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TX7 - To The Limit

Article from Sound On Sound, June 1986

Ray Elder details a way of creating new programs of your own on Yamaha's TX7 expander without having to use a DX7. All you need is a Spectrum computer, some DX7 voice editing software and the free advice contained within this article!

Making full use of the TX7's capabilities without a Yamaha DX7 IS possible. Thanks to MIDI and the home computer! Ray Elder explains how.

Like many synthesists, I longed for FM sounds but couldn't afford a DX7, and so when the Yamaha TX7 Expander - the electronics without the keyboard - was marketed at around half the price of a DX7, I saw a way to acquire these sounds.

Fortunately my bank manager was reasonably understanding and I was able to add this unit to my Siel DK80 synth. The factory sounds were every bit as good as I had expected and using the MIDI connection all the voices except the four or five which needed special control (eg. breath) played perfectly.

Although satisfied with the unit, I soon realised that without a DX7 I was only using around half of the TX's potential, as voices were alterable by the DX7 and voice banks could be stored. However, I reasoned that I should be able to have a choice of voice banks and be able to modify or create new voices without a DX7. Yamaha said it couldn't be done, but I wasn't so sure!


The TX7 is an innocuous-looking black box with a sloping front which has a row of green buttons along it. These allow a limited number of functions to be used: four deal with volume, two increase and decrease parameters or voice numbers, and the rest are for accessing tape storage, MIDI and Function selection.

Now the DX7 only has one Function memory, which is used to set up the required operating conditions for a voice; namely, how much portamento, how much velocity, the octave range or the special effects and how they affect the DX voice selected. You either have to have one all-purpose setting for all 32 voices or alter it each time you select a new voice.

The TX7, having been designed to operate in conjunction with and overcome the limitations of the DX7, has not only 32 Function memories - one for each voice which is selected on a voice change - but 32 'spare' memories too for use on the DX7's voices.

A cassette interface and lead is also included so a bank of voices and functions can be saved or loaded from the humble cassette recorder. Likewise a full set of MIDI links - In, Out and Thru - are provided and these gave me a clue as to how I could achieve my aim.


The Musical Instrument Digital Interface is a means of sending and receiving the codes that the musical instrument uses in creating the notes, pitch, sustain, velocity etc, that are formed when the instrument is played.

In the simplest arrangement the MIDI Out of the controlling keyboard is connected to the MIDI In of the instrument to be controlled. In my case, the Siel DK80 Out to the TX7 In. Now everything played on the Siel can be sounded and played in a choice of voices on the TX7 as well.

Another alternative, and in fact the manner in which I was using the two instruments, is to connect them up to a computer. In this way, depending on the software you use, the computer can act as a sequencer, a recording studio or an editor.

I use the modest, cheap and readily available Sinclair Spectrum for which I have an ElectroMusic Research (EMR) MIDI Interface. I have used other makes - the XRI Systems MICON is superb with an excellent step-time, 8-note polyphonic sequencer, and the Siel unit is also very versatile. Both these companies have told me they have similar programs to the ones I am about to describe so if you already have one of their interfaces all is not lost.


I had seen the advertisements for DX7 editors and prevailed upon Mike Beecher of EMR to send me their range to try out with the TX7. This article is the result and I hope you will forgive me writing in a simple manner, the combinations of degrees of experience between musicians and computers are many and varied so I am trying to write in a way that all may understand.


Several computers have MIDI interfaces available for them so you are not limited to the Spectrum; EMR sell interfaces and similar software for the Commodore C64 and BBC, so does Siel. Yamaha's own CX5M is also suitable. As well as a computer you will need a reliable cassette player and a TV - a small B&W portable is ideal and relatively cheap, the family colour TV can also be pressed into service.

Setting up this equipment is a simple case of reading the manual and taking things step by step and slowly.

The MIDI interface is typically a small box usually with a thick cable and a plug suited to the sockets found on the computer; from this box a set of 5-pin DIN sockets will connect to the TX7. As the programs described were originally written for the DX7 you must be prepared to experiment a little when using them with a TX7, but I can give details of the EMR/Spectrum system and the other versions should be similar.


Due to the fact that the TX7 has no keyboard of its own and is played via the MIDI In socket, once the computer is linked in there is no way to play it and hear the result of any changes you've made.

One solution is to keep changing the MIDI lead and connecting the computer and the controlling keyboard. However, apart from the time and inconvenience, this is bound to cause excessive wear on the plugs and sockets. I solved the problem by purchasing the Yamaha YME-8 MIDI selector box. This allows two sets of MIDI inputs to be switched between two banks of four outputs; this means control over the TX7 can be changed at the flick of a switch.


There are three DX/TX programs in the EMR range: a Voice Library, a Function Editor and a Voice Editor. There is also an excellent real-time 8-track tape recorder simulator which they call the Performer.

First, a few words about terminology before we look at them in detail. 'Software' or 'Program' is the computer's instructions. It should not be necessary to have programming knowledge to use a computer and with all these programs this is the case, although the instructions are a little on the brief side. The program has to be 'loaded' into the computer first before it can be used.

The musical information or data is called 'events'. Each event represents some information on note, pitch, velocity etc, which is ascertained by the MIDI protocol and, again, in-depth knowledge is not essential.

'Step time' is the method of composing/editing note by note, rather like using a typewriter to produce a letter - a very accurate method of working that allows for a great degree of fine editing.

'Real time' is when everything happens as it is played. Great for competent musicians and a lot less time-consuming than step-time note entry but editing is often very limited or non-existent.


This is probably the least useful of the three programs since the TX7, as already mentioned, has 32 Function memories and these are alterable from its front panel. The advantage of using the Function Editor is that the whole set of values or parameters for each voice can be displayed together on the TV screen for instant reference.

The method of using this is to set the computer to receive (load) by choosing this option from a menu and then selecting the MIDI send operation from the TX7 panel. The settings are then displayed and you can alter them as you wish.

There is a slight problem with this program due to it being designed for the DX7's single Function memory and I found that some Function stores failed to register. In the end I developed the technique of always working with Function 1 and then transferring it internally from the TX7 as the manual explains.

Once a set of parameters has been changed then you set the TX7 to receive and send them back from the computer (to Store 1) and then move them to the Store position required.

32 Function patches can be held in the Spectrum memory at one time and these can be saved onto tape for future use. The time taken for each move to and from the instrument and the computer is in microseconds by the way!


This is the most instant of the three EMR programs in that as well as the computer program you are also supplied with seven banks of 32 voices which you load into the computer and then pass onto the TX7, giving you 224 new sounds!

Actually several of the sounds are similar, but there is a wide range of material here from instrument synthesization to effects and most are superb. This program alone greatly extends the TX7 in that banks of 32 voices can be transferred to and from the Spectrum to either the TX7 or to tape, or a single voice can be sent to and from the Spectrum to tape or the TX7.

I spent one night building up a selection of the sounds I wanted to use the most from the whole lot available to keep in the TX7 permanently. I also compiled a set of effects which I saved from the TX7 to tape for re-loading without having to use the computer - a good idea for live work.

To create your own compilation of sounds is a job needing patience and time, but once done you may not need to repeat the exercise for a long time, if ever. Here's what you do.

Load in a bank of voices from tape to the computer, then send the bank to the TX7. All these operations are controlled by options on the screen. Run through the sounds now in the TX7 and when you have decided on which, if any, from that bank you want to use in your compilation, send a 'single' voice back to the computer.

Once it has been received by the Spectrum then save it to tape by the appropriate option. This process is repeated for each voice in each bank that you want in your final selection. At the end of this process you will have a tape containing the 32 voices you want.

Now load each voice back in to the computer from the tape, one at a time, and store it under the number of your choice in the bank in memory. When all 32 have been loaded and assigned numbers, transfer the whole bank into the TX7 and hey presto! your own individualised voice collection.

This may sound complicated, but in practice it's very easy.


And finally we come to the program which makes sound creation possible on the TX7. Not only possible but, in fact, easier than it is with the DX7.

Voice transfer is the same as for the Library program, either single voices or a bank of 32 can be moved between the TX7, the Spectrum and the cassette recorder. However, you do not get the seven banks of predesigned synth voices but instead a powerful section which allows you to edit or modify the DX/TX voices.

This is by far the most complex program of the three, as you can tell by the seven sheets of instructions you receive compared to the single sheet for each of the other two programs, and there are three separate screen displays with information which can be altered.

Each screen is in sections and voice parameters are shown numerically and graphically where appropriate. On screen one the envelope characteristics for each of the six operators can be shown graphically by pressing 'E' on the Spectrum, a visual representation which is invaluable.

When a section has been changed, then the modified data is sent to the TX7 and the changes can be heard by playing it, which is where the Yamaha MIDI switching unit becomes essential.

At this point if you only have a TX7 there are two options open to you: either you must spend many hours experimenting or you will have to get hold of a DX7 instruction manual, because in the TX7 manual they say that as it is impossible to programme voices on the TX7 without a DX7, there is no need to give details on how this is done. How wrong can you be!


For those of you who don't know, in computing circles a 'bug' is an error which stops a program from doing what it should. In the Editor program which was sent to me by EMR there was such a bug which caused a few problems.

The program would not accept the data from the TX7 into memory and kept producing a load of rubbish. EMR have assured me that it was either a one-off fault or else it was because I was using a TX7 and not a DX7. Anyhow, having suffered for my sins, I will give you the solution just in case...

STEP 1. When the program is showing the initial menu press CAPS SHIFT and BREAK at the same time on the computer. A message should appear on the bottom of the screen - ignore it.

STEP 2. Press key O, the word POKE should appear on the screen. Type in the number 32011 followed by a comma, and 159. It should read P0KE 32011,159. Now press the ENTER key and a message O.OK should appear.

STEP 3. Follow the same procedure to enter POKE 32020,159.

STEP 4. Press key G to obtain the word GOTO and type 9990 and press ENTER.

STEP 5. Put a tape in your cassette player, start it recording and then press any Spectrum key. You will have to press another key again in a few minutes and then you will have your modified and (hopefully) working copy of the error-free program for future use.

I am now very much into MIDI control of synths after discovering just what is possible with the TX7 Expander and I hope my article makes things clearer for those of you just starting to come to terms with MIDI equipment.

My thanks to ElectroMusic Research and XRI Systems for their help. If you have any queries, they are only too willing to advise and offer their assistance if you feel like phoning them.

(Contact Details)

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Publisher: Sound On Sound - SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.

The current copyright owner/s of this content may differ from the originally published copyright notice.
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Sound On Sound - Jun 1986

Donated & scanned by: Bill Blackledge

Feature by Ray Elder

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