| Author | Message | ||
| jazzyvee
Senior Member Username: jazzyvee Post Number: 4498 Registered: 6-2002 |
I've just been reading FC's thread about weight of basses and saw a picture of a Sadowsky with tone chambered body. It reminded me of a thought I had ages back about pickup movement. I understand that the body of a bass including the neck moves when a string is plucked and has an affect on the movement of the vibrating string and hence it's movement across the pickup magnetic field, which then impacts on the signal output from the bass. However I've often wondered if there is a significant input to that scenario from the pickup which would also be vibrating from the movement of the body and hence producing a moving magnetic field that would induce it's own signal as it moves relative to the string. This would presumably be different in a solid body to a hollow or chambered body and again different if it was fixed to a scratch plate of varying materials or to the body of the guitar. It first came to mind when I had alembic pickups put on my strat and mounted from a maple scratchboard. I noticed it had more of an acoustic guitar component to it's sound than my Orion guitar and that got me wondering where that difference came from. I'm just curious as to how significant this effect is and is it something designers think about when considering the construction of an instrument. | ||
| sonicus
Senior Member Username: sonicus Post Number: 4165 Registered: 5-2009 |
Jazzyvee , Yes ! Absolutely . The location of the pickup will make a profound effect. I have heard bass's with moveable pickups and the location and the results from variations of the location is remarkable. | ||
| edwardofhuncote
Advanced Member Username: edwardofhuncote Post Number: 346 Registered: 6-2014 |
There's a remarkable difference repositioning the rotating pickup on Rick Turner's Model One instruments, both basses and guitars. (which by-the-by are an acoustic chamber) Kind of a mix of what (I think) you're talking about jazzy. Funny you posted this when you did - I was just thinking about this yesterday after one of those early Model One basses popped up for sale. | ||
| elwoodblue
Senior Member Username: elwoodblue Post Number: 1602 Registered: 6-2002 |
I'm pretty sure jazzyvee is asking about how the vibrations that the pickup receives (with differing mounting systems) from the body/guard/assembly might add and subtract to the final output ...given any fixed position. I bet Leo (and other makers) knew how a single ply guard differed tonewise from a 3 ply guard.Also which springs work better than others to isolate them from the body vibes. Lots of small things that players have the luxury to not think about ;) | ||
| davehouck
Moderator Username: davehouck Post Number: 11746 Registered: 5-2002 |
I too think that Jazzyvee is asking about the difference in tone between, for instance, having the pickups mounted to the body and having them mounted to a scratchplate. Generally, in an Alembic instrument (there are exceptions), the pickups are tightly suspended between the heads of two bottom screws and two top screws, and all four screws are mounted directly in the body, which is vibrating. When pickups are mounted on a scratchplate, they lose that direct connectivity to some degree. The scratchplate is connected to the body with screws; but usually the scratchplate is made of different material than the body, often plastic. I didn't spend much time on this, but I did find an article who's writer thinks that mounting directly to the body results in more "resonance". | ||
| 5a_quilt_top
Senior Member Username: 5a_quilt_top Post Number: 519 Registered: 6-2012 |
Looking at it very simplistically (which I have to do because I'm not a technician...) - a pickup is a microphone. I think that we can all agree that mic placement in a studio relative to the room and a mic's proximity to the amp can have a huge affect on recorded tone. Even the angle at which the mic is placed can affect it. Experienced vocalists routinely manipulate microphones to enhance the tonal quality of their singing. Using that logic, pickup location / placement (including distance from strings) on an instrument can be just as critical to obtaining a desired tone. It's been said that Van Halen and Fender evaluated 80 prototype pickups prior to settling on the specs for the Wolfgang pickup. They then experimented further with placement on the guitar body. He has said that mounting the pickup directly to the body is critical to obtaining the tone he wants and that variations in placement of even fractions of an inch one way or another can have a profound affect on the presence of the harmonics. I think a pickup mounted directly to a resonant guitar or bass body would absolutely be affected by the vibration (movement) when the strings are set in motion. Since the pickup is the instrument's microphone, it's "voice" or tone would be affected. | ||
| gtrguy
Senior Member Username: gtrguy Post Number: 872 Registered: 9-2004 |
Not really... | ||
| jazzyvee
Senior Member Username: jazzyvee Post Number: 4499 Registered: 6-2002 |
Thanks guys as always, interesting responses. ElwoodBlue you have sussed me correctly I was interested if the vibrating pickup would add anything to the tone. In an extreme example if I could move the pickup at 440hz over one of the strings without moving the strings I would expect to see 440hz on an oscilloscope connected to the pickup. So from that I would take that a pickup vibrating due to the body it's fixed to would indeed provide some signal output from the guitar. How significant this is, is my question and would this signal provide an acoustic component since it is being moved by the body and not the string directly . :-) | ||
| gtrguy
Senior Member Username: gtrguy Post Number: 873 Registered: 9-2004 |
More importantly would be the magnetic effect of the field slowing down the string vibration and decreasing sustain. Sounds like what you are talking about is what the EBow can do, and there are sevaral people using them on bass with amazing results (you can see them on YouTube). https://www.youtube.com/watch?v=OAOu9sg5RFc | ||
| mario_farufyno
Senior Member Username: mario_farufyno Post Number: 1100 Registered: 9-2008 |
A Pick Up senses string movement, not to sound, as affects its magnetic field while vibration gets closer or farther from it. So we could expect some interference if a PU also moves, but in a opposite phase to the string. But there is a catch, lower harmonics and fundamental are produced by large amplitude swing of a string and may be this prevents tiny moves caused by the scratchboard from affecting them (imagine that two opposite signal off phase that almost doesn't cancel each other because one is so weak that main signal prevails). If that sounds reasonable, we could expect that just upper harmonics could be affected, since they are produced by faster and smaller vibrations. But is also true that PUs can't reproduce higher frequencies due to its own nature (electro-magnetics inductors - that is what PUs really are and what makes them able to convert movement of a metal string into electricity - also acts like a low pass filter). Notice that smaller coils cut frequencies in a higher point and that is why Alembic's low impedance PUs are more open sounding. So may be those PU movements could indeed interact with the string, but may be we can not hear it happening, or because it is too weak or because it can't be converted as an audio signal. I'm trying to figure this out although I'm aware that a hollow body will affect the string movement's nature and all its harmonic content and this will be clearly noticed by the PU (but this relates more to how mass and stiffness can change mechanical motion transferences between the string and bass body). | ||
| bigredbass
Senior Member Username: bigredbass Post Number: 2372 Registered: 9-2002 |
I'm with Mario, mics and pickups are two very different things. I also agree with EVH, I way prefer his (and Alembic's) method of screwing them solidly to the body. I've seen no end of Gibsons where the humbucker rolls around in those spring mounts like one of those floating-gimbal compasses on a ship. Maybe it doesn't make any difference, but I really don't like it. Just to make this even more aggravating (as pickups and strings are a truly black art if there ever was one), besides the vagaries of the body and hardware on the pickups, I've always wondered doesn't the magnetic field extend in all directions and not just under the strings? Joey | ||
| jazzyvee
Senior Member Username: jazzyvee Post Number: 4500 Registered: 6-2002 |
Well to add something to your last point Joey, when I went to the alembic meet a couple of years ago and collected my S2 bass, Ron was answering some of my questions about his basses and I recall him telling me that part of what he does when calibrating the Series basses is to deal with effects of the magnetic fields and little currents that are induced in and around the the metalwork on the bass when its being played. | ||
| lbpesq
Senior Member Username: lbpesq Post Number: 6058 Registered: 7-2004 |
And to add yet another twist: If we are considering the minute (mi - noot, as in small, not a unit of time) pickup movement in relation to the body, then should we not also consider the movement of the player? What effect does it have on pickup movement when the player jumps around or is otherwise physically active (ala Pete Townsend) as opposed to the statue-type player? Bill, tgo P.S. I personally believe the differences being discussed are so minimal as to have little if any effect on tone that a listener can detect. | ||
| sonicus
Senior Member Username: sonicus Post Number: 4176 Registered: 5-2009 |
Might I suggest an actual experiment using top of the line spectral test equipment such as a nice RTA ( real time analyzer) to test for actual spectral differences. A test guitar body would be rigged with various different pickup mounting systems . The same pickups would be mounted on that test guitar body each separate test in a different method and played picking the guitar identically . Next ; just look at the spectral test results and the actual numbers ! Wolf | ||
| gtrguy
Senior Member Username: gtrguy Post Number: 874 Registered: 9-2004 |
OK, I'll really add some twisted tiny thoughts. In WWII USA made magnetic torpedoes that did not work. One of the reasons (they discovered) was that magnetic fields around a ship changed size and shape as they got closer or farther from the earth's equater. | ||
| davehouck
Moderator Username: davehouck Post Number: 11750 Registered: 5-2002 |
So I'm guessing we'll have to put Wolf's test guitar on a ship in the ocean and sail it towards and away from the equator, while Pete jumps around precisely windmilling the same power chords with each change in mounting configuration. Can we wait until hurricane season is over? | ||
| sonicus
Senior Member Username: sonicus Post Number: 4180 Registered: 5-2009 |
 | ||
| gtrguy
Senior Member Username: gtrguy Post Number: 875 Registered: 9-2004 |
Just do it on a submarine!! | ||
| gtrguy
Senior Member Username: gtrguy Post Number: 876 Registered: 9-2004 |
I also think it explains why Bob Marley's old les paul jr sounded the way it did! | ||
| lbpesq
Senior Member Username: lbpesq Post Number: 6061 Registered: 7-2004 |
I believe the pickups in Bob Marley's Gibson were subject to a rastaman vibration. Bill, tgo | ||
| jazzyvee
Senior Member Username: jazzyvee Post Number: 4504 Registered: 6-2002 |
Groan...... :-) | ||
| elwoodblue
Senior Member Username: elwoodblue Post Number: 1607 Registered: 6-2002 |
I recall someone here had a decent analyzer... old good thread | ||
| sonicus
Senior Member Username: sonicus Post Number: 4186 Registered: 5-2009 |
I own a GOLDLINE DSP30 RM RTA . I also have an old White Instruments Model 140. My Rane RA27 works but is not expected to be as sensitive as the Goldline DSP30 RM and the White Instruments Model 140 is , The Old Fellow , but "Built to Last " | ||
| sonicus
Senior Member Username: sonicus Post Number: 4188 Registered: 5-2009 |
The one @ Alembic most likely surpasses mine BUT This one is way cool too ! http://www.rohde-schwarz.us/en/product/fsvr-productstartpage_63493-11047.html Yummy ! | ||
| sonicus
Senior Member Username: sonicus Post Number: 4192 Registered: 5-2009 |
OH. look! __here's one on sale on eBay [eBay link] Such a deal. (Message edited by adriaan on May 19, 2015) | ||
| bsee
Senior Member Username: bsee Post Number: 2731 Registered: 3-2004 |
I would expect that a moving pickup would be akin to using different woods on the instrument. If you were to attach a string at either end to an infinitely dense and immobile object, you'd get the perfect vibration of the string. To me, this was close to what I got when I played a neck-through Modulus many years ago. The impact of different woods on tone occurs when those woods vibrate in characteristic ways to absorb some frequencies of the string's vibration. Since the pickup is detecting the relative movement of the string, any movement of the pickup will impact the output. If the pickup could be made to move with a particular frequency, then it could act as a filter centered on that frequency. If the phases were in sync, the pickup should attenuate that frequency. On the other hand, reverse the phase and that frequency should increase in magnitude. The reality is that you are unlikely to get a consistent vibration of your pickup and any movement will have an impact on all frequencies. The more significant the movement, the more significant the impact on tone. With tone woods, their impact on the output will often be a positive one. I suppose a little positive impact is possible from serendipitous pickup movement. Personally, i'd rather have it locked down to the instrument. After all, whenever I am looking at a bass to consider buying it, the very first thing I do is play it unplugged to see what sort of natural vibrating tone it has. If I like that, then wouldn't that be what I want to amplify? -bob | ||
| elwoodblue
Senior Member Username: elwoodblue Post Number: 1635 Registered: 6-2002 |
Everything you say makes clear sense bob ...and surely it's not a simple subject. Since you asked the question about what is heard unplugged...My thinking is that the vibrations heard through the air (and maybe bone conduction), are the inverse of what the pickup reproduces as the first wavelengths travel up the string. The vibrations get complex soon , but it could be a mid heavy acoustic tone would translate to a mid scooped amplified tone . I like those modulus necks too.Especially with really good strings, the fingers really come into play more as the gatekeepers of Tone. |
