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Faital 15/5 Build

Discussion in 'Amps and Cabs [BG]' started by 5StringPocket, May 5, 2015.


  1. 5StringPocket

    5StringPocket Supporting Member

    Jan 11, 2006
    Texas
    I've tried a number of different cab configurations and a compact 2-way with 15" woofer and 5" mid really seems to hit the sweet spot. The 15 has solid low end support and the 5 adds good upper mid support and disperion. There are several parameters to consider depending on the voicing you're after including choice of driver, dedicated woofer vs full range, box volume, tuning, choice of mid driver and crossover design. I like the sound my Xsonics 1155TF delivers and wanted to build a companion cab for it. At 24"H x 17"W x 16"D it's a compact box for a 15" driver which gives a solid punchy low end that is full but not too deep which seems to get lost in the mix for me. I like it because it's easy to carry, sounds good, and hits hard. I decided to go with the Faital 15PR400 which I've wanted to try for a while and M5N8-80 which sounds great in 2 cabinets I already own. Here is the drawing I started with.
    Faital%2015.5TP_zpslizdmn9o.
    I used 18mm(3/4") birch ply for the baffle and 12mm(1/2") Okume ply for the sides and back. 1/2"W x 1-1/4"H spline bracing was run front to back on all 4 sides, then vertical and horizontal on the back. Edges are glued with PL Premium and reinforced with 1-1/4" brads from my nail gun. I went with tri-ports because they are space efficient and provide additional bracing for the box. Diagonal placement provides even loading on the woofer cone and a path for convective cooling air flow. Models were developed with both Win ISD and Eminence designer which gave similar low end response and excursion limits but Eminence designer was used for tuning the ports.
    Faital%2015.5%20Back%20Bracing%20web_zpsml66xv5v.
    Faital%2015.5%20Bare%20Front2%20web_zpsbnupji7g.
    Faital%2015.5%20Bare%20Front3%20web_zpsu2ho2fp1.
     
    Last edited: May 5, 2015
    svtb15, andruca, Strung_Low and 4 others like this.
  2. iualum

    iualum

    Apr 9, 2004
    60453
    I doff my cap to you :thumbsup: .
     
  3. basss

    basss Supporting Member

    Aug 27, 2001
    NY
    That looks great! I have a cab built by LDS with the same drivers: love it. lds-15-5-.
     
    Strung_Low likes this.
  4. Going to play with the woofer full range with mid/2 way cross over/woofer only cross over?
     
  5. zac2944

    zac2944

    Dec 28, 2004
    Rochester, NY
    Sub'd. I love a good build thread.
     
  6. wcriley

    wcriley

    Apr 5, 2010
    Western PA
    Nice!
    What's your reason for having the 1x1 strips in the port areas?
     
  7. zac2944

    zac2944

    Dec 28, 2004
    Rochester, NY
    The strips are probably to support a grill and also add strength to the corner joint.
     
  8. 5StringPocket

    5StringPocket Supporting Member

    Jan 11, 2006
    Texas
    I like that LDS build. If I didn't have something specific in mind to try I would have ordered one just like it.
     
    b-b-b-bass likes this.
  9. 5StringPocket

    5StringPocket Supporting Member

    Jan 11, 2006
    Texas
    I'm going with a 2-way crossover which can be bypassed to run the woofer full range. With the crossover in play there will be a -1.8dB pad which can be switched in for a slightly darker voice or out for more mid forward. I wanted to match my Xsonics crossover around 1500 Hz but didn't want the standard Butterworth 2nd order filter which would create a 3dB hump where the 15PR400 already has a strong response. I found this reference on a sub-Bessel alignment which provides a close approximation to a Linkwitz-Riley alignment, with zero peak or dip at the crossover frequency. It seemed like a good fit here. Interpolating woofer impedance from the Faital frequency curve and cross checking with WinISD and Eminence designer gave 11.6 ohms around 1460 Hz. I was looking for a frequency close to my target which gave woofer and mid C/L values which matched components I could buy. The numbers worked out well at 1463 Hz as shown below.
    Passive Crossover Network Design
    Faital%2015.5%20Crossover_zps48ry1uc5.
     
    dannster and BassikLee like this.
  10. 5StringPocket

    5StringPocket Supporting Member

    Jan 11, 2006
    Texas
    These are 3/4" square dowels and you are correct - grill support and corner strength.
     
    BassikLee likes this.
  11. Doug Parent

    Doug Parent Supporting Member

    May 31, 2004
    San Diego, Ca.
    Dealer Nordstrand Pickups.
    nice.
     
  12. Are the RLC filter and Zobel going to be used? The RLC center freq is below the mid crossover point, at least according to the calculator I used, and the zobel is probably not that necessary for the woofer since the impedance rise is not too drastic until past 2 octaves above the crossover point.
     
  13. wcriley

    wcriley

    Apr 5, 2010
    Western PA
    Did you take the grill into account when you calculated the ports? If not, your tuning could be way off.
     
  14. If it tests different than what you want, you can always cut the corners off the grill.
     
  15. astack

    astack

    Nov 12, 2011
    St. Louis, MO
    I've never seen 5StringPocket cut corners in any of his builds before, but there's a first time for everything. :D

    I agree though, doing corner ports just seems much riskier than tubes, for a one-off build if you don't get the tuning right, although I know he's nailed it before.
     
  16. wcriley

    wcriley

    Apr 5, 2010
    Western PA
    I'm not doubting 5StringPocket's ability to design the cabinet. I'm just curious. Most metal grills are only about 60% open, so wouldn't that need to be taken into account when sizing the ports?
     
    gary m likes this.
  17. astack

    astack

    Nov 12, 2011
    St. Louis, MO
    Hmm, have you experienced this? It's not an uncommon situation. Most cabs I can think of with metal grills have them covering the ports, including Baers, Fearless/fuls, Bergs, etc. Curious to find out the answer, too, as I've never thought of it or tested it. Could be useful as a partial-plug for different fb / voicings if the effect is sizable.
     
  18. wcriley

    wcriley

    Apr 5, 2010
    Western PA
    I have no experience with putting metal or cloth grills over ports. But it sure seems to me that they would effectively reduce the open area.
    (And for the record, fEARful/FEARLESS designs don't have grills over the port openings.)
     
  19. astack

    astack

    Nov 12, 2011
    St. Louis, MO
    Oops, you're correct that fearful and fearless cabs do not. Full-grilled Bassics and Duallys do, as do some of the Crazy 8/88's, though. That's what I was thinking of.
     
  20. Foz

    Foz

    Jul 26, 2008
    Jax FL USA
    Nice work... gig reports?
     

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