Fender Amp - Neutral EQ Setting?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by CMB, Aug 16, 2006.

  1. CMB

    CMB Member

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    For a Fender amp with volume, treble, and bass what is the most neutral eq position? Or does it vary from amp to amp?

    I know the "correct" answer is to set the eq with my ears and not my eyes. However, someone told me that the most neutral eq position for my SFVR was to turn both the treble and bass knobs full counter-clockwise - my ears don't agree that that's the most neutral setting.

    craig
     
  2. Gries Amps

    Gries Amps Supporting Member

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    That is correct. Your ears probably don't agree because it sounds, well, pretty bad. Go to Duncan's Amp Pages, http://www.duncanamps.com/, go to software downloads, & download the Tone Stack Calculator. You can see exactly what's happening & try different values as well.
     
  3. brad347

    brad347 Member

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    those amps are voiced so that the exact middle position on the control knobs is, in the designers' ears, the most neutral position. Since that amp has no midrange knob, the midrange is permanently "fixed" with a fixed value resistor that approximates the 12 o'clock position on the midrange control. That means if you turn the treble and bass controls down, it's like having the midrange at noon and treble and bass off. Not a very natural sound, especially since guitar amps are known for being voiced with a lot of midrange as compared to other types of amplifiers.
     
  4. mbratch

    mbratch Member

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    I have been under the (perhaps misguided) impression that guitar amps are voiced with a midrange scoop in the "nominally flat" EQ knob settings. The reason being that guitar pickups have a lot of midrange output. If you play a guitar in a keyboard or PA amp, it's not very pleasant. :)

    So, a truly flat EQ on a guitar amp would be obtained by turning treble and bass down to some extent.
     
  5. CMB

    CMB Member

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    Aha - that makes sense! I kind of forgot about the fixed midrange value.

    Thanks for the replies.

    craig
     
  6. John Phillips

    John Phillips Member

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    No electric guitar amp has ANY setting that is even close to 'neutral'... because the speakers don't. It's that simple.

    All electric guitar speakers roll off more or less everything above about 6kHz, and most do not have anything like flat response below that. Add in the cabinet design (open-backs cut bass, and closed-backs are usually not 'properly' designed in acoustic terms and exaggerate the speaker's resonant peak) and it really doesn't matter what the amp is doing, there's no way it can compensate for the unevenness of the cab response.

    Which is why we love them, of course... they're musical instruments, not reproducers, and the EQ they naturally add is a big part of the sound of an electric guitar. If you want to find out what 'flat response' sounds like, DI your guitar through a PA or a good set of studio monitors. If you really want to hear full-range frequency content, try it with a distortion pedal in line as well :).


    (FWIW, the Fender amps with 'no' mid control actually have the setting fixed internally at about 8, not 5 - the resistor is 6.8K instead of a 10K Log pot, which doesn't reach a value of 6.8K until quite a bit further up than "6.8" on the number dial.)
     
  7. brad347

    brad347 Member

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    thanks john for setting it straight as usual.
     
  8. bob-i

    bob-i Member

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    "Neutral" eq can be defined in a number of ways. In the stereo world it means flat response at all frequencies, which we'll never see in the guitar amp world. We wouldn't want it because guitars do not sound right at flat eq settings, just try a guitar into a stereo and you'll see on the first chord.

    Neutral to me, is the amp with the eq controls set at the mid point. It's not flat response like a stereo but it's neutral in that you can boost or cut any frequency that has a control associated with it. I always test amps at neutral settings first, and I try to engineer my amps so that they sound as close as possible to what I want at this setting. It simply allows for more tonal flexability, I.E. you can adjust better for the room.

    That's my story and I'm sticking to it :D
     
  9. JJman

    JJman Member

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    The tone stack calculator mentioned above (http://www.duncanamps.com/,) shows the freq curve based on input vs output. "Neutral" to me means "flat" which means that the curve is as straight and horizontal as possible. (Similiar to no tone circuit.) Doesn't mean it's good or bad since all the other parts of the amp are in the tone story too. The program is fantastic for learning how component values (res,cap,pot) and scheme design affect the tone controls' results.
     
  10. donnyjaguar

    donnyjaguar Member

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    Actually, the old Ampegs used the Baxandall tone stack and if you set the controls at mid-point you should indeed get flat response through the amplifier.
     
  11. GenoBluzGtr

    GenoBluzGtr Supporting Member

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    There is the old guidance that Fender Blackface amps are best set on the "rule of sixes"... volume = 6, treb = 6, Mid (if you have one) = 6, bass = 3, reverb = 2 (3x2 = 6).

    I used to have a Super Reverb and tried this once. It sounds GREAT!... a bit on the bright side, but only when playing alone. Once in a band setting, it was perfect. It cut through and sounded just right. The only thing was that 6 on the volume was a touch too loud, so I went to 4.

    When I looked into this, I read somewhere that the voltages/resistance/etc... was optimized with the controls in these postitions. Not sure of the validity, but it did sound great.
     
  12. deeval

    deeval Supporting Member

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    You almost correct but it said it was Mid at 3 and bass at 2:nono
     
  13. John Phillips

    John Phillips Member

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    That's numerologist nonsense. You can make any pattern of numbers mean anything you like if you apply arbitrary rules to them - notice you have to multiply the bass and reverb settings to get 6. (But why don't you multiply them by the treble setting, for example? Or add the numbers?)

    It also has no meaning in the context of what they do in the circuit. (Especially as the numbers don't start at 0 on a BF Fender, they start at 1. But if you turn all the tone knobs down to 1, you get 0 :)). And how does it apply to the amps with "no" mid control (eg Deluxe Reverb) - which do, they just have it internally set with a fixed resistor at about 8, not 6... and yet those amps sound great too.

    If some people find that they like the '6' settings and find it a convenient way to remember them, fine - but it has nothing to do with electronics.

    I find those settings painfully shrill and thin, even at band volume, BTW. (Especially on a Super Reverb.)

    My favorite setting on the usual rented/provided SF Twin Reverb is everything at about 5 (except the reverb, which I have at about 3, but it varies quite a lot from amp to amp), with the bright switch off - but not because I have some particular attachment to the number 5 or because it's the 'mid point', just that they sound best like that to me. Other models need different settings... that's what the knobs are for. Use your ears.
     
  14. Guinness Lad

    Guinness Lad Silver Supporting Member

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    It's funny because everything right around 4 with the bright switch "off". I think the best thing to do is set the controls all to zero and then bring them up one by one until you notice the first big jump in volume. At this point I normally don't go much higher.
     
  15. TheAmpNerd

    TheAmpNerd Member

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  16. GenoBluzGtr

    GenoBluzGtr Supporting Member

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    No, it's not "numerology nonsense", but I agree that if there was to be some "meaning" behind it would be..

    The numbers issue was simply and easy way to remember the settings that all the roots guys preferred for Blackface amps. There have been a few articles published quoting some of the studio guys of the 60s and 70s talking about the "rule of sixes"... some most likely rumor/bunk, but the one common thread is that they all agreed that it sounded good set that way.

    But, you are correct... it doesn't "mean" anything, just a numerical way to remember preferences.
     
  17. Fretts

    Fretts Member

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    If you have a visual sense of sound and a good imagination - most guitar players already do, you can very quickly dial in a "base" sound. but it takes some experience and familiarity to achieve.

    Turn the volume to a comfortable level, let's just say "2" for starters.

    Close your eyes, or at least, don't look at the knobs.
    Starting with bass, rotate the control up and down quickly until you can "see" the bass coming up above an imaginary surface of "the water" . Do the same with the mid if there is one, get it to seem at equal loudness, or equal to the surface of "the water" Same with treble, up and down, bring it into line with the others so that they are all on an imaginary line, even with the surface of this imaginary lake.
    You have to do this quickly, the whole thing in less than 45 seconds. If you get the hang of this, and do it quickly, you can dial in a great base sound to spin off from in no time flat. This is how I do it and I often get compliments on tone when I play out.
    Your brain may not be as permanently altered as mine is, but most people can do this once they get the hang of it.
    Then after it is done, you can make a note of the numbers if you want to, but it's faster and more effective to just repeat the process next time.
     
  18. JJman

    JJman Member

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    [​IMG]

    Notice the setting on the bottom left that result in the (mostly) flat curve. The -20dbs is the "gain loss" people talk about from tone stacks. Pretty significant.
     
  19. CMB

    CMB Member

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    It's a cool discussion, and I wasn't trying to stir up a sh*tstorm.

    Normally plug straight in to my SFVR - got a new pedal, plugged in, and set the bass and treble to noon. Friend of mine asked why I, and I said "neutral setting - I'll readjust once I see how the pedal performs". He said neutral is bass and treble at zero (one actually), discussion ensued, yada yada.

    Anyway - thanks for the info.

    craig
     
  20. John Phillips

    John Phillips Member

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    That's entirely true... for the tone stack.

    But it will not give a neutral EQ setting from the amp, or anything even remotely like it. I'm not sure what the frequency response of the rest of the amp circuit is - it may be significantly non-flat, especially in reverb Fenders with the level attenuator resistor and treble-pass cap before the reverb mix stage - and it really doesn't matter, because everything about that 'flat response' goes out the window when it reaches the speakers.

    Have a look at the response curve of a typical guitar speaker, especially in an open-back cab: severe bass roll-off, a strong peak around the speaker's resonant frequency, a slight dip in the low mids followed by a general rise into the high mids, then a fairly sharp cut-off at about 5-6KHz with almost no useful response above that.

    This is exactly why setting your Fender amp (or more or less any other guitar amp) to 1-10-1 or anything close to that produces a nasal, all-mids sound. You're hearing the speaker characteristics, basically - those of what is effectively a primitive bass driver in a totally untuned cabinet.

    With all respect to those who know how to work out the frequency response of tone stacks etc, IMO unless you look at the whole signal chain the results are meaningless. If you want a 'neutral response', just use your ears. When the frequencies sound fairly balanced (at least from bass to the high mids - almost no amount of treble boost will give a guitar speaker real top-end in a hi-fi sense, which is actually a good thing if you're going to put distortion through it), that's as close as you're likely to get. FWIW, on BF Fenders it's with the tone controls all about halfway. That's exactly why they're designed like that - it is an attempt to produce something that sounds more 'natural' given the limitations of the speakers. It still isn't remotely 'neutral', but it's a lot closer-sounding than trying to apply a truly flat-response signal to a final transducer which is not capable of reproducing it.

    CMB - you've got it right :).
     

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