>

4x12 cabs... particle or plywood backs

Discussion in 'Cabinets & Speakers' started by Emiel, May 18, 2021.

  1. Emiel

    Emiel New Member

    Joined:
    Jul 22, 2008
    Messages:
    25
    Likes Received:
    19
    Last weekend I bought what I think is a 1979 Marshall 1960A, retolexed in snakeskin. It has three 1979 Blackback G12M25 75z speakers and one 1974 G12H30 75hz.

    It's been years since I've had a 4x12 and I remember that some changed the particle back boards on newer Marshall cabs to one made of birch plywood for 'better' tone. Since this cab has been butchered with already, I don't mind changing more bits on it. I Googled on past threads but couldn't really find anything conclusive.

    Who has fitted their cabs with a birch plywood back and what is your opinion of it? Yes or no?
     
    FogDweller likes this.
  2. FogDweller

    FogDweller Well-Known Member

    Joined:
    Jun 19, 2014
    Messages:
    274
    Likes Received:
    498
    I bought a used Marshall cab a few years ago that had a replacement back and it was ported. I had Sourmash cabinets make a new back from birch ply. It worked out great. I’ve since sold it.

    I doubt I’d be able to tell the sound difference between a particle board back vs a plywood back, though. I have a ‘76 Marshall 4x12 with Blackbacks and it has a particle board back. Sounds great.
     
  3. What?

    What? Well-Known Member

    Joined:
    May 17, 2018
    Messages:
    1,685
    Likes Received:
    1,482
    No experience with that. I would think that a plywood back would be more resonant at the modes of the cab. In other words, modal frequencies having stronger peaks and longer decay times. Maybe the difference would be insignificant though.

    Let us know what you think if you try it.
     
  4. Dogs of Doom

    Dogs of Doom Moderator Staff Member

    Joined:
    Aug 2, 2012
    Messages:
    24,862
    Likes Received:
    30,685
    Location:
    Los Angeles
    Marshall started using MDF in the early '70s...

    MDF is high grade particle board, used in speaker cabinets.

    The MDF tames down some tone. Some people like it, because it makes the cabinet have clearer definition. The plywood backs have more spank & midrange, but also some added tones, that can be more raw.
     
    WellBurnTheSky and FogDweller like this.
  5. Torren61

    Torren61 Active Member

    Joined:
    Jan 3, 2014
    Messages:
    258
    Likes Received:
    225
    Location:
    Humboldt County, CA
    How many snakes lost their lives to provide enough of their skins for your cabinet? How do you sleep at night???? :shred:
     
  6. Thevenin

    Thevenin Well-Known Member Platinum Supporting Member

    Joined:
    Jan 19, 2019
    Messages:
    259
    Likes Received:
    518
    Location:
    Austin, Tejas
    My mdf 425A back had a hole punched through when I bought it. Replaced with birch plywood back. I'm sure it sounds good with both materials, probably more variation between the guitars I'm using.
     
    fitz288 likes this.
  7. Emiel

    Emiel New Member

    Joined:
    Jul 22, 2008
    Messages:
    25
    Likes Received:
    19
    Thanks all. One day I might be mad enough to retolex the cab anyway, so adding a birch ply back won't be too big of a stretch then!
    Don't worry, it's just a snakeskin motif, no actual snakes were harmed!
     
    Torren61 likes this.
  8. pedecamp

    pedecamp Well-Known Member

    Joined:
    Dec 7, 2009
    Messages:
    17,122
    Likes Received:
    16,361
    Youre gonna get answers in favor of both. I like an MDF back on a cab, I find an all ply cab to be too boxy sounding, the MDF back obsorbs some of the sound waves to eliminate that boxy sound. Ive done much research and many tests building cabs out of different materials and configurations to confirm my results. :yesway:

    Also not all ply is the same, I found that the more plys in plywood the better the sound, 9 or 13 layer ply sounds the best, anything less sounds terrible, there's alot of junk ply out there made out of god knows what with 3 or 5 layers, 3/4" junk with paper thin birch veneer on both sides so beware, just cuz it says birch ply doesnt mean that it is, look closely at it. :yesway:
     
    Last edited: May 19, 2021
  9. Torren61

    Torren61 Active Member

    Joined:
    Jan 3, 2014
    Messages:
    258
    Likes Received:
    225
    Location:
    Humboldt County, CA
    I was kidding
     
  10. Seanxk

    Seanxk Well-Known Member

    Joined:
    May 14, 2018
    Messages:
    752
    Likes Received:
    626
    MDF = Medium Density Fiberboard, as far as I know Marshall has never built a cab yet with MDF, I could be wrong though and would love to be proved wrong.
     
  11. pedecamp

    pedecamp Well-Known Member

    Joined:
    Dec 7, 2009
    Messages:
    17,122
    Likes Received:
    16,361
    They have, there was a period of time 1936 cabs were made of MDF, also the MG cabs are MDF, pretty sure the backs of 1960 cabs were MDF for a time too, I'm sure there are others. MDF is not a bad thing, it is used to stop resonance, sound systems are made of MDF with the purpose of deadening the cab resonance so the sound comes purely from the speakers. We like birch ply for guitar cabs cuz we want the resonance from both the cab and speaker, thats whats pleasing to the ear for guitar music. What I like are 3/4" birch play cabs with an MDF back, all ply sounds boxy to me in my experience, I know guys that have replaced their MDF or particle board cab backs for ply and swear they sound a ton better, we all hear differently so there is no right or wrong answer. :yesway:
     
    Last edited: May 19, 2021
  12. Seanxk

    Seanxk Well-Known Member

    Joined:
    May 14, 2018
    Messages:
    752
    Likes Received:
    626
    Ahh ok, so it's an export thing, probably why I've only ever seen chipboard ( particle board as you guys call it ) cab backs here in the UK or the obvious ply backs for the early cabs.
    I never knew Marshall exported with MDF backs, learn something new here every day.

    MDF is sonically is one of the best boards to use for Hifi speakers with it's deadening etc characteristics.
     
    pedecamp likes this.
  13. pedecamp

    pedecamp Well-Known Member

    Joined:
    Dec 7, 2009
    Messages:
    17,122
    Likes Received:
    16,361
    People say "MDF" like its a dirty word, its not at all! Comes in handy when you need it! :yesway:
     
    Last edited: Jun 1, 2021
    scozz, MarshallDog and Kim Lucky Day like this.
  14. What?

    What? Well-Known Member

    Joined:
    May 17, 2018
    Messages:
    1,685
    Likes Received:
    1,482
    Did / does Marshall actually use MDF (medium density fiberboard) for cabinet backs, or is it particle board? The latter is also called chip board or LDF (low density fiberboard), but probably for marketing purposes of avoiding negative connotations, no one really calls particle board by the name LDF.

    MDF is pretty fine particles with sharp edges and no really visible voids. Particle board is made from bigger particles and does have visible small voids via it's ragged edges, which is the stuff that cheap furniture which you assemble yourself is made from, covered in vinyl prints that look like wood or solid colors. OSB (oriented strand board) looks like it is made of bigger chips that look like slices of chips out of a wood chipper, which is the stuff used for building sheathing.

    Just clarifying here on the different wood products, since I have seen many people mix up the names.
     
    Last edited: May 20, 2021
    MarshallDog and Seanxk like this.
  15. junk notes

    junk notes Well-Known Member

    Joined:
    Dec 10, 2018
    Messages:
    2,602
    Likes Received:
    2,821
    Jim Marshall knew how to make a musical cabinet, and the secret is in the magical soundpost! Always remeber that gentlemen. Father of Loud knows best ;-)
     
  16. Dogs of Doom

    Dogs of Doom Moderator Staff Member

    Joined:
    Aug 2, 2012
    Messages:
    24,862
    Likes Received:
    30,685
    Location:
    Los Angeles
    & yes...

    I have a '90s Park 4x12 cab, where the shell is 100% identical to the 1960. The front & back though are LDF particle board. Cheap stuff, w/ rough sides. They didn't even tolex the rear panel, it had so much texture it could pass for tolex, well, not really, but it is textured...

    My 900 series 1960, has MDF, whereas the particle board surface is smoother than plywood. I haven't paid attention to my '70s cab, since, when I bought it, I opened it up shortly, just to look at the speakers & the wiring harness was tight, so the back didn't have a lot of play & I didn't really feel like messing w/ it, since I was just opening it to take a snapshot of the speakers...

    But, it has a '80s back on it, because they had it in a roadcase & the original back's surface mount jack was problematic. They changed it to a newer back w/ the recessed cup & it solved the problem...
     
  17. What?

    What? Well-Known Member

    Joined:
    May 17, 2018
    Messages:
    1,685
    Likes Received:
    1,482
    The only cab I have seen with an MDF back was a vintage Hiwatt cab.
     
  18. Seanxk

    Seanxk Well-Known Member

    Joined:
    May 14, 2018
    Messages:
    752
    Likes Received:
    626
    I think as soon as someone takes a picture of MDF, all will be sorted:yesway:
    I'm still sticking to '' Marshall never used MDF on a 1960 cab ''.
     
  19. Dogs of Doom

    Dogs of Doom Moderator Staff Member

    Joined:
    Aug 2, 2012
    Messages:
    24,862
    Likes Received:
    30,685
    Location:
    Los Angeles
    MDF:

    [​IMG]
     
    Mystic38, Seanxk and fitz288 like this.
  20. Seanxk

    Seanxk Well-Known Member

    Joined:
    May 14, 2018
    Messages:
    752
    Likes Received:
    626
    Bingo, now we just need to see a back panel in this.......
     

Share This Page