Adding "frequency distortion" to a guitar signal

[Rob Strand]

One of the most fascinating books I ever read was one about mechanized automated music devices.  It covered things like the paper-roll devices shown above, but surprisingly they go back a LOT farther than the late 1800s or early 1900s.  That said, those devices were commercial coin-operated sources of music.  The ones from much earlier eras (and even Da Vinci designed one) were generally privately-owned devices, made for a wealthy benefactor.  They were essentially very large music boxes.

But wouldn't you love to see an entire extended episode of "How It's Made" devoted to design and assembly of one of those paper-roll things?

I worked on a project which retrofitted computer control schemes onto Jacquard looms.   These old machines had quite evolved ideas of automation and the encoding of functions and data on to the paper cards.

https://en.wikipedia.org/wiki/Jacquard_machine

Look at the dates in the text.

My uncle did piano restorations.   He once restored a Pianola.   Can't remember much about it as I was only 8 yo or so.  But I did hide under the thing pushing the pedals with my hands at one of the Christmas parties.

[matopotato]

And if you feed it with @Mark's paper tape for his computer boot instructions, we might have ourselves a Ring Mod? "Extra vintage"

[Mark Hammer]

One of the most fascinating books I ever read was one about mechanized automated music devices.  It covered things like the paper-roll devices shown above, but surprisingly they go back a LOT farther than the late 1800s or early 1900s.  That said, those devices were commercial coin-operated sources of music.  The ones from much earlier eras (and even Da Vinci designed one) were generally privately-owned devices, made for a wealthy benefactor.  They were essentially very large music boxes.

But wouldn't you love to see an entire extended episode of "How It's Made" devoted to design and assembly of one of those paper-roll things?

I worked on a project which retrofitted computer control schemes onto Jacquard looms.   These old machines had quite evolved ideas of automation and the encoding of functions and data on to the paper cards.

https://en.wikipedia.org/wiki/Jacquard_machine

Look at the dates in the text.

My uncle did piano restorations.   He once restored a Pianola.   Can't remember much about it as I was only 8 yo or so.  But I did hide under the thing pushing the pedals with my hands at one of the Christmas parties.

We like to think that "advanced" engineering somehow began with us, when really, humans have been addressing manufacturing (as well as musical and military) objectives in ingenius ways for literally centuries.  Often, what posed the biggest hurdles were not ideas, so much as materials and technologies to leverage those ideas.

[ElectricDruid]

I've been mulling over how best you'd go about creating the frequency shift effect that OP was looking for.

Ring Mod like in the other thread gets you close-ish, but you get x+y and x-y for your inputs. E.g. each harmonic of your guitar signal going in gets turned into two signals coming out, one higher than it used to be, and one lower.

Frequency modulation does a similar thing, in that it generates negative sidebands as well as positive ones. In radio, you filter off one set of sidebands. Could we do something similar here so that we only get x+y? (or x-y, for real turn-your-signal-inside-out-and-upside-down weirdness).

That's not really possible with ring mod because the frequencies are all on top of each other, so you can't filter one group out and leave the other.

[Rob Strand]

We like to think that "advanced" engineering somehow began with us, when really, humans have been addressing manufacturing (as well as musical and military) objectives in ingenius ways for literally centuries.  Often, what posed the biggest hurdles were not ideas, so much as materials and technologies to leverage those ideas.

I've had that type of view for some time.   People 5000 years ago were probably no different to us.   It's more about building technology on the shoulders of those before.  There's also more people so statistically more chance of finding the "chosen ones" who can solve certain problems - in some ways like the continual improvements in Olympic records.

[amptramp]

I've been mulling over how best you'd go about creating the frequency shift effect that OP was looking for.

Ring Mod like in the other thread gets you close-ish, but you get x+y and x-y for your inputs. E.g. each harmonic of your guitar signal going in gets turned into two signals coming out, one higher than it used to be, and one lower.

Frequency modulation does a similar thing, in that it generates negative sidebands as well as positive ones. In radio, you filter off one set of sidebands. Could we do something similar here so that we only get x+y? (or x-y, for real turn-your-signal-inside-out-and-upside-down weirdness).

That's not really possible with ring mod because the frequencies are all on top of each other, so you can't filter one group out and leave the other.

It sounds like you are looking for a single sideband generator.

1. sin (a + b) = sin a * cos b + cos a * sin b
2. sin (a - b) = sin a * cos b - cos a * sin b
3. cos (a + b) = cos a * cos b - sin a * sin b
4. cos (a - b) = cos a * cos b + sin a * sin b

Where a and b are the frequencies to be mixed, in this case, the signal frequency and the offset you want in that frequency.  The result is on the left of the equal sign and the operations you need to get there are on the right.  You have to provide a 90 degree phase-shifted version of both the guitar output (via an allpass filter like those used in phasors) and the modulating frequency.  Since the modulating frequency is from an LFO, a quadrature phase oscillator is necessary.  The schematic and design calculations for the quadrature phase oscillator using three op amps are shown here:

https://www.hindawi.com/journals/apec/2011/320367/

Deviations from the exact 90 degrees should not be that important.  They will show up as the undesired sum or difference not being nulled but being  maybe 10 to 30 db down.  That should be enough to make them unimportant.  Let us know what you build!

[antonis]

I worked on a project which retrofitted computer control schemes onto Jacquard looms.   These old machines had quite evolved ideas of automation and the encoding of functions and data on to the paper cards.

>off topic ON<

A long time ago, I was working as electromechanical service man for a textile industry..
All the designers wanted to make a new pattern used exclusively the paper reels of the Jacquard knitting machine..!!
(like protoboard for PCB production..)

>off topic OFF<

[Rob Strand]

>off topic ON<

A long time ago, I was working as electromechanical service man for a textile industry..
All the designers wanted to make a new pattern used exclusively the paper reels of the Jacquard knitting machine..!!
(like protoboard for PCB production..)

>off topic OFF<

The designers often created their design on a special machine which followed their motions and *created* the punched card one step at a time.  If they stuffed up they cut and splice punch tapes (no different to audio editing), or, tape over the holes and do it again. 

When the design was completed they used a third machine called a punch that could copy the punch tapes.  That way they had a clean version without the edits.   They also used the punch to make multiple copies so production runs could be made on multiple machines.

In the modern age of computers designers moved to doing designs using CAD software.   The companies then needed to get the CAD output onto the punch card so the designs could be used the machines which had no computer interface retrofit.   A computer interface retrofit was placed on the punch to emulate the master punch card and it produced a punch card copy of the CAD output.

We also had a machine which could read in old designs optically from paper cards and store them on a computer.    That way companies could edit or archive all designs from their design libraries stored on paper tapes.   I'm sure you remember these were large heavy reels of thick paper which took up a very large storage space.

[PRR]

...using paper tapes with punched holes that could be re-fed back to read program instructions. Sort of a step up from punch cards.

Different industries came together.

Punchcards go to Jacquard looms and their ancestors. Hollerith (and others!) used the idea for like Census Data. Make a card for every person. How many people 43 years old? How many doctors, butchers? Electric contacts kicked-out cards with the desired hole, counters totalized the data.

Paper tape has many mothers but the big electrical use was telegraph TeleType. Telegraphy was all hand-work. Printing telegraphs and keyboard telegraphs evolved but what was really needed was "notepad", intermediate storage needing no code-skill to capture and re-send telegraphs. A real network needs a store-and-forward network node, so you take a combined feed and then split it out to the several destinations.

The card and tape hardware was VERY developed before you could rub 1,300 vacuum tubes together to do a "computer". Lots of data processing could be done with card-sorts and plug-bays, my uncle did that for a national church, publishing and budgeting.