faitalpro 15pr400 farting out

Discussion in 'Amps and Cabs [BG]' started by ngh, Dec 5, 2015.


  1. ngh

    ngh

    Feb 6, 2013
    brooklyn, ny
    so I'm confused. just popped a pair of 15pr400's into my 2 music man 115rh cabs powered by a sunn 2000s. and they seem to be distorting quite a bit at moderate volumes anywhere below a Bb. i used to run this same rig with eminence cb158's in the cabs to great effect. obviously those were much more colored speakers with lower power ratings than the faital's. I took some measurements of the cabs to provide some rough specs, the cabs volume is about 3.4 ft^3 with a slot port that is 2x26 inches give or take at the mouth (slot port runs down the back of the cab and then lets out into a big flare).
    So what am I hearing?
    will this go away once the speakers "break in"?
    are these speakers screwed?
    are these cabs just wrong for the speakers? if so how?
    is the "flat" response of the faitals just amplifying some unpleasant sounds coming out of my sunn that were masked by the old drivers?
    something else?

    I'm confused and frustrated, any help would be appreciated!
     
  2. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    What box tuning did you come up with for the new drivers? Have you measured the actual tuning to compare it to your design target?
     
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  3. Bassmec

    Bassmec

    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    Well I would try putting something in the port to try to reduce the port area by half first and see if that helps, then close the port and See what happens, or you could load the Thiel small Params for the driver and the cab measurements into some software and have a look at the port tuning frequency.
     
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  4. ngh

    ngh

    Feb 6, 2013
    brooklyn, ny
    all of this is a little over my head, I don't have a design target. just put the drivers in the cabinets.

    will definitely try stuffing the port, thanks.
     
  5. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Understood. Just trying to give you a brief overview of how to go about fixing your problem if you care to go down that rabbit hole. The flare on the port may make modeling quite a bit more complicated though, unfortunately. If you post a pic you may get some hits from the more active cab builders here. I used to be all-in, but have kind of moved on to other things recently.

    Just stuffing drivers in a random box tends to give random results, but every once in a while it worked out fine back when I was still doing things that way. Hopefully your case will be like that after a little tweaking.
     
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  6. B-string

    B-string Supporting Member

    Make sure you have no wires bouncing on the back of the speaker cones? Uneven torque of the speaker baskets causing a rub? Great speaker and great cab that just don't work together ;)?
     
  7. ngh

    ngh

    Feb 6, 2013
    brooklyn, ny
    saying as both speakers are having the exact same issue, i feel like chances are it is the latter. which is a real bummer. I will probably end up pulling them and reinstalling just to be sure though. thanks!

    yeah, ill try to get some pics up, I appreciate the help!
     
  8. ptidwell

    ptidwell Supporting Member Commercial User

    Jun 13, 2005
    Los Angeles
    Owner LoPHAT Cabinets
    You may already know this, but I must tell you that cabinets are built around specific drivers. Utilizing the Thiele-Small parameters and software like WinSD before buying and placing a speaker in a box that it was not designed for will save you time and money. Good luck.
     
    Pbassmanca likes this.
  9. mbelue

    mbelue Supporting Member

    Dec 11, 2010
    There is still a chance a modification to his boxes can help.
     
    Bassmec likes this.
  10. wcriley

    wcriley

    Apr 5, 2010
    Western PA
    Pretty doubtful given the boxes he's working with.
     
  11. mbelue

    mbelue Supporting Member

    Dec 11, 2010
    True. Those angled shelf ports are no friend to the sawzall.
     
  12. Szyszaczek

    Szyszaczek

    Sep 5, 2014
    Sound from cabinet depends on:
    1. speakers
    2. internal volume
    3. port tuning

    I assume that cabinet is well built and has no extra holes, loose screws etc. Internal volume and port tuning depends on speakers itself. Changing on of these three parameters will destroy the whole concept of particular cabinet. Your cabinet was build special for previous speakers. You cant just put another speakers and assume it will be just fine. It might be, but in most cases wont be.

    Farting of speakers, assuming that they are 100% working, is due to cone excursion. It means tha at certain point of frequency it hits beyong its Xmax. Xmax is on of the speakers parameters, it is measured in milimeters and says how far coil of speakers can get beyond normal position. (sorry for bad english). Good speaker has big Xmax. Going beyond Xmax result in farting till You hit Xdamage which result in destroying the speaker.

    It maybe that this cabinet has wrong internal volume and/or port tuning for those speakers, resulting in hitting Xmax on lower wattage.

    Use some simulator tool to change port tuning and/or to lessen internal volume.
     
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  13. mbelue

    mbelue Supporting Member

    Dec 11, 2010
    Farting and chuffing might get confused by someone without the experience to know the difference.
     
    okcrum, agedhorse and B-string like this.
  14. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    ....or make you think your grandfather is there....
     
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  15. B-string

    B-string Supporting Member

    Yep told a mix engineer once that I didn't fart that was port chuff, he couldn't stop laughing. :)
     
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  16. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    This is not true at all. A good speaker has an APPROPRIATE Xmax. For some applications, to achieve higher efficiency on smaller amps (in a combo for example), a smaller Xmax might be a MUCH better choice, along with other parameters that support the design goal.

    There are some mighty big drawbacks that come along with large Xmax, and if the advantages that it MIGHT bring can not be utilized by the application, it's a poor choice for the design.
     
  17. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    When I was young and impressionable I thought it was cool to wantonly stuff boxes however and whenever I could.

    ...Now that I'm a bit older and have some life experience, I know that I'm much happier picking and choosing my box-stuffing activities much more carefully and playing by the rules. It certainly stops any box-stuffing remorse or repercussions you may face later.
     
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  18. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Reading this, there are two very different possible meanings to your last paragraph about box stuffing activities, the alternative meaning might apply better to your earlier years... ;)
     
    Pbassmanca, JackANSI, Joedog and 2 others like this.
  19. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    I think this thread is a good reminder for TB'ers that you can't spend your life just going around stuffing boxes all willy nilly.
     
  20. mbelue

    mbelue Supporting Member

    Dec 11, 2010
    Seriously leave those boxes alone boys.
    If not wear a Jimmy cap.
     
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  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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