Yamaha QX7 sequencer / TX7 expander
Article from Electronic Soundmaker & Computer Music, May 1985
The latest additions to Yamaha's 'X' range - the QX7 keyboard recorder and TX7 expander look to be some of the most interesting yet.
QX7 sequencer/TX7 expander
Prices: QX7 £499; TX7 £699
If there's one keyboard that's dominated the world music market over the last couple of years, it has to be Yamaha's innovative DX7, the one that brought FM synthesis down to an (almost!) affordable price and ushered in a whole new era of life-like synthetic sounds. And if there's one unit which has caused more excitement and speculation than any other amongst both studio and stage-based musicians, it must be the mighty Yamaha QX1 sequencer, which holds 80,000 notes and has a built-in disk drive to entirely refresh its memory in a matter of seconds.
Two definite winners, then - but Yamaha are determined to spread the benefits of the DX7/QX1 designs as far as possible, and to this end have introduced the TX7 and QX7, which should be getting into the shops as you read this.
Basically, the TX7 is a keyboardless expander version of the DX7, and the QX7 is a small budget version of the QX1 which retains many of its innovative programming features. Now, there are a good few expander designs about, including the Roland Planet series, the Siel Expander 6 and Expander 80, and the Korg EX800, but obviously the keyboardless DX7 is the one everybody's been waiting for.
Unfortunately, non-DX7 owners will be disappointed, since the TX7 isn't much good without a DX7 on hand. Granted that you can play sounds on it under MIDI control from almost any synth, but the TX7 isn't self-editing, so you need a DX7 or a CX5 computer to alter its factory sounds. Without a touch-sensitive synth such as the DX7 you lose many of the velocity effects programmed into the TX7 s memories too, and there are many other features specifically aimed at the DX design.
Let's look at the TX7 in more detail. It's a small wedge-shaped unit no larger than a coffee-table book, and has a mere twelve buttons and an LCD display on the front panel. On the top panel there's a chart of the typical setup with a DX7, allowing the most comprehensive exchange of information possible.
The first button on the left is the Volume Low switch, which takes the TX7's output down to a pre-defined level. This level is set with the next switches, Up and Down, which alter the volume level at any given time and which call up a little bar graph on the LCD display to show you what proportion of full volume you're set to.
The fourth switch is, logically enough, Volume High, using the Volume Low and Volume High buttons you can instantly choose either of two volume levels for the TX's output, and if you want to vary these you just have to lean on Up or Down as appropriate. Next are the two Program Change select buttons, which allow you to change the TX's sounds independently or along with a connected DX7. These two buttons double as Cassette Save/Verify and Load/Protect - the TX7 does in fact load sounds from cassette, and effectively adds this function to your DX7 as well, since it's only a matter of a couple of seconds to completely exchange a set of sounds via the MIDI link.
The next button is Store TX Perf. Like the massive DX1 but unlike the DX7, the TX7 can store performance parameters for every sound, so each of the 32 onboard sounds has its own velocity and after-touch depth, pitch bend and modulation depth, portamento level and so on. The real surprise is that the next button on the TX7 is DX Function, which gives the same ability to a DX7, so that when the two are used together they'll each have a different set of performance parameters for every sound. So apart from adding cassette dump to your DX7, you're also adding performance memories - are the DX7 owners keeping count?
The performance buttons double as MIDI Mode and Dump/Initialise buttons, which allow you to select the MIDI channel responded to, transfer whole sets of voices or single voices to a DX7, and reset any sound to a basic organ-type noise for editing purposes. Next is the function key, which simply steps along from one button to the next calling up the appropriate information in the TX7's LCD display, then a Mode button which selects whether you're looking at the top set of functions (Volume, Program Change etc) or the bottom set (Cassette Verify, Initialise and so on). Lastly, there are two buttons marked No/-1 and Yes/+1, which step along the memories and allow you to make changes and decisions during the various editing procedures.
There are a good few hidden functions on the TX7 which wouldn't become obvious without the handbook in a month of Sundays. Easy enough to use once you know how, though - the most impressive of these is Split, which allows the TX7 to sound only from a certain definable range of keys on the DX7. This gives you a sort of split keyboard effect - the DX7 doesn't actually stop playing on those keys, but you can easily arrange the volume levels so that the TX7's sound swamps it out if desired. You could use two TX7s and a DX7 just as a mother keyboard if you wanted a real split, but that would be a little indulgent!
The TX7 comes supplied with two sets of sounds on tape, one for itself and one for a DX7. These sounds sometimes complement each other to form a complex or unusually thick sound, sometimes contrast markedly to achieve layered effects. You can get 127 complete files onto a cassette and 'label' them so that the TX7 loads the correct file, and as previously mentioned it's dead easy to dump sounds across to a DX7 via MIDI. The TX7 uses an MSX-type cassette socket for compatibility with the CX5, although it's easy enough to get hold of one of the triple minijack to 8-pin DIN cables if you don't have an MSX cassette machine.
One other hidden function is called Data Entry Volume, and if you switch this to On, the DX7's Data Entry slider takes control of the TX7's volume. This means that you have a miniature mixer on the DX7's top panel, with the DX7's own volume slider sitting neatly next to the Data Entry slider which now has command over the TX7's volume. You have to be careful to switch the DX7 to an innocuous function such as Battery Voltage Check if you use this facility though, otherwise you may find your Master Tuning or something equally vital changing as you fade your TX7 up!
Sound pairs on the initial TX7 set include an excellent acoustic piano, high strings, male/female choir, electric piano with time bars, PowerSynth, Fatsynth (a brassy effect with a lot of bite), jazz/Spanish guitar, cellos, Mallet (combined wood and metal sounds), Pipe Organ (with different footages represented on the DX7 and TX7) and so on. The TX7's sound-producing facilities may be identical to those of a DX7, but the combination of two sets of performance parameters, the effect of two contrasting or complementary FM sounds, and the added facilities of cassette dump, 'split' and performance memories has to be heard to be believed. At around £699 the TX7 is going to be a massive seller, even if it is a gift mainly for the existing DX7 elite.
Yamaha's QX7 sequencer is, of course, ideally suited to the DX7/TX7 combination, but it also has a lot to offer to users of Junos, Prophets, Korgs and other MIDI-equipped synths. It's a two-memory recorder which can address all 16 MIDI channels individually, so the complexity of the musical information you can store is virtually unlimited.
The £499 QX7 comes in the form of another wedge-shaped module which sits neatly underneath a TX7 (you may need a small optional support stand to balance the latter safely). The front panel has just three large buttons, eight small ones, a tempo dial and an LED display; next to the main LEDs are further small indicators for various musical values, and on the top panel is a list of all the main procedures for using the QX7 - what Yamaha call a Job Guide.
The QX7 has a capacity of around 6,500 notes, 8,500 if you don't record velocity information, and there's one working memory (Track 1) and another 'safe' memory (Track 2). When you've recorded a pattern on Track 1, you dump it to Track 2 using the Exchange function; you can then store more notes (perhaps on a different MIDI channel for a different synth) on Track 1, and 'Track Down' or combine the information onto Track 2.
The QX7 can work in several modes. Real Time sequences are accurate down to 1/384th note, but if you want a more mechanical feel you can quantise a realtime sequence to any required resolution, shifting all notes to the nearest beat. A built-in metronome gives you a two-bar count-in in 4/4 time before you start playing, and the display shows what measure you've reached. Unlike other sequencers such as Roland's MSQ 700, the QX has very advanced editing functions, allowing you to take out a single measure, to repeat it up to 99 times or append it to the end of an existing sequence.
If you do choose to quantise a realtime sequence and don't like the result, don't worry - you haven't lost the original, it's stored in a buffer memory. That buffer can be useful, allowing you to work on new parts without losing old ones even if you're not ready to combine them with the Track 2 material.
It you want more regular patterns than quantised realtime can produce, you can record in Step Time. Every time you release a key or set of keys, the QX7 will record them as a beat of a given length, perhaps eighths or sixteenth notes, and you can change the value used in the middle of a recording. The realtime and step time functions can be mixed in various ways, and there's no reason why you shouldn't use both several times in recording a complex piece.
Naturally enough, the QX7 can be clocked from various sources, including from a MIDI drum machine, and it also records MIDI patch changes so that your synth sounds can alter automatically during the course of a sequence. If you are using a DX7/TX7 combination, you obviously have the advantage of being able to record velocity, after-touch, pitch bend and even breath controller information as well.
The QX7 dumps information to tape using the same 8-pin DIN to triple minijack lead which we mentioned for the TX7 interface to an MSX cassette deck. Even with cassette dump, the specification of the QX7 may seem a little limited at first, but it's all a matter of how imaginatively you use it, and how much you can do with the various copy/append functions. Certainly the ability to take out a single bar, insert material into the middle of a long sequence, erase patterns only after a certain point and so on should be musically highly useful.
At £499 the QX7 is a sure-fire winner, and as previously mentioned, it's more suitable for non-DX users than is the TX7. However, its lack of multiple memories and cassette rather than disk loading system is going to limit it for stage use, and so it'll probably become a much-prized studio fixture rather than a powerful live proposition. For live work you'll have to save up for a QX1, which at £2,500 in the shops rather than the full £4,000 is beginning to look mighty attractive!
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Review by Mark Jenkins writing as Tony Mills
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