After instantly falling in love with a DN then DT, I was a little meh on the A4 sound. My “ah ha!” moment was a little strange, and I don’t think a common sentiment, but might click with someone out there:
Between its four (mono) voices, crazy fast envs, sequencer with all its locks, generally insane amounts of modulation, and oddly specific shortcutted modulation (vib, PW, really fast arps…) the A4 comes across to me as a very (very) upscale chiptunes tracker.
If you think of the classic sound of an NES, for example, you have to only two PWs to do most of the melody work (the tri on bass is essentially unmoddable, and the fourth channel is just noise for percussion). How can you make full and interesting melodies with just two PWs? By moding the hell out of their pitch, amp, and phase to produce vibratos, arps, delay effects, faked out reverbs, slides, trems, timbre sweeps, and all the rest, extremely quickly, on a per-step basis.
That’s what the A4 brings to the table that other synths don’t. And even if the only thing it did was back this modulation-heavy workflow with nice sounding squares, it would be a beast. But of course it goes so much further, giving us two osc with all sorts of shapes and subs (that 5th sub!) through 2 filters x 4 tracks and built-in FX.
In a way, the full-featuredness of the analog side of things (and its pretending to be poly) is what hid the “heart” of this box from me. It’s possible — maybe even easier — to try to patch it like a Prophet. But what I now love about the A4 and what made it a keeper for me is using it like a delux demoscene mod machine but with incredibly full analog sound.
That’s what a lot of people here have said, right? That it’s modulation-heavy. I just wanted to say “Yes, but x10!” The A4 to me is not an “evolving sound” ambient sort of morphing modulation (though it can do). The modulation is the sound, to the point where patches don’t really capture it — no more so than a PW captures the sound of those NES tunes. You have to hear it sequenced with all its locks to get a sense of its potential.
Edit: made it more clear what I believe A4’s advantages are above and beyond NES emulation