Much of La Ola Interior (Spanish Ambient & Acid Exoticism 1983-1990) sounds shockingly contemporary for a collection of tracks recorded in the mid to late ‘80s. Ambient as a genre was already relatively well established by the time many of the artists on this compilation recorded their songs. But as we neared the end of the century, much of the scene in the US and Japan was beginning to push into New Age territory. These artists from the Spanish peninsula were trafficking in something much more experimental.

La Ola Interior covers a lot of stylistic ground. There’s despondent drones, classic analog synths excursions, detached chants, field recordings, and, yes, even some more rhythmically forward tracks. But what unites it all is a clearly DIY aesthetic and a demand for your attention.

Often, ambient music is designed to fade into the background. It “must be as ignorable as it is interesting,” according to Brian Eno. And while some of the tracks on La Ola Interior could serve as background music, most beg for close listening. The ambience here is in its hypnotic textures and repetition, not in its ignorability.

The opening track from Miguel A. Ruiz, “Transparent,” is built around a short loop of what sounds like a piano. It’s bathed in aliased noise, suggesting it’s being played by a low-bitrate sampler. What unfolds is almost like a reverse of William Basinski’s Disintegration Loops. The lurching melancholy loop slowly fills in, adding more layers, building to a dense crescendo that abruptly cuts out.

That immediately leads to Camino al Desván’s “La Contorsión de Pollo”, which sounds like Tangerine Dream played at half speed. Finis Africae’s “Hybla” is Krautrock filtered through Spanish and Arabic folk musical traditions, arriving at something rhythmic and catchy that doesn’t feel out of place alongside the Kraftwerk sans drums of Orfeón Gagarin’s “Última instancia.” Other tracks like Javier Segura’s “Malagueñas 2” are more orchestral, almost epic — an unresolved hero’s journey in aural form.

Several artists show up on the compilation multiple times, giving you a sense of their place within this diverse, loosely related scene. You get a sense for which artists have their roots in more traditional musical forms (Finis Africae), which are heavily influenced by American minimalist composers (Segura), and which are nearly unclassifiable (Ruiz). But you also get a sense for the drive for sonic exploration that unites them.

Compilations like La Ola Interior are invaluable for preserving lesser-known works from artists often overlooked by American audiences. The label Les Disques Bongo Joe puts out a number of such collections and is well worth following on Bandcamp.