Guitar's notes recognizer

[marcbarker]

marcbarker I appreciate, but could you do a quick explanation of what it does?

It's a single-IC circuit, it takes in an audio signal and outputs a DC voltage according to pitch that's all. When there's no input signal it'll be zero volts. There'll be a 'portamento' effect going on, as the voltage ramps up to the input pitch, which could be annoying.


edit: still not drawn one out, but there are lots of examples out there frequency to voltage pll 4046 - Google Search

 

[kauedg]

Don't forget about bends, mutes and slides etc. Not sure how that would effect the frequency curve may just be a matter of sampling the note(s)... *shrug*.

Yeah no doubt, but one step at a time... =)

Today I dropped by a friend who owns a musical instruments store, and he's putting aside a single and doube coil pickups so I can make some tests...

 

[kauedg]

gabeNC I can't thank you enough for this link:

Here's a patent description for hexaphonic digital pu's some of it is fluff, some of it is interesting.
Hexaphonic pickup for digital guitar system - US Patent 7166794 Description


It has amost everything I will need, it even explains the hex pickup with two coils per string. I will try to make one and later and output it's signal to the computer, to a MIDI encoder. If it works I will go ahead and try to adapt a hardware MIDI encoder!

Thanks!!

 

[marcbarker]

Feed the unknown frequency into this circuit and it will provide a DC output representing frequency.
**broken link removed** It comes from Forrest Mimms Circuit Scrapbook.

Six of these needed, one for each individual string.

I don't know exactly what to use for six individual-channel pickup, but what I do know for sure is that the most expensive hand-wound, noise cancelling, superior-tonal quality, glowing reputation as used by Bruce Springsteen isn't going to work at all. You'd do better winding your own using roofing nails and a magnet from a hard disk drive!

 

[kauedg]

marcbarker thank you so much! The pickup I will make with some lousy spare humbucker that a friend is going to give me.

 

[gabeNC]

gabeNC I can't thank you enough for this link:

Here's a patent description for hexaphonic digital pu's some of it is fluff, some of it is interesting.
Hexaphonic pickup for digital guitar system - US Patent 7166794 Description


It has amost everything I will need, it even explains the hex pickup with two coils per string. I will try to make one and later and output it's signal to the computer, to a MIDI encoder. If it works I will go ahead and try to adapt a hardware MIDI encoder!

Thanks!!

You're welcome. Please continue to post the progress of your project, it is interesting.

I skimmed the patent article but did not read it in depth, sometimes patents are light on details on purpose and some are "prior-art". With two coils per pickup, i imagine that they are like "mini-humbuckers" and are out of phase with each other. This should reduce the ambient noise and hopefully give the preamp/ADC(?) a better signal.

This is the best picture i could find of roland's divided pickup.

**broken link removed**

 

[kauedg]

gabeNC the divided pickup coil works this way:

- Each string has one "double-coil" exclusive system;
- Each coil has it's positive and negative;
- So, for each string there is: R+, R-, L+, L-;
- From the left coil a vertical signal, with noise is created;
- A noise subtracting signal, linked to a "spare" noise coil, is applied to the vertical signal;
- From the right coil a horizontal signal, without noise is created;
- Finally, the two signal's dimensions are combined.

Quite creative huh? I'm surprised that my block diagram was almost correct, I only missed the pre-amp and the limiter:

(1) - (2) - (3) - (4) - (5)

(1) - Hex pickup
(2) - Pre-amp
(3) - Signal "filtering"
(4) - Limiter
(5) - ADC converter


I just got a humbucker pickup to make some tests. First, I'll test it and then disassemble and design the coils. I still don't know how many turns (or resistence) I'll give each coil. Any suggestions?

 

[gabeNC]

gabeNC the divided pickup coil works this way:

- Each string has one "double-coil" exclusive system;
- Each coil has it's positive and negative;
- So, for each string there is: R+, R-, L+, L-;
- From the left coil a vertical signal, with noise is created;
- A noise subtracting signal, linked to a "spare" noise coil, is applied to the vertical signal;
- From the right coil a horizontal signal, without noise is created;
- Finally, the two signal's dimensions are combined.

To me that sounds just like a modified humbucker with the exception that it is per string.

Quite creative huh? I'm surprised that my block diagram was almost correct, I only missed the pre-amp and the limiter:

(1) - (2) - (3) - (4) - (5)

(1) - Hex pickup
(2) - Pre-amp
(3) - Signal "filtering"
(4) - Limiter
(5) - ADC converter


I just got a humbucker pickup to make some tests. First, I'll test it and then disassemble and design the coils. I still don't know how many turns (or resistence) I'll give each coil. Any suggestions?

Since you'll probably be using active pickups, you can get away with a weaker magnet and less windings per coil. That's probably how Roland gets theirs in such a small package.

I bought this book about 15 years ago, it's pretty dated but has ohm readings and winding numbers for most types of pickups plus some interesting wiring diagrams (Page's les paul with 4 push/pull pots).

Amazon.com: Guitar Electronics For Musicians (Guitar Reference) (0752187423249): Donald Brosnac: Books

I've torn apart many pickups over the years, haven't rewound any yet, was close to ordering a spool of 43 gauge wire but haven't followed through yet.

Good luck.

 

[ameal]

i´ve crossed this thead looking for something else but found thetopic very interesting.
i would also benefit from such an aplication.

But i would not encourage you to make it an hardware issue, or to find an hardware solution.
Since you have software knowledge and sound samples of every kind are readly available,
i encourage you to find the note out of mp3 files first.
maybe later you could do this realtime, with dedicated hardware.
And then you already have the software to back it up.

My point is:
I love fado. This type of music consist of two guitars.
the link i sent you as a Portuguese Guitar on the left channel and a Classical Guitar on the right one. My focus is on the last one.
This actually represents the setup for the real concerts: one guitar on each side of the singer.

Get a working demo that extracts partitures from it and i´ll gladdly donate something for your beta releases.

I can not strees enough than i really encourage you to go software aproach first.

Best Regards,
Hugo
Portugal