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Resonance

This is the center block (cut away and right side up) of a 335. The bottom piece is maple, the top is kerfed (slotted) spruce and on top of that is the plywood that is the top of the guitar. Somehow it works. Thanks to Dr. Vintage for the photos.

As a writer, I appreciate it when words are spelled correctly. As a writer who is a terrible typist, I’m guilty  of plenty of spelling and punctuation errors but that’s not actually what this post is about except to say that when a guitar rings out, it is resonant NOT resonate. It resonates (verb) but it IS resonant (adjective). This is probably the most misused word among guitar enthusiasts. So let’s talk about it. By design, a 335 isn’t terribly resonant. That was kind of the idea-to make what looked like a hollow body sound like a solid body and thus avoiding the bugbears (great word) of the hollow body electric; those bugbears being feedback and lack of brightness for the kids playing that rock and roll music. It helps to understand that a pickup isn’t a microphone. It doesn’t exactly “hear” what your hear when you play the guitar unplugged on the couch, annoying your wife while she’s trying to watch “Dancing with the Stars” which you only watch for the women’s costumes anyway.  The pickup “feels” a disturbed magnetic field and turns that into the tone sound of the guitar. The concept behind pickup function is based on Faraday’s Law of Induction.  Simply put because even I don’t quite get it, a changing magnetic field causes an electric field to be set up in a nearby wire, causing a current to flow.  And I am not one to go around breaking laws.  That brings me to the idea of how resonance in a 335 affects the amplified tone of the guitar. It also brings me to a more common question which is why some 335s are pretty resonant and others aren’t. As I’ve discussed before, the center block of a 335 exists in two forms (for the early models anyway). They either have a cutout under the bridge pickup or they don’t. This was started as early as 1962 (although I swear I had a late 61 that had it)  but the transition occurred over the course of 3 or 4 years. I had a 65 stoptail that had no cutout. All 345s and 355s (even monos) have the cutout to accommodate the Varitone chokes. The reason they added the cutout to the 335 was to make it easier to get the harness installed without having to stuff it through the f-holes (don’t try this at home). There are other factors that will affect resonance in a 335 as well. The qualities of the wood involved are another. Some wood simply vibrates better than other wood. Fortunately, maple seems like a fairly consistent wood and 335s are, if nothing else, fairly consistent in resonance, at least in the early days. But what about the difference between a cut out center block and a non cut out one? My personal preference was for the ones that weren’t cut out until recently. I thought they sustained better. Now that I’ve owned a larger number of 335s/345s and 355s, I find that to be less true. In fact, I’m not even sure I can tell the difference between a cut center block and an uncut one every time. What I can hear is when a guitar  vibrates and, yes, resonates more than another. Folks talk about “woody” and “airy” tone and some 3×5’s have it in spades and others less so. They all have it to some degree-most would agree that a vintage 335 is a pretty “woody” guitar (insert joke here). I don’t think that little air pocket under the bridge pickup has much, if anything to do with it. I think the physical properties of the wood itself is more responsible. And by the wood, I really mean the center block; the guitars “box” doesn’t really resonate all that much. I’ve played  Les Pauls that are louder unamplified than some 335s. There just isn’t that much moving air in a 335 due to the center block (and perhaps some crude construction).  Sit on the couch next to your wife playing an unamplified ES- 330 (no center block) and she’ll tell you to turn it down. The larger question is how the pickups actually perceive this resonance since they aren’t microphones. For the answer to that, you’re going to have to consult a physicist or Seymour Duncan, who I’m sure knows. I do know that a resonant 335 generally sounds better to me amplified or un than one that is less resonant. More complex, more articulate, more, uh, woody. And that resonates with me.

No wonder these things don't resonate that much-there's almost as much glue as there is wood. Glue is not terribly resonant and probably does more damping than anything else. Fortunately the tone generated by the "box" of a 335 has little to do with what comes through the little wire. And you thought these were made by master luthiers with care and precision. They were essentially hand assembled mass produced guitars and yet, they sound great. That tells you how great the design is.

 

9 Responses to “Resonance”

  1. Chris Haines says:

    The acoustic non amplified resonance of my 335 (sunburst pictured on your 9_9_10 post) is a trait I have enjoyed over the years as much as it’s electric sound. It’s important too because honestly 80% of my 335 playing hours have been at home by myself. The sound is musically rich enough to stand on its own when playing for your own ear or another ear within a few feet. If my son sits down with his acoustic guitar then of course I have to get my amp and plug in. The original bridge and nylon saddles are long gone and the current steel bridge with .011s contribute their distinct signature to the guitars sound. I try to imagine how the wood effects the amplified sound. It must somehow influence and add in its own distinct harmonics to the strings vibration. By the way it’s hard to imagine a Les Paul louder than a 335 but or course you play enough guitars to have found one.

  2. OK Guitars says:

    I have actually heard a few Les Pauls that are certainly as loud and probably slightly louder than the least resonant 335. On average, however, they aren’t even close. The range is pretty surprising, however.

  3. Chris W. says:

    Along the resonant/resonate lines…. An engineer’s pet peeve is the damping/dampening mix-up. Damping is constraining vibration, dampening is wetting. The latter is used so often for vibrations that it is almost considered correct, but it’s a case of a definition bending to popular misuse. To be fair though, dampening a guitar would probably damp the sustain 😉

  4. OK Guitars says:

    OK, I fixed it-mea culpa. It’s a little like floundering (thrashing about, struggling) and foundering (sinking). It’s used incorrectly so often that nobody even uses foundering any more. Your business can flounder or it can founder-as a result of floundering, I suppose but your boat can only founder (unless you’re bottom fishing, in which case, I suppose you could be “floundering” in your boat while it founders). Let me ask you this, Chris, since you’re the scientist, how does the resonant quality of a guitar get through the pickups if its the disturbance of the magnetic field that makes the sound. Shouldn’t, logically, a 335 sound just like a Les Paul and even a 175? How does the moving air of a full hollow body affect the tone that gets to the pickups?

  5. Chris W. says:

    It’s the way the body interacts with the strings. Some frequencies are accentuated (resonance), some reduced (damping). The sound envelope also changes (ASDR) by the body type. The body affects the complex harmonics of the strings themselves, affecting frequency distribution as a function of time. This is why one guitar has a sharp trebley attack that decays quickly and warmly, while another rings like a bell, evenly as it decays. This effect on the strings is what is reproduced by the pickup. Of course the acoustic tone is the sum of the air vibrations caused by every resonating part of the guitar, and the magnetic pickup response is only an approximation of this sum of resonances. The same problem exists with acoustic guitars too, which is why any studio worth it’s salt records acoustics with microphone(s) spaced a few feet from the guitar. The best contact mics, piezos, or close mics won’t achieve the sound that the player hears, but only a small sample of a specific part resonating. On the other hand, I wouldn’t want my 335 to sound exactly like it’s acoustic tone, only louder.

  6. OK Guitars says:

    Our resident scientist/wizard/nerd really needs his own blog as a geek magnet for the site. Feel free to submit articles any time, Chris. I’ll give you your own little corner. Sort of like Bullwinkle’s Corner on the old Rocky and his Friends (later, the Bullwinkle Show). …hello culture lovers… today’s poem is “Wee Willie Winkie”…

  7. zindra says:

    My 1987 ES-175 has as much glue on the kerfing as the one you pictured. I bought it used and didn’t notice it until a close inspection at home. It has a nice tone but a bit honky, not really smooth, sometimes I get mad at it and blame the extra glue for that! My experience with other ES-175s though is that the more resonant and light is not always the better, some are great unplugged but don’t cut it when plugged, go figure. Is it very commmon to find Gibsons with so much glue? I am sort of relieved to find out it wasn’t a refinish.
    Thanks.

  8. OK Guitars says:

    Yep, tons of glue even in some of the best ones I’ve had. These are mass produced guitars. The number one goal was generally profits– not making the world’s best guitars. The high end archtops were better made than the 335s and 175s. If you get the opportunity, take a look at an ES-5 from the era or a Super 400 or a Tal or a Kessel. You won’t see so much glue.

  9. Burntguy says:

    Glue is stiffer and stronger that wood, both the brown hide glue and the yellow glue pictured wouldn’t contribute to any damping of vibrations. Don’t confuse yellow glue and white glue, carpenters yellow glue or aliphatic resin dries harder than wood, white hobby glue like elmers is polyvinyl acetate and remains flexible after drying. Actual strength of joinery comes from maximum contact of the mating surfaces being glued, gap filling with wood glues can fail from weakness.

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