The GML 8200 by George Massenburg has been an industry standard for over twenty years that can be found in virtually every major recording studio. The 8200 has five broadly-overlapping bands which offer 15dB of Boost or Cut and adjustable bandwidth (or “Q”) from 0.4 to 4. The lowest and highest bands can also be used as shelving eqs. Its extraordinary resolution, surgical precision, transparency and tons of headroom have made the 8200 the reference for many other equalizers. This 8200 gets used on the stereo buss of many consoles but also sounds great on vocals, guitar, piano, strings and brass.
Here's a Youtube video with George Massenburg showing the 8200 being used on acoustic piano: