Resonance

[mike1762]

I have an almost compulsive need to at least try and understand how/why things work (drives people crazy... sorry).  I've been visiting several bass forums lately and one of the things I keep coming across is posts of people expounding about how wonderfully resonant their ELECTRIC bass is.  I understand the need for resonance in an ACOUSTIC instrument but I don't see that as necessarily desirable in a solid body electric instrument.  I've seen the term filtering used here several times and that makes sense to me (ie. any resonance is as a result of certain frequencies being filtered from the vibration of the strings).  Of course I can appreciate how you can use this property to tailor an instrument for a particular tone, but the implication in much of what I have read is that a poorly resonant instrument is somehow bad.  We actually already had a variation of this discussion in a recent thread regarding body shapes/sizes.  One of you referenced a study done by Eric W. Moon Department of Physics, University of Illinois at Urbana-Champaign.  The results of that study stated: ...Electric guitars transmit their sound through magnetic pickups.  Vibrations are not the most important aspect of an electric guitar?s sound. Actually, large modes of vibration would draw energy from the strings and impede the sustain of notes played on the guitar.
In contrast, acoustic guitars are designed to be played without amplification. Vibrations of the guitar are the way the sound is transmitted....
 
The reason I'm bringing this up (again) is that I recently read a review on a replacement bridge in Bass Player magazine (not sure how old it was).  They stated that the purpose of the (or any) bridge was to transmit string vibration into the body and thus INCREASE sustain.  Furthermore, they implied this particular bridge was better because it was made of aluminum (brass being too heavy to effectively transmit those vibrations!).  I also recently saw an ad for a new Yamaha bass that made similar claims regarding their string thru body design.  Am I missing/misunderstanding something?

[adriaan]

Careless wording there, Mr Moon, mixing up vibration and resonance ...
 
Obviously on an electric guitar/bass you still need a vibrating string to get any tone, the question is how best to transfer that vibration into the instrument, as the actual body of an instrument (even an electric one) determines resonances, which indeed are a major factor in tone. Sympathetic resonance can help sustain, while dead spots stem from having a resonance in the wrong place.
 
Suffice it to say that part of the Alembic design is to use heavy brass hardware to isolate the vibrations of the string from the resonances of the instrument. And while they say that by so doing wood choices become less important, they also say that specific wood choices do have a recognizable impact on tone.
 
Any bit of hardware that is not sitting tight will absorb vibrations (if not rattle along) and so any construction that anchors the hardware to the instrument (like the string-thru-bridge) can be an improvement over hardware that is simply attached to the top of the instrument. And just think of a banjo or a resonator guitar.
 
There is no single truth here - people can apply different approaches to resonance in electric instruments, in order to get the results they want.

[811952]

Stiffness and mass together have the most direct impact on sustain.  
 
The person who wrote the article has no understanding of the physics involved.
 
John

[3rd_ray]

It's hard to describe sound in words, and it's even harder to explain exactly how those sounds are produced. I agree with John that the Bass Player writer had it wrong.  
 
I'm definitely not an expert, but here's my take on it...
 
Look at the energy of a vibrating string. If the string never loses its energy, it will have infinite sustain. So how does a string lose energy? Through the bridge into the body, through the nut or fret into the neck, through the pickup because of the magnetic field, and probably a little just because its vibrating in air instead of a vacuum.  
 
So you have energy that starts out in the string and ends up in a lot of places through a lot of different mechanisms. Changing those mechanisms (bridge, pickup, wood, frets, etc.) changes the sound. The initial energy in the string also depends on a lot of things, like using a pick, finger, or thumb.  
 
I also agree with Adriaan, there's no single approach for making an instrument. So for me, it's enough to understand the basics without trying to go into scientific details. You're better off building an instrument and experimenting to get the best sound. Of course, we can't all do that, so good thing that Alembic has already done this for us!
 
Edit: This all holds true for acoustic instruments, but they rely more on the body to transmit the sound.  
 
Mike
 
(Message edited by 3rd_ray on January 12, 2009)

[mike1762]

Adriaan
 
I missed that... he did mix-up vibration and resonance (or is resonance a type of vibration?)!!!  
 
I had never heard of sympathetic resonance.  It sounds like that is a phenomena (in an solid body instrument) whereby resonance in the body would feedback into string vibration and accentuate certain harmonics via a standing wave mechanism???  Is that right?  
 
If part of the Alembic design is to use heavy brass hardware to isolate the vibrations of the string from the resonances of the instrument, would it be fair to say that Alembic's use of heavy brass hardware, sustain blocks, etc is to minimize resonance of the body?  Should I put in my order for a marble Series I (LOL)
 
It sounds like the 2 extremes are:
1)  Keep the energy in the strings by minimizing resonance of the body.  This would give you the purest tone.
2)  Use the body resonance to generate sympathetic vibrations in the strings.  This would give you a colored tone.
 
This would explain the claim that different bridges (or other pieces of hardware) can change the tone of an instrument.

[adriaan]

Mike, that's pretty much my understanding of resonance. I think the #2 extreme would be the banjo, which gives you just the start of the note and not much sustain.
 
There was a science quizz on Dutch television where they had taken a recording of a melody, and chopped off 25 percent of the duration of each note, from the start of each note. Contestants had three options up-front: (a) you can't make out the pitches, (b) you can't make out the melody, or (c) you can't make out the instrument. Of course (a) and (b) make no sense, but actually it sounded like a hobo, whereas the original recording was of a trumpet.
 
So there's a lot of resonance at the start of the note that lets you recognize the instrument, but not much in the sustaining note that lets you identify the tone.

[white_cloud]

Quite simply every manfacturer claims their products are the best - I wouldnt worry about it too much. Good Pr usually sells infinite numbers of average products when it comes to the musical instrument business! The ammount of difference between most bass bridges is minimal imho. For example Leo Quan badass bridges are an excellent replacement for Fender basses but I wouldnt say they transform the instrument in a jaw dropping way. It is a definite improvement over the cheap pressed steel type though.
 
Resonance is obviously extremely relevant but I believe that the importance of sustain on an electric bass is massively overstated - who really needs huge sustain on a bass?? How many notes do you hold for as long as possible when playing bass in your band??  
 
However, If you were to join Spinal Tap and try to compete with Nigel Tuffnels infinite Les Paul sustain then buy a amp with a volume that goes all the way up to eleven and party on!
 
John.

[adriaan]

John,
 
There is a whole world of music out there that has long bass notes - you may not spend any time in that world, but it's for real. You may even find that you can take music to completely different places if you only add long notes ...
 
It's easy to stop a string from sustaining, but it's a whole different matter to coax a string into sustaining when it wants to stop vibrating. Fernandes used to market a Sustainer that would replace a regular humbucker sized pick-up. There were the E-bow and Gizmo hand-held devices. And of course there is ye olde bow.

[white_cloud]

Yes, I remember the E-bow very well from back in the day when Stuart Adamson (r.i.p) was still with us and playing with Big Country. It was a very interesting sound! There is a definite place for devices of this nature!
 
Hey, you are right, there are no wrongs - I dont spend any time sustaining bass notes for any particularly long periods during any of my performances - and I cant really think of many bass players that I have seen doing so - but each to his own. If you want to sustain notes for as long as possible then thats fine and well!
 
The point I was making is that manufacturers overplay things like massive sustain into their adverts to sell products. The replacement part business is huge and most companies want a slice of the action.
 
I believe that there is a hell of a lot of nonsense out there - there is a certain snobbishness...mine is better than yours because it has blah blah blah - Paul MCcartney, love him or not, didnt stop one day, look at John Lennon, and say John - we had better stop writing some of the most influential pop music of all time - my bass has a bolt on neck and doesnt sustain enough.
 
You catch my drift good people?

[mike1762]

Thanks guys
 
I'm getting a better feel for the Alembic strategy.  Do you agree with this statement:
 
Between the use of low impedance PUPs and the measures taken to minimize resonance of the body, the PUPs are capturing as pure and uncolored of a tone (via vibrations in the string) as is possible.  That tone can then be manipulated in a meaningful way via the electronics.  
 
I think the opposite approach explains why my MM Stingray is often referred to as a one trick pony... the signal that the PUPs capture is already highly colored, thus its hard to do much with it.

[bsee]

Sorry, Mike, I don't think you get it.  The electronics/pickup side makes sense, but not the bit about body resonance.  The instrument has a native tone based upon the woods used and construction.  The guts of an Alembic are about capturing that native tone without coloring it.  
 
The construction itself, though, is about using knowledge of wood properties and construction methods to create an instrument with a pleasing natural tone.  If you just wanted the pure vibrations of a string, you'd make an instrument from granite and anchor it to the planet.  The body wouldn't absorb any of the string's vibration, or virtually none anyway, and you'd have the pure string.  At that point, your choice of string would go a very long way to determining your tone.  Someone might want that, but not me.
 
You want a neck made of stiff and dense enough material to push the resonant frequencies outside of the musical range of the string.  That eliminates dead spots which occur when the instrument absorbs all of the string's energy through resonance leaving nothing for a pickup to detect.  
 
You can go too far, as I believe Modulus did when they offered the TBX line of basses.  That graphite composite neck-through instrument has a very sterile tone to my ears because you are getting the pure tone of the string.  The wood adds by taking away.  Tone coloration comes from the instrument having a naturally uneven frequency response.  Some frequencies get absorbed more than others and what is left determines the tone available to the pickups.  Too much absorption and sustain suffers, but you need some for the instrument to have individual character.  Even a character that kills sustain is a potentially pleasing tonal property in some cases.  It's all about finding the right balance.
 
In short, the wood is designed to allow a tuned string to generate a pleasing tone, and the guts capture it without alteration.

[flaxattack]

i agree with bob- the string has characteristics of its own- the woods add or subtract from that and the pickup amplifies that sound. As for resonance-it's a combo of the above. this is why scarlet sounds different than wolf- different woods
my a string on scarlet will vibrate for over 2 minutes when played open. This vibration goes through the entire instrument in a loop especially on neck throughs. this sound goes through the bridge block and bridge and they transmit and slightly amplify it, which one can hear as a harmonic.
 Again this is because of the wood sandwich. unplugged they also sound a little bit different.
any of this make any sense?
lol
ps- this is also why an open a sounds different than an a on low b at the 10th frett

[mike1762]

Thanks for responding Bob.  I've read a lot of your posts on such issues and you seem to be The Man when it comes to the technical stuff.  
 
You stated:
The wood adds by taking away. Tone coloration comes from the instrument having a naturally uneven frequency response. Some frequencies get absorbed more than others and what is left determines the tone available to the pickups.  
 
Actually that is my understanding of that process.  
 
When you say I don't get it, I assume you are referring to my statement that measures are taken to minimize resonance of the body.  If so, what is the utility in sustain blocks, dense hardware, etc?  Or is your point that one would never want to completely negate the influence of the wood on tone.  
 
(Message edited by mike1762 on January 12, 2009)

[bsee]

You are correct there, Mike, at least in terms of what I was responding to.  It seemed like you were simplifying body construction into the minimizing of resonance for the purpose of capturing the natural tone of the string.  While that may be the goal of some designs, I don't believe that it is the core goal of Alembic's work.  Density, especially through the neck and at the ends of the strings, can add to sustain by increasing the amount of the vibrating energy of the string that remains in the string.  That's important to many players, though apparently not all.
 
You're dead on when you say that one would never want to completely negate the influence of the wood.  Well, at least almost never.  I found that out the hard way with the two Modulus basses that I owned.  They only worked for me at all when pumped through some seriously glowing tubes.  Again, to each his own and some may like that pure string tone, it just didn't work for me.  There are just no objective absolutes when it comes to the definition of good instrument tone.  One was flame maple over alder, the other cocobolo over mahogany.  Neither had any woodiness or warmth to their tone.
 
As far as me being The Man, I think that overstates things a bit.  I have been around a while and always try to do my research for things that matter to me.  Spending thousands of dollars on an instrument is one of those things.  Getting a great bass tone is another.  So, I did a lot of investigating.  Now that I have that info in my head, I try to pass it back, particularly when it is a matter just trying to present it in a different way that someone may better understand.  There are, and have been, quite a few people around here who know more about these things than I.  I'd also note that, while I've been through the factory tour, I don't work or speak for Alembic.  When I wrote about what I believe to be their design goals, it is based on outside observation of their results and interpretation of their various postings.  I'm sure that if one did an exhaustive search of this site for info on this topic, you'd find that there isn't much that I wrote that hasn't previously been written.
 
One other note on sustain.  To me, it's one of those characteristics that would be better to have too much of than too little.  There are plenty of ways to reduce sustain or otherwise deaden a vibrating string when a performance calls for it.  On the other hand, there aren't too many performance techniques to increase the duration of a note.  I'll take as much sustain as I can get without losing the woody character of the instrument.  The traditional Alembic neck recipes that mix purpleheart and maple are just about perfect.  Swapping in some ebony in place of the purpleheart pushes it a little further.  I'm not sure what the next step might be beyond that, but I am quite happy with these recipes and see no need to push the envelope any further.
 
-bob

[white_cloud]

Are you guys musicians or scientists???  
 
Maybe its just me - I just like picking up a bass and playing it. If it sounds good...then it sounds good...if I dont like the sound I dont like it! Music does not have to be complicated to work well, i.e. touch people on many different levels - musical instrument construction is exactly the same.  
 
Sure, its great to play a piece of sublime craftsmanship with cutting edge electronics onboard like any Alembic - but there are two sides to every coin. Some of the most sacred basses ever built are early, simply constructed, Fenders that dont have massive inherant sustain or jaw dropping resonance. They simply sound fantastic - like a classic aged fine wine.
 
It has been, correctly stated many times here on this forum that there are a myriad of luthiers/builders making basses with similar (and on a par with) construction techniques used by Alembic. Even Mica admits the Fernandes Alembic copies were, when it came to the aspect of the woodworking, superbly constructed to a level similar to the very basses they were mimicking. So what sets them all apart from Alembic? The electronics? Surely not just the resonance or sustain naturally inherant in the construction! If that were the case why would basses built with a similar type of construction to Alembic not resonate/sustain just as well?
 
I honestly dont believe that Jaco, Jeff Berlin, Percy Jones etc etc lost too much sleep over playing simply constructed Alder bodied basses with a Maple neck that didnt sustain/resonate enough! Sure, they wanted to sound as good as possible but all truly great players know the eternal truth - the most important tone is in the finger.
 
I mean no offence to any fellow club members whatsoever but there seems to be a lot of analytical techno heads here at the club - but we are all musicians and players first...right??
 
John.