This genre is a bit difficult to define, since there are different schools of thought regarding its production and sound. Some of the earlier tracks of the genre tried to integrate a 1/2 tempo dub sample, whereas some Chicago DJs early on in the scene wanted to create a "harder" sound (e.g. releases from Relief Records). Techno and House music have a shared history and compatible sounds, so Tech House releases often combine elements from both styles, usually inconsistently; some releases borrow more heavily from techno, others from house. This lends itself to a gray area in defining a recognizable sound that has persisted since its conception, through the 90's and 00's, and into today.