Plugging tuned port

Discussion in 'Amps and Cabs [BG]' started by David Jayne, Mar 26, 2014.

  1. Hi, I've got an Epifani UL310 that I like in most respects, but for me, the low end is too extended into the deep bass. At the same time, it is shy in the low mid/ upper bass region which is something I'd like to get more of (more punch) . My thinking is that by plugging the tuned port, I might be able to reduce the very low bass while perhaps gaining a bit in the low mid /upper bass region. Is this a reasonable expectation? I ask because it's an awkward port to plug without doing permanent damage to the cabinet- it's a large rectangle cut into the baffle which borders the lower corner of the box.
    Worth a try? Or should I just move on? All opinions welcome. Thank you.
  2. WashburnAB95


    Nov 18, 2013
    could you try something realliy simple like sticking a sock(s) in it to see if you like the sound?
  3. Arjank


    Oct 9, 2007
    Above Amsterdam
    You will indeed reduce the low bass but you'll not increase the gain in the mid/upper bass region. Reducing the lows will probably make it sound more tight, so just plug the hole with something to try it out.
  4. It's a 5" x 8" hole.

    I figured. Thanks!
  5. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area
    I do this with an LDS 2x15 cab that has 2 ports per driver. I plug one port per driver.

    I use small cell foam (yellow, fairly firm, but still compacts in the port for a good fit) cut from long cylindrical shaped forms which can be found at fabric or upholstery stores. The cylinders come in different diameters and can be as long as you need. So, 5" x 8" would not be a problem.

    Once you find a good fit for plugging the port, you can then add black PVC plumbing caps/plugs using spray craft glue, for a more finished look for the foam plugs.

    This is a pretty cheap and effective way to do what you are thinking of doing. I think it cost me about $4-5 per plug
  6. Thanks for the suggestion but again, it's a large rectangular hole. I'll figure something out.
  7. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area

    the foam I mentioned also comes in all types of square and rectangular shapes and sizes too, and can usually be cut to fit any shape you need.

    good luck
  8. Ah Ok I'll check it out.

    Also, I should have asked if there's any chance of damaging the speakers? I know that opening up a cab too much can hurt them, is the inverse true as well?
  9. You won't DIRECTLY hurt them by plugging the ports, you'll just reduce their output. The potential damage could come when you try to push them harder to make up for the loss in output. You could max out your amp which might cause badness.
  10. Gotcha, cool thanks.
  11. Joedog


    Jan 28, 2010
    Pensacola FL
    Definitely worth a try. I've done it and been pleased. Before you go hog wild try stuffing the port w/something very temporary. A t-shirt, whatever. Experiment with partially vs. fully blocked. Partially may take you to your happy place, and still let the cab perform (more or less) as designed. That's what worked for me, with no bad side effects.
  12. Trace used to supply port tube blockers. With the two ports you could lower the tuning with one or make it infinite baffle by sealing both. You get extra bass extension but less of it overall.
  13. Well I did it, with dense plastic foam corner pieces from a cab shipping box. I think I like the result, but haven't gigged it yet. The way- low stuff is much reduced, great. This in turn allows me to bring the Bass control back up to noon or beyond which gives me some of the low mids I want because of the spillover in the eq. So far great! I will be aware of the fact that I'll have to push the cab harder than before. Thanks!

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