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Bass frequency/waterfall plots: what they mean to rigs

Discussion in 'Amps and Cabs [BG]' started by greenboy, Jan 27, 2009.


  1. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The format doesn't adequately reveal to the layman what's what here. The fundamental is about 9dB below that 2nd harmonic, and the laymen won't know that's about an 1:8 power density differential. Nor will he know that if you add the total power density of the 2nd, 3rd and 4th harmonics that they will run closer to 15dB higher in content than the fundamental. In short, the insignificance of the fundamental in this case is far less than it appears to those uninitiated in how to read the chart. But it's a start in the right direction.

    Partly because of the string length, partly because the sound sample I assume was measured with a mic, and not a pickup that's mounted well back on the string. You'd see a goodly difference between bridge and neck pickups too.
     
  2. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    That why I used a linear scale for amplitude on the waterfall plots, as WaveLab recommends. It makes the power density relationships immediately obvious to pretty much anyone. But your point about adding all those harmonics is worth echoing. Thanks for dropping in on this thread Bill.
     
  3. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    This thread is super interesting. From what I'm getting out of it, it proves that getting a strong fundamental from your speaker out of the lowest notes is about as necessary as teats on a bull.
     
  4. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I agree entirely, Bill. I was going to post pretty much what you just did as soon as I caught up on some other stuff. These plots were not done in a fashion I would choose for several other reasons as well, but they were what I could get my hands on quite a few years back when driving string research topics on ExtendedRangeBassist.com - at that time I didn't feel like going back and forth in email nags to have my way.

    Still, understanding the scale of the graphs will allow one to parse the data and arrive at useful conclusions.
     
  5. davio

    davio

    Nov 2, 2006
    Boston, MA
    I don't want my bass guitar to sound like my URB.

    I may have missed the point in all that.
     
  6. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Hmmm...I think you're right about the EUB sample being miked, contrary to what I posted above. Unfortunately I didn't tag the sample at the time I did the plot, but I'm guessing it was a recording using an Audix reference mike, and my DIY 3-way cab which is a 15"/6"/1" format.

    If I'd realized this thread was going to take on such a life of its own I would've just made new samples to begin with rather than use old ones I had on hand.;)

    I'm going to borrow one of Mal's Fender fretteds later today, and I can re-do the EUB sample while I'm at it. It's trivially easy to do these plots in WaveLab.
     
  7. rbonner

    rbonner

    Sep 25, 2008
    Well you could say that Jimmy, but what I was saying is we have a deficiency in the instrument due to its size.

    A concert grand piano does not have a deficiency, and a string bass still does but is closer to its correct reproduction of its note. If we started comparing pianos to basses we'd start seeing some more information.

    Its this relationship between the fundamental and the harmonics that needs to change IMO, and if we do that we'll pick up additonal information.

    DO we have to do this? NO, but what do we gain if we do? I think we'll benefit. I'm going to experiement here.

    BOB
     
  8. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    This entails a number of issues where there are currently deficiencies in the majority of products and practical use thereof:

    1) string design
    2) pickup design
    3) bass construction
    4) sound reproduction

    and 5) ear's relative lack of low frequency sensitivity
     
  9. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    The EUB is a stick bass with a small hollow section and no f-holes. I have a wolf tone killer (felt mute) on the afterlength beyond the bridge. Pickups are 4 piezo elements in the bridge, and the preamp is a proprietary Bartolini one with unknown EQ characteristics.

    The fretless BG is a one piece sapele body, maple neck-through, ebony board. It's not inherently a bright fretless at all.

    I like where you're going with this Bob. Although that discussion may be better served in the Bass Forum...
     
  10. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    But again, that would be entirely dependent on the mic used to amplify the piano. Still, I'd like to see some piano recordings with a really good mic charted out just to see the difference.
     
  11. joelc1319

    joelc1319

    Sep 12, 2007
    +1. While I agree with what rbonner was saying in terms of not settling for the electric bass's "limitations" (I'll go into that in a second), I think the point of this thread is more to show how we don't need that fundamental to be strong in order to get a bassy sound.

    When I say limitations, which is what I think rbonner was getting at, the so-called limitations are what makes the electric bass an electric bass and not an electric upright bass with frets. I think the focus here is on sound reinforcement of the instrument, without needing to have a gigantic rig capable of a flat frequency response down to 20Hz, especially since the average bass guitar doesn't output a "flat" (meaning the fundamental with all of its harmonics at the same volume level) signal in the first place.

    This is the tone we have come to know and love, even with its flaws and limitations :D
     
  12. davio

    davio

    Nov 2, 2006
    Boston, MA
    Ok, I'm curious. I'll bite...what do we gain by having a stronger fundamental on such low notes if they become increasingly difficult to hear (other than loss of bowel control and heart palpitations :D )?
     
  13. joelc1319

    joelc1319

    Sep 12, 2007
    One could make the argument of being able to feel the bass rather than hear it...:smug:
     
  14. rbonner

    rbonner

    Sep 25, 2008
    One thing to think about here. The fundamental is the note...

    The second hamonic is not the fundamental note, sure it makes up part of the content. If you remove the fundamental you no longer have the note you have the next octave. You always need some content of the fundamental.

    By increasing the quality of this fundamental I say we increase the quality of the Note itself.

    I am not a super low guy and I have stated before I'm not for anything that goes below the lowest key on a piano. But we do need to reproduce the fundamental and all of its harmonics. BOB
     
  15. joelc1319

    joelc1319

    Sep 12, 2007
    The fundamental is still there, but just to a lesser degree. If it weren't there at all, as in 0dB, then I can see your point as stated. But it's still there, whether it be at 85dB and the first harmonic is at 105dB, it's still there. The premise here is not needing equal dB of the fundamental with all harmonics, in fact we don't necessarily need the fundamental to be the HIGHEST dB out of all the tones that make up a note.
     
  16. seamonkey

    seamonkey

    Aug 6, 2004
    Great info.

    This is exactly how Waves MaxxBass works. It arranges harmonics to allow the ear to think it's hearing more bass. And as Waves will point out this is what pipe organs have been doing for centuries. One of review of MaxxBass has the opinion that it's not psychoacoustic but actually a function of how our cochlears work.

    MaxxBass is too expensive, and hard to license, but could be used in some applications. I've seen a few sound companies around here hauling around the MaxxBCL.
     
  17. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    No plucked or struck string instrument does that. No instrument using acoustic principles does that. As you go up in frequency it becomes increasingly harder to derive energy. But still, loudspeakers need to be capable of near flat response above the fundamental just to adequately present this phenomenom.

    Anyway, here's an interesting tech lecture given to a luthier association, by Ralph Novak of Novax FANNED FRETS fame - Dingwall Basses being perhaps the most notable bass-oriented company to license the technology:

    Transcript of Ralph Novak’s Lecture on Scale Length and Tone to the 1995 G.A.L. Convention
     
  18. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    It does but you're making one really fatal error. The response of an electric upright is nothing like that of an acoustic upright. Measure an acoustic upright double bass with an accurate microphone and you will find there is no audible fundamental content on the lowest notes. In fact there isn't much energy at all below 100Hz. Same with all non-amplified instruments apart from pipe organs. Even a huge grand piano has hardly any fundamental output on the lowest keys.

    In my opinion you should be aiming to reproduce the fundamentals well down to about 60Hz and below that you should accept that the 2nd harmonic is sufficient to get a great deep sound. However, you should also ensure that the cab has sufficient ability to reproduce all this low frequency energy with minimal distortion, otherwise the human brain will have much greater difficulty appreciating the tone of the note and calculating the fundamental based on the harmonic series (and that is exactly what it does, and not just the human brain, even animals' brains generate the fundamental from the harmonic series).

    Alex
     
  19. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    Sorry but that is totally incorrect. This has been tested in accurate experiments and as I alluded to before, not just with humans. Read "This is your brain on music" for deeper elucidation - that guy knows his stuff!

    Alex
     
  20. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Au contraire, it does, and for the same reasons. The only bass instrument which doesn't suffer too badly is a pipe organ, but lugging around a hundred or so pipes up to 64 feet long would tax even the Clair Bros.