Sludge metal combines the low-tempos, heavy rhythms and dark atmosphere of doom metal with the shouted vocal delivery and high-tempos of hardcore punk. This fusion of a "slow" musical genre with a "fast" musical genre produces songs with contrasting tempos.
The string instruments (electric guitar and bass guitar) are heavily distorted and often use a high level of audio feedback to produce a sludgy sound. Often, guitar solos are not present, although this is not always the case. Drumming bears similarities to the style of drumming present in hardcore punk, although the beats may be slowed considerably. The tempo usually falls somewhere between 50 and 80 beats per minute (bpm). Vocals are usually shouted as in hardcore, and lyrics are generally blue-collar in nature; reflecting on society, generally in a depressive, cynical or downtrodden manner