How to TWO

ed packard · Post by **ed packard** » 14 Jul 2006 1:31 pm

For those that did not get enough in the Scale Length/Total String Length wars, here are the SL & TSL values for the 32 PSGs.

And to go with the long winded (but far from complete) blurb on pickups, here is the pickup info for the 32 PSGs. This list is not "fleshed out" with much of the info needed, but you can see some of that info in the "changer photos" for any given instrument when we cover it.

The second of this series is for Jim Wests FESSENDEN...1 year old.

The third of this series is a 1968 EMMONS PP bolt on.

Compare the three instruments for frequency content, frequency loss vs. time, and depth of the frequency dependent notches.

These first three are chosen to show the extremes of the PSG world. A 14 string C9 with a 30" neck keyless vs. a 12 string Uni with a 24" neck, vs. a EMMONS 1968 PUSH/PULL bolt on.

Look up the details of the instruments in the above lists and photos.

The pickups are quite different. The List gives the BEAST pickup location as the neck, and the maker as Danny Shields. The pickup being used for the graph is the bridge pickup, and it is a Di Marzio.

For the purpose of showing ALL that the pickup can pass, aload of several megohms is used as opposed to the more common 500K Ohms. The result is a bit more high frequency response.

[This message was edited by ed packard on 15 July 2006 at 11:01 AM.]

ed packard · Post by **ed packard** » 18 Jul 2006 9:24 am

let's talk SHO BUD: Here is the 0,2,4,8 second performance, open strings, excited at fret 12, for six Sho Buds. THEY ARE DIFFERENT!!! The details of the pickups, bodies, ages, et al may be found in the "lists".

Apply your "pet" theories to the differences and see if it can explain them. Look particularly at the top traces, their distance above the second traces, and the 60 Hz (hum) amount. How about the frequency depoendent bumps differences between instruments?

Could the differences be due to body to hardware connecting screw torque values?

Perhaps on e might have a misadjusted/bad pickup, but then the rest are still different.

The hardware photos are not put up here...they, and the graphs are available at http://s75.photobucket.com/albums/i287/edpackard/?start=40 for those that might like to prowl around.

Looks like I botched the numbering, but you can figure it out until I clean it up. #30 & 31 S/B # 31 & 32.[This message was edited by ed packard on 18 July 2006 at 10:44 AM.]

Ray Minich · Post by **Ray Minich** » 18 Jul 2006 9:42 am

The note (frequency) generated by an open string is function of string diameter, string tension and span, if I'm following this correctly.

OK, so when I'm winding a new E9th 3rd string (an .011 for example) onto a 24" scale, to get to G# (gotta crank on it and hope it doesn't go flying...)I reach a given tension.
To get to the same G# note on a 25" scale (regardless of whats "behind the roller nut") the tension to get to G# will be a little higher, because of the longer span.
Because the "free span" is greater, won't the changer on a 25 inch scale, also have to impart just a little more tension on a raise to get to the target raised note than the changer on a 24 inch scale?
It would seem that a longer scale length makes the string work harder for the same results.[This message was edited by Ray Minich on 18 July 2006 at 10:45 AM.]

ed packard · Post by **ed packard** » 18 Jul 2006 9:52 am

Ray...how true! and it will "stretch" more also. The rule is that in the "linear" (straight line) part of the stress strain curve for a given material (music wire), every Oz of applied tension gives a the same amount of stretch. This is a nice straight forward relationship. The problem in seeing it comes because we are talking halftones, which are a long ways from being linear re tension. The amount of stretch per halftone for a given string exponentially as the halftones increase.

C. Christofferson · Post by **C. Christofferson** » 18 Jul 2006 7:40 pm

E.P. Very interesting. And excellent work. Incredible input from everyone involved.

ed packard · Post by **ed packard** » 19 Jul 2006 8:10 am

CC...Glad you enjoy.

Now that you have seen that all SHO BUDs are not equal, lets look at the EMMONS under the same test conditions. Thanks to JD for bringing his instruments in for the tests.

These will be the last of this type of image posted in this thread. From now on we will announce which instrument's graphics have been added to the PHOTOBUCKET link, and those that are interested can go there to compare all 32 instruments (as they are put up).

What you see is just the beginning. The next data gathering session will be at Jim Palenscar's steel shop on July 29. I will be joined by Joe Meditz. The plan is to get WAV files of the various instruments, so that much more information is available to be mined. Strums of various types and locations, scrubs, individual string responses, finger harmonics, etc. will be on the menu. If you have nothing better to do, drop by.

Scott Swartz · Post by **Scott Swartz** » 19 Jul 2006 8:56 am

Great graphs and info, Ed.

If I look at the fundamental, it looks like JD's Emmons has about 15 dB loss from time zero to 8 seconds, where the Shobuds are 20-25 dB loss for time zero to 8 seconds.

However the harmonics decay on the Shobuds in a more linear fashion with respect to time (the Emmons loses more upper harmonics compared to the fundamental in the first 2 seconds than many of the Shobuds).

At 8 seconds, both guitars have lost similar amounts of harmonic content, but the Emmons has lost about 5 dB less fundamental signal voltage, so you could say it has more “sustain”, but if having strong upper harmonic content at time 2 seconds is important to you then maybe you would prefer the Shobuds.

The best thing about these graphs is they are independent of the pickup frequency response curve, since this filter is applied equally at times 0,2,4,8 seconds and you can see the harmonic vs time characteristics of the guitar itself.

Joseph Meditz · Post by **Joseph Meditz** » 19 Jul 2006 9:22 am

In the Sho Bud graphs, the 60 Hz tone of No. 21 was the lowest of that set. Then, referring to the list we see that No. 21 has a single row alnico pickup, i.e., non-humbucking. Yet its 60 Hz rejection is lower than the No.18 Lawr 710 humbucker! (I'm assuming two rows of pole pieces means its a humbucker, but it doesn't have to be.)

No 31 Sho-Bud's first graph shows a very bright freq resp. Its winding resistance is low being at 10.8k. OK. Low winding resistance ==> brighter sound. But then you look at No.32 which has a lower winding resistance of 10.1k and see that it is not as bright. Both pickups are Sho-Buds. One axe is a ProII the other a Professional. Are ProII's considered to be, in general, brighter?

It's certainly going to take some time before this data is digested!

Joe

ed packard · Post by **ed packard** » 19 Jul 2006 11:10 am

SS...one problem that must be overcome is that a "system" of terminology has to be developed to use in comparisons. This is somewhat compounded by having instruments with a short spectrum (E9 10), a bit longer spectrum (C6 10), Universals(E9/B6, Bb6,Eb9 12, E9/B6 14) and the BEAST (C69 14).

I tend to think about breaking the spectrum into octaves starting with C1,C2,C3,C4,C5,C6 etc.

Having established such categories, we may talk of the fall off of octaves re the 0 sec levels in terms of db loss per second...or octave n being xdb lower than octave n+1 at t=y. This might be extended to -db per octave per second, or similar.

Joe...I tend to think of hum as being X db below the 2 second signal level (would prefer 1 sec signal level, but that was not taken last time.

The EMMONS numbers look to be about -40db for that categorization.

The Sho Buds look to be about - 30 to -40 db. #30 seems to be -30db, but #30 has weird curves to begin with.

Changing the wire size from 38 to 40, or to 36 can greatly affect the Ohms. Magnet Wire Sales (MWS) has this type of info available on line.

How the wires from the pickup are handled (shielded, twisted, twisted with ground, etc), plus where/how the ground is tied to the chassis can make or break the hum thing. Just touching the strings on some instruments makes a large difference. Our tests were "hands off" the strings before capturing the signal(s).

Lots of fun ahead.

ed packard · Post by **ed packard** » 19 Jul 2006 1:56 pm

Five MSAs have been added to the PHOTOBUCKET site. One is the PLEXIGLASS D10. One is the modern LEGEND. One is a "HUM" dinger.

#5 MSA had a HI Z load on the pickup (5 or so meg-ohms, hence the undamped high freq bump on the top trace. Mentally roll off the hi's for the other traces a bit.
http://s75.photobucket.com/albums/i287/edpackard/?start=40 [This message was edited by ed packard on 19 July 2006 at 03:03 PM.]

ed packard · Post by **ed packard** » 20 Jul 2006 10:55 am

The STRUM OS F12 SMOOTHED 0,2,4,8 SECS series is now up at http://s75.photobucket.com/albums/i287/edpackard/?start=40 . They should be in the same order as the instrument photos they represent. DEKLEYs, BMIs, EMCI, ZB, GFIs, SIERRA, PSTs PALI, ANAPEG, MULLEN, have been added.

Re HUM: compare the hum levels between the aluminum necks/bodies and the non metallic necks/bodies...[This message was edited by ed packard on 20 July 2006 at 11:56 AM.]

David Doggett · Post by **David Doggett** » 20 Jul 2006 2:33 pm

We have to be careful that looking at these graphs doesn't degenerate into reading tea leaves. I don't see what Scott saw. I'm thinking the fundamentals are the squared off part of the 0 strum line between about 100 hz and 800 hz (G# at the 12th fret is 831 hz). The overtones for the highest strings would be beyond that (out through 1600 hz), but the overtones of the others would be within that. For me the most informative line is the 2 second line. That corresponds to a half note in slow 4/4 time, and about the timeframe over which we mostly hear sustain or not while playing music. Eight seconds would be beyond what music commonly calls for, and would be a sort of artificial test of listening to the strings until they die out. The Beast and the Emmons Bolton are remarkably squared off at 2 sec. over the fundamental stretch from 100 to 800K and out through the overtones to 1600, close below the 0 strum and holding the same shape. Holding the same shape is more important than being linear. It means the strings sustain the fundamental and the overtones. A sloped shoulder on the right means the overtones are being lost quickly. The Sho-Buds hold the 0 strum shape less, especially in the highs, indicating a darker tone to me, in spite of low ohm pickups. The worst two are the Sho-Bud S10 (#8) and (surprisingly) the Emmons P/P (#27), which is listed as a D10 on the graph, but an S10 on the spreadsheets. If both of these are S10s, that certainly looks like less response on the mid to high fundamentals, even at time 0. Or maybe they just had old strings. Am I interpreting things right, Ed? [This message was edited by David Doggett on 21 July 2006 at 08:27 AM.]

ed packard · Post by **ed packard** » 20 Jul 2006 6:30 pm

DD...had not thought of "tea leaves"...was more inclined to getting a divining rod though.

The photos are the best source for determining if a typo or transposition was made re either the spreadsheet, or the FSA labels. #27 & #28 are both EMMONS D10s, and both JDs. If you look closely at the keyhead photos for them you will see spaghetti tubing on the center strings overhang. JD is very tone fussy in his choice of instrument, and how it is decked out, right down to the strings. He was there for the session, and I thank him for bringing the instruments.

This data comes from a first run at gathering data on a variety of PSGs. Each PSG had 8 traces taken for the open string strum excited at fret 12 with a thumb pick.

4 of these traces were without and changes activated, and 4 were with P1P2 activated. The "tuning dependent" bumps are visible, and any change influence on tone/sustain etc..a non issue at this scale.

The open string strum fret12 was chosen as it had the least people effect/influence involved. Other strums will be captured, as in up the neck, etc. These will involve the bar, and the player more. "Pick" of the individual strings is in the cards. Pick of the same note on different strings will show the differences in harmonic content for the same notes in different locations.

"Scrub" is another approach that will be used. In the intro graphs where the effect of changing pickup settings on the BEAST were shown, both strum and scrub were captured. The os strum gave a top trace that was sort of flat. The scrub gave a top trace that was "arched". One might ask why. OS strum shows what the open strings give for amplitudes of their fundamentals and harmonics as passed thru the pickup. Scrub shows the highest output for all places on the neck and strummed at all places. This means that any and all fundamentals and their harmonics may be found in many places, and may have more amplitude as seen by the pickup than those limited ones of the open string strum. The nulls and loops chart for the neck shows that for an open string the most ODD harmonic signal would be seen by the pickup if it was positioned at fret 12...The even harmonics would be minimized at that point.

Now look at the magnitude of the signals as you mentally move the pickup toward the bridge.

The "arching" of the scrub signal response is showing the band pass filter characteristic of the pickup...the Q of these pickups is very low, so they are quite broad on top.

I am sure that there are typos and transpositions in the data. The real point is that the differences between instruments and associated hardware may be seen in the charts/graphs, even within the product of a given maker. If there were no differences to be seen, then the exercise would be as one chap in a long past thread predicted ..."pointless". So far I have not seen the need of a "picking machine".

This is just the first step in what may be a long journey. Joe Meditz has done some interesting things on the subject, and I assume that he will make these known when the time is right.

ADDED: The pickups on #27 & #28 are both "PITTMAN" pickups...so we not only have two EMMONS instruments, owned by the same tone particular picker, but the E9 pickups are by the same Mfg. I E mailed PITTMAN to get some tech data on the pickups, but they/he did not acknowledge the E mail.

All the instruments were FSA tested in the same place in Jim's shop, and facing the same way, so that any hum info would be comparative.

Re Paul F's "Bell" description of PSG tone from another thread...The top trace in the graphs would contain the sound of the clapper hitting the bell casing = the attack from picking the string(s). The 2 second trace would be like the amount of (freq & amplitude) of the casings vibration at the 2 second mark, etc.. The greater the drop from the first to the second trace the more damped the bell casing would be in the analogy.

The Sho Bud that you mentioned would have a very sharp (relatively speaking), and a large damping factor. It would sound "dark" after the initial excitation, but "bright" at the moment of attack (assuming no volume pedal activation to "sneak into the sound)...seems to be one of the preferred Nashville/Bakersfield sounds...and we have only addressed the open strings so far.

[This message was edited by ed packard on 21 July 2006 at 07:21 AM.]

David Doggett · Post by **David Doggett** » 21 Jul 2006 7:40 am

Okay, I've revised my analysis a little and edited it. The fundamentals are between about 100 and 800hz (G# at the 12th fret is 831 hz). From 800 out to 3000 would be overtones. Holding the shape of the overtones is probably what we perceive as bright tone and good string separation. JD's Emmons p/p compares well to the Sho-Buds and others, but just looks not so great compared to the bolton and the Beast, which are both remarkably squared off at 2 seconds out through the overtones. This is interesting stuff, but I'm not sure anyone should loose faith if their favorite doesn't show up so well in these graphs. It could just be an old set of strings, or an inconsistent strum.[This message was edited by David Doggett on 21 July 2006 at 08:42 AM.]

ed packard · Post by **ed packard** » 21 Jul 2006 7:56 am

DD...The object of the exercise is NOT to judge good vs. bad, rather to show that the differences may be defined in terms of repeatable experiments with repeatable numeric results. From this data/method each may find a way of describing their (or favorite picking hero's) in terms more definitive than the abstract adjectives presently used.

Scrub includes fundamentals up to, and beyond the 36th fret...a bit extreme perhaps.

Alan Brookes · Post by **Alan Brookes** » 21 Jul 2006 8:24 am

With a longer string length you would expect to keep the same tension and tune to a lower pitch.

Concerning vibration of the string. We did some experiments at a recent meeting of the Northern California Association of Luthiers regarding how a string vibrates immediately after it is plucked. If you pluck in the middle of string it immediately vibrates at its fundimental frequency, plus the usual overtones of fifths and thirds which occur a fraction of a second later. But no-one plucks at the center of the string. If you pluck close to the bridge the string vibrates first at the distance from the bridge to where you are plucking, then almost immediately at a point the same distance from the nut. Then within a minute fraction of a second it vibrates as if the string were open from the finger to the bridge. The reason for the experiment was to work out how to prevent fret rattle, but the same physics applies whether you shorten the sounding length with a finger against a fret or a steel bar. You change the overtones by where you pluck the string, and this can be heard quite plainly.

I hope I haven't wandered from the original subject.

ed packard · Post by **ed packard** » 21 Jul 2006 8:36 am

AB...you have wandered back to the string vibration chart/graph above in a previous post in this thread. By viewing the graph in different ways one may see how the pickup location vs. the vibrating string(s) would give different harmonic content, as well as would where the string is excited.

Agreed, most standard guitarists spend very little time exciting the string(s) at the 12th fret, but as they progress up the neck, they will spend more time exciting the string at it's halfway point.

Can you say how you approached the measurements that you used for your experiments = equipment et al?

Bobby Lee · Post by **Bobby Lee** » 21 Jul 2006 8:37 am

This is why we often say "tone is in the hands". The overtones generated are dependent on where and how the string is picked.

Some say that the best tone is produced when you pick halfway between your bar and the bridge - the "middle of the string". Certainly that point will generate the most energy for a given amount of picking force. Whether the tone is "best" at that point or not is subjective judgement.

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<img align=right src="http://b0b.com/b0b2005.gif" width="78 height="78">Bobby Lee (a.k.a. b0b) - email: quasar@b0b.com - gigs - CDs, Open Hearts
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Sierra Laptop S-8 (E6add9), Fender Stringmaster D-8 (E13, C6 or A6) My Blog [This message was edited by b0b on 21 July 2006 at 09:38 AM.]

C. Christofferson · Post by **C. Christofferson** » 21 Jul 2006 11:56 am

I believe it's a fact (although subjective) that to help keep the listener's (including the player's) interest throughout the course of, say, a 4 or 5 set evening, that most everything that can be 'modulated' here and there BE modulated. For example, using chorus effect on the occaisional tune, quiet on some songs, loud on others, metal slide on some, plastic on others - getting the BEST sound you can on some, and getting the WORST sound you can also - obviously, in order to keep dreaded monotony from.... The point - even the worst sound sounds refreshing in a tasty context.

Scott Swartz · Post by **Scott Swartz** » 21 Jul 2006 11:57 am

David D.

Not sure if I was conveying my thought well earlier, but I was trying for something like your statement of holding the shape of the graph is more important than the exact shape. It is however intertwined with exactly how you define sustain, is it better to have the overtones die off before the fundamentals or all freqs decaying equally?

If the graph were exactly the the same at 0,2,4,8 seconds that would be similar to holding down keys on an organ (for something like a B3 sound without modulation). Keyboardists would call this sustain I guess.

If you took the organ example and decreased the volume over the 8 seconds, you would get the same shape repeated lower as time passed, it would look like a ladder.

If you took the organ example, decreased the volume, and applied a volume controlled lowpass filter over the 8 seconds, you would get graphs similar to the steel graphs.

With the new graphs, I noticed another trend.

All the graphs show that most all the steels have a bright attack (not surprising given most are maple body, maple is well known for bright attack).

Note that the Beast and the other Sierra 14 tend toward more uniform graph shapes, since the are completely different in construction material (ie aluminum body), perhaps that is not a surprise.

Graphs of other materials of construction would be interesting to compare…..

Whatever conclusions you draw this is interesting stuff.
[This message was edited by Scott Swartz on 21 July 2006 at 12:58 PM.]