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What is flat EQ?

Discussion in 'Amps and Cabs [BG]' started by the low one, Oct 10, 2009.


  1. Chris Ramlar

    Chris Ramlar

    Feb 8, 2006
    Mexico
    little thread hijack, anyone knows the flat settings in a 70's SVT?
     
  2. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    That's smart advice in any instance : } ...Acclimatizing and doffing the old habits is definitely the way to go if one wants to get the best out of new gear.
     
  3. mongo2

    mongo2

    Feb 17, 2008
    Da Shaw
    IME it will always sound like an SVT no matter what you do.
     
  4. Munjibunga

    Munjibunga Retired Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    So it would make sense to try the mid either full off or full on while checking the tone button's effect.
     
  5. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Thank God for that!

    I can sort of approximate a flat sound by rolling off the bass knob to about 10 o'clock and boosting mids at 800 to about 2 or 3 o'clock. If that's a flat sound I have no idea but it sounds kind of flat to me. But the 2nd channel of the 2 channel SVT's is a lot closer to flat. It and the LMII (which IS near flat) sound very similar tonally. But things like that can be somewhat affected by the type of tubes you use, so YMMV.

    BTW, Bass Gear Magazine's next issue is all about Ampeg, and they'll be running bench tests on SVT's so we'll all get to see a little better what's doing under the hood.
     
  6. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    My cursory look at the SVT schematic, without studying it too carefully, suggested to me that it's a flat amp when the tone knobs are centered. There. I'm placing my bet. Now it will be interesting to see what Bass Gear Magazine determines.

    Wouldn't it be ironic if the SVT sound turns out to be the sound that everybody says can't sound good.
     
  7. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    F, there is definitely a mid scoop going on. I always thought SVT's were a flat response amp too, but then I got a flat response amp and discovered they're not.
     
  8. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Well, that's what I get for a solid state guy trying to eyeball a tube design!
     
  9. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I didn't follow the SVT stuff in this thread, but sure that's not the enclosure?
     
  10. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Um, no?

    ;)

    But it sounds like I have a project tomorrow...AB the LMII and SVT for frequency response.
     
  11. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Another poll in the works? :D
     
  12. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    :D Nah, I think I'm done with that poll stuff. I've done informal ABing with it, but I haven't really sat down and tried to nail the freq response. But I've got the LMII which is near0flat and I know how to set the VT for near flat, so I should be able to get more of a lock on it by tomorrow evening.
     
  13. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Are the sensitivity gains the same up and down the freq spectrum? I'm going to guess you'll say no, but thought I should ask. Would I be better off using a single driver cab instead for this little experiment?
     
  14. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Actually I thought I was replying in another thread, Jimmy. But really the accurate test of an amp's or preamp's FR doesn't involve an enclosure.
     
  15. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Ya Greenie, I realize the informality of it, but I seem to have pretty good ears for that kind of stuff as long as I have a reference to go back to, so I think I can do it. We'll see when Bass Gear #4 comes out ;)
     
  16. Just saw this. You can't have boost in a passive tome stack. I don't know if it is a terminology problem or what, but that is that. Passive tone stacks are all cut. You can change the taper or the pot wiring so that different things happen in different directions, and to different degrees, but you can't boost in a passive tone stack. Not being a jerk, just alertng you to a potential problem.
     
  17. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    It's cool. The Fender stack, however, is passive even though it boosts treble and bass...I always thought it was active, but it isn't. Just found this article on it...can't understand it, but it does say it's passive:

    http://www.pentodepress.com/tonestack.html
     
  18. A lot of it depends on the particular amp.

    On my bass head, when the EQ knobs are set to the middle, that's considered "flat."

    I have a 30-watt tube combo for guitar that has three EQ knobs (bass, mid, and treble) and a bright switch, and "flat" is when the knobs are turned up all the way and the bright switch is off. When the knobs are turned down all the way, the amp is silent. It's also virtually impossible to get an unusable sound from it via fiddling with the knobs, unlike my bass head.
     
  19. And now after reading this thread I guess it has to do with active vs. passive tone stacks
     
  20. seamonkey

    seamonkey

    Aug 6, 2004
    One effect with flat eq is the Equal-loudness contour/"Fletcher-Munson"' curves/"Robinson and Dadson" curves.
    Our hearing is different at different volume levels. A setup that is truly flat may not sound good and flat until you crank it. A store volume good sounding amp is going to be a smiley face curve with the knobs set flat to fool the consumer.

    Tube amps when cranked loose bandwidth and damping at high frequencies when cranked. They essentially turn down the bass and treble by themselves when cranked.
    Mackie is doing the same in some of their PA speakers. I suspect GB is doing something similar. Maybe even more amps are doing this now? I just adjust it myself.

    You need a flat reference point to start with to know which direction to go.
     
  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.

     
    Apr 12, 2021

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