String pluck detector??

[markusw]

Please forgive me but I still cannot grasp what you are trying to achieve.

I would like to reliably get a pulse each time I plug a string. It should also work for fast runs and if notes are played legato. Of course hammer-ons would be cool too 
Actually, I don't need an envelope, only if it's part of the pluck detector.

Regards,

Markus

[Mark Hammer]

Without wishing to be too much of a contrarian, I can't see why someone would want a trigger pulse and NOT want an envelope voltage unless the intent was simply to apply envelope generators to fairly normal effects like a phaser, etc. and use those to process a fairly conventional guitar signal.  The thing about having an envelope signal at your disposal is that you can add it to whatever envelope generators you have.

[puretube]

FX-Tracker...

[EDIT]: found it... - impressive!

[markusw]

Without wishing to be too much of a contrarian, I can't see why someone would want a trigger pulse and NOT want an envelope voltage unless the intent was simply to apply envelope generators to fairly normal effects like a phaser, etc. and use those to process a fairly conventional guitar signal.  The thing about having an envelope signal at your disposal is that you can add it to whatever envelope generators you have.

I just need the trigger pulses to switch a sample/hold circuit and a few other connections within a PLL-based harmonizer. Since I intend to feed the harmonizer signal as a carrier into a ring modulator there is no need for an envelope.
Plain, reliable pulses with every pluck would be more than great 
So far the idea worked out pretty well but I'm not really happy with my current pluck detector.

Regards,

Markus

[markusw]

FX-Tracker...

[EDIT]: found it... - impressive!

definitely impressive 

[puretube]

I think the guy has been here once, a year or 2 ago...

[Mark Hammer]

Dare I say it, he could be too smart for here.  That's one heck of a product.  Of course, it could be too smart for most musicians, too.

[puretube]

at that time it appeared, I was not at all interested, coz I thought it were some computer plug-in,
or "virtual" software thingy (from the look of the first image-renderings...

but a recent thread at HC opened my eyes 

(BUT: it`s digital  )

[toneman]

had not ever heard of this!!   

thanx!! for the link & info PT 
gonna go back an watch the videos   

the BOSS RC-50 is supposed to be the ultimate looper.
I have an RC-20 and it's OK, but the hardwired switch for changing loop really sucks.
I've heard demos of the Boomerang also.

I'm looking to do the same as Markus--  some type of harmonizer into my RingModulator carrier input.
BTW. I googled for "slew detector"  and couldn't find a thing!   

may all your loops be fruity!!   
afn

T

[Meanderthal]

 WOW! That's something completely different! I especially like the MIDI clock out (even though I haven't used MIDI in years). This is the kinda stuff that's been in my 'I wish it were possible' mental list for a long time. One of the coolest things I've seen in a long time! Waveform outs, jeez it goes on and on.

I wonder how effective it really is? Like the tracking and stuff... If it's REALLY good it might even work on bass...

[johngreene]

I think if I was to try and make a 'pluck detector', I would try to utilize the fact that when a string is 'plucked' it is more or less percussive. [speculation]This means it has a really sharp rise time, probably not harmonically related to the string being 'plucked'[/speculation]. A sharp rise time can be differentiated into a (non-ideal) impulse. Or a pulse of finite time in the real world. This can be setup to trigger just about anything you want. There would still be some 'thresholding' but it would be more of how hard/purposely do you have to pluck the string in order for it to be detected than how 'loud' the signal is coming from the string.

That's how I would approach it anyway.

FWIW,

--john

[markusw]

A sharp rise time can be differentiated into a (non-ideal) impulse.

Hey John,
thanks for your help! 
My current pluck detector has one differentiation step (of the envelope). I think of adding a second one.
Is it what you mean??

Regards,

Markus

[StephenGiles]

Please forgive me but I still cannot grasp what you are trying to achieve.

I would like to reliably get a pulse each time I plug a string. It should also work for fast runs and if notes are played legato. Of course hammer-ons would be cool too 
Actually, I don't need an envelope, only if it's part of the pluck detector.

Regards,

Markus

I see, I'll look at the Arp Avatar manual over the weekend for anything that may be of help.

[markusw]

I see, I'll look at the Arp Avatar manual over the weekend for anything that may be of help.

Cool!  Thanks a lot!!

Markus

[StephenGiles]

FX-Tracker...

[EDIT]: found it... - impressive!

definitely impressive 

I agree - impressive but hardly of use in a band!

[markusw]

I breadboarded the AMS-100 pluck detector yesterday evening (modified for a single 12V supply) and it works pretty nice. Definitely better than my home-made "fwr-envelope-follower-double differentiator" thingy. It's very sensitive and triggers quite nicely over the whole guitar range. Depending on the gain it still has a preference for the lower or higher frequency range but it defintely is a valid option. Will start tweaking the various pots now to see how they change the response.

Regards,

Markus

[Mark Hammer]

Just curious.  How did you evaluate the responsiveness of it?

[markusw]

Just curious.  How did you evaluate the responsiveness of it?

Firstly, there is a 555 connected to the pluck dtector wired as a pulse stretcher that gives a "on signal" for 100-150 ms. This pulse drives an LED indicator which clearly flashes with each pluck.
Secondly, the pluck detector is connected to a 4046 PLL plus a sample/hold stage. The PLL only changes frequency if the pluck detector triggers.
Once I optimised the whole mess I'll post the schematics so we can discuss how to improve it (or whether to forget it) 

Markus

[Mark Hammer]

Cool.  Worth waiting for patiently.

[markusw]

Here is a sound sample of the PLL circuit with the AMS-100 pluck detector (PD). The PLL is set to 2 or in the second half of the clip to 3 octaves up and fed as a carrier into my Ring Stinger clone.
The PD triggers a NE555 which is set to give a "on signal" for about 100 ms (don't know exactly yet) with each pluck.
So with each pluck the circuit goes for 100 ms to sample and then back to hold keeping the VCO freq constant until the next pluck. A LF398 samples the 4046'S PC2 out voltage.
In sample state the 4046's PC2 out is connected directly (via the loop filter) to the 4046's VCO-in. After 100 ms the LF398 goes to hold and two 4066's disconnect PC2-out to VCO-in and connect LF398-out to VCO-in. At the same time the comparator that during sampling feed's the squared guitar signal into the 4046 is disconnected by another 4066 and the VCO is connected with the PLL's input. Therefore, after going back to hold  PC2-out remains at the level of the last note played.
In my hands this trick speeds up the lock-in or at least makes the glitch at the beginning of each note a bit less noticeable.
Interestingly, the PLL locks in faster when the strings are plucked a bit harder although the guitar signal squarer works at much lower levels. Also performance is better when the strings are plucked with a pick. Since I never used a pick with bass the clip is also done without. It's a cheap Strat copy at neck pu and recording was done directly into the PC w/o cab sim.

Let me know what you think 

http://www.aronnelson.com/DIYFiles/up/Ring_Mod_PLL_SH_2_3_octaves_up_14-03-07.mp3

Markus