Eerie-sounding music is as much a part of the soundtrack to the Halloween season as lovelorn carols are to Christmas.

Certain music may not have had an initially otherworldly intent. Bach’s Toccata and Fugue in D minor for organ might merely have been an exercise in organ-playing, otherworldly as it may sound, though who really knows what Bach had in mind — if he even wrote it (there’s some doubt nowadays about his authorship of the piece). Yet for us it has come to conjure up images of mad scientists, deformed henchmen and a Phantom of the Opera-like wraith running skeletal hands along a dusty keyboard before the wrath of retribution falls on a well-chosen band of victims.

On the other hand, Gounod’s jaunty-hesitant Funeral March of a Marionette (used as the theme music for the classic television series Alfred Hitchcock Presents) probably was intended to evoke a somewhat sinister afterlife. Yet it has a faint comic tone (which is what probably drew the droll Hitchcock to it), evoking a frisson of delight in the potential for elegantly evil doings. Certain operas such as Faust give us the devil and devil’s bargains set to beautiful and haunting music, and certain other works, like Mussorgsky’s Night on Bald Mountain (especially in its Rimsky-Korsakov version), provide the bombast of aural immolation, and are now associated with a kind of possessed abandon; indeed, Mussorgsky wrote it as a theme for an imagined witches’ Sabbath.

Closer to our era, a group known as Aklo has recently released a recording called Beyond Madness, which invokes the moods of the classic horror writer H.P. Lovecraft. The music on the disk sounds alternately like the ambient background to a video installation (fitting, as so many installations often bring to mind aimless wanderings and uncertain divagations), or a new-music thesis from a Goth grad student or a haunted-house soundtrack. It uses harsh strings, electronic bleeps and loops, echoes, reverb and an overall dislocating effect. Not exactly seduction music.

It is decidedly sinister-sounding even without knowing Lovecraft’s images (but vivid enough to stoke a fevered imagination). In it, however, I couldn’t detect one of the most eerie-sounding of instruments, the theremin, that early electronic instrument named after its Russian inventor, Léon Theremin.

The theremin has been used a lot since it invention in the 1920s, in soundtracks for Hitchcock’s Spellbound and Billy Wilder’s The Lost Weekend (both with scores by Miklós Rózsa), to sci-fi classics such as The Day the Earth Stood Still (with a score by Bernard Herrmann). Classical composers such as Dmitri Shostakovich, Charles Ives, Percy Grainger and Edgar Varese have used it in their music.

But as happens with new inventions in our electronic what’s-next age, some composers grew tired of the theremin (preferring not to err on the side of eerie, perhaps) and turned to newer instruments such as the varieties of synthesizer that offer a wider range of sounds. There have even been fairly recent mutations, so to speak, of many non-electronic instruments that are what a musical group from H.G. Wells’s island of Dr. Moreau might play, such as the daxophone (a string instrument that looks like a sort of flattened decoy fowl) and the gravikord (a kind of double harp).

Still, the theremin remains the granddaddy of electronic instruments, and perhaps the 20th century’s main contribution to the unworldly in terms of musical sounds. Nevertheless, nothing is more haunting than the human voice when it comes to tingling the spine.

Consider the opening music for the original Star Trek series. It sounds like it incorporates a theremin, whooping and soaring as the starship Enterprise hurls through the unknown quadrants of space. But actually it was a soprano trying to sound like a theremin.

How eerie is that?