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Port Position: Front or Rear?

Discussion in 'Amps and Cabs [BG]' started by Bassin' 'Round, Feb 26, 2006.


  1. Bassin' 'Round

    Bassin' 'Round Banned

    Apr 30, 2005
    As long as the tuning is correct, does position (front or rear) make make any difference at all?
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Assuming that the cab is properly damped so that there are is no reflected midrange coming out the port, no.
     
  3. Dont matter, I actually prefer rear ports. It makes the cab more compact.
     
  4. Bassin' 'Round

    Bassin' 'Round Banned

    Apr 30, 2005
    Yeah, makes it smaller. Lighter, too. Thanks very much.:hyper:
     
  5. chadds

    chadds

    Mar 18, 2000
    With rear porting, the sound of your cab will change depending on it's proximity to a wall or no walls as in an outside gig. This can be significant.
     
  6. Blues Cat

    Blues Cat Supporting Member

    May 28, 2005
    Katy, Tx
    You want front ported definitley. The problem w/rear porting is that if there's no wall behind you, all the bass goes away. Proximity effect. Rear ported cabs will be more inconsistent from room to room.
    If you're outdoors you're hosed.
    I play through a rear ported Ampeg 15" @ church w/the built in tuner & it is so hard to get a good sound but w/the wall 1' behind, it is tolerable.
    Last Christmas eve we did an outdoor service. The nearest wall was 80' away. All the bass was gone. I ended up boosting the bass & low mids & I found myself really digging in. The amp was sounding terrible. I ended up putting everything back to basically flat & got a 3' rack front door & put it behind it & it was better but still an unpleasant sound.
    I will never purchase another rear ported cab.:rollno:
     
  7. syciprider

    syciprider Banned

    May 27, 2005
    Inland Empire
    Why didn't you face the port towards the audience?
     
  8. Aguilar/Dave B.

    Aguilar/Dave B. Aguilar Amplification Commercial User

    Nov 8, 2003
    New York City
    President: Aguilar Amplification
    What you experienced has nothing to do with the ports. When there is a wall behind your cabinet, the bass will increase. If you put your cabinet in a corner, you'll greatly increase the bass.
    The ports impact the tuning of the cabinet, and as long you don't literally block them (thereby changing the tuning of the cabinet) it doesn't matter if they are on the front or the back. Assuming that other parameters are equal.

    Playing outdoors is a tough gig! Think about what you're dealing with regarding the room acoustics!:eek:
     
  9. This has been beaten to death and discussed endlessly.

    Do a search on it.
     
  10. Blues Cat

    Blues Cat Supporting Member

    May 28, 2005
    Katy, Tx
    I used to own an SWR GoliathII rear ported & @ some med sized gigs I would turn it around. I got some comments on how nice the bass was coming out of this cab, turned around. Speakers facing forwards I got no comments on sound.:eyebrow:
     
  11. Blues Cat

    Blues Cat Supporting Member

    May 28, 2005
    Katy, Tx
    I agree. Do a search & you'll find out how this thread will end up.
    Either you get it, or you don't. Use you ears.
     
  12. I had a Mesa Powerhouse that was rear-ported. And it had more than enough bass response. Without having to put it in front of a wall. I and just got an Aggie S cab thats also rear-ported that sounds awesome.
     
  13. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    +1. These are called boundary effects and have little to do with the speaker.
     
  14. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    How Rude!

    :D:D:D

    Joe.
     
  15. illidian

    illidian

    Jul 2, 2004
    In theory, it doesn't matter.
     
  16. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    You know, this has been my general experience also.

    But I think the confusion may lie mostly in what we are referring to as bass.

    Heck, the lowest bass notes are omnidirectional, right? So if you are referring to those notes, then ports make no difference in bass response if they are done correctly.

    That being said, could there be a difference between front and rear porting as the frequency rises?

    Ummm...I know what I meant to say but was that clear to anyone else??

    :D

    Joe.
     
  17. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Yes, if the cabinet isn't properly damped as I stated above. A poorly constructed cabinet will send reflected midrange out through the port, and in that case the port orientation matters. But if you've got midrange coming out of the port then the cabinet is going to sound like crap period.
     
  18. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    Nope,

    that's not quite what I meant.

    Let's say that you have 2 speakers constructed so that they are identical in frequency response and speaker brand/model. The only difference being one is ported to the front and the other to the back.

    If it needs a different size box, so be it. If it needs different bracing, so be it. Whatever, so long as the response is the same and the drivers are identical.

    Will they sound identical?

    If there is a change, at what frequency would it occur?

    Granted, I may be displaying my ignorance but I'm used to it. Just educate me.

    :D

    Joe.
     
  19. Has anyone tried testing this with two identical cabinets, the only difference being front or rear port? I.E. Identical drivers, cabinet design, tuning etc. Just a difference in where the port exits.

    I see a lot of people using anecdotal evidence to argue for one or the other, but not a lot of empirical evidence.


    For the record, I have done this, I'm just not telling what we found..... Yet. :D
     
  20. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    Tease.

    C'mon! Give!

    :D

    Joe.