The titans of siren.

I’ve always been the kind to obsess about musical details.

It’s not my most endearing trait — especially to Bay City Rollers fans — but it’s just how I’m wired.

Something brought me today to the Wiki page dedicated to the Thunderbolt siren, a common piece of American civil defense ordnance in the second half of the 20th century.

That reminded me of Black Sabbath’s “War Pigs” and Grand Funk Railroad’s “Paranoid,” two songs from my long-ago heavy-metal youth. I hadn’t heard either in quite a while, but I remembered that both used the chilling sound of a siren to good effect.

And that brought two questions to my mind, fired by the same synapse that sometimes makes me ask, “Hey, is that a Strat or a Telecaster he’s playing on that solo?”:

1. Wonder what model, make or type of siren is being “played” on “War Pigs” and “Paranoid”?

2. Wonder if it’s the same siren?

To answer the second question first: Yeah, I imagine so.

If you listen to “War Pigs” and “Paranoid” (and you only need to listen to the first 45 seconds or so of each), you’ll hear that both songs feature the stereotypical siren sound we all know from World War II movies.

The siren in “War Pigs” moves more quickly between tones, keeping pace with the music at times, while the siren on “Paranoid” takes more time shuttling between its two notes.

But they’re clearly the same model, and they could well be from the same sound-effects recording. I imagine that, even in the days of analog tape, a professional engineer would have had no problem doing a little snipping to make the siren move up and down faster.

Here’s what they sound like:

That question being settled enough for me, I headed to YouTube to check out videos of civil defense sirens, hoping to identify the specific kind that produces that distinctive sound.

It wasn’t a Thunderbolt. It only took one or two Thunderbolt clips to show me that Thunderbolts have a different tone — a sound with a recognizable grit or sizzle around the edges.

A brief sample of the Federal Signal Type 2, made by the same company that made the Thunderbolt, didn’t convince me.  An ACA Allertor 125 wasn’t the machine I was looking for, either.

Then I started getting into the British-made sirens, and it became clear to me that — like gin, toffee and Marshall stacks — nobody does it better.

A 1952 Castle Castings siren, made in Lancashire, sounded remarkably like the one(s) on the records. So, too, did a World War II-vintage siren of similar design made by Gents of Leicester.

I imagine that the young men of Grand Funk, who grew up in Michigan, were probably familiar with the sound of a Thunderbolt in action. It’s interesting to me that they turned instead to the familiar British siren sound when it came time to make a record. I guess nothing says “impending desolation” quite like those vintage sirens.

(Or, maybe the British sound just happened to be on the first sound-effects tape their engineer put his hands on, and they weren’t fussy. I can believe that too.)

Unfortunately, that’s where the trail stops.

British air-raid sirens are not as easy to differentiate as, say, Hammond and Farfisa organs. So I won’t have the satisfaction of a firm answer to this particular digression.

But I’ve gone far enough in that direction to be content, and I know more than I did when I started. I’ll take it.

I’ve also learned, somewhat to my surprise, that Grand Funk got the sound on record before Sabbath did.

GFR’s self-titled “Red Album,” with “Paranoid” on it, was released in December 1969, while Black Sabbath’s “Paranoid” album (what is it with paranoia and sirens, anyway?) came out in September 1970.

That concludes tonight’s test of the emergency alarm system. I’m gonna go listen to the Jackson 5ive now — I need something light and fluffy to chase these damned sirens out of my ears.