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hi-pass filters ?

Discussion in 'Amps and Cabs [BG]' started by lexington125, Oct 15, 2013.


  1. lexington125

    lexington125

    Sep 11, 2013
    hollywood, baby......
    someday I will find 4 or 5 other guys who want to play the blues the way it was played before it became all about guitar heroics
    reading about some unfortunate situations with blown drivers (on other forums).

    The #1 preventative measure was to NOT randomly load some aftermarket speaker in whatever cabinet is laying around. Cabinets and drivers need are engineered to work within certain parameters and a specific driver requires a cabinet with specific characteristics.

    But close behind that was the #2 suggestion - utilize a high pass filter to avoid sending frequencies down below the cabinet frequency.

    Now, many amps have a filter built in; but even more do not. Short of buying a new amp, or some high end pro-audio EQ box that includes a hi-pass filter is there any other way to incorporate this kind of protection into your rig? Especially for anyone who gigs with a single speaker (1-15 cab, typically) and needs to rely on the "health" of that single speaker.
     
  2. Look up the fDeck HPF-3.
     
  3. Yep https://sites.google.com/site/hpftechllc/ there is also the "Micro Thumpinator" from accross the pond. They will cut the frequencies where the speakers "unload" and face mechanical damage (and waste amp power).
     
  4. Arjank

    Arjank

    Oct 9, 2007
    Above Amsterdam
    Just checked the site, looks like this guy makes some great stuff!
    Maybe I might get one of these Thumpinators one day.
     
  5. BurningSkies

    BurningSkies CRAZY BALDHEAD Supporting Member

    Feb 20, 2005
    Syracuse NY
    Endorsing artist: Dingwall Guitars
    Francis Deck's HPF Series 3 is a permanent part of my rig.
     
  6. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    Pretty much all audio amps have a hpf built in, its just set lower than is useful, at like 15 or 20hz, and you want more like 30-40hz.
     
  7. Or even 50hz or 60hz, leaving you free to goose the bass EQ on the amp.
     
  8. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    Going above the tuning frequency of your cab can be counter-productive. The cab power handling is highest there, and least jsut above, so if you cut off where the cab is happiest, you end up boosting where its weakest to make up for it. 60hz is generally considered a too high tuning for a cab, cheap nasty territory.
     
  9. The tuning frequency of my Trace 1518 is low 40's iirc. It loves being relieved of subwoofer lows. I have never run a proper highpass filter on it but cut lows on graphic 12 band, only boosting 100hz upwards.

    The cab is relatively inefficient at 60hz but it's no dog. Response rises rapidly after that so I accept a weaker open B / C and it boogies with D. Small price for being able to get full noise.
     
  10. 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
    +1

    Picked one up used for ~$100, iirc. Like it, though the jury is still out with upright, as the EQ on my Tech21 ParadriverDI has me spoiled.

    For electric, the fDeck is a always between my Jazz and my M9. My fEARful and UL1 410 both like it. I run the Q around 40hz. :p
     
  11. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I buy cabs that don't need HPF's ;)
     
  12. Arjank

    Arjank

    Oct 9, 2007
    Above Amsterdam
    And those are?

    Every cab/amp takes profit from removing the "rumble" (everything below the fundamental). And yes, even closed cabs take profit from a hpf.
     
  13. JimmyM doesn't need a HPF for his sealed cabs but he isn't slamming a big GK with a drop tuned 5 string ( and popping drivers left and right with fundamentals )
     
  14. Arjank

    Arjank

    Oct 9, 2007
    Above Amsterdam
    Then his playing situation doesn't call for a hpf, not his cabs ;)
     
  15. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    What's the difference? If my playing situation dictates that I don't need a HPF, neither do my cabs.

    BTW, I am no stranger to playing really loud through my rig and/or using a 5 or an octaver. Just because I don't do it much anymore doesn't mean I never did it. Never blew a speaker, either. I guess if you're trying to get away with the smallest cab you can find and plan on punishing it, then I could see a need for an HPF. That ain't me. If I need that kind of volume, I just use a big cab.
     
  16. Jungy

    Jungy

    Jun 9, 2011
    Oz
    Don't be so sensible Jimmy.
     
  17. I play with fEarful stack, and I recently got an FDeck Series 3 HPF, but more for my amp, than the cabs. I play without PA support, and in some bigger rooms my Streamliner 900 seems to be running out of gas at the end of the night when we're at our loudest. It's generally enough to get by, but usually also enough strain to push me away from how I like my EQ to try and squeeze out more volume. I find the HPF is doing a great job reducing load to the amp by cutting out those unuseful frequencies, plus I think it improves the sound, as well, tightens it up.

    Maybe these improvements are in my head, it's not exactly an easy thing to measure, but it seems like having a HPF in my rig gives me more options in a variety of situations. It just seems like something that's never going to be useless or counterproductive. I would have a hard time picking $100 that I spent better.

    (As an aside, FDeck's US/Canada only policy is limiting to those of us not blessed to live in those places, but he's fine with using a reshipper, I use ShipIto, personally)
     
  18. If you're playing with heavy heavy distortion and unfiltered, the Jimmy Maxim is harder to escape, even with a sealed cab.

    "If it sounds like it's about to blow up, it probably will"
     
  19. arai

    arai Banned

    Jul 16, 2007
    That is a good thing and something I do myself. But yet you bag amps that have a HPF built in. :confused:
     
  20. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Good point and particularly true of several ported cabs I've used. This is my one and only complaint about the DriveCore amp series: the lowest available HPF freq is 50 hz. Suitable in many situations but sucks the low-end response from my LDS and Acme cabs while creating a bump further up the spectrum.

    Riis
     

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