Amplification in the 21° century

The question is obvious: if in the last thirty years we have had a rapid evolution of music technology, what can we expect in this new millennium? Music itself is everlasting and it's easy to imagine that it will always be one of the most important art forms. Nobody knows what musical types will survive in the near future, or even foresee what new types will come. Certainly, nobody would have imagined in 1800 that one day a certain black guitarist would have imitated the sound of an airplane battle with the guitar. Today we have some well defined musical directions, musical types that are born, that disappear, that come back. We should hope that the roots of every musical genre (good or bad, depending on your personal taste) doesn't end in the history books or in the furrows of a disk. We hope that in the 22° century there will be classical groups that are happy to spend evenings playing in bars or even as street artists.
This romaticized preface is intended to give you an idea of things that just a few years ago would have seemed far away. For instance: try to imagine being in the 70's and playing an entire concert with only one guitar. Now we have the possibility to pass from a Fender Stratocaster type sound to a Gibson 175 or to a Martin D-45 type (an acoustic guitar). But thats not all, we can also choose the type of amplifier, such as a Marshall, Mesa Boogie, Fender, etc. Today all of this is possible thanks to technology. Lets get back to the story starting with the midi guitar.

Guitar Synth

The subject of this chapter is the midi guitar. Even if this is the most common term, its not correct. It's best to define this type of instrument as a guitar synthesizer or guitar synth. The synthesizer is an electronic instrument that, after having created a tone, reproduces it into a wide variety of tones. The first synthesizer experiments began in the 1960's. A inventor of this instrument was Dr. Robert A. Moog in 1964, which was driven by a keyboard similar to that of an organ. Over the years, the synth has gone through a series of changes, mostly for keyboard players. The guitar synth is distinguished by the fact that the synthesizer is driven by the guitar through a special hexaphonic pick-up.
The synth can be used for simulating the sound of any instrument, creating a new sound or a combination of the two. A synthesizer is controlled by varying the voltage levels. If the synthesizer is controlled by a guitar, you need a tone-voltage converter, which tells the synth which notes the guitar is playing. The synth uses this voltage to guide the basic sound through a device called the oscillator (VCO: voltage controlled oscillator). This is a complex component that produces saw tooth, square, sinusoid and triangular wave forms. These wave forms can then be modified to produce a larger variety of sounds.
The synthesizer also contains another device, called a noise generator. The noise generator creates white noise, which is a mixture of wave forms taken from the frequency spectrum, and pink noise, which is similar but with more bass. After the VCO has created the sound, the VCF (voltage controlled filter) intervenes, which cuts the frequencies. This can be compared to a tone control or to a graphic equalizer: it eliminates some frequencies to emphasize others, according to a defined subractive synthesis. In a similar way, the intensity of the sound is regulated by a voltage controlled amplifier or VCA.
Synthesizers are also equiped with an ADSR system, which controls the attack, decay, sustain and release, hence the acronym ADSR. The sound coming from the guitar synth is not a modified version of the sound from the guitar strings but the actual sound from the guitar.
The first synthesizers were monophonic and couldn't play more than one note at a time and therefore didn't have great performance. The pseudo-polyphonic synths allowed you to play a determined number of notes at the same time. The modern polyphonic synths have an independent circuit generator for each note and therefore the liberty to overlap the notes.
In the early 1980's, the first guitars synth starting appearing on the market thanks to companies like Roland, a long time leader in this sector. Some of the first models were the Roland GR 100 and the GR 500, followed by more sophisticated models such as the GR 300, the GR 50 and the latest GR 30's. Other manufacturers are Axon (Neural Guitar Midi Controller NNGC 77), and Yamaha (Guitar Midi Converter G50). They are able to expand with sound generation modules, even if it's to best use those internal. A common problem with this equipment was the delay between the played note and its elaboration. In the first models this delay was notable (on the order of milliseconds). Today, technology has reduced this time practically to zero.
The hexaphonic pick-up, like the Roland GK-2, can interface with almost any synthesizer units (except the Yamaha G50, which works only on a proper pick up). The hexaphonic pick up has six poles that are set up in correspondence to the strings of the guitar being used. Each pole reads the frequency for that string and sends it to the converter (or controller) attached to that same pick up. This is the brain of the entire system, because it translates the Midi data that arrives and directs it to the sound module. This emits the programmed sound, and it is here where the delay that we talked about before could appear, due to the way in which the recognition and conversion is done.
The process is quite complicated: the played notes, analysis of every single chord and its frequency (number of vibrations of the string) that creates the height of the sound and therefore the note, possible extraneous notes (not wanted) coming from imperfect execution or from particular techniques (slide, bending, tapping, hammer-on and pull-off) which chews up the conversion time, the actual conversion and the dispatch to the sound generation module. As you can see, the path is long. To avoid this problem, new equipment was designed such as the Zeta SynthAxe or the first Casio's, which didn't look very much like a guitar. The designers more or less succeeded, but they however introduced a new problem: the fact that guitarists wanted to hold a real guitar. From this came the success of the hexaphonic pick ups, which can be installed on any guitar. There are also guitars that have normal and hexaphonic pick ups as standard equipment (Fender Stratocaster, Roland Ready, some Godin or Aria models, and even the Ovation). We can now play our guitar with the sounds that we want.

Guitar and virtual amplification

It's obvious that with the advent of computers and virtual reality, that the technology in the musical industry has also advanced greatly. We have analyzed the various systems of hexaphonic pick up, convertors and synthesizers that create particular sounds or are connected to other instruments. But what we are about to learn is a totally new world, based on virtual simulation both for the guitar and amplification. But why do we need to artificially recreate the typical characteristics of guitars and amplifiers when we can use real ones? After trying this kind of system myself, I must say that the answer is convenience. Try to imagine using a Fender Strato and Telecaster, a Gibson Les Paul, 175 and 335, a Martin and an Ovation, a Rickenbacker, a Gretsch etc. Then the amplifiers: Fender Twin, Vox AC30, Mesa Boogie Mark (1, 2, 3, 4), a Roland Jazz Chorus, a Soldano etc. What do you do if you are playing a series of concerts or sessions in the recording studio and you need sounds typical of these instruments?
First of all you need to rent a truck to haul around the instrumentation, a security guard and one or two roady's to load and unload. For those of us who don't want to have all the above mentioned instrumentation, there is virtual reality.
The first step is to understand some terms, starting with physical modeling. This is a technological procedure that describes an acoustic or electric instrument and all of its physical characteristics, sound and performance through the use of an elaborate system of mathematical rules and laws, that can be elaborated and therefore represented on a computer. Today it is possible to quantify the data for guitars: the wood, the form, the pick ups, the strings, etc. For the amplifiers: the valves, the speakers, the microphones, etc. A new piece of equipment such as the Roland VG8 has in its memory all the characteristics of the amplifiers and the guitars that we spoke of before. Everything is "sectioned" in the system that Roland calls the COSM, which is Composite Object Sound Modeling. This is practically the founder of an entire series of perfected equipment that function according to these criterion. The VG8 is connected to the guitar through a hexaphonic pick up (Roland GK-2), and this could make you think that we are dealing with a guitar synthesizer (even if it is able to produce analogous sounds), but the system is based on other principles. The opposite of a common guitar synth, the VG8 uses the signal of the hexaphonic pick and elaborates the complete audio signal. There are two other approaches to signal modeling:
- the VGM (Variable Guitar Modeling), which ables the system to recreate the sounds of a large number of existing guitars and amplifiers;
- the HRM (Harmonic Restructure Modeling), which works on the harmonics of the instrument, elaborating them as desired and creating completely new non-synthesized sounds.
Yamaha has the DG1000, a unit that funtions like the VG8, but imitates the amplifiers using a technology called ECM (Electric Circuit Modeling). In this case every component is simulated that belongs to the original circuit of certain amplifiers. A guitar using the DG1000 doesn't need the hexaphonic pick ups, because the machine uses the normal pick ups. Another instrument similar to the DG1000 is the Line6 "AxSys212" or the Johnson "Millenium" by Digitech.
Line6 also has the "Pod", which is a nice gadget that is normally used on stage and offers some really interesting sounds, and has a good quality-price ratio. Among amplifier emulators, the Pod is currently the most popular, besides the "colleague" J-Station by Johnson.
Another new piece in this sector are the virtual pedals. They imitate the typical sounds of some common pedals, such as the Tuba Screamer by Ibanez, Ecoplex Maestro EP-3, the Electro Harmonix Deluxe Memory Man and so many others. The newest pedals are the Line6 DL4, the Akai E1 and the Lexicon MPX G2 (a awesome rack system destined to be great). All have the precise scope of offering numerous historical pedal effects in one piece of equipment.

It needs to be said that the technological evolution is prepared for the new millennium and the equipment described above proves that. Obviously we can never replace a real guitar or amplifier: comparing them with their "virtual" relatives you can say that the similarity is such to have at least the benefit of the doubt.