2 Pickups distance create phase

[walters]

When having the pickup selector switch in the middle turns on both pickups
and it create phase

What is the theory behind this because the pickups frequencys ADD and notch out frequencys and create phase cancellations

Do u measure the distance between the pickups?

How do u find out what frequencys they "add" or "notch out" at?

The mixing of the 2 pickups create phasing,adding,summing frequencys
but what frequencys ? how do u find out?

 

[Frebnedzo]

Re: 2 Pickups distance create phase

Pretend that the string only vibrates vertically. If the string is moving
up over one pickup and down over the other, and the pickups are
connected in phase (or are doubly out of phase as in a humbucker) then
the string motion is out of phase with respect to the two pickups (up,
and down). This string movement will therefor be attenuated.

Similarly, When the string is moving in the same direction over the two
pickups, that motion will be summed.

So, an easy example of an attenuated pitch with both pickups on.

Choose a point directly between two pickups. Measure the distance to
the bridge. Reflct that distance from the midpoint in the other direction.
Assuming you have reached the fingerboard, then we have just shown
that the first overtone of this pitch will be attenuated.

If you didn't reach the fingerboard, add the original measured length
again. Assuming you have now reached the fingerboard, you are
demonstrating that the second overtone of this pitch is attenuated.

etc.

Theoretically, there is a comb filter effect happenning here, where a
certain range of frequencys is attenuated in certain picup combinations
and that range repeats at pich doublings across the freuency spectrm.

However, since strings actually vibrate in a complex manner, with all
overtone components, you never truly cancel any pitch. Also, vibration
strength is not uniform across the string. Near the bridge, the amplitude
of the low overtones has been comromised. The high overtones didn't
have such a high amplitude to begin with, so sampling the string there
(bridge pickup) is much brighter (lower overtone attenuated because the
string can't move as far).

Fun fact comparing strat and 3 HB Gibson. Strat pickups lie between the
coils of the humbucker. Therefor, for quack tones, using the adjacent
coils on the neck and middle HB SHOULD provide closest strat sounds. (On
the Dimarzio website they recommend inner coils of HB with SC on HSH
style guitar for this reason. Back to the 3 pup Gibson, we ALSO get the
same relationship if we take the coils that are non-adjacent. Going
back to the first paragraph, what we are doiing is playing with that
midpoint between the pickups.

 

[walters]

Re: 2 Pickups distance create phase

Yes the "string distance" from pickup#1 from pickup#2 makes the notches and reinforcements of the frequencys creating a phase shift or twang sounds

 

[Gibsononly]

Re: 2 Pickups distance create phase

Physical placement is a factor as well. The pickups on a LP are placed where the 24th and 36th fret would be, right under the harmonic. If you have a 24 fret finger board it will sound different from a 22 fret due to pickup placement. Optimal placement varies with scale length as well.

 

[walters]

Re: 2 Pickups distance create phase

Are u saying a strat 1954 year is different than a 1956 year from the neck length and this create phase?

If i had a 1956 strat with a 1956 neck the phase from the pickup would be different because of the string length and neck length ?

If i had a 1956 strat with a ""1954 neck" the phase from the pickup would be difference because of the string length and neck length?

 

[Gibsononly]

Re: 2 Pickups distance create phase

Every strat I ever heard of ( although I don't really play them) has a scale length of 25 1/2 inches. I don't believe that this varied from year to year. It is part of what gives a strat it's sound. So no, changing necks on a strat no matter what the year should not make a difference.

 

[walters]

Re: 2 Pickups distance create phase

delay (in microseconds), by distance between pickups--distance from strings

pickup's locations distances creates Delays?


The 24 fret necks "Displaces" the frong pickup? creates a Twang or phase?

the strat bridge pickup is some distance from the bridge and "angled".
What does the "Angle" do to the bridge pickup?

 

[Frebnedzo]

Re: 2 Pickups distance create phase

The tilting of the strat neck pickup incraeses the highs that are
picked up by the treble side of the pickup by moving it closer
to the bridge.

On my strat, the bridge is compensated such that the high-E
is almost a full strat pickup width shorter than the low-E.

Both of these effects will change where the nodes are and what
specific frequencys are attenuated by how much, IF we pretend
the string is nicely behaved.

The string is NOT nicely behaved. Think about how it looks just
before the pick "lets go" of the string, especially if we're doing
something like getting a pinch harmonic. Now you have wild
tangential vibrations going up and down the string from the
strike point, reflecting at the bridge and fret. Pretty quickly
the noise settles down, but the harmonic components in left
in the string may still be even more crazy than the comb filter
effect of the pickup placement.

i.e., its in the hands.

Google for discussion of the Karpus-Strong string plucking algorithm
used in digital audio synthesis.

 

[walters]

Re: 2 Pickups distance create phase

comb filter effect of the pickup placement

How do i get different comb filter effect from pickup placements?

The pickup placement create delays from pickup#1 to pickup#2
how do i adjust the delay of the pickup placement or adjust the
comb filter?

The pickup placement creates a delay but the 2 pickups add frequencys
and create phases how do i "change" the added frequencys and delay phases?

 

[Frebnedzo]

Re: 2 Pickups distance create phase

comb filter effect of the pickup placement

How do i get different comb filter effect from pickup placements?

Just move the pickups. This will move the location of the node between
the pickups relative to the string, hence attenuating/amplifying a
differnet range of frequencys. There was a guitar that was built with
a channel on the body and the pickups could be slid forwards
and backwards. You could tune the pickup placement for every song.

However, I don't know if there are really that many choices that have
panned out. Most 2 pup guitars have basically the same placement for
neck and bridge pickups, and 3 pup guitars put the third pup directly
between. Perhaps electric basses (and Fender Mustang?) have their
two pickups in a different relationship...

 

[walters]

Re: 2 Pickups distance create phase

If i keep the bridge and neck pickup in the same distance how can i change the "delay"? and phase? and frequencys?

Is there a way to change the "nodes" magnetically?

How do i change the nodes phases?

The 2 pickups from bridge to neck have different frequencys but "angle" the pickups would changes there frequencys? different windings?