GuitarFreak - guitar frequency response calculator

[JohnH]

Oct 22, 2016 3:17:16 GMT -5 perfboardpatcher said:

As promised, I tested Guitarfreak_6_41_161016.ods in LibreOffice under Windows and got the same results with regards to the 3 buttons on the main sheet. LibreOffice looks for the buttons in Module1 but "clear" is in Module10, "ref" is in Module11, there's no match for "save" or "save trace".

Thanks for investigating. I get very little feedback on how GF works for others, so it is always appreciated.

I downloaded the same file as above from the link, and it keeps working fine for me. The macros for the three buttons on the Main and Tone pages are indeed Module 1, as follows:



The macros that they call up have the letters LO on them, to identify that they were added for the LibreOffice version. There is a separate set of three for use from the 'Tone' page, so it returns to 'Tone' after pasting to the 'Chart' page.Do you see them on your system? Also, what version of LO do you have?

The file is also full of lots of excel macros (many are now redundant), which came over when I ported the Excel version into LibreOffice. Excel macros generally don't work in LO, since it is a different code format, though they can exist in the file. maybe I should delete them?

Call out to others reading this:

Anyone who has tried the LibreOffice version, or is willing to do so, I would be very grateful for feedback on if it works for you. It needs the latest fresh version of Libreoffice, and what we are testing here is the three main 'Save', 'Reference' and 'Clear' buttons.

LibreOffice can be freely downloaded here:

www.libreoffice.org/download/libreoffice-fresh/

with thanks

John

[perfboardpatcher]

No I don't have these LO-macros in My Macros - Standard - Module1.

Now I'm not sure about this but my guess is that this Module1 is not part of the Guitarfreak ods-file but a local file. I found a Module1.xba file on my Linux-system in ~/.config/libreoffice/4/user/basic/Standard/ . Perhaps you know a way to include the macros in the ods-file, John, to make them appear under Guitarfreak... - Standard - something.

[JohnH]

Ok thanks I think my next move will be to find a fresh machine to put LibreOffice on, and test it just with the downloaded .ods file to see if those Macros are there or not.

[JohnH]

Well thanks for that tip, you were quite right. The link should now bring a LibreOffice version with the macros in it:

www.jocidapark.com.au/circuits/GuitarFreak_6_41_161016.ods

the excel versions should be fine

[perfboardpatcher]

Oct 26, 2016 6:44:32 GMT -5 JohnH said:

Well thanks for that tip, you were quite right. The link should now bring a LibreOffice version with the macros in it:

www.jocidapark.com.au/circuits/GuitarFreak_6_41_161016.ods

the excel versions should be fine

Yep, the macros work! "Save traces" is indeed a very useful addition to Guitarfreak. I'm going to experiment with recording macros to build in the same functionality in my spreadsheets.

[andyholmes]

Hi, just started using GuitarFreak on Linux as well. Just thought I'd point out some of the default fonts used by Office aren't available for Linux users. I hunted down the Calibri fonts (probably not legally) and the formatting of the sheet already fits a lot better. If it helps, most of the older MS fonts like Arial, Verdana, Times New Roman and Trebuchet are available to us.

Aside from that, fantastic spreadsheet. I'm toying with your 6-part model and some of the figures in your table of pickups to build a decent SPICE library with switches, pots, pickups and a few wiring schemes. If it turns out to be useful I'll probably post it here in the forums.

[JohnH]

I never thought it could run in Linux! Did you start with the Excel or the Libreoffice version for that? Thanks for the tip about fonts.

[andyholmes]

I just use the LibreOffice version since that's the Office suite of choice on Linux. Excel formats are pretty touch and go, contrary to what LibreOffice claims. Here's what the main page looks like if you're interested:

[JohnH]

Great and thanks! That looks as expected!

[col]

Mar 10, 2012 18:58:07 GMT -5 JohnH said:

I have just edited the first post, to update it and add Version 3.0. The main new thing is a 'snapshot' button, to allow two settings to be compared.



See the first post for more info, and download in current Excel format here:
GuitarFreak3.0

cheers
John

Retrieved image.

[col]

Nov 3, 2012 23:51:20 GMT -5 JohnH said:

I just thought I’d share some ‘work-in-progress’ on the GuitarFreak spreadsheet.
See the first post on this thread for the current finished version GuitarFreak3

For the next iteration, GuitarFreak4, I want to add a few extra capabilities, so it can help with the design of some more of the non-standard configurations that keep coming up on GN2.

In particular, I'm thinking of series wiring with part bypass of one coil or one pickup. This will help check out systems such as ‘spin-a-split’, ‘broadbucker’ and general part bypass with caps and resistances, to find tones between single and humbuckers.

All of this can be done on modelling programs such as 5Spice, but the advantage with these spreadsheets is to be able to put the main controls on slider bars, and view the graph of output interactively as you tweak it in real time – the previous GF’s have this.

So far, I’ve got the main coding done, and alpha tested, with fixed numerical inputs (no slider bars yet). I think it works, but needs QA.

This is the sketched schematic that i’m working with.



There are two coils each with inductance, resistance and winding capacitance, and each with a set of caps and resistors to bypass them. I run the numbers by analysing the output from one coil at a time, and adding the two parts together. It’s done by considering the circuit as a network of impedances, as you would a resistor network, but calculated using complex numbers to pick up reactance and resistances. I could explain more but that would depend on anyone wishing to know more.

Here’s a plot, with no bypass on the coils, to represent a full humbucker.



Here it is with the lower coil fully bypassed by a 1 ohm resistance, ie its a simple coil-cut



And here is a more interesting part bypassed arrangement, of the type that this system could potentially investigate quite easily. In this case, the lower coil is bypassed by a 12k resistor and a 10nF capacitor. See how the peak is like the single coil version but there’s more low end tone?.



The next step is to test this against a 5Spice model to check, and then add all the interactive bells and whistles to make it quick and intuitive to use.

But before I do that, (and the reason for this post), I'm interested in any opinions as to other features that could be built into the schematic. It would be fairly easy to extend the code a little more at this point. They should be things that can be adjusted by component values rather than switching, and which have come up more than once on the forum. Eg, I’ve got the inductor in the tone circuit, so that varitone arrangements can be tested (will that capture it?). Also thinking about a bass cut control? Any other ideas?

Cheers
John

More retrieved images. They all need to be copied/saved.

Every example has worked so far. I'll leave it there - I'm messing up threads.

[JohnH]

It's been about a year since I last added to GuitarFreak and the latest version is now GuitarFreak 6.5 whch I just uploaded:

GuitarFreak6.5 (excel 2007)


New features in 6.5 include the following:

• A considerably expanded range of pickup models, both as complete sets and individual pickups
• An additional resistor added to the treble-bleed network to enable a new option of the Fender Tonesaver circuit, as built into current 2017 stock American Stratocaster Pro models
• A few minor tweaks and bug fixes

The pickup models are all based on the detailed testing by Antigua, and huge thanks are due for his diligent and comprehensive work. For GuitarFreak, only a small selection is included, mostly cherry-picked to cover the main types focussing on well-known and classic models. There are several LP, Strat and Tele versions, plus new for 6.5, two Gretsch-based sets (Filtertron and TV Jones) and a combined Jazz/Precision bass.

See below for all test results:

guitarnuts2.proboards.com/board/30/pickup-testing-modelling

If anyone running GF wants to use it with other pickups from the testing archive, let me know. it doesn't take long to derive the models, though it is not an automatic process.

For the Bass model, which has a 34" scale, the N and B pickups represent the J-bass with pickups in their classic positions, while the M pickup is the single P bass. pickup, with the treble side of this split PU defining its position (adjustable).  To properly use the bass model, set the A string to 55hz on the 'Strings and Pickups' page, and use strings 3, 4, 5 and 6 for a four-string bass.  

GF was first written to investigate treble-bleed circuits, so when Fender started to build them into their stock US models, I wanted to be sure their design can be captured. The Fender TB circuit is a parallel 150k/1.2nF R & C all in series with another 20k resistor. There is now a dedicated option button in GuitarFreak for this, since I suspect it will become the most common TB design on any stock guitar. Ill run some comparisons in another thread soon.    

Linked above is an Excel version for Excel 2007 and later. I'll be happy to post 1997-2003 or Libreoffice versions if requested, but particularly the Libreoffice version takes significant work to manually update to match the Excel. But Version 6.4 linked on page 1 is in all formats and pickup data can be copied in as needed.

Happy Christmas!

[willybee24]

This is awesome!  I have a ton of questions...but I'm still crazy interested 

[JohnH]

Sept 1, 2018 13:20:54 GMT -5 willybee24 said:

This is awesome!  I have a ton of questions...but I'm still crazy interested 

Hi willybee24. Thanks for your interest and welcome to GN2. Happy to answer any questions about GuitarFreak. You can post them here on this thread.

[stevesledge]

Great Excel Spread Sheet Calculator !!

One Question :

When I want to buy a dream pickup , which is not in the database, but I know it's electrical parameters ( by example : Inductance , DC-Resistance )
and I like to compare it to a pickup which is in your database, there is one thing I can't calculate :
the output level - 
because I don't know the relative output of my dream pickup. Right ?   

Cheers
Steve 

[JohnH]

Hi Steve, thanks for your message and welcome to GN2. I see you are an EE, which gives you have a good chance of being able to get the most out of these testing and analysis discussions.

Yes relative output between pickups is an order less defined and more qualitatively assessed in GuitarFreak, as it is in the pickup testing from Antigua and Stratotarts on which it is based. We just dont have a good quantitative way of creating a consistent and meaningful output-level benchmark that can be tested. And it depends greatly on pickup height and magnets, and ths best tones from different pickups come from different heights. We have a much better grasp on the tonal characteristics.

In GF, there's a parameter that sets overall level and I picked values that put the various pickups in reasonable relationship to each other. eg, 0db for very vintage low-wind singles, a db or two more for hotter singles. Strum tests on my own guitars lead me to about +5db for PAFs, more for hotter etc. Dimarzio gives some kind of output level in mV for their range. Mot sure what its based on but I took that into account too.

So from pickup specs available, you get a bit of a guide, at least if you know the general construction of the pickup and the inductance. There's probably a model in the data that is near enough to use to help make choices on wiring etc, which is what GF is for.

If you buy the pickups, maybe one of the guys could run the tests if you shipped them each way. Then you'd get a better handle on tonal features but still output is best-guess. If that happens, Id be happy to process the test to make a model for GF, allowing for damping etc (ie 6 components)

[stevesledge]

Hi John,
thanks for your welcome.

As I read again today the pickup specs in the excel-calculator table , it seems to me that the relative output level is proportional going up or down in relation to it's inductance, or ?
I sorted the rows against L1 ( line 84 ) and all the db's are going up now ( except one Super.Dist para ) 

So :
pickups with the same inductance, have the same output levels ( +/-1db ),
if their distance to strings and position are the same.

Would you agree on that ?

 

 

[JohnH]

Yes thats reasonable and inductance is a fair clue to likley output, better than dc resistance. But its an assumption in the data, rather than a measured conclusion such as the tonal parameters. For example, two similar pickups with different magnet strength could have the same inductance but different output.

[stevesledge]

Yes , I forgot the magnet strength ( B ). It has influence too.

U=B*L*v 

B= magnetic flux density [ Gauss]
L=inductance [ Henry ]
v= velocity [ m/s ]

So, if magnet type ( A5 , A2 ) , inductance, string distance, position are the same , the outputs are similar .

Yes ?

[JohnH]

Better throw in the base plate and cover materials, dimensions, string gage etc., plus how hard the strings are plucked ie, Two similar pickups will probably have similar output if installed and played similarly!

All the thinking that you note is highly reasonable, but we just cant quantify it enough to get specific about overall relative output between two fairly similar but somewhat different pickups. But usually its not a huge deal, and a tweak of a gain control somewhere down-stream of the guitar can cover the range.

Id tbink that one of the cases where relative output would be nice to understand better would be in selecting a set of different pickups to go on one guitar. eg. My Strat is HSS, and how I use is greatly affected by the availability of a few extra db's from the bridge. Thats how I like it, but I can also adjust heights and bring them all to tbe same volume.

[mb1685]

Hi JohnH,

Thank you so much for this amazing effort! I've been having a blast using GuitarFreak for the past few weeks. Although I don't have much electrical knowledge, I've found it very interesting and it dispelled a lot of myths out there about how tone and volume resistance and capacitor values actually affect things.

I am currently experimenting with cap and resistor values for the bass cut circuit. I'm trying to figure out a combination that gets in the ballpark of the bass rolloff of a Tube Screamer pedal when the full bass cut is active. Based on some frequency response analyses I can find of Tube Screamer circuits, I see that the corner frequency is 720 Hz, and it looks like 100 Hz is about -10 dB (relative to the amplitude at 720 Hz) and 300 Hz is roughly -3 dB. I know I'll never be able to get the slope close to perfect, but I'm trying to get fairly close at those 3 frequency references.

My understanding is that it's not really possible to do an apples-to-apples comparison for this by using GuitarFreak (even using the buffered output and trying to make the total output loading equal to that of a Tube Screamer circuit) since obviously no pickups have a perfectly flat response to use as a baseline, correct? Would it make the most sense to just use a simple circuit frequency response simulator such as this? Using that simulator I am able to get quite close to those figures by using a 500k resistor and a 1.1nF cap, which seems plausible since I believe these are exactly the values of some of Reverend's bass contour circuits. A 1M resistor and 0.47nF cap also appears to be pretty close in that simulator, but there's a really big difference in how each of those looks in GuitarFreak with all other things being equal (I see that this seems to be at least partially influenced by the loading of the volume pot). Could you shed some light on this? Do you know of values that would in theory most closely match the low-end rolloff of a Tube Screamer or have insight on how I can best analyze to find out?

[JohnH]

Aug 9, 2019 15:38:50 GMT -5 mb1685 said:

Hi JohnH,

Thank you so much for this amazing effort! I've been having a blast using GuitarFreak for the past few weeks. Although I don't have much electrical knowledge, I've found it very interesting and it dispelled a lot of myths out there about how tone and volume resistance and capacitor values actually affect things.

I am currently experimenting with cap and resistor values for the bass cut circuit. I'm trying to figure out a combination that gets in the ballpark of the bass rolloff of a Tube Screamer pedal when the full bass cut is active. Based on some frequency response analyses I can find of Tube Screamer circuits, I see that the corner frequency is 720 Hz, and it looks like 100 Hz is about -10 dB (relative to the amplitude at 720 Hz) and 300 Hz is roughly -3 dB. I know I'll never be able to get the slope close to perfect, but I'm trying to get fairly close at those 3 frequency references.

My understanding is that it's not really possible to do an apples-to-apples comparison for this by using GuitarFreak (even using the buffered output and trying to make the total output loading equal to that of a Tube Screamer circuit) since obviously no pickups have a perfectly flat response to use as a baseline, correct? Would it make the most sense to just use a simple circuit frequency response simulator such as this? Using that simulator I am able to get quite close to those figures by using a 500k resistor and a 1.1nF cap, which seems plausible since I believe these are exactly the values of some of Reverend's bass contour circuits. A 1M resistor and 0.47nF cap also appears to be pretty close in that simulator, but there's a really big difference in how each of those looks in GuitarFreak with all other things being equal (I see that this seems to be at least partially influenced by the loading of the volume pot). Could you shed some light on this? Do you know of values that would in theory most closely match the low-end rolloff of a Tube Screamer or have insight on how I can best analyze to find out?

Hi MB, thanks for your comments and interest in GuitarFreak - I'm really glad its working for you.

With the bass-cut controls, the key parameters are the value of the bass-cut cap and the value of the volume pot. Its these that form the RC filter that rolls off the bass. If you are using that very clever app to compare to, these are the relevant values when looking at a simple RC high-pass filter. The bass pot itself bypasses the cap, reducing the effect until its fully gone. GF takes a lot more into account, but the basic theory is the same as any modelling program.

The bass-cut works best with 250k pots, but you should obviously use the pot that suits the pickup. To get somewhat what you describe, is was finding that a 1M bass pot, 250k volume pot and a 2.2nF bass cap would get about 8db of roll-off from 700hz down to 100hz, with most pickups. A smaller cap may better suit a 500k volume pot.

But having used modeling to explore, its best to do real tests to decide the final version.

[mb1685]

Aug 9, 2019 23:41:19 GMT -5 JohnH said:

Aug 9, 2019 15:38:50 GMT -5 mb1685 said:

Hi JohnH,

Thank you so much for this amazing effort! I've been having a blast using GuitarFreak for the past few weeks. Although I don't have much electrical knowledge, I've found it very interesting and it dispelled a lot of myths out there about how tone and volume resistance and capacitor values actually affect things.

I am currently experimenting with cap and resistor values for the bass cut circuit. I'm trying to figure out a combination that gets in the ballpark of the bass rolloff of a Tube Screamer pedal when the full bass cut is active. Based on some frequency response analyses I can find of Tube Screamer circuits, I see that the corner frequency is 720 Hz, and it looks like 100 Hz is about -10 dB (relative to the amplitude at 720 Hz) and 300 Hz is roughly -3 dB. I know I'll never be able to get the slope close to perfect, but I'm trying to get fairly close at those 3 frequency references.

My understanding is that it's not really possible to do an apples-to-apples comparison for this by using GuitarFreak (even using the buffered output and trying to make the total output loading equal to that of a Tube Screamer circuit) since obviously no pickups have a perfectly flat response to use as a baseline, correct? Would it make the most sense to just use a simple circuit frequency response simulator such as this? Using that simulator I am able to get quite close to those figures by using a 500k resistor and a 1.1nF cap, which seems plausible since I believe these are exactly the values of some of Reverend's bass contour circuits. A 1M resistor and 0.47nF cap also appears to be pretty close in that simulator, but there's a really big difference in how each of those looks in GuitarFreak with all other things being equal (I see that this seems to be at least partially influenced by the loading of the volume pot). Could you shed some light on this? Do you know of values that would in theory most closely match the low-end rolloff of a Tube Screamer or have insight on how I can best analyze to find out?

Hi MB, thanks for your comments and interest in GuitarFreak - I'm really glad its working for you.

With the bass-cut controls, the key parameters are the value of the bass-cut cap and the value of the volume pot. Its these that form the RC filter that rolls off the bass. If you are using that very clever app to compare to, these are the relevant values when looking at a simple RC high-pass filter. The bass pot itself bypasses the cap, reducing the effect until its fully gone. GF takes a lot more into account, but the basic theory is the same as any modelling program.

The bass-cut works best with 250k pots, but you should obviously use the pot that suits the pickup. To get somewhat what you describe, is was finding that a 1M bass pot, 250k volume pot and a 2.2nF bass cap would get about 8db of roll-off from 700hz down to 100hz, with most pickups. A smaller cap may better suit a 500k volume pot.

But having used modeling to explore, its best to do real tests to decide the final version.

Thank you so much for your help!

I'd definitely like to utilize a 500k volume pot because the pickup is a humbucker (although it's on the brighter side), so after a bit of experimentation, I determined that 1M bass pot and 2.2nF is about as close as I can get and seems like a safe bet.

I ended up making a spreadsheet and notating the figures at a few points on the frequency spectrum, but volume matched at 720 Hz (the corner frequency). Doing that, it became apparent that 1M + 2.2nF is really close! I ended up using the "Bass" pickup since the low end and midrange was extremely flat, making it easy to analyze the theoretical response without the pickup's tonality coloring the analysis too much. I did this both with the buffered output and the 10' cable output, and 1M + 2.2nF was the closest in both cases. And although the resonant frequency shifts by a few hundred Hz when engaging the bass cut all the way, I found that 1M + 2.2nF exhibited practically no difference in the relative amplitude of the resonant peak with maximum bass cut, unlike some other values which would increase it. That was a lot of fun!

I have no idea if anyone else would find it useful, but when I was doing this I thought it would be really cool if GuitarFreak gave you the option to select which frequency is used for the volume matching of response curves (rather than being fixed at 440Hz).   

[JohnH]

I have no idea if anyone else would find it useful, but when I was doing this I thought it would be really cool if GuitarFreak gave you the option to select which frequency is used for the volume matching of response curves (rather than being fixed at 440Hz).   

That's not too hard, Ill add that wish to the wish list.

Id be interested to know if you have any other suggestions. I might do another minor update soon.

But, beyond such small tweaks, the next major update might be very major, hence I haven't changed GF in a couple of years. This would be to improve the way that it handles more than one pickup in combinations. Currently, these are combined into one equivalent single pickup, with tonal contributions from each as a weighted average based mainly on inductance. Its accurate for similar pickups wired directly to each other in various ways. Its very close if the pickups are similar, like different winding numbers within a single-coil set, and somewhat reasonable for direct connection of different pickups, like on an HSS for example. What it can't deal with is if one pickup has its own volume or tone pot turned down, or is partly bypassed. To do this may need the main calc pages replicated independently for each pickup, ie x3. And I might also increase the resolution of the results from one semitone per data point, to 2 or 3 per semitone.

But, its not likely soon!

[JohnH]

A minor update to GuitarFreak, the first in two years

The latest version is now GuitarFreak 6.6, which is a minor enhancement since versions 6.5 and 6.4


GuitarFreak6.6 (excel 2013, 2016, 365)

Version 6.6 should also run in Excel 2007 and 2010 but I haven't tested it.

New features in 6.6 include the following:

• Additional components in the Tone circuit, to allow a standard tone resistor/cap to be in parallel with a more exotic version
• The parallel treble bleed will select an optimum resistor depending on volume pot value 

[frets]

John,
I could not open the update to Guitarfreak using Excel 2003. It comes up with an “unrecognized format error.”

[JohnH]

Dec 7, 2019 12:51:10 GMT -5 frets said:

John,
I could not open the update to Guitarfreak using Excel 2003. It comes up with an “unrecognized format error.”

Hey frets, Microsoft changed the format of Excel files for 2007 onwards. But, just for you I have down-saved it to versions 97-2003! (id really like you to try it)

GuitarFreak6.6 (excel 97-2003)

If it works, that's 22 years of backward compatibility!

I cant test it myself in 2003, but this version opens back up in later Excel's Ok, so I think its OK - let me know.

Version 6.6 has the tweaks to enable it to deal with your last-weeks dual tone gadget. If you open the file, its set right there using the 'custom' tone option. Sweep the tone pot to watch your inductive circuit work. The GB treble control is set to max = 500k, and its R7 on the tone page. Change cell O24 on the Tone page to reduce it, down to 3.9 for its minimum.


Your next device, with the dual gang, I'm thinking about, it may need one more further modelling part to test.
.

[frets]

Thank you John, I appreciate you doing this for my version of Excel. I’m addition, the added flexibility to explore the effect of novel tonifiers is exciting.

[pasqualino]

WOW!!!

I've been working quasi-independently as an EE/CSE, started my own LLC in 2014 and elected to be an S Corp in 2018.  For 2 years I worked on a spreadsheet which allows me to figure out what salary to pay myself, how much to put into my 401(k), etc.  it's very complicated and I have it down to just how many hours I've worked or how much $$$ came in that week/40.  It makes things real easy and up until I saw this work of art I was contorting my body to pleasure itself over the accomplishment.  Mere child's play!  Now what you have hear is something to make Da Vinci erect.  (sit up in his chair, get your mind out of the gutter   )   

I'm going to be busy with this for a while.  Thanks to you and everyone involved in this!  

[pougnetpedals]

New to the site. Am I missing something? It doesn't look like the link to the GuitarFreak macro works anymore? Is it still available?