pads but no change. Then dad fit his Tweed cab with furniture casters which made a substantial difference in how the amp connected to the room, so I may just have to try that. Or perhaps some kind of rubber feet to further isolate the cab from the floor.

Fact of the matter is I bought three sets of those casters when father bought his the price being so ridiculously low. Then they look rather small to be convenient... But could try them on for the heck of it.
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby pckpat on Thu Dec 04, 2014 1:13 am

Maybe you've got a standing wave issue at some resonant frequency peak due to the volume of the cab. Perhaps also a baffle brace from the backboard like the 4-12's have might help alleviate the woof.(woof-woof! :D )
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby sitka_spruce on Thu Dec 04, 2014 10:48 am

In reference to what Dave said on the feet: I must have been confusing things as clearly the cab with an issue is the only one of them with these taller, tapered feet. The other two which are later models (actually one is a 2556) have shorter and narrower, cylindrical feet.

pckpat wrote:Maybe you've got a standing wave issue at some resonant frequency peak due to the volume of the cab. Perhaps also a baffle brace from the backboard like the 4-12's have might help alleviate the woof.(woof-woof! :D )

Thanx, yes this could very well be the case here. But I figure that such an issue would decrease opening the cab up. I also padded the sides and back boards but that seems to have minimal if any impact. But then padding would technically only sort of artificially enlarge the cab which would be the fix for a boxy sounding one or one that required more low end. So I may actually have made the matter worse by doing that.
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby pckpat on Fri Dec 05, 2014 12:55 am

Soory, Sitka -you're right. I must have temporarily unplugged my brain. forgot about you having it running open-back with no improvement. Well, how's about this ...standing wave in the listening room.... :D :P
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby sitka_spruce on Fri Dec 05, 2014 5:22 pm

pckpat wrote:Soory, Sitka -you're right. I must have temporarily unplugged my brain. forgot about you having it running open-back with no improvement. Well, how's about this ...standing wave in the listening room.... :D :P

Cheers! I have tried it in different rooms at my place and at my parents', but yeah: that could be it.

If I may add something on the topic: my other 1966s seem to have... let's call it a resonant peak somewhere in this frequency range, which make them quite large sounding. But somehow it's as if that resonance just goeas overboard with this cab. And in fairness: the Celesionesque Webers were far from this woofy when I had those, so some of it could be attributed to the speakers that are in there now.

Back boards are solid pine, btw. That's supposed to be a huge no-no with speaker cabs, but in the case of the other two (closed back) cabs it actually helps making them larger sounding.

And I recently did some tapping tests (like you would with tonewoods for acoustics) of the various boards from which the cab is constructed to compare with the others, but from what I can hear they sound pretty identical.
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Re: Marshall 1966 2x12 unnaturally woofy sounding.

Postby sitka_spruce on Fri Dec 12, 2014 6:57 pm

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