High resonance [Q], hi-pass filter sweep.
Likely playing one or more notes of the chord structure as it changes - this will be a significant part of the sound, switching up the inversions & spread of the notes as this section increases in sonic impact. What the sound is underneath would be quite hard to tell, but obviously one with a lot of high frequency in it, perhaps a saw-tooth base. There may be some noise mixed into it, but I'm not really hearing any. I'd guess the sweep was done manually rather than as part of the patch, as the speed changes over time [& is a bit lumpy in places] - one hand for the notes, the other for the filter knob.

The record's release date of 1978 would be perfect for it to have been played on the then newly-released Prophet 5, the first mainstream polyphonic synth.

You can get software imitations of the Prophet these days - notably that by Arturia

High resonance [Q], hi-pass filter sweep.
Likely playing one or more notes of the chord structure as it changes - this will be a significant part of the sound, switching up the inversions & spread of the notes as this section increases in sonic impact. What the sound is underneath would be quite hard to tell, but obviously one with a lot of high frequency in it, perhaps a saw-tooth base. There may be some noise mixed into it, but I'm not really hearing any. I'd guess the sweep was done manually rather than as part of the patch, as the speed changes over time [& is a bit lumpy in places] - one hand for the notes, the other for the filter knob.

The record's release date of 1978 would be perfect for it to have been played on the then newly-released Prophet 5, the first mainstream polyphonic synth.

You can get software imitations of the Prophet these days - notably that by Arturia

Other potential candidates from the time may have been the Yamaha CS-80 or [imo less likely] the Oberheim Poly or the PolyMoog

High resonance, hi-pass filter sweep.
Likely playing one or more notes of the chord structure as it changes - this will be a significant part of the sound, switching up the inversions & spread of the notes as this section increases in sonic impact. What the sound is underneath would be quite hard to tell, but obviously one with a lot of high frequency in it, perhaps a saw-tooth base. There may be some noise mixed into it, but I'm not really hearing any. I'd guess the sweep was done manually rather than as part of the patch, as the speed changes over time [& is a bit lumpy in places] - one hand for the notes, the other for the filter knob.

The record's release date of 1978 would be perfect for it to have been played on the then newly-released Prophet 5, the first mainstream polyphonic synth.

You can get software imitations of the Prophet these days - notably that by Arturia

High resonance [Q], hi-pass filter sweep.
Likely playing one or more notes of the chord structure as it changes - this will be a significant part of the sound, switching up the inversions & spread of the notes as this section increases in sonic impact. What the sound is underneath would be quite hard to tell, but obviously one with a lot of high frequency in it, perhaps a saw-tooth base. There may be some noise mixed into it, but I'm not really hearing any. I'd guess the sweep was done manually rather than as part of the patch, as the speed changes over time [& is a bit lumpy in places] - one hand for the notes, the other for the filter knob.

The record's release date of 1978 would be perfect for it to have been played on the then newly-released Prophet 5, the first mainstream polyphonic synth.

You can get software imitations of the Prophet these days - notably that by Arturia