4x12 Back Panels

CrazyNutz

CrazyNutz

Well-known member
Particle Board vs Birch Ply vs Birch Ply w/Poly Fill

I've seen a few debates here and there. I've owned many 4x12's, and still do. I've heard people call manufactures cheap, cutting corners, doing it wrong, etc. for using particle board back panels on their high-end line of cabinets.

So I decided to experiment for myself. Or more accurately, I have been experimenting when I get free time over the last few months.

I've always been curious, however what really sparked this Is when I acquired a Bogner 4x12 v30 cab. While it sounded good, there were some things about it I could not jive with. It was stiff, seemed like it cut the breakup/distortion down (like turning the gain knob back a notch or two) could not get it to set well in a live band mix, bass was weird, and I had some worse than normal ear fatigue from the highs (probably from having to turn my amp up louder than normal to get it to cut through).

First thing I did was carefully remove the staples, and pull out the poly fill. This helped. I then put a pair of greenbacks up top (I like this combo and have used it in several other cabs). Now the bass got loose at high volume with the GB's up top, and the poly fill removed. So I put it back in, It was pretty decent now up to mid volume.



But I still had problems at high volume.

So I thought, I've had my fair share of Marshall 1960 A's, AV's, B's, BV's, etc. From the 70's, 80's, 90's, and 00's They all were birch ply with particle board backs. They always sounded punchy, tight, and for the most part generally fantastic. The Bogner being pretty much a clone of the Marshall 4x12 with one of the largest difference being the back panel.

We'll went to Home depot, grabbed a sheet of 5/8'' particle board (closest size to the 15mm used on marshalls, and clones) and got all sweaty building a new back in the July Texas heat.



Whats the verdict? FCUKING AWESOME :rock:
Punchy, Bass is bigger and tighter, has a nice thump to it, Louder, more pissed off sounding. It is clearer, more articulate (which is the opposite from what I hear when people put birch ply backs on their marshal cabs). It sounds way better at high volume. If you ask me it sounds the way it's supposed to sound?

Anyhow I'll do another play/listen session tomorrow to make sure my ears are not lying to me.
 
This is interesting. People assume so much about sound by looking at something, where it is made, what materials are used.
 
MDF is a bit more "dead" sounding than plywood (that's why full-range speakers often use them) so I'm not surprised that it'd make the cab sound tighter.
 
My buddy and I put polyfil in our cabs. His a B-52 slant and mine was a Splawn 4x12. Made notes more immediate and sounded great compared to not. We put them on three sides. I no longer have the splawn, but it did help
 
I did some experiments too, but only with a Marshall slant greenbacks loaded. I use a MDF back panel now, but was nice open back too (with a big hole like the Keery Wright).
Not had good results with plywood back panel, but maybe is my cab, or the slant construction.
 
Thanks to the OP for taking the time and posting the results.
Go ahead and take the rest of the week off. :thumbsup:
 
Interesting. One thing I've found with older Marshall cabs is almost every baffle screw is loose, some even to point of being backed out and the screw head not even making contact with the baffle. Makes for some really bad rattles at high volume.
 
stephen sawall":39zpipy2 said:
This is interesting. People assume so much about sound by looking at something, where it is made, what materials are used.
Click to expand...

You are very correct. I've seen people get all weird about how the tone knobs are set on their amp, I always have to remind people to tweak with your ears not your eye's.

godgrinder":39zpipy2 said:
MDF is a bit more "dead" sounding than plywood (that's why full-range speakers often use them) so I'm not surprised that it'd make the cab sound tighter.
Click to expand...

Yes, I might try MDF too. I had an ampeg cab that I gigged for many years, had a MDF back, sounded great.

I think the "dead" part is the key here. You just don't want that back panel to resonate much, because if it does it's fighting the speakers. It seems several manufacture try to solve this with the poly fill, while this works to deaden it, (too me at least) it sucks some life out of the sound, and feel.

Right now with the particle board back, I have harmonics easily bouncing off the fret board, where as before I really had to dig them out.

Luca79":39zpipy2 said:
I did some experiments too, but only with a Marshall slant greenbacks loaded. I use a MDF back panel now, but was nice open back too (with a big hole like the Keery Wright).
Not had good results with plywood back panel, but maybe is my cab, or the slant construction.
Click to expand...

Good info thanks
 
SpiderWars":2cgqn2ho said:
Interesting. One thing I've found with older Marshall cabs is almost every baffle screw is loose, some even to point of being backed out and the screw head not even making contact with the baffle. Makes for some really bad rattles at high volume.
Click to expand...

Same here, every one I've owned I had to re-tighten baffle screws, and sometime the center post. However I do not recall having to do that more than once, perhaps shrinkage occurs sometime after they leave the factory. You have a lot of compressible material between the baffle and that flange in mounts to. Pinstripe, grill cloth, tolex, tolex glue. If that material flattens out causing the the screws to get just a little loose, they will continue to back out overtime due to vibration.
 
CrazyNutz":2b8x7bzt said:
SpiderWars":2b8x7bzt said:
Interesting. One thing I've found with older Marshall cabs is almost every baffle screw is loose, some even to point of being backed out and the screw head not even making contact with the baffle. Makes for some really bad rattles at high volume.
Click to expand...

Same here, every one I've owned I had to re-tighten baffle screws, and sometime the center post. However I do not recall having to do that more than once, perhaps shrinkage occurs sometime after they leave the factory. You have a lot of compressible material between the baffle and that flange in mounts to. Pinstripe, grill cloth, tolex, tolex glue. If that material flattens out causing the the screws to get just a little loose, they will continue to back out overtime due to vibration.
Click to expand...
Good to know. They went in a little easier than I'd like but once tightened seemed tight. I was maybe a little concerned they would back out again. Interstingly, my 70's cab seemed to have softer wood than the 80's cab just based on how easy the screws went in and how tight they seemed to get. My 80's cab also had loose speaker mounting screws and one was stuck to a magnet. :confused:
 
Interesting info here.

I'm loving the sound of my new EVH 412 right now, and it has a solid birch back panel. I've had it cranked up relatively loud but admittedly not to gig levels yet, but its stayed plenty tight and ridiculously punchy at almost ear splitting volumes. When I get settled into the new house and get some spare time, I might have to try the same just for shits and grins.
 
MetalHeadMike":32lzjpht said:
Interesting info here.

I'm loving the sound of my new EVH 412 right now, and it has a solid birch back panel. I've had it cranked up relatively loud but admittedly not to gig levels yet, but its stayed plenty tight and ridiculously punchy at almost ear splitting volumes. When I get settled into the new house and get some spare time, I might have to try the same just for shits and grins.
Click to expand...


Yeah, I've heard a lot of praise for that cab.

I have a Mesa OS 412 It has a birch back, and it sounds great at high volumes, however I have heard complaints from people that they have flubby/loose bass with the Mesa OS cabs.
 
CrazyNutz":2hseeict said:
MetalHeadMike":2hseeict said:
Interesting info here.

I'm loving the sound of my new EVH 412 right now, and it has a solid birch back panel. I've had it cranked up relatively loud but admittedly not to gig levels yet, but its stayed plenty tight and ridiculously punchy at almost ear splitting volumes. When I get settled into the new house and get some spare time, I might have to try the same just for shits and grins.
Click to expand...


Yeah, I've heard a lot of praise for that cab.

I have a Mesa OS 412 It has a birch back, and it sounds great at high volumes, however I have heard complaints from people that they have flubby/loose bass with the Mesa OS cabs.
Click to expand...

That is the exact experience I had but I think it depends on the amp. I have a Rev 2 Uberschall and it is pretty Bass heavy. Even with the Bass at 0 it was "flubby" with the Mesa cab.

I love the cabs I have now (Mills) BUT I am interested in this thread. I used to have a Peavey ms412. Pretty sure it had a MDF back and it sounded great with V30 x 75's.
 
I think people confuse having better ingredients as automatically being superior.
But it comes down to what YOU want/like and what best suits YOUR needs.
 
D-Rock":1vp1tvok said:
I think people confuse having better ingredients as automatically being superior.
But it comes down to what YOU want/like and what best suits YOUR needs.
Click to expand...

Indeed. 17 years ago my band did an album with a well known producer (David Prater, produced Dream Theater's Images and words, and other notable)
The other Guitarist, and I were really worried of how he was setting things up (from his bag-o-tricks). For example he tracked vocals through a beat up old Boss Compression pedal (meant for guitar use) with the controls dimed running into some ancient DBX noise reduction unit. But it sounded incredible.
 
MetalHeadMike":3crq3k7z said:
Interesting info here.

I'm loving the sound of my new EVH 412 right now, and it has a solid birch back panel. I've had it cranked up relatively loud but admittedly not to gig levels yet, but its stayed plenty tight and ridiculously punchy at almost ear splitting volumes. When I get settled into the new house and get some spare time, I might have to try the same just for shits and grins.
Click to expand...


Hell yeah!!! A great cab!!!! :rock: :rock: :rock: :rock:
 
I've dimed most of my heads through my EVH 4x12, but then I have Creambacks up top and V30s in the bottom. I always wear earplugs when I do it too. Once an SLO gets to 7, it's a different amp. I think most 100w heads put out more than 100w. So, unless your speakers are rated accordingly, I'd be worried about blowing one or more after a few slammed power chords at full tilt.
 
-great thread crazy nuts, one of my favorite topics...

-about half of what your hearing as an improvement-(and its not a subtle either, is indeed the Birch ply, the other 50% is the thickness of the Birch ply.

-want it to sound even better, give the baffle the same 5/8" Birch ply treatment as the back panel. POOF!!-much better!!-and yet another! -COUPLING- the cab to the floor by having as much surface contact as possible between them, easy way is putting the cab on its side-(what the floor is comes into play as well, concrete, carpet, wood etc. A rubber matt or carpet atleast the same size will do the trick, also couple between the top & bottom of a stack.

-VARIABLES make a difference, but no as much as making the cab 100% -5/8"- Birch ply, I've been making my own cab's for the last 10+ years, I've bought many manufactured cabs to harvest speaker's & because it was a package deal with the amp, and sometimes I find a good deal on one of the "MAGIC CAB'S" that are available.

-(the best 4x12 I've come up with to date- 3/4" - OS-(more so in the deep dimensions, than tall & wide)-CABINET GRADE, BALTIC BIRCH PLY-(currently "de-tuned" with 3 speaker's)-I'll put her up against any 4x12 cab-

-(variables)-some of them make a bigger difference than other's,the first 2, big difference.
-(CONSTRUCTION)-it has to be structurely sound, re-enforce, all corner's, over kill is mandatory, one of the biggest reasons some front loaded cabs sound so good, isn't because of the speakers mounting surface being front or back, but that of its construction, the ones with the sealed, can't be removed, back panel.
-(THICKNESS of PLYWOOD)-BIG DIFFERENCE- a structually sound, made of 100%, 3/4". cabinet grade, Baltic Birch, plywood cab, will sound bigger, tighter and just overall better, than an exact duplicate cab, with the only difference being 5/8" instead of 3/4" thick, hands down, especially if your put high powered speakers in it, and play down tuned, and the most BRUTAL BROOTZ OF ALL TIME!!
-(grade of plywood)- it matters, but as long as its not junk, full of knot holes, pulled out of the bargain bin, with more glue than wood, it's a small %, if you go cheap, you'll have trouble working with it, like sanding, fitting & cutting it & applying any kind of tolex.
-(what's it made of)-some cabs are made of solid wood board's,...... PINE-&-POPLAR are the only 2 solid wood board cab's that came from a amp manufacturer I've seen,
and there both in the MAGIC-CAB, hit list, wood board & plank cab's have solid wood board outer shell-(top, bottom & both sides)-and a ply back & baffle, both can be improved, PINE & POPLAR both are very similar sonically,
they're dynamic & musical, they add another dimension, I LOVE UM!!!... there's only one negative, which can be fixed, not alot of -"THUMP"-here's some fixes for the lack of THUMP, -PORTED-(an engineered to be PINE/POPLAR cab, is the best of both worlds, there's only one I know of,

-KRANK-(POPLAR BOARD)-an oversized, engineered to be ported, and in stock form,... KICK'S ASS!!!.. AND!!.. Replacement of the baffle & back panel with 5/8" Baltic Birch,... Shit can the shitty speakers, & BANG!!... BITCHES!!!..... Now this ported, factory cab, that is still under the radar, and can be found in the $400 range!!!!!..

-FENDER-2x15-BASSMAN-PINE BOARD-(60's to early 70's)-(this cab started it all for me, replaced the 2x15 half inch, chip board baffle, with a 5/8" plywood baffle, to make it a 4x12, filled it with greenbacks,... FUCK!! -(instantly became my favorite cab, she sent many of 4x12's listed in this thread,.... and more!!!... that are supposedly the best,.... packing!!! And it didn't matter what speaker's I put in it,... or what amp I through on top of it, it just added something, that I never heard before, must be MAGIC!!-(this cab, with many different speaker's, sold me a lot!! and I mean A-LOT OF AMPS!!
 
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