Generally, the best thing to do when confronted by electronic music you've never heard before is to relax and listen, just listen, and often the composer's intentions (or some of them at least) will reveal themselves to you. If you try to think or to figure the music out, all sorts of irrelevancies tend to intrude.

Priscilla and Barton McLean, who Brought the McLean Mix," a program of their own electronic compositions to the National Gallery last night, made it hard not to think.

For one thing, except for "Ah-Syn!" which appears to be a rhapsody to a synthesizer, scored for electronically modified autoharp the compostions were programmatic.

For another thing, there were instruments to watch and to wonder about What was the significance of the soprano, alto (blue), tenor and bass crow bars, slung on stand and played with box wrenches? These sounds and the sounds of the recorders, piano, voice and autoharp were indistinguishable from the wealth of sounds on the tapr,t so why weren't they on tape too?

By and large, the most interesting piece was the first one, "Ah-Syn!" in four sections. It had a nice variety of sounds and textures. The other did nice things with space and color but sounded generally static.