Images Of Sound
Paul Gilby outlines JVC's AV Graphic Synthesizer which has some rather novel ways of representing music in a visual sense.
Hiding in the pages of the JVC catalogue, the VS1-B Graphic Synthesizer has some interesting and novel ways of representing music in a visual sense. Paul Gilby takes a look.
The idea of visualising sound has always been an attractive one, though the rules which determine the colour to frequency relationships have never been written. However, it's a generally held opinion that dark/dull colours seem to relate to low pitches and light/bright colours to high. The psychology of the matter alone could fill the whole magazine!
The design and software element of JVC's Graphic Synthesizer makes some bold attempts to illustrate sound. The unit offers five different visual interpretations of any sound input and these are divided into two groups: useful and gimmick. On the useful side are the Peak/VU Meter, Spectrum Analyser and Musical Keyboard. As for the gimmicks, there's the Sound Space display which shows a cosmic landscape with spherical objects floating around and the Sound Image display which indicates the stereo position of a frequency band.
The Graphic Synthesizer forms part of what JVC call their Crossmedia Series which is essentially a range of products that cover hi-fi, video, digital sound and the unit in question which appears a very odd member of the bunch.
It's difficult to identify the true reason for designing the Graphic Synthesizer other than for it's educational value and it's in this field that the unit would be of serious use. Any pretensions to being a serious piece of studio equipment should be dismissed, as it is intended to form part of a home entertainment system. In this respect, it would still seem to be out of place for it neither has the variation to keep your interest or an application that would make you switch it on everyday. It also fails to be of any real serious use within the studio as what are potentially exciting uses such as a large Peak/VU readout for the control room, have been lost due to the lack of any means of calibrating 0VU.
The Graphic Synthesizer's best use would be as an educational tool that enables simple concepts of a sound's frequency and level to be illustrated with great ease. In this department it's unique and it's a winner.
The unit is straightforward to hook up and will plug into the aerial socket of any television set or monitor to display the selected screen shot in colour. Any audio input may be used and provision is made for a video tape machine, line or microphone source. Once the signal has been selected, it's a simple matter of using the up/down nudge buttons to set the correct input level as indicated on the eight segment LED. Selection of the five different screens is as simple as ABC, and D and E.
Program A selected by the button A is the Peak/VU screen. This displays a stereo sound input as both a peak and VU reading, both sharing the same scale (Figure 1). A peak hold pointer is also shown for the maximum level of sound in either meter mode. The meter scale itself has a range of -30dB to a maximum of +10dB though. What is not stated is the reference point for 0dB or any way of calibrating the scale to meet your own standard.
When this display is selected, the sound input is divided into 26 individual frequency bands and represented as vertical coloured bars.
The spectrum analyser's display (Figure2) may be controlled in various ways by the use of the Display Control cursors positioned at the far right hand end of the unit. Options available are: Hold, which displays the maximum level a frequency has reached; Stop, which freezes the display for three seconds and Fast, which speeds up the decay time. With its ability to split the sound into bands of 1/3rd octave each, the Analyser worked well and behaved reasonably close to its intentions and should certainly prove a useful, basic teaching aid. Watching filter sweeps move from high down to low frequency is particularly informative.
Program 3 is the stereo sound image indicator. The screen shows the sound divided into 10 horizontal frequency bands with the high frequencies at the top and the lower at the bottom (Figure 3). The length of the bars indicates what amount of frequency is present and in which part of the stereo image. What's more, you can change the colour of the background to white, black, grey or blue.
This display is exceptionally cosmic! (Figure 4). Without any sound present, you're looking at a landscape grid which recedes into infinity. Applying a musical input makes coloured spheres appear on the landscape and travel around in what seems to be a random manner. It is, in fact, not random, but conforms to a rule which has the low pitched sounds in the distance and the highest in the foreground. These floating globes often move both front to back and side to side if a stereo mix is used. As with the Sound Image screen, you can change the colour of either the land or sky to produce some very weird looking pictures. JVC have given these changes names like: Spring, Winter, Summer, Autumn and Night, just to set you in the right mood.
The final screen is that of the Musical Scale which captures and analyses the music input and displays each note on a stave. (Figure 5). Note lengths are indicated and these may be altered in a variety of ways including octave shift and tempo change. Also, when you're in this mode you can access up to 36 pages of musical information via the control parameters. Any musical note played will be displayed both on the keyboard in the picture and the musical stave.
The last program is F which is purely a menu of options.
Finally, the Graphic Synthesizer may be computer controlled via the RS 232 interface of a home micro to display visual patterns generated by your own software.
The Graphic Synthesizer would seem to be caught in No-Man's Land, for it offers facilities like the Spectrum Analyser and Peak Meter that would be of little use to the home hi-fi enthusiast. Yet, these very same facilities would be immensely useful to a small studio if only the unit was less domestically orientated and allowed level calibration. If your application leans more towards education than recording, then the AV Graphic Synthesizer is probably an ideal way of representing audio information.
Feature by Paul Gilby
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