Running a 1912 and a 1936 simultaneously with a 2203x or another amp

Discussion in 'Cabinets & Speakers' started by mrp, Sep 22, 2020.

Tags:
  1. mrp

    mrp Member

    Joined:
    Dec 19, 2016
    Messages:
    78
    Likes Received:
    53
    Do you think it's a good idea for recording to capture one same amp with different speakers and enclosure types simultaneously? Namely, a 1x12 1912 and a 2x12 1936?

    Will one cab muffle the other due to speaker number, efficiency and impedance differences?

    Will there be any phase issues with same mic configuration?

    Thanks.
     
    SkyMonkey likes this.
  2. SkyMonkey

    SkyMonkey Well-Known Member

    Joined:
    Oct 28, 2018
    Messages:
    2,584
    Likes Received:
    3,354
    Location:
    The 'Burbs
    If the two cabs are still stock then there should be no impedance or efficiency conflicts.
    The G12B-150 in the 1912 is 8 ohms @ 98 dB.
    The G12T-75s in a standard 1936 are wired in parallel to 8 ohms @ 97 dB (mono).
    A 1 dB efficiency difference is negligible.

    The enclosure types are fairly similar too.
    Both are closed back, but the 1912 is ported.

    Also the concept of combining different speaker types through a single cab are commonplace.
    The X-Pattern way of loading a 412 cab is widely accepted.
    Also the stock JVM 212 cab has the Celestion Heritage G12H + Vintage 30 mix.
    If the listener is hearing both speakers simultaneously, then a recording to reflect that wouldn't be unusual.
    But if the 1936 has 2 x G12T-75s then there is little point in mic'ing both of them.

    If the cabs are stock wiring then there should be no phase issues.
    Reversing the wiring of one cab, if there are phase issues, should be a simple job.

    In short, if you have the mics to cover 2 or 3 speakers, go for it.

    If your 1912 is still stock here are the specs for the G12B-150:

    Nominal Diameter - 12”
    Power Rating - 150W
    Nominal Impedance - 8ohm
    Sensitivity - 98 dB/W
    Chassis Type - Pressed steel
    Voice Coil Diameter - 2”
    Voice Coil Material - Round copper
    Magnet Type - Ceramic
    Magnet Weight - 50oz
    Frequency Range - 60-4000Hz
    Resonance Frequency - 77Hz
    DC Resistance - 7ohm
    Unit Weight - 4.8kg (about 11lb)
     
    Sustainium and mrp like this.
  3. pedecamp

    pedecamp Well-Known Member

    Joined:
    Dec 7, 2009
    Messages:
    15,372
    Likes Received:
    13,076
    What he said...
     
  4. mrp

    mrp Member

    Joined:
    Dec 19, 2016
    Messages:
    78
    Likes Received:
    53
    Thanks so much, man!

    However, how correct is that the 2x12 reads 1 dB quieter than the 1x12, isn't the 97 dB reading related to a single speaker running at 8 Ohms rather than a duet of speakers?

    I thought twice the speaker area would be about 2-3dB louder as a rule of thumb.
     
    Last edited: Sep 22, 2020
    SkyMonkey likes this.
  5. SkyMonkey

    SkyMonkey Well-Known Member

    Joined:
    Oct 28, 2018
    Messages:
    2,584
    Likes Received:
    3,354
    Location:
    The 'Burbs
    In a 212 cab each speaker receives half the power from the amp, i.e. 50W each (from a 2203).
    So technically it should sound the same volume.
    But the perceived sound will be somewhat 'Bigger' than a 112 cab.

    If you ran both cabs the 1912 will get half the power and the speakers in the 1936 will get 1/4 power each.
    The total can never add up to more than 100W.

    But the G12B-150 in the 1912 might sound slightly louder than the two G12T-75s in the 1936, due to it's higher sensitivity.

    All this is redundant though if you are only concerned about recording the two cabs, as you can rebalance the two recordings in post-production.
     
  6. mrp

    mrp Member

    Joined:
    Dec 19, 2016
    Messages:
    78
    Likes Received:
    53
    I've heard that the 1912 has a certain sweet spot resulting from the size of the enclosure that doesn't necessarily take lots of volume. Might be quite different for the 1936. By the way, there used to be an oversized 1x12 called 1933.
     
    SkyMonkey likes this.
  7. SkyMonkey

    SkyMonkey Well-Known Member

    Joined:
    Oct 28, 2018
    Messages:
    2,584
    Likes Received:
    3,354
    Location:
    The 'Burbs
    Not sure about that.
    I have never tried to record from mine, and I changed the speaker anyhow (see sig).
    Post the results when you have a go! :thumb:
     
  8. mrp

    mrp Member

    Joined:
    Dec 19, 2016
    Messages:
    78
    Likes Received:
    53
    I have none of the gear listed in the heading anyway, neither the funds at the moment)) Won't be making a pledge. :ohno:
     
    SkyMonkey likes this.
  9. SkyMonkey

    SkyMonkey Well-Known Member

    Joined:
    Oct 28, 2018
    Messages:
    2,584
    Likes Received:
    3,354
    Location:
    The 'Burbs
    :slap: Start saving!

    Confucius say: "Every journey starts with a single Marshall tube amp".

    Or something like that :fingersx:
     
    junk notes and mrp like this.
  10. pedecamp

    pedecamp Well-Known Member

    Joined:
    Dec 7, 2009
    Messages:
    15,372
    Likes Received:
    13,076
    I have a home built 1936 and 1912, the 1936 sounds much bigger since it's a bigger cabinet with 2 speakers.

    You don't need to run the 1912 with the 1936 when you're running the 1936, just toss the 1912 in the corner and forget about it it's your grab and go cab is all it really is, and it doesn't sound bad for a small cab but it will never sound as good or big as the 1936. :yesway:
     
    Sustainium likes this.
  11. mrp

    mrp Member

    Joined:
    Dec 19, 2016
    Messages:
    78
    Likes Received:
    53
    Is your 1912 Birch ply?
     
  12. pedecamp

    pedecamp Well-Known Member

    Joined:
    Dec 7, 2009
    Messages:
    15,372
    Likes Received:
    13,076
    I typically build my cabs with birch ply sides and mdf front and back. All birch ply cabs sound too boxy to me and all mdf cabs sound dead, the mix gives me the best of both worlds. Regarding ply make sure to get ply with a minimum of 9 layers and best is 13, dont be tempted to buy the cheap 5 layer ply, its not even birch it's rubbish with a birch veneer and sounds terrible. Heres a pic of my 1912:

    [​IMG]
     
  13. mrp

    mrp Member

    Joined:
    Dec 19, 2016
    Messages:
    78
    Likes Received:
    53
    BTW, Marshall takes special orders on Ply 1912's indeed, stock is all MDF.

    Not sure about layer number and MDF fronts, backs, baffles though.
     
  14. What?

    What? Well-Known Member

    Joined:
    May 17, 2018
    Messages:
    1,000
    Likes Received:
    905
    Some of the best cabs ever made used both plywood and mdf. I'm not sure about the baffle, but the old Hiwatt cabs had an mdf back. Heavy suckers though.

    The last all ply 412 I had did sound very boxy (Avatar). My current old Peavey VTM cab I think is all ply, but it is heavy ply and heavy weight. It never sounds boxy. I think it is probably more about the overall density and rigidity of the wood.
     
  15. SkyMonkey

    SkyMonkey Well-Known Member

    Joined:
    Oct 28, 2018
    Messages:
    2,584
    Likes Received:
    3,354
    Location:
    The 'Burbs
    My 2005 1912 is MDF.
    It sounds great to me.
    I think the small size of the 1912 makes MDF construction less of an issue strength wise.
     
  16. pedecamp

    pedecamp Well-Known Member

    Joined:
    Dec 7, 2009
    Messages:
    15,372
    Likes Received:
    13,076
    I've built cabs out of all kinds of wood and configurations, what I mentioned before is what sounds best to me. :yesway:
     
    Sustainium likes this.

Share This Page