The Acoustic Sound Of The Electric Guitar; why it is of pivotal importance

Discussion in 'Guitars in General' started by Terry McInturff, May 5, 2008.

  1. Terry McInturff

    Terry McInturff 40th Anniversary of guitar building! Gold Supporting Member

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    Hello all,

    Much of my own delight in perusing the various threads here at this outstanding forum involves discussions regarding the latest electric guitar hardware...bridges, tailpieces, pickups, tuning machines, finishes, etc....

    I have learned quite a bit about such things here, as I am sure that many of you readers have as well.

    I would like to address a very pivotal and primary aspect of the sound of the electric guitar...one which I feel may get far less attention than it deserves...the unamplified, strictly acoustical sound of an electric guitar...and why it is of real importance.

    I shall limit my "lecture" a bit in order to (hopefully) generate questions in the Socratic style; therefor, it will be encumbant upon the readers to make this thread a success, by means of some of you asking good questions that I can help develop into a true understanding of the subject-at-hand.

    1) The acoustical nature of any electric guitar imposes firm boundaries/limits upon what can ever be heard thru the speaker cabinet.

    The acoustic/unplugged sound of any electric guitar will reveal the limits of it's amplified tonal capabilities.

    Let us imagine the acoustic sound of an electric guitar as being the fence that surrounds a baseball park; there is a bit of space surrounded by a hard boundary.

    The "fence" represents the limits of what the acoustical nature of the given guitar can produce, tonally; the space surrounded by the "fence" is the place within which we can influence the tone via hardware, pickups, strings and the like;

    We can "steer" the amplified tone this way and that way via hardware, string, and pickup choices...but only within the boundaries of the "fence".

    We cannot efficiently boost any frequencies that do not reside (with any strength) in the acoustical nature of the guitar.(It is true that via various types of electronic trickery an extended harmonic series can be generated...I am talking about the basic, organic tones here).

    This may be why we often end up "chasing our tail" when it comes to trying to mod a guitar to our liking; all too often, what we want to hear is something that does not reside in the acoustical nature of the instrument, and therefor cannot be had by any means.

    2) Recognising/hearing the acoustic nature of an electric guitar.

    In contrast to, say, a D-28 or any other wholly acoustic guitar, the tonal qualities of an electric guitar (the "ballpark"...remember?) are not so immediately apparent. Obviously, an acoustic guitar is designed to "speak" by means of it's loud acoustic nature..."what you hear is what you get".

    This is no less important in the case of an electric guitar, but it is harder to hear and thus to judge it's acoustic "voice".

    Because the amplitude of the unplugged electric guitar is weak, we must consider how to listen to it, in order to best judge it's potential.

    a. Be sure that new strings are installed on the guitar. We need all of the help that we can get!

    b. Take the guitar into a small, resonant room...a smallish bathroom can be perfect...and play the guitar. The room will act amplify the sound..and the sound of the room has to be taken into account...but any small, reflective space will help.

    c. While playing, ocassionally press your ear against the side of the guitar. This will not be an accurrate representation of the sound, but it will give you extra information regarding the low mids and bottom. Remember that these lower tones have the least amplitude (thats why your Strat sounds so "stringy" when you strum it casually...you are hearing the higher frequencies the easiest). It is hard for the string energy to move that solidbody to any loud register in those lower frequencies...but they are there..

    d. Invite a learned friend to listen too.

    e. Take the guitar into your oft-used living areas, and play it unplugged there as well. Your brain has become very used to the acoustics of those areas (TV room?) and thus these are good areas to listen for "good tone".

    That is enough for now.

    Suggested Topics for further discussion include (but are not limited to)...

    1. What attributes am I listening for?
    2. Why does the acoustic tone affect what I hear out of my amp?
    3. If the acoustic tone is so important, why then should I care, if my sound is built from wholly electronic means, ie, massive amp gain, signal processing, and the like?
    4. If the acoustic sound is so important, why am I getting such a different tone from my new pickups/bridge/tailpiece/etc?
    5. What about the role of chambers in a semi-hollow electric?

    I will be happy to address these questions...should questions like them actually arise.

    But the main aim is to get you all talking about these things among yourselves, every bit as aiming Q's at me.

    I am not aware that this topic has ever been adressed in print, anywhere, to any great degree...I may well be wrong.

    Get talking..I'll be around.
    Your friend Terry
     
  2. decay-o-caster

    decay-o-caster Member

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    Smiling... Thanks for posting this, Terry!

    I enjoy a plugged in electric as much as the next guy, but when actually guitar shopping, I don't see much reason to plug it in. The acoustic voice tells me a lot, now that I listen to it.

    One point (that I am stealing from someone!) that I have seldom heard being discussed is the impact the body vibrations have on the way the pickups register the vibrating strings. Not only is the string vibrating over the pickup, but the pickup is vibrating under the string. I find that concept faskinatin'!
     
  3. AaeCee

    AaeCee Member

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    As though we didn't already know all that stuff?? Next time try telling us something we didn't know! [​IMG] All kidding aside, GREAT read Terry. I've actually thought about some of that in vague terms, most notably your use of the 'tonal boundaries' analogy, but it's great to read about some of the more precise reasoning and logic from someone of your obvious experience and ears. Thanks!
     
  4. Terry McInturff

    Terry McInturff 40th Anniversary of guitar building! Gold Supporting Member

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    Many of us have intuitevly known alot of this all along, as you guys have already pointed out. Thanks for your input!

    As for the "vibrating of the pickups"....let's think of the pickups as not being called "pickups" but for the purposes of this discussion, think of them as another type of "microphone".
     
  5. Frankee

    Frankee Wartime Consigliere

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    Great addition! Thanks Terry. I've always "auditioned" prospective guitars for purchase unplugged, and made my choices based on BOTH dry and amped sounds. ( I didn't say "tones"!) However the info you've posted far exceeds what I was aware of. Thanks again.
     
  6. The bear

    The bear Member

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    Thanks for the write-up Terry!
    I always practice my electrics without amps....
     
  7. lifeson1

    lifeson1 Supporting Member

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    About a year and a half ago I drove home to Ohio for the holidays, where I brought my new Tyler Classic home to show off to my brother, a professional guitarist out in LA. All his gear was out in LA, mine in Memphis. . . My brother took out my Classic in our parents house, played one Open E chord, and his grew wide. He said, "that's an amazing sounding guitar". I thought he was joking around with me - the guitar wasn't even plugged in. He went on to tell me that whenever he played an electric guitar for the first time, he let it sing acoustically first, judging it's sonic values before plugging it in.

    I've since acquired that habit and it's helped me in some considerable purchases. I guess what I'm saying is, I agree whole heartedly with Terry.
     
  8. Terry McInturff

    Terry McInturff 40th Anniversary of guitar building! Gold Supporting Member

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    (spoken with a Cockney accent) "But I am Babe In The Woods, what are you guys listening for?"
     
  9. SimonR

    SimonR Member

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    Thanks for your interesting and thought provoking post, Terry.

    Maybe this is a good juncture for me to seek your opinion on something?

    I own two Gibson Custom Historic 1959 Les Pauls (a 2006 and a 2007). The 2006 is the heavier of the two. Acoustically it feels less resonant than the 2007, its sound/tone is duller and it is acoustically quieter. The 2007 is appreciably louder acoustically, the tone is brigher and has more "air" and "zing". All in all, a much better proposition acoustically.

    Now plug the guitars in and the roles are reversed. The heavier 2006 sounds livelier, brighter, harmonically more rich than the 2007, which sounds like a blanket has been placed over the speaker by comparrison. Both guitars are dead stock with Gibson BB pickups. I have gone to great pains to ensure pickup heights, bridge height, stoptail height, overall action is as close as possible to identical on both guitars.

    I'd love to hear your views on this apparrent anomaly!

    Cheers,
    Simon
     
  10. Terry McInturff

    Terry McInturff 40th Anniversary of guitar building! Gold Supporting Member

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    Oh, Goody! Now we are starting to get some real "meat" to work with! (not that I do not appreciate the prior posts!).

    Simon, I can only guess...not being there to listen for myself...but your descriptions seem very good so let's go with them for sure!


    Simon, a Les Paul is very difficult for the strings to drive acoustically, since the body is so stiff and dense (to varying degrees!).

    It is my guess that, upon really close inspection, the louder, brighter, airier, indeed zingier 2007 will prove to have a really predominant upper midrange content....that is the range that we can hear most easily from a gtr like that....combined with the "zizz" from the plain strings. But if we listen with care...we may find the acoustic nature of that guitar to be rather unbalanced. It is not at all uncommon for a delightfully loud (acoustically) solidbody to be unbalanced in that way...lots of energy in the mids. Thats what is giving it the sheer volume. The "zing" and "air" is coming right off of the strings, I am guessing.

    By contrast the duller, acoustically quieter 2006 may well have...upon close inspection...a better balance betwixt the lows, mids, and hi's. This would be reflected thru the amplifier.

    Cannot tell you since I am not there but...the guitar that is weighted in the mids seems to sound weighted in the mids thru the amp, according to what you have described.

    Assuming that all four microphones are matched....they are reflecting the acoustical nature of those two guitars.

    It is possible to weight the tone via the mics (pups), but again, never outside of the ballpark.

    Here's an analogy....a hi-hat will sound very different when mic'd with an SM-57 than when it is miced with an AKG 414....but niether mic is "inventing sounds"...they are emphasising different parts of the "ballpark". Same cymbal, different sounds. The 414 will be alot brighter than the 57...but if we want to make the 414 even brighter, at some point we'll just be boosting hiss and noise, not cymbal.
     
  11. Terry McInturff

    Terry McInturff 40th Anniversary of guitar building! Gold Supporting Member

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    P.S. to Simon before I head off to bed...

    Dial up a clean sound on then amp, and then carefully play from F to A on the G string on both guitars and carefully note the sustain quality of those notes.

    I am guessing that on one of those notes...probably Gflat, G, or Gsharp (11th, 12th, 13th fret) you will notice that one of those notes has a distinctly less amount of sustain on the 2007, and that the 2006 will sound rather even...I might be wrong!

    If you DO notice an anomoly such as I have described, dial up a bit more gain on the amp and play the exact same note that was "dead" on the G string, but play it on the B string now instead, and let it sustain. Listen carefully and you will hear the overtone series shift to an octave higher.

    If so....There you have a bit of inappropriate neck resonance. You will be able to hear that without the amp if you listen carefully.

    If all of the above is still holding true, then put a "C" clamp on the headstock of the 2007 and see if all of that goes away...and the guitar will likely have quite a different overall responce.

    Just guessing..I could be wrong! Let us know.
     
  12. HammyD

    HammyD Member

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    Thank you for that informative post!
     
  13. digthosetubes

    digthosetubes Senior Member

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    You mean I gotta read all this?

    I have suspected that what you have entitled your thread is, indeed, important.

    Often, however, I hear the idea dismissed with disdain.

    I appreciate your making the effort on our behalf.

    I think the acoustic sound of a guitar whether it is plugged in or not is important. I think the wood is important. The frets, the neck, all that stuff. The bridge, etc.

    Now let me hope I can muster the courage to read your ideas in more detail.
     
  14. edward

    edward Supporting Member

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    I gotta admit (my apologies to Terry who is clearly beyond the hack at this keyboard :) ), that I was not terribly struck with the first post. But the aforementioned discussion of the two LPs ...now THAT is interesting to me. Not to mention it explains some of my own experience.

    If I may, for eons, I've also heard/read of the importance of said "acoustic" tone ...only to find that ultimately, plugging in is still the definitive test; and just as often as not, having little-to-no correlation with the unamplified "goodness" quotient, if you will. Mind you, this is casual observation over the years, of which my memory could have colored a few over time. But I still hold that the acoustic tone is not enough of an indication of thumbs up/down ...I just HAVE to plug it in. Without doubt, how she *plays/feels* is critical, and this alone will prompt me to play further or immediately put it back on the wall. But acoustic tone? ...still have to plug in.

    Like Simon, I love the sound of my 80 Strat, which is no where near as light or resonant as most garden-variety strats today, MIA or MIM, or even a recent one I just picked up. But there is NO denying the beauty that comes from my 80Strat when plugged in, despite the less-than-flattering unplugged tone.

    So yes, your explanation does explain some of the "mystery" behind why the "contradictions" exist between acoust vs. plugged tone. Thanks for the insight, Terry. Now I've got something else to toss around in the ol noodle.
    :)

    Edward
     
  15. Bhodie

    Bhodie Member

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    Just curious.. if the acoustic "sound" of a guitar is an indication of its plugged in ability, why are not all electric guitars hollow or semi hollow as they have a greater acoustic ability? (strictly speaking). Also, as I understand it, and I am certainly no expert, so this is a legitimate "physics" question.. if it is the vibration of the strings through the magnetic field of the pickup poles that create the amplified sound.. wouldn't something that had the absolute most stable, rigid platform for that string create the most "tone" since all the vibration is in the string, not spread out over the wood of the body, the neck, tuners bridges and tail pieces?
     
  16. WayneM

    WayneM Member

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    Terry,

    As an Engineer, I have designed many metal Towers and Stacks. These structures (as all solids objects) have a natural frequency. When excited, these objects will vibrate at it's maximum magnitude.
    In a structure like a Bridge, Tower or Stack a single wind speed can generate the largest stresses and can destroy the structure if not considered in the design (think the Memorex Tape glass commercial)

    The solid guitar then too has a natural frequency which when excited it too will vibrate the greatest. The vibrations generated by the strings may excite the the guitar structure.

    The stiffness is the variable that defines the natural frequency of the final fabrication.

    Using this line of thought......the stiffness (or lack there of) defines the acoustic properties of the guitar.

    I believe the term "tuning" the guitar when designing this system (wood, joints, bridge, etc.) all play a part of the final stiffness and therefore will define the natural frequency of the final product.

    Unfortunately.....I believe that I do not know a way to analyze the natural frequency of a guitar....and neither do I know the "best" natural frequency that will make the guitar's acoustical tone sound "best" or even loudest for that point.

    Just some rambling by a ol' engineer..........it's all in the ear of the beholder!
     
  17. digthosetubes

    digthosetubes Senior Member

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    Cool. :stir
     
  18. GCDEF

    GCDEF Supporting Member

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    The only time I play my electrics acoustically is when I'm practicing on my own. I don't care what they sound like then. I do care what they sound like when they're plugged in and that's the only tone I care about. There may be validity to your points, but if listening to it acoustically can help predict what it will sound like plugged in, why not just plug it in and listen to it the way you're going to use it?
     
  19. Shooter Bob

    Shooter Bob Member

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    Perhaps the most important piece of information here is the "quality" of the acoustic sound. It seems that most arguments on this subject spawn from the claim that "acoustically loud electric guitars sound better when they're plugged in than guitars with less acoustic volume."

    The key point here is the "quality" of that tone which Terry has explained. So, with this in mind, the theory says we need to know what to listen for when we strum an electric guitar acoustically.

    Being a guitar builder of several years myself let me first say that I have the utmost respect for Terry's work and products. I have played several of his guitars that exhibit great tone and playability. On the other side of this coin, I see a bunch of people who, in eanrest are trying to buy the best sounding guitar possible. And while there actually is something behind the merits of this discussion, it still comes down to, "plug it in and play it."

    So while picking up an electric guitar, strumming it with a discerning ear, and then proclaiming it to be acoustically balanced might be a fun excersize, the true tone of the electric guitar isn't really revealed until it's plugged in and played in anger. This is by no means meant to discredit anyone.

    To me, the real importance of a an electric guitar's acoustic properties lie in the arena of "my guitar sounds like crap, what should I do?" In this area, the trained ear might be able to decipher the offending frequencies which would lead to either modifying the guitar, or abandoning it for something more suitable.

    In the grand scheme of things, and I'm sure Terry will agree, 9.8 out of 10 of us do not have a refined enough ear to identify the acoustic differences as they relate to real world sound and playing. The thing we most often tout as "great acoustic resonance" is really nothing more than volume.

    I respectfully submit that the acoustic properties are important to those who's ears are sufficiently developed to hear and know the difference.

    Great perspective Terry on a subject that has become quite heated on other forums. This old dog just learned something new.
     
  20. reeced

    reeced Member

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    Terry, a very interesting article



    Have you heard of the Dragonfly powerless amp ? - http://www.truenorthmusicproductions.com/DragonflyPage_Order.html

    It's sold as a "battery-less" personal amp for electric guitar, but I've found it to be a very good diagnostic tool also.
     

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