going through my library have acquired quite a few soundtracks without watching the film/tv series, primarily just for the composer...here's a few:
ordered EXTREME PREJUDICE-JERRY GOLDSMITH
own-TANGERINE DREAM -HEARTBEEPS , HANS ZIMMER-SMILLIA'S SENSE OF SNOW, JAMES HORNER-BATTLE BEYOND THE STARS,MARK SNOW -X FILES + MILLENIUM (a lot of episodes not seen) and more.....
I bought all of these without having seen the films:
Lion of the Desert High Spirits The Cassandra Crossing* Coma* The River* The Adventures of Tintin The Lion in Winter* The Shadow The Land Before Time The Grifters Return of the Magnificent Seven Glowing Autumn Quo Vadis* Crossed Swords* Man on Fire The Lonely Guy Agnes of God
I have many soundtrack and film music recordings in my collection where I have never seen the movie, and an even larger part of my collection where I bought the music because of the composer without having seen the movie at that time, but having seen it since.
I very rarely buy a soundtrack to a film I have not seen because I like to picture the film in my mind as I'm listening to the music as If I were watching a DVD isolated score.
I do make an occasional exception such as with two John Williams scores. Images and Memoirs of a Geisha.
I recently bought the Quartet CD of Images and instantly regretted it. Listened to it twice and never want to hear it again. Gave away the CD.
Memoirs, on the other hand, I loved immediately and listen to frequently. It's a bit of a crapshoot, soundtrack buying.
This is not an uncommon happening at all. I think most of us who have favourite composers have bought soundtracks for them without having seen the films. I've done that with plenty of Horner's work.
To be honest I'm surprised the question even comes up - when we like a rock or pop artist or group, do we question whether we would buy their next album? I suppose if we've been let down by a prior work then we might, but most times I think most people would buy / download / stream that artist or group's new work without hearing it first.
* I started watching, but never finished those (yes I watched the first hour of Avatar but boy it was boring... Same for Supergirl and Doctor Who Series 11)
