The soundtrack is more of an environmental ambience-- wildlife/nature sounds, gunshots, speech, with perhaps an instrument or two making a punctuation or a short melody, rather than fully composed tracks.
In an earlier post, I quoted James Gunn as saying that the music in the game is actual Spaghetti Western tracks. I'm not sure what he meant by that, but I definitely don't think he means it literally. There are some newly composed songs by popular artists, but the main musical experience is one of short ambient sound stems, all composed in the same key and pulse, that weave together based on the action you experience onscreen. In other words, if you're just riding around looking at the scenery, you've probably got mostly ambient sound happening, if you pass someone in trouble, the music might start up as you slow your horse to help, and if you get into an all out gunfight, the music really gets going.
Some of my favorite in-game moments are those where you meet someone out in the wilderness who's playing the harmonica, or you enter a saloon and hear the piano. The game designers were even so clever to have the audio follow the angle of the camera very precisely-- in other words, as you approach the saloon, you don't hear the piano as much because the camera is behind Marston as he's approaching, yet as you leave the saloon, the camera is still from the vantage point of being closer to the saloon and at the same point where you don't hear anything as you're approaching the saloon, you do hear it as you leave. It's as if you carry the audio experience of where you've just been with you. In other words, the spacial positioning of the audio is very cleverly crafted.
This format leads to an incredibly interactive audio that immersed me in the game. At home, I've got a surround sound stereo system, so the audio literally helped me as I could hear which direction I needed to turn to find the person shooting, person talking, bird squawking, etc. Only a few times in the game did the audio not match up with my playing experience. For instance, when I was trying to figure out how to tame horses with Jack and I fell off for about fifteen minutes his snippets of dialogue got extremely repetitive and irritating-- granted, I was sucking at this part of the game and taking way longer than the designers expected, but perhaps a non-repeat function would help at a certain point. Also, a trained RPG player, I almost always checked the bodies of victims as I fought my way across the land somewhere-- and sometimes the music was very intense while I was just running around picking up money and ammo. Thus, it became very noticeable to me because it was a totally different character from what I was doing since all the bandits around me were dead and I was looting up before going on to the next objective checkpoint. I have to say one of the biggest disappointments for me about the audio was how rarely-- if ever?-- it underscored the set video sequences from the main story line; these are almost entirely void of music, using only spoken audio.
Overall, though, this has to be one of the absolute best audio experiences I've had in a modern game. Completely different from what I was expecting as well. The audio tracks that are stand alone performances of songs with words really stand out when they appear and are incredible. The ambient nature sounds reminded me of my childhood in rural North Carolina. The interactive quality of the audio almost never pulled me out of the moment of the game, in fact it immersed me more deeply and helped me with locating objectives in the game. What higher praise could a game soundtrack have?
Interestingly, this is one of the first games I've played whose audio I can definitely say one cannot experience merely by listening. As much as it's possible with some other games, and particularly earlier games, to watch gameplay videos and have a pretty good understanding of the audio, this game audio experience is so different based on your particular playing session that one really must experience it as a player to fully appreciate it.
Here are some of the best web resources I've found about the audio of Red Dead Redemption:
The soundtrack, available via iTunes, is put together based on the motives of the game audio to give a feel of the ambient nature of the sound, but it's a completely different experience from playing the game. The soundtrack can also be heard on YouTube.
Straight from the Rockstar Games Red Dead Redemption site, this has links to samples of the audio, behind the scenes creation videos, and plenty of information about how the audio and soundtrack were created. Incredible. Every game should have such an awesome audio tool!
How can you better learn about game audio than via the composer's mouths? Gamasutra has a fantastic interview with Bill Elm and Woody Jackson as they discuss the score, composing, developing the music, working with other musicians, and the influence Morricone had on the score.
Here's an incredible article from gamermelodico that details some of the best features of the game music and audio. I never thought about the audio experience of the Dead Eye feature, but Kirk Hamilton details it as well as the authenticity, space/positioning, and ambient score superbly in this article.
Keith Stuart's article from the UK's Guardian details plenty of audio information about the soundtrack from the game and its construction.
Here's another blog I'm just encountering, gamertheories.wordpress.com. For something a bit more heady, this article discusses the use of non-diegetic songs in Red Dead Redemption and Far Cry 3. Not quite as much of a focus on the game music, but an interesting consideration from the player's perspective.
I also perused this article from a blog I need to check out more, creaedigitalmusic.com. This refers to the game soundtrack as an "interactive collage" and puts the soundtrack in broader scope of being in the "post sampling age." Not quite sure what that means, but I'm hoping it'll make more sense as I keep exploring this genre.
Finally, for more of a focus on the audio design than the music-- also an incredible part of Red Dead Redemption, check out this interview with audio director Jeffrey Whitcher.
For more, you can always check out the Game Audio Relevance iasig site.