With the exception of bands using seven-, eight- or recently nine-string guitars to extend the instrument's range downwards, rhythm guitar for modern metal almost universally uses stepped-down versions of standard or drop D tuning, with professionals and amateurs alike commonly using terminology like “tuning to C” (same pattern as standard tuning, but all strings lowered by four half-steps) or “Drop C tuning” (drop-D tuning lowered two half-steps). Conversely, other tuning patterns are rare, with the few popular acts using them commonly widely recognized for the fact (prominent examples being the bands Sonic Youth and Soundgarden).