Forgive me if this has already been covered, but regarding pickup placement, could someone explain what a "sweet spot" is? Does it have something to do with where the pole pieces are located in relation to the string harmonics?
Would locating the pole pieces directly below the strong harmonics result in a more overtone and less fundamental sound?
Thanks for sharing,
Mike

Forgive me if this has already been covered, but regarding pickup placement, could someone explain what a "sweet spot" is? Does it have something to do with where the pole pieces are located in relation to the string harmonics?
Would locating the pole pieces directly below the strong harmonics result in a more overtone and less fundamental sound?
Thanks for sharing,
Mike

yep...it has to do with where along the string length you get that "sweet" mix of fundimental and the 3rd harmonic...

you see, odd harmonics on a string are the ones that go together to produce that trombone-like sawtooth shaped wave form, that some folks refer to as "growly".

As per your second question, you'll always get more fundimental than anything else, but it diminishes as yougo back toward the bridge...

next to the bridge is where it begins to sound "thin" and "brittle".

For the highest fundimental content, you'd have to put the pickup under the 12th fret...:D

Right: near bridge tends to thin/brittleness, near center has more fundamental.

Wrong: Odd-numbered harmonics only (in a logarithmic power series) produce a square wave, which sounds thin and hollow. A triangle wave is a combination of all harmonics, odd and even, and sounds fuller.

Sweet spot smeet spot.......all fiction to me!

Sweet spot smeet spot.......all fiction to me!

Really? You never studied accoustics, thats for sure. A sound wave is probably the most complex thing I have ever encountered !

Really!? Prove it, build a bass and prove it I bet you can't! The term is coined by companies that are too cheap to use multiple pickups. The term "sweet spot" sounds better than "we are too cheap to put in a pair of pickups so we will do our witchcraft and put a humbucker in the sweet spot and you will be none the wiser" If you believe everything your told that’s pretty sad, insulting me because I don’t is even worse. Oh and by the way its acoustics! And please explain to me what acoustics have to do with a pickup that works via a magnetic field.......:spit:

Thanks for weighing in. Just after I posted this question, I did a search for "harmonics" and found a bucketload of info, including interesting discussions among some of you regarding wavelengths, logarithms, etc., and even a link to a graphic representation of pickup placement (which also generated some discussion). Thanks for an informative three hour session. My head officially hurts!

From what I gleaned last night, and from picking above the existing pickups, I don't want to locate the pickups directly below a harmonic as this will cancel the frequency from the spectrum, leaving a less complex (read: less rich, less full) tone, correct?

BTW, thanks for explaining things in layman's terms here, as well.

Thanks for weighing in. Just after I posted this question, I did a search for "harmonics" and found a bucketload of info, including interesting discussions among some of you regarding wavelengths, logarithms, etc., and even a link to a graphic representation of pickup placement (which also generated some discussion). Thanks for an informative three hour session. My head officially hurts!

From what I gleaned last night, and from picking above the existing pickups, I don't want to locate the pickups directly below a harmonic as this will cancel the frequency from the spectrum, leaving a less complex (read: less rich, less full) tone, correct?

BTW, thanks for explaining things in layman's terms here, as well.

I think what you're talking about is avoiding placing a pickup in a harmonics' node. A couple of problems I can see with this is:

1) Each fret will have nodes with diffferent locations.

2) Depending on the aperture size of the pickup (sensing area) the fact that the pickup is located at a node won't necessarily mean that is doesn't pick up any of the harmonics with nodes at that location.

IMO the dual pickup system is a good solution... sensing the string at two different locations.

Really!? Prove it, build a bass and prove it I bet you can't! The term is coined by companies that are too cheap to use multiple pickups. The term "sweet spot" sounds better than "we are too cheap to put in a pair of pickups so we will do our witchcraft and put a humbucker in the sweet spot and you will be none the wiser" If you believe everything your told that’s pretty sad, insulting me because I don’t is even worse. Oh and by the way its acoustics! And please explain to me what acoustics have to do with a pickup that works via a magnetic field.......:spit:

Ive studied the science of sound, waveforms and psychoaccoustics, I know enough to say that phase coherency is definitely something that will affect a tone. Ever Mic a drum set? I believe it is the same thing when you are cathing the vibrations of a steel string and blending in both pickups. Phase cancellation man ! study and debate if you want. as its been told so many times on this forum, this is just my opinion based on my knowledge of science. I dont believe in God yet most of you will say science undeniably proves he is real..... Peace dude.

Two soapbars centered at the 36th fret. That's sweet-spot for you!

Adjustable for any sweet spot.

http://images.google.ca/imgres?imgurl=http://www.wowmusicalinstruments.com/pictures/sliding_pickup_04.jpg&imgrefurl=http://www.wowmusicalinstruments.com/examples.html&h=646&w=908&sz=90&hl=en&start=1&tbnid=33e1EFM62pDgzM:&tbnh=105&tbnw=147&prev=/images%3Fq%3Dsliding%2Bguitar%2Bpickup%26gbv%3D2%2 6svnum%3D10%26hl%3Den%26safe%3Doff%26client%3Dfire fox-a%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DG

Ok Ok scotty, I have no idea where you got the impression I might have insulted you... no idea. let me explain phase coherency a bit.

A soundwave is like a wave you would find in the water, right, it goes up and down, up and down, when the wave is above the reference point, it is called compression, when it is below, rarefaction, this is everything you need to know to understand Dynamic Mics as well Speakers, condenser mics are a bit different since they work with electrostatic. but the idea is still the same, difference in mollecules in the air create what we hear, get it yet? so if the same wave is 'catched' at the same time during the compression, and the rearfaction, it creates phase cancellation. just like if you would throw two rocks in the water, the two waves created by the rocks would cancel, or almost cancel each other out. Its very simple. this is the main problem with recording drums in studio, its very easy to get a poor snare sound because of phase incoherency. and I truly believe its the same thing if you have two pickups getting signals from two opposite sides of the soundwave. does that make sense? now what im trying to figure out, the wave does change length depending on the pitch, 20Hz is 20 cycles in a second where as 100Hz is 100 cycles in a second, or rotations, complete 360 degrees from the reference line. so since the wave does change length, the whole idea of having the two 'peaks' meet at the same time becomes completely pointless, since it will be different if you play the 12th or 17th fret. any input on that?

Yeah... I think...

At any spot you put a pup along the string it will pick up most strongly the partials or harmonics (also in this case, the same basically as "string waves") that have antinodes above the pickup point; it will not pick up at all those partials that have nodes above the pickup point; all others will fall between these extremes.

As far as the cancellations with two pups: these certainly do happen. And the end effect is dependent on the relative amplitudes of each harmonic at the pickup points, and whether they are in phase or 180 deg. out of phase (there's no "slight delay/slight phase shift available, since this is a standing wave).



The bigger issue is that there's no "perfect spot" for a pup. Even if you get rapturous enjoyment at hearing a sound with a particular partials amplitude pattern, that pattern is totally different for any other fretted note.

There can certainly be a spot that sounds great to many people for many fretted notes, but there can be no mathematically provable / physics provable "sweet spot."

Strictly speaking the water wave you're describing is transverse and does not have compression and rarefaction like a longitudinal wave, it's normally called a crest and trough. The rest of what you're talking about is difficult to understand and I'm not really sure but I think you're asking a question. If you are could you restate it?

And, what pilotjones said. I believe that trying to mathematically determine pickup locations based on is a pointless exercise.

Thats what im thinking too, I think the distance between both pups is extremely important, but the placement is only about how the pickup sounds. This is probably what the manufacturers mean by 'sweet spot', in which the pups are distanced properly one from another.it is a pointlees exercise indeed, I am not asking a question, the water wave is the same idea as a sound wave, just the names are different, when the water is calm and it doesnt move, its the same as the reference point on a sound wave right? and it reacts the same way too !

Thats what im thinking too, I think the distance between both pups is extremely important, but the placement is only about how the pickup sounds. This is probably what the manufacturers mean by 'sweet spot', in which the pups are distanced properly one from another.it is a pointlees exercise indeed, I am not asking a question, the water wave is the same idea as a sound wave, just the names are different, when the water is calm and it doesnt move, its the same as the reference point on a sound wave right? and it reacts the same way too !

I've never seen sweet spot used in reference to basses with two pickups, always with one pickup or two pickups sandwiched next to each other. My point about the water and sound waves you were referring to is that they are different kinds of waves, one is transverse (water one you described) and the other is longitudinal (well arguably the water wave is a combination of transverse and longitudinal waves and is different from either). They can be analagous, but I was just nitpicking terminology.

well, now, I'm gonna have to agree with Jack Handy on this one and add that I think you're all in agreement. In physical terms Geoff and Pilot have answered my question directly and simply (thanks), but I realize now that my question in practical terms was limited in scope.
Though I did consider the changing wavelengths due to fretting, I thought perhaps there was a mathematical determination as to where these might "average out" to get the most "musical" output without losing the "fundamental" to a more pronounced overtone (quotes around subjective terms). I didn't think of pickup size and magnetic field in terms of harmonic gathering, only volume. And since the perceived fundamental is no more than a collection of harmonics (the true fundamentals on bass being out of our hearing range) the sweet spot may well be a moveable feast and purely subjective.

well, now, I'm gonna have to agree with Jack Handy on this one and add that I think you're all in agreement. In physical terms Geoff and Pilot have answered my question directly and simply (thanks), but I realize now that my question in practical terms was limited in scope.
Though I did consider the changing wavelengths due to fretting, I thought perhaps there was a mathematical determination as to where these might "average out" to get the most "musical" output without losing the "fundamental" to a more pronounced overtone (quotes around subjective terms). I didn't think of pickup size and magnetic field in terms of harmonic gathering, only volume. And since the perceived fundamental is no more than a collection of harmonics (the true fundamentals on bass being out of our hearing range) the sweet spot may well be a moveable feast and purely subjective.

The fundamental of every note on every bass I've ever played is well within out hearing range. The only exceptions I've seen are basses with low C# strings which have about 3 notes that are sub 20 Hz and arguably not audible. A 4 string bass tuned EADG has a lowest frequency fundamental of 41.2 Hz which would only be inaudible to someone with considerable hearing damage and even a low B is a very audible 30.9 Hz.

Ok Ok scotty, I have no idea where you got the impression I might have insulted you... no idea. let me explain phase coherency a bit.

A soundwave is like a wave you would find in the water, right, it goes up and down, up and down, when the wave is above the reference point, it is called compression, when it is below, rarefaction, this is everything you need to know to understand Dynamic Mics as well Speakers, condenser mics are a bit different since they work with electrostatic. but the idea is still the same, difference in mollecules in the air create what we hear, get it yet? so if the same wave is 'catched' at the same time during the compression, and the rearfaction, it creates phase cancellation. just like if you would throw two rocks in the water, the two waves created by the rocks would cancel, or almost cancel each other out. Its very simple. this is the main problem with recording drums in studio, its very easy to get a poor snare sound because of phase incoherency. and I truly believe its the same thing if you have two pickups getting signals from two opposite sides of the soundwave. does that make sense? now what im trying to figure out, the wave does change length depending on the pitch, 20Hz is 20 cycles in a second where as 100Hz is 100 cycles in a second, or rotations, complete 360 degrees from the reference line. so since the wave does change length, the whole idea of having the two 'peaks' meet at the same time becomes completely pointless, since it will be different if you play the 12th or 17th fret. any input on that?

If this is directed to me to help explain whatever theory you have in your head is, thanks for the effort but your way off base from what the original question was. In bass terms the "sweet spot" is a spot where a SINGLE pickup usually a humbucker is placed to get the "best" sound that a single pickup can get. Since a single pickup will never get the range of sound that two pups can the companies came up with "the sweet spot" to make it more appealing. The term in itself is a load of crap. Sorry... my 2 cents, It doesn’t have nothing to do with acoustics, rocks, water waves, drum mics ect. It has everything to do with marketing.

You're right, Geoff, I stand corrected. I guess I should pay closer attention to what I read.
20 to 20Khz is what I've re-read for normal human hearing range. I'm getting it mixed up with the part where the brain will perceive a missing fundamental frequency given the rest of its harmonic series (which may or may not be off-topic).
Anyway, I think I understand that the "sweet spot" may be located anywhere between the neck and the bridge, depending on what one likes to hear. Methinks I overthink.

If this is directed to me to help explain whatever theory you have in your head is, thanks for the effort but your way off base from what the original question was. In bass terms the "sweet spot" is a spot where a SINGLE pickup usually a humbucker is placed to get the "best" sound that a single pickup can get. Since a single pickup will never get the range of sound that two pups can the companies came up with "the sweet spot" to make it more appealing. The term in itself is a load of crap. Sorry... my 2 cents, It doesn’t have nothing to do with acoustics, rocks, water waves, drum mics ect. It has everything to do with marketing.

Jesus, take the chip off your shoulder.:scowl:

I think Im actually gonna stay off this forum... seriously, Jimbow , youre right. This kind of **** just gets annoying. What the **** is the point?

And, what pilotjones said. I believe that trying to mathematically determine pickup locations based on is a pointless exercise.

Looks like I'm late to the party, but I want to throw my 2 cents in anyways. I have always understood the term "sweet spot" to refer to the traditional pickup placement on either a Precision or Stingray bass. These locations were arrived at experimentally (ie: by placing the pickup somewhere, then seeing how it sounds), not by trying to somehow calculate a "perfect" position based on a modal decomposition of the string's vibration. Many players agree that pickups in these locations sound "sweet," but the locations are by no means set in stone.

I think Geoff hit the nail on the head with his statement above.

Jesus, take the chip off your shoulder.:scowl:

I already have.....I also made my point as well

Good day Gentlemen :rollno:

Wrong: Odd-numbered harmonics only (in a logarithmic power series) produce a square wave, which sounds thin and hollow. A triangle wave is a combination of all harmonics, odd and even, and sounds fuller.

In a rare moment, you're mistaken here. A triangle wave contains only odd harmonics, just falling off even faster (I can't recall the exact rate) and with a different phase relationship to the fundamental. A saw tooth does contain odd and even harmonics (maybe this is a semantic issue?).

If a waveform is symmetrical across the x axis, then it contains no even order harmonics, if it is not symmetrical then it does.

Edit: On a reread, it seems clear to me this is in fact a matter of semantics, instead of trying to correct Peter, I should have just clarified and expanded. Ignoring tone, the content of my post is accurate. http://en.wikipedia.org/wiki/Image:Waveforms.svg aptly illustrates the difference between a few basic waveforms.

Right-o. Sawtooth and triangle are different, as you said. Triangle has an inverse square dropoff, instead of an inverse ratio (power series IIRC) dropoff.

From a tone standpoint, on analog synths you would likely use a square (or adjustable/variable pulse if available) as the basis for a bowed string voice, saw for a brass voice, and a triangle with a touch of pink noise for a flute patch.