So we need to talk about that speaker cab I made.

Discussion in 'Amplifiers' started by NBW, Dec 4, 2021.

  1. NBW

    NBW New Member

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    So I posted a photo of a cab I built a couple of years ago in a thread here. Thing is I have played a couple of amps through it, a homemade 5 watt from the Bud kit and a DV-Mark micro CMT. No matter which amp I used playing I was bugged by how A chords sounded somewhat boomy. I thought it was the hollowbody, maybe the pickup pole pieces.

    It seem the the cab has a big old resonance right around 440hz, I am unsure how to handle it, maybe some rock wool?
     
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  2. veinbuster

    veinbuster Zombie Three, DFZ

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    Rock wool will definitely slow down reflections inside the box, just don’t breathe any of it in.

    It might slowdown the air enough that it kills the character of the cab though. You might have to experiment a bit to get the right amount of dampening in the right place. If I wasn’t so lazy, I would math the wavelength of 440hz and put a thin layer of something on one side that is a multiple/fraction of that to start.
     
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  3. NBW

    NBW New Member

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    The wavelength is 2.37 feet, so the node is at 1.185 feet or 14.22 inches which is pretty much the dimension of the width and height of the cab. I didn’t even think of that when I built it, I should be ashamed as I am a PhD physicist.
     
  4. Moondog Wily

    Moondog Wily Howlin' At The Moon!

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    As long as you have learned from your mistake and don't repeat it, then no need for shame!
     
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  5. veinbuster

    veinbuster Zombie Three, DFZ

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    Then I would put something on the top and one side.
     
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  6. DreamTheaterRules

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    Try 2" if polyfil on the bottom, then bottom and top, or bottom and one side.

    Edit: ha, I see Veinbuster posted this right while I was posting.
     
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  7. qprs

    qprs New Member

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    Measure twice, cut once. Assuming this reduces the effective dimensions linearly, where will that move the resonant peak?
     
  8. NBW

    NBW New Member

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    I made a new box using dimensions of a manufacturers cab. It seems better. I am currently wrapping it in Tolex.
     
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  9. DreamTheaterRules

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    Reduces?
     
  10. NBW

    NBW New Member

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    If the box is smaller the resonant frequency increases. Larger it decreases. I had two dimensions that were pretty much identical which were close to the half wavelength of A440. That’s an issue to be sure.
     
  11. NBW

    NBW New Member

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    I finished the tolex yesterday. I have a few more things to do. But I don’t necessarily thing it was entirely the old enclosure’s issue.

    I just bought an inexpensive DI interface and I have been using VU levels to try to even out the loudness of individual strings on my Hollowbody. The lowE on my Hollowbody SE is hugely louder than the other strings on the neck pickup. That combined with the resonance was really bad.
     
  12. Goran Lorencin

    Goran Lorencin New Member

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    Did you try playing different guitars? Getting that on bridge and neck pickup? Maybe also try different cables and EQ settings. Did also do a cab mod myself and used some damping in the end, still have to play it in a better environment to hear what it does.
     
  13. NBW

    NBW New Member

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    I brought the amp (easy since it’s a D V Mark micro CMT) to my buddy’s place and plugged it into a crate 4x12. Sounded great. Maybe the Eminence Canabis Rex just isn’t to my liking. That would suck.
     
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  14. Goran Lorencin

    Goran Lorencin New Member

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    I've had quite a ride looking/listening for good speaker demos online and also considered the Cannabis, who does not like a good reefer ;) but I found it to be a bit too boomy, low middle strong and without the sharp edge in the highs ... in the end decided to buy the Jensen Electric lightning or Jensen Jet Lightning (depends what name the store is using - 16 Ohm) which has a nice balance between low/mid/high while still being very detailed. Replaced one of the V30's in my 2x12 cab because I wanted to tame the sharp highs just a bit, although the V30 are very nice to start with, well depends what sound you are after, but the Jensen really covers it all (combined with the V30), clean and lead with my MT15.
     
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  15. Moondog Wily

    Moondog Wily Howlin' At The Moon!

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    It's a shame you gave up on the Cannabis! I hope you had tested it in a medicated state of mind!! I think they sound a lot better in that condition!!! All joking, I know more about the price of tea in China than I do about cabs and amps! Enjoy your new cones of wave production!!!
     
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  16. dmatthews

    dmatthews Dave's not here...

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    What would happen if you ported the cab? Full disclosure, I know nothing of this...
     
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  17. NBW

    NBW New Member

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    My cab has a removable back. I am still testing it. I tried it closed now I’m trying it open.

    the Cannabis Rex is highly though of by jazz players, which is the tone I’m trying to achieve. But I agree it seems kind of bassy, and the DV Micro amp might be exacerbating the issue.
     
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  18. NBW

    NBW New Member

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    My next project is going to be a sonotube speaker.
     
  19. Goran Lorencin

    Goran Lorencin New Member

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    You would get a good thing going, I made just that, a ported cab. Well it is not a regular port, more looking like a horn. Replaced the back with my own "invention" inspired by Barefaced (they make cabs), and I tell you it really makes a big difference when it is put in a non-treated room, becomes very "omni", before I had to stand almost right in front of it to hear the definition, now it is all over the room while still retaining the chuggah-chuggah properties. Must say I am satisfied and will probably do another one, maybe a single speaker.

    https://flic.kr/p/2m6Rp1T
     
  20. Goran Lorencin

    Goran Lorencin New Member

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    Yep, Cannabis should work for jazz just fine if you ask me, it has the character.
     

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