Hi all,
I'm studying Electronic Engineering. Next schoolyear, I have to make a Master's Thesis. My interest is off course: audio.
Most of students will do this thesis in cooperation of a company. I contacted a lot of companies, but most of them didn't had the time/place/... at the time. The few that were positive didn't have an interesting subject.
But we are also alowed to make a thesis without a company; just in our school.
Now I was thinking of doing something with DSP or something else digital. This semester I have classes about DSP and just a few labs (only some MatLab stuff). Most of the things we learn are theoretical, so I don't have any experience with DSP in practice.
So, now I'm brainstorming to find a suitable subject. And looking for some help. ;)
Are there any new developments the last years on the subject of DSP in audio? New ideas, new processors, ...?
Is there something that you always wanted to see made; but have no time for?
...
All help is appreciated
Thank you.
"Master's thesis: a piece of work for conclusion of the master's program. By doing so, the student shows an analytical and synthetical capacity or an independent problem-solving aptitude on an academic level. The delivered work reflects the student's general critical-reflective or research-minded attitude."
What about an attempt to divide a mono guitar signal to six different outputs? Extracting the string signals exactly would be impossible but what if it was a synth that would analyze the input signal and use up to six oscillators to achieve a similar result to six independent audio outputs or, more practical yet, as midi output.
Well it's better than nothing. :D
----------
Jimbo
Quote from: JimRayden on May 14, 2008, 11:46:52 AM
What about an attempt to divide a mono guitar signal to six different outputs? Extracting the string signals exactly would be impossible but what if it was a synth that would analyze the input signal and use up to six oscillators to achieve a similar result to six independent audio outputs or, more practical yet, as midi output.
Well it's better than nothing. :D
----------
Jimbo
Thank you for your tip.
I think it will be very similar to the guitar synths of roland. And I already talked with a professor about midi; and he thinks that the time for midi as an output signal is over.
Other tips, links to usefull sites, ... ?
Thanks...
Don't be afraid to contact researchers, even outside of your country, you'll be surprised sometimes how they can be happy to talk about their works and futur avenue and possibilities...Sure some would not respond...but some do!
Just a suggestion, maybe it does'nt fit at all, but you'll got the idea:
http://www.ee.surrey.ac.uk/profiles?s_id=1376
Dan
Where do you go to school? Im a EE from Georgia Tech.
Quote from: JimRayden on May 14, 2008, 11:46:52 AM
What about an attempt to divide a mono guitar signal to six different outputs? Extracting the string signals exactly would be impossible but what if it was a synth that would analyze the input signal and use up to six oscillators to achieve a similar result to six independent audio outputs or, more practical yet, as midi output.
Well it's better than nothing. :D
----------
Jimbo
That's an idea that has merit - but rather than using MIDI, use six separate A/D's. Once you've got your digital signal you can do anything you want to it. This way you could get much better tracking for multiple notes. Think Whammy pedal that pitch shifts an entire chord. Or you could drop your E and A strings an octave, keeping the original signal as well, but leaving the rest untouched. Or to only put delay on certain strings and/or notes. Or on the fly tuning correction - so long as the strings are 'close enough' you're sweet!
Mate, the possibilities are endless!!
Quote from: carrejans on May 14, 2008, 07:04:33 PM
Thank you for your tip.
I think it will be very similar to the guitar synths of roland. And I already talked with a professor about midi; and he thinks that the time for midi as an output signal is over.
Firstly, as far as I know, Roland uses a hex pickup for their synths, not one mono signal from regular guitar pickups. Secondly, isn't MIDI the standard on all of today's synthesizer systems or have I missed an innovation to replace that technology.
---------
Jimbo
Quote from: ACS on May 14, 2008, 11:01:59 PM
Quote from: JimRayden on May 14, 2008, 11:46:52 AM
What about an attempt to divide a mono guitar signal to six different outputs? Extracting the string signals exactly would be impossible but what if it was a synth that would analyze the input signal and use up to six oscillators to achieve a similar result to six independent audio outputs or, more practical yet, as midi output.
Well it's better than nothing. :D
----------
Jimbo
That's an idea that has merit - but rather than using MIDI, use six separate A/D's. Once you've got your digital signal you can do anything you want to it. This way you could get much better tracking for multiple notes. Think Whammy pedal that pitch shifts an entire chord. Or you could drop your E and A strings an octave, keeping the original signal as well, but leaving the rest untouched. Or to only put delay on certain strings and/or notes. Or on the fly tuning correction - so long as the strings are 'close enough' you're sweet!
Mate, the possibilities are endless!!
Very, very interesting idea. But how to divide the audio signal into 6 different outputs?
- If you just use a normal guitar cable; you will have to filter the one audio signal into an output of each string. But this is impossible. You cannot 'see' in your audio signal which frequency is coming from wich string. Because you can play one same note on different strings; but the frequency will be the same.
- If you make a pick-up and an audio cable with six different channels; you will face another problem. The six different microphones in your pick-up will not only pick-up the signal of the string above, but also of the other strings.
- You could make a digital pick-up; but that's been done before. (Roland synths)
So, it is an interesting idea; but I think impossible to make.
Please, keep the solutions and ideas coming.
Thank you all
Quote from: The French connection on May 14, 2008, 08:37:03 PM
Don't be afraid to contact researchers, even outside of your country, you'll be surprised sometimes how they can be happy to talk about their works and futur avenue and possibilities...Sure some would not respond...but some do!
Just a suggestion, maybe it does'nt fit at all, but you'll got the idea:
http://www.ee.surrey.ac.uk/profiles?s_id=1376
Dan
I emailed about 80 companies over the world, that I was interested in. Only 12 replied. :)
This weekend I'm going to visit an AES convention in Amsterdam. I hope I can find a company willing to cooperate; and maybe some inspiration for a subject.
Quote from: JimRayden on May 15, 2008, 08:05:44 AM
Quote from: carrejans on May 14, 2008, 07:04:33 PM
Thank you for your tip.
I think it will be very similar to the guitar synths of roland. And I already talked with a professor about midi; and he thinks that the time for midi as an output signal is over.
Firstly, as far as I know, Roland uses a hex pickup for their synths, not one mono signal from regular guitar pickups. Secondly, isn't MIDI the standard on all of today's synthesizer systems or have I missed an innovation to replace that technology.
---------
Jimbo
You are totally right.
But like said in a few posts above this one; it is not possible to extract the signals from the different strings out of one mono signal. (I think)
But thank you for your thoughts; they are very usefull. I appreciate it.
Quote from: defzeppardica on May 14, 2008, 10:09:52 PM
Where do you go to school? Im a EE from Georgia Tech.
In Leuven, Belgium.
Quote from: carrejans on May 15, 2008, 03:52:48 PM
Quote from: ACS on May 14, 2008, 11:01:59 PM
Quote from: JimRayden on May 14, 2008, 11:46:52 AM
What about an attempt to divide a mono guitar signal to six different outputs? Extracting the string signals exactly would be impossible but what if it was a synth that would analyze the input signal and use up to six oscillators to achieve a similar result to six independent audio outputs or, more practical yet, as midi output.
Well it's better than nothing. :D
----------
Jimbo
That's an idea that has merit - but rather than using MIDI, use six separate A/D's. Once you've got your digital signal you can do anything you want to it. This way you could get much better tracking for multiple notes. Think Whammy pedal that pitch shifts an entire chord. Or you could drop your E and A strings an octave, keeping the original signal as well, but leaving the rest untouched. Or to only put delay on certain strings and/or notes. Or on the fly tuning correction - so long as the strings are 'close enough' you're sweet!
Mate, the possibilities are endless!!
Very, very interesting idea. But how to divide the audio signal into 6 different outputs?
- If you just use a normal guitar cable; you will have to filter the one audio signal into an output of each string. But this is impossible. You cannot 'see' in your audio signal which frequency is coming from wich string. Because you can play one same note on different strings; but the frequency will be the same.
the
fundamental frequency will be the same. but you don't need an oscilloscope to know that each string has its own sonic personality. if i were trying to do this, i would see whether you could "train" the software to recognize each string in analogy with training for voice recognition. i think it's doable.
Quote from: carrejans on May 15, 2008, 03:52:48 PM
Quote from: ACS on May 14, 2008, 11:01:59 PM
Quote from: JimRayden on May 14, 2008, 11:46:52 AM
What about an attempt to divide a mono guitar signal to six different outputs? Extracting the string signals exactly would be impossible but what if it was a synth that would analyze the input signal and use up to six oscillators to achieve a similar result to six independent audio outputs or, more practical yet, as midi output.
Well it's better than nothing. :D
----------
Jimbo
That's an idea that has merit - but rather than using MIDI, use six separate A/D's. Once you've got your digital signal you can do anything you want to it. This way you could get much better tracking for multiple notes. Think Whammy pedal that pitch shifts an entire chord. Or you could drop your E and A strings an octave, keeping the original signal as well, but leaving the rest untouched. Or to only put delay on certain strings and/or notes. Or on the fly tuning correction - so long as the strings are 'close enough' you're sweet!
Mate, the possibilities are endless!!
Very, very interesting idea. But how to divide the audio signal into 6 different outputs?
- If you just use a normal guitar cable; you will have to filter the one audio signal into an output of each string. But this is impossible. You cannot 'see' in your audio signal which frequency is coming from wich string. Because you can play one same note on different strings; but the frequency will be the same.
- If you make a pick-up and an audio cable with six different channels; you will face another problem. The six different microphones in your pick-up will not only pick-up the signal of the string above, but also of the other strings.
- You could make a digital pick-up; but that's been done before. (Roland synths)
So, it is an interesting idea; but I think impossible to make.
Please, keep the solutions and ideas coming.
Thank you all
What about using a piezo system? This would be far easier to isolate each string. Yes, it would require a custom piezo solution (afaik they con't have six outputs as standard - but I may be wrong!!), but then you can easily run six outputs from there to your A/D's. In fact, if you set the guitar up with a USB connection to the processor, you could put you A/D's on board at the guitar, drawing their power from the USB bus...
Quote from: carrejans on May 15, 2008, 03:57:34 PM
You are totally right.
But like said in a few posts above this one; it is not possible to extract the signals from the different strings out of one mono signal. (I think)
Well I believe it's pretty doable, in one form or another. Would need some massive amounts of frequency spectrum analyzing and a whole bunch of lines of code.
One way could be identifying peaks in the frequency spectrum - one would just have to start from low frequencies, and when detecting a major peak, start an oscillator of that frequency. Thereafter it would subtract the assumable harmonics of that note from the rest of the frequency spectrum and continue moving upwards with the same process. And as gaussmarkov suggested, one could set up the machine by playing different notes on the guitar as the program prompts, so it could adjust its harmonics database to your guitar. Pretty utopic but, why the heck not? :)
One wouldn't even have to do it at a great rate since the oscillators take care of the sound fidelity, a few hundred times a second would be sufficient I think.
Besides, using hex pickups would be just plain boring. :D
---------
Jimbo
Quote from: gaussmarkov on May 15, 2008, 04:28:13 PM
the fundamental frequency will be the same. but you don't need an oscilloscope to know that each string has its own sonic personality. if i were trying to do this, i would see whether you could "train" the software to recognize each string in analogy with training for voice recognition. i think it's doable.
What is exactly this "sonic personality"?
But wouldn't this "sonic personality" be different on each guitar and brand of strings?
If I understand you correct, you have to use the audio signal for the "training" and not the frequency?
Quote from: ACS on May 15, 2008, 07:16:21 PM
What about using a piezo system? This would be far easier to isolate each string. Yes, it would require a custom piezo solution (afaik they con't have six outputs as standard - but I may be wrong!!), but then you can easily run six outputs from there to your A/D's. In fact, if you set the guitar up with a USB connection to the processor, you could put you A/D's on board at the guitar, drawing their power from the USB bus...
Hmm, very good thinking. I will investigate the piezo system this weekend. Thank you.
Quote from: JimRayden on May 15, 2008, 07:25:23 PM
Well I believe it's pretty doable, in one form or another. Would need some massive amounts of frequency spectrum analyzing and a whole bunch of lines of code.
One way could be identifying peaks in the frequency spectrum - one would just have to start from low frequencies, and when detecting a major peak, start an oscillator of that frequency. Thereafter it would subtract the assumable harmonics of that note from the rest of the frequency spectrum and continue moving upwards with the same process. And as gaussmarkov suggested, one could set up the machine by playing different notes on the guitar as the program prompts, so it could adjust its harmonics database to your guitar. Pretty utopic but, why the heck not? :)
One wouldn't even have to do it at a great rate since the oscillators take care of the sound fidelity, a few hundred times a second would be sufficient I think.
Besides, using hex pickups would be just plain boring. :D
---------
Jimbo
Few, I had to read this twice to understand what you mean. Theoretical it sounds that it could work; but if it is doable in practice. I have to think about this for a while. :)
Do you think that the output will still sound nice; and not artificial?
Thank you all, for contributing to this topic. Very usefull.
Quote from: carrejans on May 16, 2008, 12:24:09 PM
Few, I had to read this twice to understand what you mean. Theoretical it sounds that it could work; but if it is doable in practice. I have to think about this for a while. :)
Do you think that the output will still sound nice; and not artificial?
Artificial? Oh heck yeah, definitely not as pretty as using hex PU. It would certainly have at least some glitches and "jumps", especially when pulling off double stops and such. My idea behind this is not to make it control digital patches of different guitar models or any sorts of realistic instruments, but rather use it as an input for an (perhaps virtual-)analogue synth where excellent tracking and guitar-y feel aren't that important. It would certainly need a bit different approach to playing also, just like EHX's monophonic synth pedals and octavers, where you'll just mess up the tracking if you don't take it gentle and back off the tone knob.
The problem with frequency analyzing is that it needs a pretty long sample of the signal, so that sets the "refresh rate" of this device quite low (not influencing oscillator fidelity, as I mentioned before). The sixth string is 83Hz, so one would need to aim lower than that. Then again, I might be way off here, I'm not familiar with the exact algorithms.
---------
Jimbo
Quote from: carrejans on May 16, 2008, 12:17:33 PM
Quote from: gaussmarkov on May 15, 2008, 04:28:13 PM
the fundamental frequency will be the same. but you don't need an oscilloscope to know that each string has its own sonic personality. if i were trying to do this, i would see whether you could "train" the software to recognize each string in analogy with training for voice recognition. i think it's doable.
What is exactly this "sonic personality"?
But wouldn't this "sonic personality" be different on each guitar and brand of strings?
If I understand you correct, you have to use the audio signal for the "training" and not the frequency?
i think JimRayden and i are thinking along the same lines. as an example, each string has different amounts of each of the overtones that accompany a fundamental. this is one of the things that makes the strings sound different even though you may play the same note on each. so when you pick out a fundamental from the signal, you also pick out its overtones and look at the relative amplitudes. that may be enough to identify which string is making the note.
and yes, each set up would probably require some training with the software so that it can memorize the relative amplitudes. because it seems a lot simpler than word recognition, i am guessing that a relatively small amount of training would be needed. who knows? maybe you play 4 notes on each string and you are calibrated.
Thank you guys for all your input.
I've made an overview, to show to my thesis-partner tomorrow to discuss the possibilities.
PROCESSING ELECTRIC GUITAR OUTPUT PER SEPERATE STRING
The ultimate goal with this product:
- pitch shifting each string seperately (no need for tuning your guitar for alternate tunings)
- put delay on only those strings, chosen by the user
- put any effect on only those strings, chosen by the user
- ...
Two possible ways of dividing the guitar signal into 6 seperate outputs
Possibility 1: - keeping original pickups
- connection between guitar and the processing box with normal instrument cable
- dividing the audio signal into the 6 different signals inside the box
- processing the seperate signals inside the processing box (pitch shifting, delay, ... with the help of DSP)
Possibility 2: - using/making pickups with outputs for each string
- using/making a cable for the 6 seperate signals
- or putting ADC's inside the guitar/pickups and sending the signals via ethernet or USB cable
- processing the seperate signals inside the processing box (pitch shifting, delay, ... with the help of DSP)
Solutions for the problems of splitting the signal
Possibility 1: - problem: same note on different strings have the same frequency
- possible solution: each string has its own sonic personality. The fundamental frequency will be the same, but each string
has different amounts of each of the overtones that accompany a fundamental. So we pick out a fundamental from the signal
and pick out its overtones; then we have to look at the relative amplitudes.
- another problem: this sonic personality will be different on each guitar and probably each string brand
- possible solution: before using the box, the user has to "train" the software to calibrate the system (cfr. voice recognition
software)
Possibility 2: - problem: when using a normal magnetic pickup, each polepiece will not only pick up the vibrations of its corresponding
string
- possible solution 1: isolating each string and its accompanying polepiece from the others
- possible solution 2: using piezoelectric pickups
- possible solution 3: using optical pickups (fairly recent development (1969) that works by sensing the interruption of a light
beam by the string
Advantages & disadvantages
Possibility 1: + no extra pickup has to be placed, originals can be used
+ no special cable is necessary, normal instrument cable can be used
- theoretical possible; but is it possible in practice? Difficulty?
- user needs to train the software
- will the sound loses its character? Will it sound a bit artificial?
Possibility 2: - extra pickup needs to be placed
- requires a special cable
+ easier to implement in software
+ no need to train the software
+ no excessive filtering; sound will be less artificial
Quote from: carrejans on May 17, 2008, 08:13:45 AM
Thank you guys for all your input.
I've made an overview, to show to my thesis-partner tomorrow to discuss the possibilities.
Dude, that looks great!! Best of luck - the possibilities are endless... I'd buy one ;)
Found this - thought it might be just what the Doctor ordered... All the hard work's done for you! :lol:
http://www.stewmac.com/shop/Electronics,_pickups/Pickups:_Guitar,_electric/1/Graph_Tech_Ghost_Pickup_System_for_Guitar.html (http://www.stewmac.com/shop/Electronics,_pickups/Pickups:_Guitar,_electric/1/Graph_Tech_Ghost_Pickup_System_for_Guitar.html)
Quote from: JimRayden on May 16, 2008, 02:11:04 PM
Artificial? Oh heck yeah, definitely not as pretty as using hex PU. It would certainly have at least some glitches and "jumps", especially when pulling off double stops and such. My idea behind this is not to make it control digital patches of different guitar models or any sorts of realistic instruments, but rather use it as an input for an (perhaps virtual-)analogue synth where excellent tracking and guitar-y feel aren't that important. It would certainly need a bit different approach to playing also, just like EHX's monophonic synth pedals and octavers, where you'll just mess up the tracking if you don't take it gentle and back off the tone knob.
The problem with frequency analyzing is that it needs a pretty long sample of the signal, so that sets the "refresh rate" of this device quite low (not influencing oscillator fidelity, as I mentioned before). The sixth string is 83Hz, so one would need to aim lower than that. Then again, I might be way off here, I'm not familiar with the exact algorithms.
---------
Jimbo
- Actually I'm not so interested in making it control an analogue synth. I prefer to use it like ACS suggested (using all kinds of effects on user-selected strings)
- I am not that familiar with frequency analyzing in practice with audio. So, I have no idea if Gausmarkov's and yours idea of it, is really possible; and will be fast enough to not have a delay.
Quote from: carrejans on May 17, 2008, 08:13:45 AM
Thank you guys for all your input.
I've made an overview, to show to my thesis-partner tomorrow to discuss the possibilities.
Dude, that looks great!! Best of luck - the possibilities are endless... I'd certinaly buy one ;)
Found this - thought it might be just what the Doctor ordered - six discrete outputs... All the hard work's been done for you! :lol:
http://www.stewmac.com/shop/Electronics,_pickups/Pickups:_Guitar,_electric/1/Graph_Tech_Ghost_Pickup_System_for_Guitar.html (http://www.stewmac.com/shop/Electronics,_pickups/Pickups:_Guitar,_electric/1/Graph_Tech_Ghost_Pickup_System_for_Guitar.html)
Quote from: ACS on May 17, 2008, 08:35:21 AM
Quote from: carrejans on May 17, 2008, 08:13:45 AM
Thank you guys for all your input.
I've made an overview, to show to my thesis-partner tomorrow to discuss the possibilities.
Dude, that looks great!! Best of luck - the possibilities are endless... I'd certinaly buy one ;)
Found this - thought it might be just what the Doctor ordered - six discrete outputs... All the hard work's been done for you! :lol:
http://www.stewmac.com/shop/Electronics,_pickups/Pickups:_Guitar,_electric/1/Graph_Tech_Ghost_Pickup_System_for_Guitar.html (http://www.stewmac.com/shop/Electronics,_pickups/Pickups:_Guitar,_electric/1/Graph_Tech_Ghost_Pickup_System_for_Guitar.html)
Haha, yeah thank you.
I never heard or played with a piezo pickup.
Is it always acoustic-sounding? If it is so, that would be a pitty.
The normal piezo pickups, is it just one piezo sticking on the wood of your guitar?
ACS, the ones you posted have indeed 6 outputs; and can be usefull. But too bad you have to replace your bridge saddles.
I have to investigate more on this piezo system.
Quote from: carrejans on May 17, 2008, 10:00:19 AM
I never heard or played with a piezo pickup.
Is it always acoustic-sounding? If it is so, that would be a pitty.
The normal piezo pickups, is it just one piezo sticking on the wood of your guitar?
ACS, the ones you posted have indeed 6 outputs; and can be usefull. But too bad you have to replace your bridge saddles.
I have to investigate more on this piezo system.
Yes, piezo sounds more acoustic because it preserves the high and low frequencies magnetic ones don't. But that's a good thing. If you've got all of your frequencies intact, it'll be easy to simulate different pickups and guitars with filters and such. Yes, the piezo pickup for acoustic guitar is just one piezo stuck to the inside of the body, for electric guitar it's built into bridge saddles, I have yet to see a different implementation.
Let me warn you that the hex-pickup thing is very similar to the Gibson digital guitar concept.
---------
Jimbo
Quote from: JimRayden on May 17, 2008, 12:01:43 PM
Let me warn you that the hex-pickup thing is very similar to the Gibson digital guitar concept.
Oh, man, it was too good to be true. >:( :)
But the Gibson has a breakout box, with 6 jack outputs. Nice for in the studio; but not for the avarege player at home or on stage.
So, it is still different than the Gibson concept. I want to have a box, with a LCD, so the user can chose to put effects on the strings he likes.
Any idea what kind of pickup system Gibson uses? Magnetic or piezo?
Both, apparently. I'm sure the hex output is from a piezo bridge.
---------
Jimbo
We handed in our proposal to a professor. Now, we have to wait... Let's hope...
Thank you everyone for helping out.
I will keep you updated if we are allowed to do this.
Ok, so the professor of DSP thinks our idea is great for a thesis. So, we are probably allowed to do this.
One of the teachers of analog electronics, who is a guitar player, doesn't think it is a good idea. He thinks if we do it with filtering, the signal will sound really bad; and if we use the other option (piezo or opto pickup) there is no advantage to the Roland GK system.
Do you think there are advantages? (I have never used the Roland GK system)
Plus, he thinks that if we use the piezo, the sound will not sound as great as if you would use your humbucker. (I never used a piezo either)
Quote from: carrejans on May 28, 2008, 09:54:53 AM
Plus, he thinks that if we use the piezo, the sound will not sound as great as if you would use your humbucker. (I never used a piezo either)
The sound will be horrible with piezo. This is where the research part of your thesis comes in. What sort of filter can you apply to make the signal sound good? My guess is that it would be some sort of lowpass filtering, combined with a delay-based comb filter, where the delay is based on the distance between the bridge and the humbucker. The humbucker will not be a "point source" pickup; it has a wider magnetic field, so the comb-filtering will not be as sharp as with a single-coil pickup with a tight magnetic field.
Theoretically, the piezo pickups will have all of the harmonics present from the string, so you can modify them to your heart's content. If this doesn't hold true, a paper that discusses this would be useful as well.
Ideally, you could come up with a variety of filters, to emulate various pickups and pickup combinations. Perhaps you could figure out some sort of analysis method, to capture the impulse responses of different pickups in different locations. I don't know if anyone has come up with an analysis technique for this yet, since it wouldn't work with the standard microphone/speaker combo used in capturing impulse responses for convolution.
Sean Costello
http://www.gibson.com/RobotGuitar/guitar.html
look at the tail piece.....
isolating each string has been done.
manual
http://www.gibson.com/robotguitar/robot-guitar-manual.pdf
pg24
i think low latency networking of music signals is a good thesis.
like yamahas mlan. digital transport...
And it is likely we will see Yamaha expanding on mLAN with work on Open Generic Transport. Read up on it here:
http://linuxaudio.org/en/press/lud53-Audio_Libre.pdf
4 Feb 2003 The Institute of Electrical and Electronics Engineers Standards Association (IEEE-SA) has begun work on a standard to extend the reach of musical instrument digital interfaces (MIDI) by allowing for MIDI transmission over Ethernet and IEEE 802.11 (TM) networks. This promises to give those in the music field significant new creative possibilities for composition and performance.
The new standard, IEEE P1639 (TM), "Standard for Transmission of Musical Instrument Digital Interface (MIDI) Data within Local Area Networks: Distributed MIDI - DMIDI," should be finalized by the end of 2003. It will retain backwards compatibility with existing hardware and software under the original MIDI specification, which is now 20 years old.
http://standards.ieee.org/announcements/p1639app.html
http://www.midi.org/about-midi/ethernet.shtml
http://openmuse.org/transport/mip_intro.html
cat5 to microphone connector
with a specially designed switch/hub
the dice 2 chip is good place to look
http://www.tctechnologies.tc/
https://dev.tctechnologies.tc/tcat/tags/release/public/latest/docs/firmware/DICE_Firmware_DevEnv_User_Guide.pdf
https://dev.tctechnologies.tc/tcat/tags/release/public/latest/
Here is an update.
A while ago, it was ok for the school to do this project. Then when we handed our proposition in, they said "no", because we didn't have a supporting company. After discussing a while, we are allowed to do this project, if we find a professional musician, who will cooperate. So the search can begin. :)
Here is an updated version of our proposal:
Quote
PROCESSING ELECTRIC GUITAR OUTPUT FOR EACH STRING SEPARATELY
The ultimate goal with this product:
The user will be able to choose an audio effect for each string of his guitar separately. On the black box he can choose the effects on each string separately with the help of an interface (LCD + buttons).
He is able to:
- pitch shift each string separately (no need for tuning your guitar for alternate tunings)
- put delay (echo) on only those strings, chosen by the user
Possible extensions:
- more possible effects can be chosen (phaser, chorus, reverb, distortion, ...)
- an implemented effects loop (some effects sound better after the preamp of the guitar amplifier)
- six output jacks for each string separately (can be interesting in studios, to put every string on a separate track of the mixer)
- ...
Two possible ways of dividing the guitar signal into 6 separate outputs
Possibility 1:
- keeping original pickups
- connection between guitar and the processing box with normal instrument cable
- dividing the audio signal into the 6 different signals inside the box
- processing the separate signals inside the processing box (pitch shifting, delay, ... with the help of DSP)
Possibility 2:
- using/making pickups with outputs for each string
- using/making a cable for the 6 separate signals
- or putting ADC's inside the guitar/pickups and sending the signals via Ethernet or USB cable
- processing the separate signals inside the processing box (pitch shifting, delay, ... with the help of DSP)
Solutions for the problems of splitting the signal
Possibility 1:
- problem: same note on different strings have the same frequency
- possible solution: each string has its own sonic personality. The fundamental frequency will be the same, but each string has different amounts of each of the overtones that accompany a fundamental. So we pick out a fundamental from the signal and pick out its overtones; then we have to look at the relative amplitudes.
- another problem: this sonic personality will be different on each guitar and probably each string brand
- possible solution: before using the box, the user has to "train" the software to calibrate the system (cfr. voice recognition software)
Possibility 2:
- problem: when using a normal magnetic pickup, each polepiece will not only pick up the vibrations of its corresponding string
- possible solution 1: isolating each string and its accompanying polepiece from the others
- possible solution 2: using piezoelectric pickups (these are built into the saddles of the strings)
- possible solution 3: using optical pickups (fairly recent development (1969) that works by sensing the interruption of a light beam by the string)
Advantages & disadvantages
Possibility 1:
+ no extra pickup has to be placed, originals can be used
+ no special cable is necessary, normal instrument cable can be used
- theoretical possible; but is it possible in practice? Difficulty?
- user needs to train the software
- will the sound loses its character? Will it sound a bit artificial?
Possibility 2:
- extra pickup needs to be placed
- requires a special cable
+ easier to implement in software
+ no need to train the software
+ no excessive filtering; sound will be less artificial
I am now making an email for some musicians. I also want to explain the advantages to the existing Roland system. The problem is, I never used such a system. So, I want to ask you, is it correct what I state here?
The Roland system always uses MIDI. They don't use piezo-pickups, but MIDI-pickups. It generates MIDI-signals, that will trigger samples in the synth. So, you don't hear your guitar, but samples.Thank you for all your help. I will keep you updated. And let's hope that
possibility 1 is really possible and won't sound artificial. It would be nice to have this system, without having to make adjustments to your guitar.
Hi there, as far as I'm aware the Roland hex system controls a synth via midi - but the pickup system is not piezo based. There are however other systems that use a piezo pickup, but again to control a midi synth. So both what you've come up with here, and what I suggested earlier in the thread are original ideas as far as I know!
Again, good luck with it - it's great idea either way, with some outstanding possibilities.
Aidan
Hey man great project ild definatly be keeping an eye on this.
go laser/optical sensors...!!! that would be wicked :D
This week I will give an update on this. Subject has changed a bit.
Now, I am looking for hex pickups (non MIDI ones). Do you know any?
Thank you...
The only midi pickup I can think of is the RMC ones and the ones factory fitted the parker midi fly guitars. All the rest are hex pickups that are converted to midi by an external unit.
The standard for hex pickups is the 13 pin output. This is used by Rolands gk-2a, gk-3a, the graph-tech piezo ones, the yamaha ones, and the godin guitars factory fitter ones. Some of these use piezos elements in the bridge and some use little humbuckers.
The 13 pin output contains 6 separate audio feeds, a mixed feed and some control signals. There is a pinout here...
http://johnp.net/projects/guitar-synth/roland-pinouts.html#13pin
The 13 pin sockets are hard to find. The easiest option is to buy a 13pin cable and cut it in half to bust out the 6 seperate feeds. You will need to supply the hex pickup with power though as they usually contain preamp circuits.
I had a thought this morning, and I know I won't have the bandwidth to follow up on it. I don't know of any system that works this way currently.
You could add a piezo pickup for each string to an electric guitar and then used the outputs to tell you the fundamental frequency and attack point for each string. This may give you enough information to intelligently filter the analog output so that each string could be treated separately in an analog effects system (or digital if you prefer). The upside is that you could use the real pickups to create the sound, as opposed to filtering the piezo output to model an electric pickup sound. You could create really cool envelope follower effects with this (where each note was tracked well). You could also do separate distortion on each output of the filter to get a sound like a hex pickup running into 6 different distortion boxes. If you are interested in this, try to find the Craig Anderton QuadraFuzz article (I can't remember if it was in Guitar Player or his book). It makes a cool sound because the modulations between strings aren't amplified by the distortion.
I think with onboard circuitry you could send the string information via a serial channel, and you might be able to just use a stereo 1/4" jack to connect the guitar to the offboard system. What do you think? ???
--Will
The bit where you "intelligently filter the analog output so that each string could be treated separate" sounds difficult (impossible?)....especially in the analog domain.
If you want "real" hexaphonic pickups, check out this...
http://musicthing.blogspot.com/2008/08/six-output-pickups-for-stereo-guitars.html
Quote from: widdly on November 19, 2008, 09:42:24 PM
The bit where you "intelligently filter the analog output so that each string could be treated separate" sounds difficult (impossible?)....especially in the analog domain.
Yes, I was thinking of using a DSP for this. You could have adaptive filters controlled by the frequency info from the piezo pickups. It wouldn't be easy, but he was looking for a thesis subject. People above were talking about analyzing and filtering the analog output, which would be much harder without knowing the frequency beforehand. It would still not work if you played the same note on two different strings -- that case really needs a hex pickup with independent outputs.
http://www.sweetwater.com/store/detail/LPDGBMNH/ (http://www.sweetwater.com/store/detail/LPDGBMNH/)
I sat in on a demo at Sweetwater where they had this guitar running through a 6.1 surround system.
It offered some creative possibilities that would otherwise be impossible--1 effect for each string (if you want), infinite EQ possibilities, ability to edit out minor flubs easily, etc.
Uses CAT5 cable, packaged with software to cover any need you could want. (I'm not sure about the pitch-shifting, but once you have a separate track for each string, pitch shifting becomes easy, software-wise.
Very expensive, but very cool. Has the analog outputs you're looking for.
This idea is something ive always wanted to do, have separate outputs for each string so i can put different effects on each one. hopefully something i say here might be helpful to you.
reiterating what has already been said:
The GK3 pickup has a separate audio feeds for each string, the GR-20 or 33 etc guitar synth pedals runs a pitch to MIDI conversion on each string, and uses midi to play GM sounds. i think the GR-33 you can even plug a mono guitar in, but it will only do pitch to midi mono-phonically.
Looking into the HD Gibson guitar.. and the new darkfire out in a few weeks (darkfire is basically the robot guitar and HD guitar built together and upgraded) these have separate hex pickups in the humbucker pickups, so you would get a tone very close to that of a normal humbucker.
Where as the Roland GK3 pickup is a single pickup for each string that goes right near the bridge of the guitar, so the tone would be very light and tinny. suitable for converting to a midi signal, but wouldn't sound that good direct. similar with a peizo pickup on each string, its not going to sound like a 'real' guitar.
Now the Roland VG-99 uses the same GK3 pickup, but has tone modification and modeling to replicate different pickups, or even synth sounds. so the sound of the pick up is what you are hearing, though heavily processed, and not MIDI.
The VG99 allows pitch shifting on each string, and a distortion prior to mixing down into 2 channels of effects. so you can re tune the guitar, distort each string individually for a cleaner distortion sound. then pan the string between 2 effects chains, and then mix them at the end, or pan left and right.
This allows say the EAD to have distortion and GBE to be clean with chorus and delay.
Putting effects on the natural guitar sound, one output for each string, and leave out the pickup modeling part for me would be the ideal solution.
The darkfire has a Break out Box like the HD guitar, but it also comes with Guitar Rig 3, and the BoB has a firewire interface as well, which i think is a good way of doing it, rather then needing to have 6 effects processors, one for each string.
separating 6 strings from a mono output, i think would be quite hard to do, and there would be quite alot of tone loss. as im sure you are aware, playing 2 guitar strings adds harmonics, and like has been stated before, how do you tell the difference between the same note on 2 different strings.
I came to the same conclusion as hoopshot, if you have a 6 individual piezo pickups, and a normal guitar pickup, you could use the piezo pickup to know which string is being played, and subtract it from the mono guitar pickup. i guess there would be a fair different tone between the pickups, but it could make it easier to determine what is being played.
Hi guys,
Here a small update from my project.
I did a research for deviding the signal into the six signals. Conclusion: not possible yet!
I read a lot of papers (about 70) about doing this. With the most advanced algorithms, it is pretty good possible; but not in real-time.
There need to be made a lot of complex calcutlations, that require a lot of processor time.
If someone is interested, I can mail you the papers. (most of them are from IEEExplore)
I lost a lot of time doing this research. Now I changed the subject a bit.
I will just use a hex pickup; and focus more on the digital effects.
I probably going to focus on distortion. Why?
Because, not many guitarist like the digital distortions. Now, I read something interesting in some papers. They devided an audio signal into three bands (like treble, mid, bass); and then distorted them separatly. Then they joined the three distorted signals back together. The total signal was superior to a distortion on the whole signal.
I have to reread the papers; (it's been weeks that I read them; have had examinations in the mean time) but I think that if I will distort the six signals separately, I can make a better distortion then other digital ones.
I will see how long, this will take. I can also make delay and pitch shifters. Pitch shifter can be interesting too, I think.
Now I have to buy a hexafonic pickup.
I have a question. The midi pickups; do they also have six analog outputs, before they are converted into midi-signals? If so, I can use them, I think.
Do you think, that the hex pickup from the digital gibson is available separately?
If you guys are interested, I will try to keep you updated.
I will open a new thread, for the dsp development board I'm using. Think it can be interesting for other people too.
Quote from: carrejans on January 27, 2009, 02:47:46 PM
I have a question. The midi pickups; do they also have six analog outputs, before they are converted into midi-signals? If so, I can use them, I think.
Do you think, that the hex pickup from the digital gibson is available separately?
Can anyone help me with this question? Can't find this info on the web.
Quote from: JimRayden on May 15, 2008, 08:05:44 AM
Secondly, isn't MIDI the standard on all of today's synthesizer systems or have I missed an innovation to replace that technology.
---------
Jimbo
yes, but networkprotocols are tipped to take over as midi is so archaic.
Check out http://opensoundcontrol.org/ (http://opensoundcontrol.org/) protocol instead.
How about doing this for your thesis:
Write all your effects on a pc.
Get yourself a beefed up multicore computer that can handle realtime processingof multiple inputs.
Get yourself/make yourself an N (lotsof bandwidth) wireless lan receiver/transmitters.
Use network protocols to stream the digitised audio and compress it (you could do some fancy stuff here, is there a way you can send only "key" information, let the computer know what guitar and pickups you have, and have the computer "reconstruct" the full sound, and stream it real time wirelessly to pc running aformentioned effects.
Wirelessly send the processed data to a PA and a monitor.
Control effects parameters using another wireless foot controller.
Finally, get the computer to control effects for multiple instruments simultaneously, and stream the audio to Monitors and PA's.
Now you have a wireless band! no more wires trailing around the stage to snap/trip over! And now your band just needs to worry about having a pc and wan equipment ateach venue, no more effects pedals, heavy amps or drums to cart around!
You could also think about adding in multi-touch screen "Mixers" for each musician.
Now you have a wireless stage AND you've done away with the soundman!
One more idea - make yourself a device that produces a variety of noises/pulses and analyses the acoustic response of the room, then have apeice of software model the rooms acoustics exactly. Now you can sound like you're playing guitar remotely and wirelessly in big cathedrals!
Thanks for the tips; but I already started the project. I'm programming on a dsp development board from freescale. (it has 8 mono inputs) The board is called: Symphony SoundBite.
Quote from: carrejans on February 26, 2009, 10:04:14 AM
Quote from: carrejans on January 27, 2009, 02:47:46 PM
I have a question. The midi pickups; do they also have six analog outputs, before they are converted into midi-signals? If so, I can use them, I think.
Do you think, that the hex pickup from the digital gibson is available separately?
Can anyone help me with this question? Can't find this info on the web.