Luthier As Synthesist

[László]

I posted this on Vintage Rocker, but thought I'd post it here because the PRS folks are more expert than I am. This hasn't even risen to the level of a theory. I'll call it a postulate:

As some here know, I'm heavy into studio work that involves a lot of synthesis. Most synthesizers create their sounds by taking a waveform (whether that's caused by oscillators or samples, etc.) and modifying the waveform with subtractive filtering. I'm used to creating sounds by using these filters, and after 25 years of working with them, I know how to create sounds from scratch, what the filters do, etc. Bottom line, I'm a listener, and a tweaker, when it comes to audio. I do a lot of sound design, and I think I almost understand it!

Luthiers, working with woods for centuries, have learned how to alter the waveform in similar ways, but they don't use the same terminology. For example, a hollow body guitar is just a big resonator that accentuates and removes certain frequencies and partials like the resonant filter on a synth.

On a subtractive synth, the filters alter sound by subtracting from what's in the waveform. There are also filters that cause a resonance effect to emphasize a certain part of the waveform but all it's really doing is amplifying one part of it, not adding something. This subtraction actually creates different partials or harmonics to stand out, to disappear, and so on, thus changing the timbre of the sound coming out of the synth. This is modified by ADSR envelopes and low frequency oscillators to give the sound some movement. The ADSR (attack, decay, sustain, and release) also play quite a large role in the note played. The ADSR envelope of a piano with its fast attack, short decay, long sustain, and immediate release is one of the things that our ear uses to differentiate that sound from, say, a violin at the same pitch, with its long attack, long decay, short sustain (after the bow stops moving) and release.

The filters don't ADD anything to the waveform. They do their work by removing certain harmonics, partials, etc.

I think the woods (and metal parts) operate in the same way on the vibrating string, and in the case of hollow bodies, on the resonating sound. These differences between the filtering job the species of woods do give us the sense that certain woods are "brighter" or "darker," etc. It's similar to a synthesist deciding between a Moog filter and a Waldorf filter.

After having various PRSes and other guitars over the years, with various kinds of woods, fingerboards, trim and what-have-you, I'm going to postulate that the different pieces, woods, parts, bits and bobs change the sound of the guitars by means of subtraction, not addition (unless a metal part is rattling), much like a synthesizer's filters. The problem is that I can't test this scientifically; I've only been able to use my ears listening over the years to my own instruments for long enough to understand the sounds they produce. Still, I think it may be worth thinking about.

There are those who say that wood type doesn't matter on an electric guitar. I don't believe that. Our guitars sound different from one another for a reason. And changing the woods does give one a different sound. Just play a DGT Standard and a DGT maple top, and you'll understand that. In fact, no two guitars sound identical, and every one of us has experienced that when we go guitar shopping.

Example: Folks say that an ebony fingerboard is brighter. Well, no. Carefully listening, I think what an ebony board does is filter some of the midrange allowing the lower and higher partials to stand out. We hear this as brightness and a clearer pick attack, with maybe more string-to-string definition because there's fewer midrange partials (that we hear as "complexity") happening. Just as with a filter on a synth! We're not really hearing more high end. In fact, I think that rosewood may actually be less of a filter from low to high end. And there's faster note decay with ebony; it's marginally less than RW, seems a titch longer than maple, i.e. the ADSR filter is set a little differently.

Again, this contributes to the clarity of chords. This comes about because of the filtering properties of the wood, not the additive properties. In fact, it's obvious to me now why jazzers and classical musicians usually have ebony boards on their instruments: they want the articulation that the ebony helps them attain. They don't need big, sustainy chords, they need shorter and less chunky stuff that decays more quickly so they can get more clarity from chord melodies, fast single note runs, quickly change inversions without muddiness, etc.

It's my thinking that possibly maple tops filter the natural resonance and sustain of mahogany. Mahogany rings when tapped, maple does not so much. It's my postulate that what a maple top is doing is not adding brightness to the signal, but removing and damping the resonances of the mahogany just like a filter. The result is the removal of some midrange partials, changing the ADSR envelope, and we hear it as accentuation of the brighter partials that are already present in the waveform. This filtering/damping improves the articulation of the notes, but takes away some of the growl. And that's great for certain sounds we need, not so for others!

This may be why f'rinstance Chris' demos of the DGT Standard sound so chunky and the DGT maple top sounds a little more articulate on the top end.

Anyway, I'm not a scientist, just a synthesist, and these haven't even risen to the level of theories. Just up for discussion. Nor have I scratched the surface in this post, it's just something I've been thinking about for the last few days. When Paul Smith and company sit around designing guitars, they're synthesists!

I'm not, repeat, NOT trying to convince anyone this theory is correct, just stuff to discuss and think about.

 

[swede71]

I very much believe in what u say here.I changed the PRStrem brassblock to a steelblock and noticed a tighter sounding frequency spectrum,not brighter as most thinks.I have for many years tried to avoid the pickupswapping so common and concentrated on the things u talk about.Not knowning any of the technical terms,just gut feeling.

 

[László]

I very much believe in what u say here.I changed the PRStrem brassblock to a steelblock and noticed a tighter sounding frequency spectrum,not brighter as most thinks.I have for many years tried to avoid the pickupswapping so common and concentrated on the things u talk about.Not knowning any of the technical terms,just gut feeling.

It's interesting to think about and experiment with this stuff, isn't it? I'd say most of it has been intuitive over the centuries, just as you have done.

 

[swede71]

I call it my Fender filter .From my love of the Fender Stratocaster,the steelblock a big factor to the stratsound.Does this make my PRS guitar sounding like a Fender strat?Nope,it still sounds like a PRS with little difference in the attack and the midrange character.

 

[CHARISMAFIRE]

DEEP, VERY DEEP. All I really know is what tones I like, and those I dislike. If I was eating soup and it was missing something, I would notice. If the soup had too much of something, I could tell. I definately think that you are on to something but.......everyone had different tastes in tonal soup! So, the only formula that is perfect is the one for YOU. I owned an original Ibanez Jem7V with the alder body, and real ebony fretboard. The tone was amazing! Now go to a music store and play one of the new ones with the basswood body, and rosewood fingerboard....its like the soup without salt ( a little cold too ). Does that automatically mean that a PRS made with these ingredients will sound great? Of course not. I think mahogany and rosewood is magical on a PRS. Far too many variables to be scientific, especially the subjectivity of "tone" itself. Personally, after conversing with you extensively about my Angelus PS build, and reading some of your posts, PRS should employ persons like yourself in their research and development dept to test some of these working theories. So many factors though: finish, wood, pickups, glues, construction, etc., heck even strings! How many times has one swaped the pickups, or even simply readjusted the pickup's height, and had a reborn gtr. Like I said, I just know good when I hear it. I think we should ever strive to crack to tone code, but I feel that ultimately it will always be a little trial and error. Often people with kids, and others buying their first gtrs ask me which one to purchase. I ALWAYS tell beginners to let me peruse the pawn shops with 100 bucks and find them one. My meaning is that we who are experienced know that no two gtrs are the same. So to say for instance:" get a Gibson, or a Alvarez " would be grossly misleading, since maybe one out of twelve might somehow sound completely magical no matter what you spend. It is so hard to put a finger on it. I can show you a Yamaha classical right now that with your eyes closed sounds like a 5000 dollar guitar! It cost 150 bucks. The way i see it, all our theories are like trying to fly to the moon without a computer. We do however, know enough to get pointed in the right direction, and sometimes, we hit the target. Thats just the way I see it man......don't stop though because the obvioius reality to me is that gtrs have been evolving for the better, not the worse. Thanks...............

 

[veinbuster]

Interesting, and I think it has much merit. There are a couple local (Toronto) luthiers that would agree with much of it. Interestingly the two seem to come from very different angles. Grit Laskin seems to be very much on the arts side of the coin in his approach and David Wren is definitely on the scientific side - David records many of his thoughts on his web site discussing woods and bracing and measuring and moving bits to get the results he wants. It makes for very interesting reading and isn't far off from your populations on some matters.

Grit, however, is the guy I would go to if I wanted an acoustic to do certain things, but had no idea what to ask for to get the right result.

 

[László]

It's funny, a couple of the guys over at VR pointed out that Paul Smith has made some comments indicating that he feels that the process is subtractive, so he's obviously got this concept in his thinking, and is far more astute than I will ever be.

I was unaware of this, since I was thinking along the lines of synths with oscillators, something I'm more familiar with. Similar to the string being a substitute for the electronic oscillator, and the woods taking the role of the subtractive filters and other operators, such as LFOs, ADSR envelopes, etc.

I'm actually relieved that folks don't think I'm crazy! Or at least, that my idea isn't crazy.

 

[kingsleyd]

I'm actually relieved that folks don't think I'm crazy! Or at least, that my idea isn't crazy.

I think you should post it in the "Small Company Luthiers" forum on TGP. I'd love to see what some of the builders who hang out there have to say... ...I know Terry McInturff would agree and probably write half a novel in response, LOL!

 

[Brewer]

Very interesting, Les. Some random thoughts...

I think it is a multi-part issue. What you are saying might certainly be true with acoustic guitars (it seems quite logical, in fact), but I think that with electric guitars, the vast majority of what you hear comes from the pickups, other electronic components, and the amplification you choose. So in a manner of speaking, the wood matters much less on an electric guitar because it is a much smaller component of what creates the sound. Obviously, having a wood that produces good sustain is important, but aluminum and other metal guitars sound very much like their wood counterparts even though the properties of metal and wood may be quite different.

Of course it is possible that the configuration of the instrument might have more effect on the sound than the material used to construct it. A hollowbody might make more drastic changes to the sound than the materials used to construct it.

The subtractive filtering idea is intriguing. With a synthesizer, I assume you would start out with a broad spectrum wave and remove bits of it through filtering. I suppose there is no guarantee that a guitar would start out with a broad spectrum wave, so perhaps it might be additive in some cases?

Thanks for posting this. Great topic.

 

[László]

Very interesting, Les. Some random thoughts...

I think it is a multi-part issue. What you are saying might certainly be true with acoustic guitars (it seems quite logical, in fact), but I think that with electric guitars, the vast majority of what you hear comes from the pickups, other electronic components, and the amplification you choose. So in a manner of speaking, the wood matters much less on an electric guitar because it is a much smaller component of what creates the sound. Obviously, having a wood that produces good sustain is important, but aluminum and other metal guitars sound very much like their wood counterparts even though the properties of metal and wood may be quite different.

Of course it is possible that the configuration of the instrument might have more effect on the sound than the material used to construct it. A hollowbody might make more drastic changes to the sound than the materials used to construct it.

The subtractive filtering idea is intriguing. With a synthesizer, I assume you would start out with a broad spectrum wave and remove bits of it through filtering. I suppose there is no guarantee that a guitar would start out with a broad spectrum wave, so perhaps it might be additive in some cases?

Thanks for posting this. Great topic.

I think what happens is that the string is the starting point of the waveform, an oscillator if you will; the string itself gets operated on as it vibrates by interaction with the wood's vibrations and filtering effect The pickups thus "reproduce" a sound that is already filtered. I have the word "reproduce" in quotes, since guitar pickups aren't exactly hi fi instruments like a good microphone, they color the sound a lot.

It's probably true that the electronics play a big role. However, all you have to do is play, say, a DGT Standard and then a DGT Maple Top with the same pickups, into the same amp at the same settings, to realize that the woods play a very significant role in an electric guitar. I can't quantify it as a percentage, except to say that an older SAS sounds different from an older McCarty, though both used the same McCarty pickups. And even with an electric guitar, a maple fingerboard sounds different from a rosewood fingerboard. This is true on Strats, it's true on PRSes, and it's true on other makes.

I'm honestly not sophisticated enough to know whether there's an additive effect; additive synths are fairly mysterious beasts, and are actually kind of rare because a tremendous amount of processing power is needed to create the many. many partials that make what we call overtones happen. In contrast, a subtractive synth starts with a complex waveform with partials. In the days of hardware synths, the only real additive synth on the market was a $17,000 beast, and as a result, the maker didn't survive very long as a company.

So my experience with additive synthesis is less, although I do have an additive software synth that I fool around with from time to time.

 

[kingsleyd]

I think it is a multi-part issue. What you are saying might certainly be true with acoustic guitars (it seems quite logical, in fact), but I think that with electric guitars, the vast majority of what you hear comes from the pickups, other electronic components, and the amplification you choose. So in a manner of speaking, the wood matters much less on an electric guitar because it is a much smaller component of what creates the sound.

Well... ...yes and no. As Les said, hold the other stuff (pickups, electronics, cables, any other signal-processing, amp, and speaker) constant -- or just leave 'em out entirely, and you'll hear that the wood and components DO have a significant impact on the overall timbre.

At the same time, it's absolutely true that with electric guitar you're dealing with a system that has a lot of elements, each of which plays a role in what eventually hits the air as sound waves.

The subtractive filtering idea is intriguing. With a synthesizer, I assume you would start out with a broad spectrum wave and remove bits of it through filtering. I suppose there is no guarantee that a guitar would start out with a broad spectrum wave, so perhaps it might be additive in some cases?

The vibrating string generates a pretty broad-spectrum wave. In terms of the guitar itself, the only energy that is additive is what the player does to the guitar: picking, plucking, hammering, E-bowing, whatever. But since the amplifier can generate a significant amount of energy via the speaker, those sound waves can energize the guitar, as anyone who has ever played a Les Paul through a cranked Marshall amp can attest. That's really the only other additive element, unless you've got one of those "infinite sustain" pickups which excite the string.

Obviously, having a wood that produces good sustain is important, but aluminum and other metal guitars sound very much like their wood counterparts even though the properties of metal and wood may be quite different.

Depends on what you mean by "very much." Again, I'd argue that if you hold the whole electronics-amp part of the circuit and listen carefully, the guitar itself is gonna sound very different. For a long time I had one Klein Electric with a Steinberger composite neck, and a couple of other Kleins with rosewood necks. I could really hear the difference the composite neck made. For better or worse.

Of course it is possible that the configuration of the instrument might have more effect on the sound than the material used to construct it. A hollowbody might make more drastic changes to the sound than the materials used to construct it.

Hard to quantify that stuff. As Ken Parker likes to say, "It's a LONG equation!"

Hollowbodies do have a couple of significant things going on that really shape the timbre. One is that the body itself is generally far less dense and stiff, i.e., it's more absorbent in terms of energy, so the vibration of the strings tends to dissipate more quickly. On the other hand, they also respond to the energy coming from the speaker(s) at a lower level, so they can sound/feel more dynamic at some playing levels. Within that, you start to experiment with things like solid/carved vs. laminated tops; posts under the bridge to blocks that run from the neck to the base of the body... ...all of those things change the dynamic behavior.

That said, I've done a lot of careful comparing of my different guitars. I have a vintage Les Paul Standard with PAFs that is sort of my "reference guitar." I've had Historic LPs as well as a number of other Les Paul Recipe guitars, real top-shelf stuff, as well as a PRS McCarty that was specifically voiced to sound like an old LP, and ya know what? Of all my guitars, the one that comes closest to matching the timbral spectrum of that vintage LP is this, which is made out of similar woods (and electronics -- the pickups in particular are custom-wound humbuckers that really nail the PAF thing, at least the sound of the PAFs in my old LP) but is a semi-hollow guitar with solid top and back and a 335-style block inside.

 

[CHARISMAFIRE]

Have you watched Paul ( wonka ) Smith's "rules of tone" Youtube vids??? He subscibes to the same subtractive school of thought as you, but from a different source than your synth inspiration. You and he should seriously talk for real. This is a real possibility because i found him to be a very gracious character, and he would be certainly digging your ideas.

 

[László]

Have you watched Paul ( wonka ) Smith's "rules of tone" Youtube vids??? He subscibes to the same subtractive school of thought as you, but from a different source than your synth inspiration. You and he should seriously talk for real. This is a real possibility because i found him to be a very gracious character, and he would be certainly digging your ideas.

I haven't seen that video - I'd of course love to meet Paul and talk with him, as I've been a fan of his work for 21 years!

Maybe next year I can go to Experience. This year...working on an ad project and can't do it.

 

[CHARISMAFIRE]

Take a few and watch part one of that video.....your concept paralells Paul's. I can't make a pilgimage to the chocolate factory this year either, but that day will come. Another bit of controversy for some. Because I take a similar "subtractive" approach to amplifier equalization, both of my PRS electrics are hardwired with no tone knobs. I have always left it wide open on 10 when it was there, and all my signal goes to the amp or effects where I there do my tone tweeking. The tone knob on a guitar only cuts frequencies, and since I never rolled it back, it was useless to me. Without it the result is same as the tone knob fixed on 10 all the time. Without a lengthy explanation, I simply believe that one can't shape sound that isn't already there. Cutting highs leaves natural bass, while cutting bass leaves the natural highs. Ha, Ha, ha, I just said natural highs!......... Hey man, it works for me that's all.

 

[rugerpc]

I have similar thoughts about the tone control on guitars. Every time I play with one, I'm disappointed. It doesn't seem to make any difference what guitar, what pup or combination of pups or whether or not they are tapped, rolling off on the tone control not only reduces the highs, but muddies the mids and dampens the lows a bit as well.

As a consequence, my tone controls seem to always be at '10' as well. I'm very conscious that the tone control is a pot that reduces signal, and I'm an 'all in' kind of guy. I like the various tones different guitars make because of their voicings, materials, etc without stripping things from the signal.

I have never thought of bypassing the tone controls in my guitars, but CHARISMAFIRE has me thinking. I see some experimental soldering in my future.... It would be easy to just jumper around a tone pot without removing it so I could always revert if wanted to or if I intended to sell a guitar (har, har, har, sell a guitar! ) .

edit: I'd be curious how other forum members use their tone controls and why they set them the way they do for what sounds on what songs or genre...

 

[swede71]

Try the Jeff Beck trick,lots of highs on the amp and toneknob rolled down.Eric Johnson use a similar thing but turns off all presence on the amp.

 

[CHARISMAFIRE]

If, and I mean If, I ever left the tone control on another electric, I would try to find a knob that stopped in place on all 10 settings so the thing could be consistantly set and couldn't move while I was playing. The knobs in the place of the former tone controls on my gtrs are now volume controls for the piezo ghost saddles. Some may argue that you still need the capacitor of the tone knob in the signal path because it also cuts some highs even in an inert state on 10. I haven't hade a problem with any excessive brightness without it that I could ever notice. Some say without it its like the tone knob stuck on 11. I say B.S. (baloney sandwich) its like a tone knob stuck on 10. All I know is it works for me, and my entire set up is a no B.S. one. Only someone with the audio engineering equipment to measure such things accurately can settle an arguement like that. I still wouldn't re-install the tone controls though so its moot to me. I have some 2-channel combo amps for small stuff still, but my main rack goes through a multi processor so I can have a pre-programed EQ setting for each different bank. I am replacing my current gear with an axefx2 next week or so, depending on shipping time. I still plan on keepeing my Groove Tubes Trio preamp, and either my BK Butler real tube reverb or my Peavey Valverb reverb or both, which is the true guts of my tone that I doubt any box can recreate. Its going to be interesting to find out though!!!! Hey man no controversy just discussion please.......thats just my opinions and how I like to do things. Remember the first law of music: "Whatever sounds good, IS good". But before there was music......there was tuning up!!!! (Ha,Ha)