The bass volume when unplugged to the amp

Discussion in 'Luthier's Corner' started by Flamingstream, Apr 21, 2018.

  1. Flamingstream


    Jan 13, 2015
    I recently notice that some bass, like sire v7, is very loud when playing without amp/cab, just unplugged. But the bass I built by my own, is about 6 db lower than the sire. I'm curious about how this happen, or what could affect the unplugged volume.
  2. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    You are also feeling it as well as hearing it, right? You can feel your Sire v7 vibrating in your hands, much more than your other bass.

    What you are feeling and hearing is an indication of the overall stiffness of the frame of the bass. On the bass that's loud, the frame is structurally weak enough that it's microscopically flexing and vibrating along with the motion of the strings.

    The bass that's quiet has a much stronger, stiffer frame. It's resisting the motion of the strings and is barely moving at all. Almost all of the flexing that's going on is within the string itself.

    What does this mean? This frame flexing (or not) affects the final amplified sound through the amp, too. The flexing draws energy out of the vibrating string, changing how it's vibrating at various frequencies. So, it changes what the pickup "sees" as it looks at the moving string. This frame flexing isn't even up and down the frequency scale; it has dead spots and resonance points. As the frame vibrates, it can soften some of the harmonics that were ringing on the string. It can also bring in new background harmonics that wouldn't be there on the string itself.

    Through the amp, the bass with the soft frame and loud mechanical sound will naturally sound warmer, with extra harmonics filling in the background. If the frame is too soft, it will be mushy and muddy with short sustain. Regardless of what pickups and amps are there. The pickup can't change how the string is vibrating (with a few minor exceptions)

    Through the amp, the bass with the stiff frame and quieter mechanical sound will naturally sound colder, clearer, more ringing and metallic. The pickup is hearing the string by itself, with hardly any modification from the frame.

    All this is, of course, at the heart of the endless arguments about Does Wood Matter???? Simple answer: If the bass frame is built sufficiently stiff, then it isn't participating in the amplified sound. It doesn't matter what wood species, type of construction or type of material it's made from. If it's too rigid to vibrate, then it isn't able to change the sound on the string. The sound to the amp is strings and pickup.

    But, if the frame is built softer, so that it does flex, then the characteristics of the wood and the construction definitely do matter. The frame is able to alter the sound on the string, which affects the sound going to the amp.

    This is where we Luthiers play. Adjusting and tuning the overall sound by working with how the frame flexes. Adding character that you can't get from pickups alone.

    With your question, you are opening the door into the mysterious world of Bass Tone. Proceed with caution, for many will react with disbelief and anger!
    Last edited: Apr 21, 2018
  3. charlie monroe

    charlie monroe Gold Supporting Member

    Feb 14, 2011
    Buffalo, NY
    Great post
    mapleglo likes this.
  4. There's lots of voodoo logic about this situation.

    I for one deny that wood makes any difference on a slab-style guitar. I've seen an experiment where a Fender Strat was built out of cardboard and it sounded just like it's wooden counterpart. Point made.

    I do believe this though - the body and/or neck of any guitar is a black hole for sound.

    What makes the body buzz, shake or resonate, doesn't get into the magnetic pickups - barring any microphonics from loose coils or just plain ol' bad construction of them.

    There's no way in H - E - double hockey sticks that resonances can in any way re-energize a string to vibrate in the magnetic field of a pickup. If re-energizing was possible, we'd have zombies walking the streets looking for handouts - because nobody would hire dead people to work for them.

    There would be golfers hitting perfect 2-shots - including the close game.

    No - wood is just a pretty place to mount the strings and controls and stuff.
  5. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    No, Joe, you are wrong. I don't know how else to say it. You probably build all your basses very stiff, and they all sound the same. But that's not the only way to build basses.
    SurferJoe46, nouroog and JIO like this.
  6. Wood that isn't stiff is silly putty and we usually call it balsa (although balsa is considered a hardwood - (go, figger) and if using a wet noodle as a wood substitute is somehow superior - I can't see it being a good idea at all.

    Any time wood vibrates - and we're talking a SLAB or solid body here - it is absorbing vibrations, 'tis true. This only kills by absorption, the sound in certain affable frequencies - the "Black Hole Effect" as I stated.

    WYSIWYG. Not!

    That there might be considered some 'stiffer' or contrapositive Jello*-like woods - would only comparatively absorb more or less, certain vibrations.
    *apologies to General Foods for my snide reference here.

    Again, I cite the cardboard Strat that had no - absolutely NO expression changes at the amplifier compared to a true-wood-Fender-built guitar.

    Imagine that!

    Superior stiff man made cardboard ... flagrantly compared to naturally occurring (therefore 'organic' by definition) and yet vastly inferior (because of it's Jello-ishness) - WOOD!

    According to the Fender Custom Shoppe - they sounded exactly the same.

    Sound creation requires strings (in this situation, but whacking a cardboard or wooden box with a stick is also music by definition, so there!) - something to set them (the strings) into motion (usually fingers) - something detecting the strings moving through the magnetic aperture of the pickup coil(s) ---> and then send that sound to an amplifier.

    Anywhere along that sound-generation-amplification chain, something can be adjusted, changed or muted to create a certain voicing for that instrument. I'd better understand if someone told me that oxygen-free cables made on Orion III sound better than old style cables that were actually made on oxygen-rich earth.

    The body and neck and even the screws that hold the neck to the body - have nothing to do with creating or generating a sound (as an end product).

    HOWEVER - that being said - the body, neck or the screws can detract from the observed voice of that instrument - because of subtracting from the available vibrations --- bleeding them off really, and absorbing them --- they that are NOT at that moment entering the Black Hole of Sound.

    Dominic DeCosa likes this.
  7. Addendum: If you can feel it - it ain't getting to the amplifier. Or: IYCFIIAGTTA.

    I swear that some day I'll start up a new club here called: "IYCFIIAGTTA".
  8. Anecdotal story: Gibson used to make a version of the Les Paul called the Studio Lite. Basically it was a hollowed out Les Paul where they filled the middle with balsa (although they called it chromyte for marketing purposes.) I used to own two of them, a blue one and an amber one.

    They both sounded good, but the amber one was the best sounding Les Paul I'd ever heard. In fact, I used to bring it into music stores and compare it to every Les Paul on the wall and it would always blow them away.

    Sadly, the guitar developed a warped neck and I wound up trading it even-up for a brand new Parker Nitefly that I wanted to like but never really gelled with. It seemed like a good idea at the time, but years later I regret not keeping the Les Paul and doing what was necessary to repair it.

    So that's just a long way of me saying: don't discount balsa wood.
    SurferJoe46 likes this.
  9. Flamingstream


    Jan 13, 2015
    Thanks Bruce, I do agree with you, I believe wood play a huge role in shaping tone, would you mind to talk some about how to change the stiffness of frame, please?I’m not sure if the connection of neck and body or some hole within the bodywood could help. And if a bass guitar was built in a stiff way, do I have something to do I do to increase the vibration of the wood?
  10. Spidey2112


    Aug 3, 2016
    Thanks, Bruce! As usual, awesome! As I read your post, the first thing that popped up (in my mind, anyways) was the differences associated between say a Steinberger (composite material) and any other instrument (wood, only)...

    ... I realize they really are two different beasts, but can the 'same' explanation apply? Although I loved playing it, I never sensed 'warmth' from the Steinberger.
  11. Scoops

    Scoops Why do we use base 10 when we only have 8 fingers Supporting Member

    Oct 22, 2013
    Sugar Creek, Wisc
    I am perplexed by the responses of both @SurferJoe46 and @Bruce Johnson

    Joe states "vodoo" while Bruce states "physics"

    Who cares I say! :)
    SurferJoe46 likes this.
  12. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    I care. For the sake of discussion, I will take @Bruce Johnson's statement as gospel (a pretty safe bet at any rate.) That raises a question; if the wood vibrates, since the pickup is attached to the wood, won't that cause the pickup to vibrate and affect the signal produced? Won't that create a loop affecting the signal even more?
    Last edited: Apr 22, 2018
  13. saved


    Aug 14, 2012
    I have 2 main basses
    The one sound very warmth when unplugged and the other more definited.
    I have send to @Passinwind a few samples to make a frequency comparison.
    I will attach the charts,and guess witch frequency belong to each bass,and then i will tell you witch one is the super stiff bass,you can kill an elephant if you use it like a bat
    Here is the Low B

    and here the F

    The basses have different pickups and other things,but,lets try to figure out..
    papasteack likes this.
  14. papasteack


    Oct 11, 2012
    English is not my native, but i'll try adding my pinch of vodoo partial interpretation of physics.
    Of course, energy can be absorbed, dissipated, or resonating, partially gived back. The point is in the last part. How can a structure give back some of his energy. Low frequency content is barely hearable since humain earing is not so much sensitive in low frequency range. So a low energy content, will (mostly) be restored in some faster energy content/higher pitch, when a solid resonate. A complex energy frequency content will add some intermodulation content. What the hell do i am talking ? It's all about harmonics. Harmonic of low frequency content allow us/human to reconize the original frequency. There's lot of talk about "the missing fundamental". Harmonic content is that shaging stuff that make a triode amp sound so warm. Some prefer triode sound, some penthode....etc...there some more or less typical signatures. It's all as with photos, saturating some colors/changing exposure, contrast, luminosity, adding blur effect... It's always the same photo, but there's lot of small parameters that will affect our subtil satisfaction.

    About wood. maple is not the same as another maple. Depending of where/how the wood has grown, it parameter chimical and physical varies. Stradivarius took is wood in a forest where wood took lot of silice => less aborption, a bit more weight.

    Back to subject, carbon, for exemple, has very low absorption coefficient, and high stifness (Aluminium has more/less same stiffness, but higher absorption, and is denser) So it will give back lot of energy. But here, we don't have yet talk about constraint put to a neck. To simplify a looooot, the more flexion constraint we add a structure, the less it can generate higher order harmonic. Again, what the hell ??

    If string tension of a instrument is maintained by external structure, there is less harmonics generated by the instrument, AND more absorption. Why more absorption ? The more a structure is stressed, the more it become rigid.
    So is there so many difference between a very rigid neck, or a soft wood neck compensated more by the truss rod ? Loose car supension does no more absorb energy, it give it back..

    Weight. Weight add another parameter. depending of it weight, dimension, a structure has it own resonnance frequency. It will resonate more or less depending of the frequency.

    Same rigidity can lead to different energy absorption. It's just how structurally "movement" is converted in heat. There's lot of papers about it. Kevlar, for is rigidity, absorb a lot energy. Balsa is funny depending the axe of fibers, does not absorb a lot in compression, but a lot perpendicular to fiber. That funny seeing wrong orientation of double top guitar with balsa wood with fibers of balsa oriented in the same side of tables leading...

    Then we read a normal speaker frequency curve, we read in reality the level of sound generated for each frequency sent to the speaker. For exemple we can get 110 db at a frequency of 50hz generated by agenerator. But in reality a fft analyser will telle use we in fact got only 106db produced at 50hz, plus lot of harmonics. The speaker in itsef generate lot of hamonics.

    And the worst since is that we mostly ear at environnement resonnances...I won't get into, but there's a lot to say too...

    There's lot of thesis and paper about all of that, and some go far in instrument construction. A lot of stuff can be found looking at speaker science. But lacking of true mathematical basis, all i managed, is to convert it to this poopy vodoo ideas. :)
    SurferJoe46 likes this.
  15. Jon Clegg

    Jon Clegg Supporting Member

    Feb 9, 2015
    Northern Virginia
    Look at this thread: Headless four string ”Brucefied”

    @Bruce Johnson gave @MPU a lot of input.
    SurferJoe46 likes this.
  16. Hmmmm... then there's this:
    Not! That's from the same School of Voodoo Physics. That dog don't hunt.

    All one can surmise is that something's different (by it's own admission) - but in this case too much is different.

    Shame on you for trying to prove physical laws of the universe are available for you to bend to suit your needs and desires. The values are too nebulous to even try to arrive at a conclusion that holds water.

    Your 'Project Bootstrap Theory" that says it's the law just ......because .... it's the law...., doesn't work because you say so.


    Thank-you for this:

    Last edited: Apr 22, 2018
  17. Addendum: I like the quality of the build for Bruce's bass. It shows a total commitment to engineering and good design.

    It's most impressive to see all the details and actual building phases of his bass. I'm totally convinced that Bruce is also an engineer - a machinist - a neurosurgeon and a fine luthier (there! I said 'luthier' - something I don't bandy about as a title for just anyone!). This guy's really good at his craft.

    I particularly like the chambers - and I have used kinda the same approach, albeit for entirely different reasons. I don't have Bruce Bars - I guess that's correct - in that I tend to build neck-throughs now -

    But in the days when I am building a screwed-on neck - I tend to strictly adhere to Leo's designs as I find them modern and yet so old-school at the same time. Aesthetics - I guess.

    I have built a few of my bass designs with chambers, not necessarily for the sounds - as I find that chasing of the Voodoo Winds of Tone - but for weight control and balance.

    Since some of my basses - in years past - were made from 2x4 and 2x6 construction cut-off scraps - just to prove that the wood is a nice place to put the hardware - I can attest to their isacoustic qualities on par with the bass they represent.

    I have never found that if I built a Jazz with scrap wood - or took another early 1800's pure cedar (prolly from Lebanon!) pipe organ (wooden pipe) out of my secret stash to build another custom bass - they all sounded pretty much like a Jazz bass.

    P-basses likewise. I like to mix up the woods that I use for necks - black walnut, red oak (supposedly impossible to work with) or even cherry, laminated with complimentary woods for looks and possibly for neck stability. Thankfully - and so far - none of my necks came back across my threshold as warped. That in and of itself is a good thing.

    I digress - again.

    Nah - I ain't buying into much of this Voodoo Logic - I also say that there is no way to truly test the theories proffered by experts. I also agree upon their tastes and desires to produce an ultimately great, if not perfect - instrument and for that I laud them.

    Congrats are mine to you, and that's not just a conciliatory statement. I truly mean it.

  18. Scoops

    Scoops Why do we use base 10 when we only have 8 fingers Supporting Member

    Oct 22, 2013
    Sugar Creek, Wisc
    I don't care and consider it a waste of time to zero this in!
    Man in his greater wisdom has not figured this out yet. If this were figured out, the world would be full of perfect instruments.

    It's not!
    papasteack, Beej and SurferJoe46 like this.
  19. saved


    Aug 14, 2012

    C'mon joe..pick a color.
    Which you think is soft wood (basswood) bass->warm sound,
    and the hard wood (maple+ash) bass->sterile sound
  20. What I think is that a softer wood MIGHT absorb some constituents of a note more-so than a harder wood --- but that it isn't predictable nor is it engineered-in by any means of repeatableness. (that's my new word for today: "repeatableness").

    "Color" - again one of those Voodoo Qualities that we cannot nail down. More Jello-ness for ya.... but I think the whole OP's statement was that he/she could actually feel the audio qualities of a bass by it's resonance.

    That's just wrong on so many levels - some of which have been bandied about by me and several others here today in this post.

    I'll grant that a softer wood properly loaded along it's grain-axis - is stronger because of the pressure and compression upon it, than if it were not under compression. As far as musical qualities - let's agree to not agree - in certain dog fight arenas anyway!

    papasteack likes this.