As you probably realise by now, modular keyboard systems are currently all the rage. Most keyboards manufacturers generally have some form of modular Expander/Remote Keyboard set-up amongst their range of instruments — Oberheim, Roland, Korg and now Yamaha with their rackmounting TX816 at the top end of the market and the TX7 at the lower end.

Essentially, the TX7 consists of a DX7's sound generator with two sets of 32 function memories, 32 acting on its internal sounds, and 32 acting on the DX7 that the TX7 should ideally be linked to.

A DX7 on its own has 32 internal voice memories which will store the programmed sounds, yet it has certain parameters that are separated from these sounds which are called function parameters — Poly or Mono mode, Portamento, Modulation Wheel Operation etc. In the more upmarket keyboards such as Yamaha's DX5 and DX1, the differentiation between these function parameters and the voice parameters becomes more blurred as they can all be memorised for instant recall from one memory; and now this is also the case with the DX7 when linked to a TX7, as the TX7 has all the memory for the DX's function controls.

Appearance-wise, both the TX7 and QX7 are very smart and a bit on the 'cute' side. Measuring 14" x 9½" x 1½", which is very small for sophisticated equipment such as this, they are designed in such a way as to enable them to be stacked one on top of the other. Their front panels are angled and have a display on the lefthand side which informs the user as to the internal goings-on. On the TX7, this display consists of a DX7-like 16 digit LCD screen, yet with only one row of displays (as opposed to the DX7's two rows).

To the right of the LCD screen is a row of 12 switches, most of which have several functions. Starting on the left, the first four control the TX7's output volume — giving two switches for a user preset table high and low volume level, and two switches for incrementation of the level. When any of these switches are depressed, the screen displays the output level in a horizontal ladder form, and in this way it gives you preset volume levels and visual indication at the touch of a button.

The next two switches are dual function. In their primary mode they select between combined or individual change of programs, and the secondary mode is for cassette dumping of information. When in the combined mode, changing a program number on the DX will also change the voice on the TX7, and this also works the other way 'round with the TX7's program change also affecting the DX's.

The next pair of switches are again dual function, and control memory storage of DX's function and the TX7's function memories, as well as MIDI control information. The TX7's MIDI capabilities are much more versatile than those found on the DX7 and 9. In addition to the standard MIDI channel select, it offers an Omni mode and separate switching for 'Receive Data', 'Control Change', and 'Data Entry Volume' On/Off, the latter of which assigns the DX's Data Entry slider to control the TX7's output level.

The next switch along on the TX7's front panel is labelled 'function' with two arrows above and beneath it. This switch will scroll through the function parameters — assigning Modulation Wheel, Aftertouch, Breath Controller, etc, as well as overall output attenuation (in seven steps) and the split keyboard functions. What this last feature does is to store any position on the keyboard (decided by the user by simply depressing the key at which the split should occur). In fact this is not simply a split keyboard function as it assigns the lowest and highest notes on the keyboard between which the TX7's voices will sound, and this feature is only available in the TX's set of function memories.

Finally, the last three switches on the TX7's front panel are for switching between the dual modes of the previously mentioned switches, and for Data entry — Yes/No/+1/-1.

Over on the rear panel are all the sockets — MIDI In, Out and Thru, sockets for line output and headphone output, and an eight pin DIN socket for the cassette interface. Via the cassette interface all voice memories and function memories can be saved and loaded to and from cassette, and this is just one more facility which makes the TX7 an attractive proposition to DX7 owners, as it offers a very cheap means of building up a library of DX voices.

QX7

Looking almost identical to the TX7 is Yamaha's budget priced MIDI sequencer, the QX7. This is an 8,100 note polyphonic two channel sequencer which can store over 6,000 notes with velocity, aftertouch, Modulation Wheel, etc, data, as well as overdub and dump to cassette. It is designed in quite a unique way, as it uses the two channels for data transfer back and forth for editing, copying, merging etc.

The QX7's front panel has a simple red dual number display from which all information is displayed. This is achieved by flashing abbreviations of words which can be deciphered from the panel on the QX7's top panel. Beneath the display is a listing of the first two sets of job commands. There are four sets of job commands in all, and it is from these that all system control is based.

To the right of the display are a group of eight small black switches, followed by three large coloured ones and a large tempo control knob. As is normal now on Yamaha gear, all the switches have several functions each, and the eight small switches are essentially for job command selection and control, track assign and Data entry. The three large buttons' primary functions are for starting and stopping of the record and playback modes, whilst they also double as cassette interface control switches.

The functions or job commands that are available on the QX7 are fairly extensive for a machine of this price — real time, overdubbing or step time recording of sequences onto track one, infinite or programmable repeat, quantising (auto-correct) of data recorded in real time, a temporary buffer, an echo back feature (sending any MIDI In information directly to the MIDI Out port), and a mode which displays MIDI status; ie, every piece of MIDI information that it receives has its relevant status byte number displayed, thus turning the QX7 into a MIDI status monitor rather than a sequencer.

The actual procedure for recording on the QX7 is quite a simple one: On power-up, if channel one is empty, by simply pressing the large record switch, followed by the large start switch, you are given a two bar count in (a visual display counts down in addition to there being a audio click on every beat). Then after the count down has ended the display counts the beat number and the click continues, yet with a higher pitch at the beginning of every bar. Once the first track has been recorded, it can then be quantized if there are any minor timing imperfections, and then it is sent to track two for safe keeping whilst you continue recording on track one. Once another section has been recorded onto track one, it can then be joined onto the first recording on track two. In this way, track one can be exchanged, chained, layered, or inserted into track two, thus making the recording of a complex passage quite a simple task.

Step time programming too is very straightforward, with full control over step size (note length), ties, rests and bars. Both step time and real time sequencers are automatically divided into bars of user-definable length, from which editing of the sequences is done.

On the QX7's rear panel are the MIDI In, Out and Thru sockets, a footswitch socket for start/stop control of the sequence, and the cassette interface socket for dumping of the sequence data to tape.

Although the QX7 has many useful features, and is a very versatile and functional MIDI sequencer in its own right, by far the most attractive thing about it, which is bound to be the basis of its popularity is its price. It was only a couple of years ago that one had to spend upwards of £500.00 for a CV/Gate sequencer which could only hold a maximum of 600 monophonic notes and now we have a very powerful sequencer capable of holding over 6,000 notes in full polyphony.

Conclusion

As a working system, the TX7 FM Expander and the QX7 Sequencer could work very well with any MIDI keyboard, with the QX7 being able to control both the TX7 and MIDI keyboard with a great deal of versatility for such a relatively small sum of money. The TX7 itself would certainly be a useful addition to any MIDI synthesizer, however it really comes into its own when used in conjunction with a DX7, as not only can it then be programmed, but it also greatly expands the DX7's performance power with split keyboard, function control memory for every internal voice, and of course twice the programming power.

If you area DX7 owner, or even DX9 owner, then I would strongly suggest that you check out the TX7 FM Expander, and for those of you in the market for a powerful MIDI sequencer, then the QX7 is well worth having a look at too.

YAMAHA TX7 FM EXPANDER & QX7 SEQUENCER - RRP: £699 & £499