Polyphonic Audio and MIDI box for Polyphonic Electric Guitar
The premise of this project was to build a hardware unit which provides polyphonic audio (separate audio signal for each string) as well as MIDI data (pitch and velocity) for each note executed which could be utilised for mapping purposes. Such a hardware unit would allow the user to maximize CPU power for signal processing. Following on from a previous “break-out box” project, I purchased the Axon AX-50 board from Terratec (Germany) to allow for MIDI data for each note. The tracking is excellent in combination with Graphtech’s “Hexpander” MIDI interface.
Initially, I wanted to hack the board so it supported polyphonic audio and MIDI concurrently, however, the Axon board is inherently noisy and a series of the DIN pins carry a rather unfortunate mains noise rendering the board unusable for audio. So, I devised a separate power supply (9v battery) acting as a piezo amplifier, powering the Axon unit separately with an adapter. I devised a DIN splitter cable so that the Axon board is able to receive the audio derived from the guitar, whilst maintaining separate power sources, ergo eliminating the ground noise issue. My thanks to Jun Kwon for his assistance with installing a series of isolator transformer to improve the quality of Audio/MIDI data translation.
In separating the ground of the piezo amplifier from the Axon AX-50 board, one is presented with a different noise problem, whereby noise generated by MIDI data is present in the audio signals. A separate MIDI interface was tested, which reduced the noise but it did not eliminate the noise altogether. To eliminate the ground noise completely, a USB isolator may be required. This project is on-going.
Mapping Strategies
The premise of this project was to reflect pitch structure in my chosen DSP during real-time performance. I built the following patch in PD (Pure Data), in an attempt to reflect pitch structure in pre-programmed signal processing during real-time performance, which can be dictated by the chosen pitches executed by the performer while maintaining an element of improvisation. The electric guitar is inherently a multi-parameter mapped instrument. For the most part, it maintains a many to one relationship, concerning many attributes of a physical instrumental technique utilised by the performer to produce a desired sonority. It is important to maintain an approach which is conceptually clear, one that maintains musical meaning versus technical mapping.
The patch collects pitches played by the performer, then generates random index via a counter. The random index is then re-called from the [coll]. In this example MIDI note 60 (C3) is mapped to an automation clip in Ableton Live. The automation clip triggers a series of signal processes specified by the user. This example is using the built in mic on my laptop.
PD to Live - Phase 2 from Ricky Graham on Vimeo.
“Killing your Darling”
After some discussion, there is further potential to develop the patch into a more modular, versatile, and interactive performance system, which may allow the patch to operate with a greater degree of independence, encouraging the performer to engage with the system via a new performance approach, versus a learned or repetitive performance practice. I intend to develop the patch to further accommodate statistical analysis of pitch class development and additional string information, such as velocity, and note onset and offset. Thus, temporal phrasing will become an interactive part of the mapping and performance process. Other approaches include the utilisation of pick position data to trigger appropriate timbral processing, resizing the [coll] size in real-time to vary the rate at which a signal process is triggered, and the real-time drawing of automation values.
My thanks to Daniel Schorno for his feedback on this project.
Performance in Antwerp
This was a great opportunity to improvise with themes I have been developing for the forthcoming album by signalsundertests. I scored some motives to work with during the performance, but I am still developing an appropriate method of scoring pitch, timbral, and spatial attributes of each theme. I would like to work with a stave per string in future, and it is my hope that the score will also be applicable to acoustic instrumentation. All in all, an excellent experience.
signalsundertests performing at the Live Looping festival at Arenberg, Antwerp.
Thank you to those who provided photography on the night, including Ingrid, Sjugge, and Benjamin. My thanks to Sjaak and Ingrid for their hospitality, and to the amazing musicians which were a part of this wonderful event. And of course, thank you to all the staff at STEIM for their support. It was a very productive and enjoyable residency.
New recordings are available following on from a series of recent performances by signalsundertests at the Black Box in Belfast, N.Ireland.
signalsundertests - Live at the Black Box, Belfast - 31.08.09 - Test 1
signalsundertests - Live at the Black Box, Belfast - 31.08.09 - Test 2
New Audio available on MySpace
The perception of dynamic trajectories in live music performance has become of immediate importance since the conception of the Signals Under Tests project [1]. The relatively short sustain of plucked notes on an electric guitar can present limited scope in multiple speaker array performances [2]. One method of remediation has been to employ “live looping” techniques [3] and other experiments with DSP. However, at this early stage of the project, perhaps DSP is not an appropriate method to encourage sustain beyond the natural resonance of the electric guitar. A sustain pickup seems to be the most heuristic method for the time being. The Fernandes Sustainer [4] and the Sustainiac Stealth Plus [5] are the two pickups that seem the most available and suitable.
Alan Hoover at Maniac Music explains the similarities between the two models;
“The Sustainiac Stealth Plus and the Fernandes sustainer are both Electromagnetic sustainers for electric guitar. Both take the bridge pickup signal, amplify and process it, and then apply this amplified/processed bridge pickup signal to the electromagnetic driver transducer (”driver” for short). The driver then transmits a pulsating magnetic field in response to the amplified bridge pickup signal. This pulsating magnetic field causes the string vibrations of the guitar to be sustained as long as you hold the note. Simple hand-muting stops the sustain. Both systems have different “harmonic modes”. In other words, we do other electronic processing which forces the strings to vibrate differently, in such a way as to produce harmonics, kind of like a very loud amplifier does (only much more forcefully and musically, and also predictably). It is a very cool sound for many types of music. This is where the similarity stops.”
Alan Hoover at Maniac Music explains the differences between the two models;
“Our patented circuit designs allow you to use common push-pull controls which simply replace your existing guitar controls, in most cases without having to drill new holes in your guitar body. Installation of the Sustainiac circuit into most guitars can be done without having to route a new (large) cavity into the guitar. With the Fernandes, you will likely have to do a substantial route into the back of your guitar in order to fit it in. These are the main differences.”
While the Sustainiac seems to be tidier in terms of specification, the Fernandes sustainer is a little more affordable and it just so happens that I have a luthier who I trust to cut a new cavity in my guitar. Also, I have been trying to shift a little of the weight of the body since it is made of ash and it is quite heavy. I have included a short overview of the installation process below.
A new cavity had to be cut to fit the Fernandes sustainer circuit board.
The pickup system needed to be wired to the existing pots, the three way pickup selector, and the existing jack socket. The cavity was grounded with aluminum foil in an attempt to reduce any noise that was present.
Two toggle switches are present on the board to switch between the two harmonic sustainer modes and to switch the pickup on and off. These are located under the bridge of the guitar.
The pickup works relatively well and helps to further develop performance techniques in multiple speaker array based live performances. However, I am interested to see if Maniac Music will develop the polyphonic sustainer pickup they have mentioned here. [6]
A short audio sample is available below;
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Thanks to Alan Hoover at Maniac Music, Mike Barkley for your routing expertise (and patience), and to Andres Jaramillo at Fernandes Guitars.
References
[1] Signals Under Tests. (2009) Myspace. http://www.myspace.com/signalsundertests. Accessed on 23.07.09.
[2] Bates, E. (2008) Adapting Polyphonic Pickup Technology for Spatial Music Performance. ICMC, http://www.endabates.net. Accessed on 23.07.09.
[3] Looper’s Delight. (2006) Looping Tools. http://www.loopersdelight.com/tools/tools.html. Accessed on 23.07.09
[4] Fernandes Guitars. (2009) Fernandes Sustainer. http://www.fernandesguitars.com/sustainer.html. Accessed on 23.07.09.
[5] Maniac Music. (2009) Sustainiac Stealth Pro. http://www.sustainiac.com/st-pro.htm. Accessed on 23.07.09.
[6] Maniac Music. (2009) Hexaphonic Model. http://www.sustainiac.com/st-pro.htm. Accessed on 23.07.09.
The diagram above breaks down the pin assignments of the 13 pin DIN connection. The break out box would allow me to access individual audio for each string on my electric guitar. In researching the construction of this box, I found two excellent sources of information.
The first was Jeff Berg’s website, Unfretted.com, and the second was Dublin based Electroacoustic Composer, Enda Bates. Pins 1 - 6 correspond typically to strings 1 - 6, the 7th pin corresponds to the sum of all 6 strings, and pin 12 is where power is sent via a 9v battery. In my case, the 7th pin will correspond to the 7th string of my electric guitar. Jeff Berg’s excellent guide to building your own break out box is available here. It is very important that you read Jeff Berg’s instruction and that you ground the box properly. Do not construct this in the bath etc.
I required a female 13 pin DIN connection, 7 female jacks, and some heat shrink tubing so that I could make the connections more robust. Thanks to Taku for the recommendation of heat shrinking.
I soldered pins 1 - 7 to the tip contact of each female jack socket. It is important that you ground the sleeve of each jack along with the shield of the 13 pin DIN connection.
Once the connections began to take shape, I then built it into a cable. I used a little bit of PCB for all my grounding.
And then into a box. I managed to fit the cable into a box the size of a D.I. box. One thing I would suggest is that you use a box with a little more weight if you plan to use a loom cable so that the box does not become damaged due to the weight of the cable.
Thanks to Enda Bates, Takuro Lippit, and Jeff Berg for their direction with this project.
The aim of this project is to make my electric guitar fully polyphonic. I have chosen to install the Ghost Modular Pickup System by Graph Tech Guitar Labs.
The piezo pickups come preloaded in a Floyd Rose saddle for an easy installation.
The existing saddles are replaced by the piezo saddles. The piezo connection is then threaded through the cavity of the guitar to the Hexpander board. The DIN 13 jack socket is connected to the Graph Tech “Hexpander Board” that conditions the piezo signals. “The Hexpander Modular Pre-amp features a proprietary harmonic damping system that results in tracking that is unequaled by any other system on the market today, with responsive and accurate triggering.” [1]
The term “Hexaphonic” is misleading in that it assumes that users utilise the pickup system on a six string guitar. Inventor and Musician, Matthias Grob explains this on his website.
“Some say “Hexaphonic”, which is only correct as long as the instrument has 6 strings, so we prefer “Polyphonic” here: Polyphony has its specific meaning in the music history, but the word itself simply means that there are several “sounds” and we understand several “voices” or notes. Of course this is the case for any ordinary guitar, but conventional technology treats all notes as a single sound source - which is often not in the sense of the musician!” [2]
A seventh pin is provided to allow a user to connect the sum of all the piezo pickups. Given that I am using a seven string guitar, I simply connected a seventh piezo to the seventh pin so that I have independent audio for all seven strings. I intend to mix the magnetic monaural pickups with the piezo pickups.
edit; 12/11/2009
The 7th pin (marked with a circle) on the second row of the Hexpander board ceased to function once the Fernandez sustain pickup was installed. Audio for the 7th string could be obtained once again by reconnecting the piezo pickup for the 7th string to the magnetic channel (marked with an M) on the first row of the Hexpander board. My thanks to Morgan Ahoff at Graphtech Guitar Labs for helping to resolve this issue.
Here are two early audio examples of the polyphonic guitar system. This is material being developed under the alias of Signals Under Tests, a project with DJ and programmer, John King.
Polyphonic Guitar Sample 1
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Polyphonic Guitar Sample 2
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Thanks to Michael Barkley for his Luthier skills, and to Morgan Ahoff at Graph Tech Guitar Labs for all his direction on this project. The next step is to build a break out box that provides the pickup system with power.
References
[1] Graph Tech Guitar Labs. (2009) Ghost Modular Pickup Systems. http://www.graphtech.com/products.html?CategoryID=2. Accessed on 15.07.09.
[2] Grob, M. (2008) What do we mean by Polyphonic? http://matthias.grob.org/pParad/WhyPolyGuitar.html. Accessed on 15.07.09.
5 Jul 2007 12:00
Kaetsu Music Festival, Tokyo
9 Jul 2007 20:00
Kaetsu University Seminar, Tokyo
Big thanks to Simon “Sensei” Clay at Kaetsu University for the invitation to perform at such a receptive University.
9 Jul 2007 21:00
Rock Factory, Tokyo (Roppongi)
Performance time - Approx 15 minutes
Music - “1314″ & Improv
Audience - 20+, very receptive. Local music moguls were thoroughly impressed. Jammed with Tokyo based Hip-hop artist, Dave Whitaker.
10 Jul 2007 19:00
The Pink Cow, Tokyo (Shibuya) - Workshop
Performance time - Approx 50 minutes
Music - “1314,” Improv, & “Decadence”
Audience - Very receptive. I networked with some very enthusiastic Musicians from Tokyo and Fuji. Traded music and contact information etc.
10 Jul 2007 20:45
Cosmo’s, Tokyo (Shibuya)
Performance time - Approx 60 minutes
Music - “1314,” Improv, “Absolution,” “Music Box,” “The Sky Above,” & “Decadence”
Audience - Mainly those who followed on from the previous workshop. An intimate atmosphere and a very receptive crowd.
10 Jul 2007 22:00 *
Ruby Room, Tokyo (Shibuya)
Performance time - Approx 15 minutes
Music - “1314,” & Improv
Audience - 50+, very receptive crowd and a very intimate setting. Perhaps the best performance of the tour.
11 Jul 2007 21:00
Ruby Room, Tokyo (Shibuya)
Performance time - Approx 20 minutes
Music - “Absolution,” “1314,” & Improv
Audience - 30+, mainly Japanese & American. Networked with A&R at KR-International, CD Lunch, and other Tokyo based music representatives with ties at Sony BMG, Tokyo.
I fell asleep around 5am in a Punk bar, during which time Ross and Duncan covered me in ice cubes. Cheers lads. I believe my name is also written on the wall of the bar along with some other visiting Musicians. Ross had also written his name underneath in what would appear to be morse code. Thanks to the bar staff for playing old school Metallica all night. A nostalgic night was had.
12th Jul 2007 21:00
Cosmo’s, Tokyo (Shibuya)
Performance time - Approx 30 minutes
Music - “Absolution”, “1314,” & Improv feat. Dave Whitaker.
Audience - 20+, intimate crowd, very receptive, & thoroughly enjoyable.
I later got up to jam with three Jazz musicians, two of which were from Tokyo (Guitar & bass) and the other from London (Saxophone.) We jammed for about an hour or so. This gig was a great way to end a successful tour.
Thanks to Dave and Meg at KR-International for organising a great induction tour of Japan. I’m looking forward to working with you both and the label in 2008. Thanks to Ross (as always) for being himself and his amazing host family, Koido, for looking after us. Thanks to everyone who I met at Wakeijuku. Thanks to all those who I met up with while I was in Japan, especially Duncan, Dave Whitaker, Hide, Megumi, Claire, Nosomi (Mimi), Anna, Maria, Simon, and Toma and the lads.
Mata ne,
Ricky
2 May 2009 21:00
Ottorisha - “Con Tempo” - Kita-Senjyu, Tokyo
Set List: 3 Pieces for Polyphonic Guitar: I (E Major), II (E Major), & III (Ab Minor)
Tonight was the first show of the tour upon invitation from recent acquaintance, Wataru Shoji. The venue was an old Japanese house that had been converted into a performance space by Shoji and his colleagues from the Tokyo National University of the Fine Arts and Music. It reminded me of my time at STEIM in April, which is where I made Shoji’s acquaintance. It had a lot of character.
Regardless of how bad my jet lag had been since my arrival in Tokyo, I had been anticipating this performance with a great deal of enthusiasm. I had put together a short set in a more experimental vein that I hoped would be more appropriate for the venue.
Shoji and Odawara commenced proceedings with a laptop set that utilised a series of customised controllers. It was an interesting sound world that I very much enjoyed. The next performance was given by a Japanese Irish Traditional trio whose standard would challenge traditional musicians from home.
You can view the Harpist’s blog here
After what had been a relatively successful sound check, I began to prepare for my set. To my dismay my break out box for my polyphonic guitar had become inoperable. Some ‘off the cuff’ live soldering was required. Once rectified, I began my set.
Samples of the sounds prepared for this set can be heard below.
Polyphonic Guitar Sample 1
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Polyphonic Guitar Sample 2
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View Waturu Shoji’s Flickr Page
Download the poster for this event
3 May 2009 20:00
Pink Cow - Shibuya, Tokyo
Set List: Improvisation I, Without, Music Box, 1314, Rain Down Fire, Pilate, & Improvisation II
I played the Pink Cow the last time I was in Tokyo and had enjoyed it thoroughly. It is a very relaxed affair. The performance started off a little slow, but by the second track momentum built and the crowd engaged. My execution of each track was good overall, although some moments could have been a little more together. This event was a concept that had been put together by the owner to serve as an opportunity for indie musicians to network with one another.
The Pink Cow streamed this performance via UStream
5 May 2009 20:00
Ruby Room - Shibuya, Tokyo
Set List: 1314, Music Box, Pilate, & Improvisation II
I went cycling around Tokyo today before a meeting with Dave and Ross from the label. It was a good experience, regardless of nearly falling off the bike a few times. We made our way to the Ruby Room around 6pm. The Ruby Room is a small club located in Shibuya that I had played twice before in 2007. I enjoyed it then, and tonight was no exception. It was great to hear my set through a bigger sound system. All was well received by the audience and management. There were some interesting performances from punk right through to a man with a didgeridoo. I love this venue. It has great character. After the gig, I gave a workshop on my equipment to a few local musicians. This was a good opportunity to network contact information and music.
6 May 2009 22:00
Daisy Bar - Shimokitazawa, Tokyo
Set List: Improvisation I, 1314, Without, Music Box, Rain Down Fire, Pilate, & Improvisation II
A brilliant gig tonight. The Daisy Bar is a highly established venue in the artist district of Tokyo. I was accompanied by two other acts by the name of Miracle Works and This Is A Pen. The latter are an impressive female electronic duo from Tokyo. Do give them a minute of your time.
I received a recording of the gig on MD, a popular but obsolete format still in circulation in Japan. They still use VHS at this particular venue, which I find interesting. The recording will be available shortly, once I find an MD player.
The gig was listed in Tokyo’s Juice magazine, a magazine similar to NME
The gig listing can be viewed here
7 May 2009 22:30
Seco Lounge (EP Launch) - Shibuya, Tokyo
Set List: Improvisation I, 1314, Without, Music Box, Rain Down Fire, Pilate, & Improvisation II
Despite extremely poor weather, the turn out was O.K. and the performances went very well. I received a recording of the event in full, and on listening back I am very happy with my live mix. The label intends to book Seco Lounge again on my return as it is an established venue with an unusually large venue capacity for Tokyo. My thanks to those who attended the show and to Noe, Odawara, and Shoji for providing their support.
You can listen to the recordings below. Thanks to Taro for the recordings.
Pilate (Live at Seco Lounge, Tokyo)
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Rain Down Fire (Live at Seco Lounge, Tokyo)
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1314 (Live at Seco Lounge, Tokyo)
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The gig listing can be viewed here
8 May 2009 19:00
Encore - Shibuya, Tokyo
Set List: Without, & Music Box
Encore served as an opportunity to perform a shorter set in a relaxed club environment as part of their ‘Platinum Live’ event. Encore has an interesting concept allowing customers to select live concerts via a touch screen that are then displayed on a screen on stage. The tables in the venue seated one person per table. It was if I was performing in front of a classroom of school pupils. It was an interesting but unfamiliar concept.
A DVD recording was made by the staff, which is available here. My thanks to the Encore staff for their welcome, professionalism, and accommodation.
9 May 2009 17:00
Koido House (Workshop) - Warabi, Tokyo
Materials: Technical Exercises, Major Modes, & CAGED System
The workshop was organised by the Koido family in the Warabi area of Tokyo. The workshop covered rudimentary guitar techniques, CAGED system, modes of the major scale, relative minor theory, and other soloing concepts. The workshop lasted 2 hours in total.
Workshop Materials (Available for Download)
Please download Power Tab
Technical Exercises (Legato, Alternate Picking, & Sweep Picking)
http://www.artscouncil-ni.org/
My extended thanks to the Arts Council of Northern Ireland and to Dave and Ross at KR-International and CD Lunch for all your hard work in booking and promoting this tour. My thanks to the Koido household and to the students at Tokyo University of Fine Arts and Music. Thank you to all who attended the shows and to Laura, my family, and friends for your continued support. Mata ne.
Tour dates for Japan during May 2009 are now available. Thanks again to Dave & Ross at CD Lunch and KR-International, and to the Arts Council of Northern Ireland for making this possible.
Tour Dates
2 May 2009 20:00
Ottorisha Tokyo
3 May 2009 20:00
Pink Cow Tokyo
5 May 2009 20:00
Ruby Room Tokyo
6 May 2009 20:00
Daisy bar Tokyo
7 May 2009 20:00
Seco Lounge (EP Launch) Tokyo
8 May 2009 13:00
Encore Tokyo
9 May 2009 20:00
Koido House (Workshop) Tokyo
More info: ross@kr-international.com
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