Here is a list of soundscapes for use in Day of Defeat: Source. An easy way of testing them is to use the playsoundscape console command, which includes limited searching for soundscape names so you shouldn't have to print out a copy of this list for reference.
Anzio
| Name
|
Description and Notes
|
Anzio.MainAmbient
|
|
Anzio.Pond
|
|
Anzio.Sewers
|
|
Argentan
| Name
|
Description and Notes
|
Argentan.BlownStation
|
|
Argentan.Indoors
|
|
Argentan.MainAmbient
|
|
Argentan.Windmill
|
|
Avalanche
| Name
|
Description and Notes
|
Avalanche.MainAmbient
|
|
Donner
| Name
|
Description and Notes
|
Donner.AlliedSpawnAmbient
|
|
Donner.AxisSpawnAmbient
|
|
Donner.MainAmbient
|
|
Flash
| Name
|
Description and Notes
|
Flash.InsideTown
|
|
Flash.OutsideTown
|
|