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Curious Cab port question?

Discussion in 'Amps and Cabs [BG]' started by DWBass, Jan 1, 2012.


  1. DWBass

    DWBass The Funkfather

    Ports are common on the front or rear of cabs. Why not on the sides?
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    They'd 'look funny'. :eek:
    There's no engineering reason not to put them there. As a matter of fact, I do.
     
  3. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Given typical box proportions, a side port could be longer than a front or rear port, making it easier to get the needed port length without being tempted to make the port too skinny.
     
  4. Hi.

    Because it would divide ported design fans into three fanatic sections instead of two ;).

    On Hi-Fi field the port location varies more than on the MI/PA field IME, especially on larger subs where the sub is often disguised as a table.

    Depending of the machinery, front ports are often "more convenient" to make as well.

    Regards
    Sam
     
  5. DWBass

    DWBass The Funkfather

    Was just a thought! I figured it could solve the old 'rear port, can't put the cab against the wall deal'! Definitely wouldn't bother me in the least if they were on the sides.
     
  6. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Only until one of your band mates comes along and puts his amp next to yours........
     
  7. kraigo

    kraigo

    Jun 21, 2007
    Minneapolis, MN
    I thought you wanted to keep the port a quarter of a wavelength of the box tuning away from boundaries. It's what I've read anyway. Is that wrong?

    KO
     
  8. DWBass

    DWBass The Funkfather

    Ha! Good one. Fortunately, I have my own space on my current gig so I won't have that issue.
     
  9. BogeyBass

    BogeyBass

    Sep 14, 2010
    that is the only reason it stopped me from doing it.
    aside from the usual banter, its the real reason front ports work the best since the front contains speakers (most the time) and no bodys gonna block them, so why not put the ports there too.
     
  10. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    That's precisely where you don't want it, as it will cause output cancellation.
     
  11. kraigo

    kraigo

    Jun 21, 2007
    Minneapolis, MN
    Gotcha, I think. A typical bass cab, rear ported, a foot from the rear wall would be OK, stay away from a quarter of a wavelength. Confirmed?

    KO
     
  12. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    Reckon if I make a box the ports will double as handles.
     
  13. will33

    will33

    May 22, 2006
    austin,tx
    1/4 wavelength makes the cancellation. The distance between source and boundry determines what's going to get cancelled or enhanced. Mid and upper frequencies are more directional, moving forward from the cone. Below 100-150 hz or so?, they become omnidirectional so the wall behind the cab affects the sound made by the cones in front. When you get beyond a couple feet or so, the cancellation gets moved into the lower frequencies that suck the "heft" out of our rigs. This can make or break you in subwoofer placement. There you use the boundries to get more output for free, or at least not cause anything destructive.

    In a bass rig in a particularly bad room, you could use the cancellation to your advantage to help eliminate boom, like setting a cab on a chair.

    Measurements here. Boundary Cancellation and Room Modes

    For example, raising the cab 2.8 ft. off the floor will cancel 100hz.
     
  14. Mike Arnopol

    Mike Arnopol Supporting Member Commercial User

    Jan 4, 2005
    Chicago
    Owner of MAS Soundworks
    Side ports are fine---I'm starting to use them on really small cabs to be able to get longer ports (smaller boxes require longer ports for the same box tuning)
     
  15. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    And how right you are and perceptive too. I never thought of that facet!

    P.S. Happy New Year Sam. :D
     
  16. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Four, actually. You'd have right side versus left side proponents. :D
     
  17. klokker

    klokker

    Jan 7, 2009
    Steele City, NE
    Just for giggles, my computer subwoofer is side ported.
     
  18. mrjim123

    mrjim123 Supporting Member

    May 17, 2008
    Elkhart, IN
    It's called a "port" for a reason. It belongs on the left side; otherwise it would be called a "starboard". :eyebrow:
     
  19. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    Five - ya forgot the top! :D
     
  20. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    DWBass,
    You can definitely have the ports on the side of a bass cabinet, but I think it's a little easier to put them on the rear of the box. Euphonic Audio's Wizzy 12 M Line has a side port, but it is a Transmission Line Cabinet that needs the extra length.

    Ric
     

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