This month Yamaha/Kemble Hi-Tech specialist Ken Campbell steps into the confessional with two programmes for the DX7 which you can patch in behind the security of your own flying buttress.

In future issues we'll be asking other expert knob twiddlers from the country's major keyboard manufacturers to suggest new programmes for their own synths. Then you and I can happily rip them off.

Thanks to Ken for pelting back from the seriously fab DX Owners' Club Convention in time to get these to us. More programmes in forthcoming One Twos.

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Here are two DX7 programmes using different techniques, one of which I shall explain, the other which I won't. So there.

The first FLANGER (strictly speaking, inaccurate), makes use of the unusual feedback loop on algorithm four. This loop encompasses three operators.

According to the laws of physics, life the universe and everything, it takes a finite amount of time for the output of the loop to reach the input. We can make use of this fact and create a sound with a slow periodic rhythm which, when fed back on itself, will create a useful phase effect.

This rhythm can be created in one of two ways. You can either use the detune parameter on one operator (or half a degree of fine tune), or else change the mode of an operator to Fixed Frequency and chose a frequency around 1Hz.

There are two things to remember about this type of sound. The first is that the output of the carrier must be relatively close to those of the modulators as it is an effect acting as a modulator itself. The second thing is that if you use the carrier to create the beat frequency then the amplitude will beat along with the phase effect. Try shifting the fixed frequency operator to operator five and listen to the difference.

The second programme INTERFERON makes use of a little quirk of the DX7 and must be used with the After Pressure set to maximum, with pitch on.

Try hitting the notes around C4 and use after pressure. I don't have a fully satisfactory explanation for this effect, but I suspect that it could involve intermodulation distortion of the tertiary cross modulation by the LFO.

Where's the Aspirin. I think I've got a headache.