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frequency response: just how important is it?

Discussion in 'Amps and Cabs [BG]' started by andrewd, Mar 2, 2004.


  1. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    Anyone care to comment?

    Alex
     
  2. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    Buddy, he's obviously saying that he isnt experiencing this psyco acoustic effect you are talking about. He's saying that he doesnt hear that strong bass you say his brain is tricking him into hearing.

    Peace
    Nick
     
  3. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia

    Let me confuse the issue further. My Nemisis 4x10 is -3dB at 38Hz. My JBL 15" is -3dB at 50Hz. Why then does the JBL sound a lot deeper than the 4x10? On paper it shouldn't.

    Read my sig.
     
  4. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    I cant answer your question.

    You know what though, those Nemesis have more bottom to them than a lot of other bass cabs Ive tried.... as the specs say they should.

    Peace
    Nick
     
  5. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Really? As a stand alone I feel like it's missing bottoms. It's very good with a 2x10 extension but brilliant with a 15. (IMO it's a very under-rated cab once you fix the horn)
     
  6. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    Oh, well I have the 2-10 combo and maybe thats where the difference is but then again the first one I tried was the 4-10 combo so I guess it comes down to a differnce in opinion.

    Maybe we like different kinds of bottom?

    Peace
    Nick
     
  7. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    Oh and I agree that they are incredibly underated!

    I love mine so much that Ive juggled the idea of copying its preamp section and using it in my rack for big gigs where the 210 wont cut it.

    Peace
    Nick
     
  8. MJ5150

    MJ5150 Moderator Staff Member Supporting Member

    Apr 12, 2001
    Olympia, WA
    The Nemesis 210 combo from Eden can take an extension cab? I did not know that. How many watts does it push then?

    -Mike
     
  9. I think there's a misunderstanding here. First, I don't see where brianrost said anything about any "strong" bass; he just said you could hear the fundamental when it's not there. He also did NOT say it sounds the same as when the fundamental is truly there.

    To me, this psychoacoustic phenomenon obviously exists. Why? Think about it. If you hear a bassist play a low F over a small speaker, how do you hear it as that F and not an F an octave or two higher up? Because a lot of the time, you obviously *do* hear it as the correct pitch, even when you know the speaker can't produce it. Why and how does this happen, if your brain does not somehow tell itself it's hearing a frequency that isn't actually there?
     
  10. metron

    metron Supporting Member

    Sep 12, 2003
    Denver
    My Berg speakers are the same way, the 210 -3dB point is at a lower frequency then the 115. The 115 sounds deeper partly because its a bigger speaker and it moves slower.

     
  11. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    I have no idea.

    It says 200 Watts @ 4 ohms on the back, but Im not sure what the impedance of the internal drivers are.

    Its louder than a lot of 200 watt amps Ive played FWIW.

    Ive run it with my 4 ohm Eden D210XST for a long time though without problems.

    Peace
    Nick
     
  12. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    There actually have been tests where the fundamental of a harmonically rich bass note is suppressed, yet the listening subjects identify it as being there. It doesn't sound an octave higher because the harmonic series isn't the same as if the fundamental were an octave higher.

    For example, if the fundamental were 40 Hz:

    1st harmonic: 40 Hz
    2nd harmonic: 80 Hz
    3rd harmonic: 120 Hz
    4th harmonic: 160 Hz
    5th harmonic: 200 Hz
    6th harmonic: 240 Hz
    etc.

    If the fundamental is attenuated, as might happen in a loudspeaker system, the ear still hears the harmonics of a 40 Hz note, and the mind fills it in psychoacoustically.

    The harmonic series of an 80 Hz note are not the same:

    1st harmonic: 80 Hz
    2nd harmonic: 160 Hz
    3rd harmonic: 240 Hz
    etc.

    … so it doesn't sound the same as the 40 Hz note.
     
  13. In most cases the resultant bass does sound the same when the fundamental is missing especially when it is like 40hz, but, it doesn't feel the same. ;)
     
  14. Mark Reccord

    Mark Reccord Supporting Member

    First things first. Bruce; I did not lift that statement directly from Harvey Gerst. I've never heard of Harvey Gerst, let alone read any of his articles...

    Ok. I'm not in the business of saying things that I can't back up. I don't know what scope traces you guys have been looking at but I just took measurements from both of my basses with a high resolution spectrum analyzer. The results are very congruent with what I said earlier in this thread. I've seen many spectral analyses of bass guitar notes and they're all similar. There's way more energy at the 2nd and 4th harmonics than at the fundamental.
    Screen captures are attached.

    As for the math, are you familiar with the standing wave ratio? It's a measure of the strength of the standing waves developed on a transmission line for various frequencies. The higher the SWR for a given frequency, the stronger the standing wave developed. Now the SWR is determined (basically) by the relationship between the transmission line (ie string) and the wavelength of the frequency of interest as well as the impedances of the media in question. Line lengths that are a larger percentage of the wavelength of interest tend to have higher SWRs than shorter ones. So, at 40Hz on a bass guitar E-string the SWR is lower than it is at 80Hz so the amplitude of the 80Hz harmonic is greater than the amplitude of the 40Hz one. Now this isn't the whole story because a lot of the 40Hz wave is being transmitted into the body of the bass, which makes the body vibrate at the fundamental which is transmitted to the string again, and the body vibration itself may contribute to the amount of fundamental. This is why you'd expect NT basses to have a larger fundamental component than BO ones, because there isn't a joint to impede transmission of vibration. Even the best BOs exhibit at least a bit of this, but it isn't necessarily a bad thing. Even on a NT bass, the fundamental won't be stronger than the 2nd harmonic though.
    Alex: If there was other stuff between your bass and the spectrum analyzer, your results are inconclusive. The only way to test this properly is to connect the bass directly to a spectrum analyzer, lots of preamps have built in EQ curves that are invisible to the user.

    As for extended range speakers. Well, I've operated PA systems that responded flat to 27Hz (Meyer) and the hifi speaker system I'm working on right now is flat to 17Hz. I've got a reasonable idea of what extended bass response is like.

    Notice I didn't ever say that there wasn't any fundamental or that the fundamental isn't important. All I said is that it's not the be all end all of bass tone, and that the necessity of having speakers that can strongly produce the low fundamentals is very subjective.
     
  15. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    Any idea why the 3rd harmonic (120Hz) is so low? Is that normal?
     
  16. DEVILMAN

    DEVILMAN

    Nov 24, 2001
    New York,NY
    @ bgavin,

    +1...

    @VicDamone,

    Agreed, 1000%...

    ~S~
     
  17. Mark Reccord

    Mark Reccord Supporting Member

    It's consistent on the two basses, so it's a function of the SWR of the 3rd harmonic on a 34" scale. There just isn't a strong standing wave at that frequency. I could sit down and figure out the exact SWRs if I looked up the impedances of the materials. I may do just that when work settles down a bit, too busy right now..:D

    The two basses are a 1997 MIA Jazz bass with Basslines Hot Jazz pickups and a 2000 Stingray5, BTW.
     
  18. If you are a bassist in the club scene, or care to be:

    1) You will gain much more knowledge, and ultimately satisfaction with acoustics and tone, by getting your feet wet and performing live with various bass rigs, through a variety of PA systems, on a variety of stages, experimenting with cabinet placement, and by asking questions.

    2) Nit picking over a few hertz difference of cab A vs. cab B ??? You'd invest your time better by arranging to try them under real - world situations. Play set one with cab A and set 2 with cab B. Imagine for a minute, that what you hear is more important than a specification.

    Don't forget that the enjoyment of playing music, is about the music. Knowledge of acoustics and practice will take you much farther than 'the awesome new CaBz D00d'.

    :)
     
  19. DEVILMAN

    DEVILMAN

    Nov 24, 2001
    New York,NY
    @blimplizkit,

    Some people only play 1 set(me) per club...



    ~S~


    PS: Sometimes my rig KILLS sometimes it just "cuts the mustard"...it also depends on the PA & soundman(another whole ball of wax)...
     
  20. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    Fascinating post.

    I would be very interested in seeing the spectrum analysis of a NT bass for comparison with the BO instruments you tested. I have not measured any but based on performance with cabinets I would tend to agree that a NT has more fundamental energy than a BO; I just have no idea if that's a 3db difference or a 10db difference.
     

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