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Fdeck's HPF

Discussion in 'Amps and Cabs [BG]' started by Mike Arnopol, Mar 18, 2012.

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  1. Mike Arnopol

    Mike Arnopol Supporting Member Commercial User

    Jan 4, 2005
    Owner of MAS Soundworks
    Tb'er Fdeck has come up with a new variable High Pass Filter that has a fixed 12db/octave filter at 35 hz and another variable 12db/octave filer from 35 to 140 hz.

    Francis sent me one to try. I've been so busy pumping out cabs that I hadn't had the chance to try it.
    My big thing is obviously how does it affect the performance of my cabs. I took a Crazy 8 and got it loud enough for port chuff. I love the word chuff. It's an onomatopoeia. Which means that the word sounds like what it describes. What does port chuff sound like? Chuff. Fortunately the C8 goes very loud before you hear it. Which I'm very happy about.
    So, got it to chuff.Plugged in the Fdeck HPF. Didn't even have to get it past the initial 35 hz. Chuff gone.

    Took the HPF out. Now don't try this at home. One great thing about the Faital drivers---they go really far without farting out. I played it SO loud (as loud as my 12" 3012ho) and got it to make the nasty sound when the voice coil hits the back plate. Fortunately I don't have to buy the owner of the cab a new woofer. Put in the HPF and dialed it up at the highest setting. The clack was gone. As I expected---but so was the low bass. Kept dialing it down. I wasn't a whole lot past the lowest setting when I didn't really notice the missing bass. But no more voice coil smack. The interesting thing---the C8 actually got LOUDER. I think it was because I was no longer using my amp's recources amplifying crap I didn't want to amplify anyways.
    The C8 as well as the 88 go substantially louder with the HPF. Substantially louder. I would tell my customers that the C8 would be fine handling a jazz trio gig with drums at piano trio volume. Let me up that to a quartet with the HPF. Or maybe---shall I say it?---a jazz group with guitar!

    I then tried it with electric bass with a C8 + C88 stack. Just set it on the lowest setting. It went louder and sounded more effortless. I boosted the bass until I started chuffing (it was hard to tell--that stack goes really loud---I had to discern between the chuffing and half of my house making weird sounds). I then dialed the HPF up just a bit. Only enough so that I didn't feel like I was compromising the bass sound. Big difference,

    I'm recommending it for e-bass too.

    I didn't ask for a cut on this nor do I want one. I know that Francis isn't making a bunch of dough here---just a labor of love. I'm just happy that it makes my cabs sound better!

    And by the way--in my typical narcissism I failed to mention that it would give any amp and speaker a bigger dynamic range.
  2. BurningSkies

    BurningSkies CRAZY BALDHEAD Supporting Member

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    Any news on a release date for the new HPF that's been discussed? Either as finished units or as kits? We've been waiting patiently.
  3. Jeff Scott

    Jeff Scott Rickenbacker guru.......... Supporting Member

    Apr 11, 2006
    I'd like to know more; what is it's form factor, how/where does it hook up in a bass system, pics, etc.
  4. Jim Carr

    Jim Carr Dr. Jim Gold Supporting Member

    Jan 21, 2006
    Denton, TX or Kailua, HI
    fEARful Kool-Aid dispensing liberal academic card-carrying union member Musicians Local 72-147
    Pics? Price?
  5. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    It's in prototype.
  6. Jazzdogg

    Jazzdogg Less barking, more wagging!

    Jul 29, 2006
    San Diego, CA
    If it also had a VLPF, it could function as a compact crossover to divide frequencies between a crazy8 and a small sub. :bag:
  7. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Good for F. Good guy who makes a preamp a lot of folks like.
  8. lowfreq33


    Jan 27, 2010
    Endorsing Artist: Genz Benz Amplification
    I'd love to see 8 of these in a single rack space. I the HPF on my mixer is fixed at 80Hz, and sometimes I'd like a little more flexibility.
    terrymo likes this.
  9. BryanB

    BryanB Moderator Staff Member Supporting Member

    sign me up. i'm very interested.
  10. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    so the new one is going to be just an HPF without the preamp? if so, i'd like to buy one as soon as they're available. i think that it would be great to use an adjustable one (35-140hz) in an amp's effects loop, or would the piezo pre one that Francis currently makes be just as good for that?
  11. will33


    May 22, 2006
    This would be brilliant.
  12. BryanB

    BryanB Moderator Staff Member Supporting Member

    I hope this takes a line level balanced/unbalanced signal and is unity gain.
  13. Stumbo

    Stumbo Wherever you go, there you are. Supporting Member Commercial User

    Feb 11, 2008
    Song Surgeon slow downer. https://tinyurl.com/y5dcuqjg
    Seems like they should come as an option with every speaker cab. Or even standard to get a higher performance out of smaller cabs.
  14. kringle77

    kringle77 Supporting Member

    Jul 30, 2004
    Massena NY
    I've been loving my origional fdeck preamp/hpf for awhile. I don't understand how this one is different? I've e-mailed him in the past about doing a HPF/LPF version but, didn't get a response. A great product though.
  15. lowfreq33


    Jan 27, 2010
    Endorsing Artist: Genz Benz Amplification
    A lot of bass amps have a HPF built in at a fixed frequency, usually around 20-30Hz. SWR amps come to mind as one that doesn't, at least on the pre-Fender models.
  16. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Mike, thanks for the report! I'm off to my day job, but will try to provide some more details tonight.
  17. BryanB

    BryanB Moderator Staff Member Supporting Member

    fdeck - Would you include power requirements? Thanks.
  18. Jim C

    Jim C Is that what you meant to play or is this jazz? Supporting Member

    Nov 29, 2008
    Bethesda, MD
  19. Interested:

    I always use the HPF on my Crown XLS2000 but the lowest freq is 50hz, Would Like one of these actually in my cab.
  20. kris pung

    kris pung

    Jul 25, 2003
    Chicago, IL
    Very interested in this

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