Graphic EQGraphic EQWeek 2 PowerPoint

What is Graphic EQ?What is Graphic EQ?

GRAPHIC EQ: Common type of EQ, has banks of SLIDERS to control specific FREQUENCIES

Sliders can ADD or SUBTRACT dBSubtractive is usually betterBANDS: Each specific frequency controlCAR: May have as little as 2 bands

(BASS and TREBLE)LIVE SOUND: 25 to 31 bands

DefinitionsDefinitions

THIRD-OCTAVE EQ: Most amount of bands. Each is a third-octave from the next

2/3 octave EQ: Second most bands.Less precise, but more general controlOften used to eliminate FEEDBACK

Some HistorySome History

Historically, the first use of slide controls in an equalizer was in the Langevin Model EQ-251A which featured two passive equalization sections, a bass shelving filter and a pass band filter.

Each filter had switchable frequencies and used a 15 position slide switch to adjust cut or boost. The first true graphic equalizer was the type 7080 developed by Art Davis's Cinema Engineering. It featured 6 bands with a boost or cut range of 8 dB. It used a slide switch to adjust each band in 1 dB steps.

Davis's second graphic equalizer was the Altec Lansing Model 9062A EQ. In 1967 Davis developed the first 1/3 octave variable notch filter set, the Altec-Lansing "Acousta-Voice" system.

BSS Audio FCS-960BSS Audio FCS-960

DBX 215: Dual 15-BandDBX 215: Dual 15-Band

Behringer Mini FBQBehringer Mini FBQ

Logic Graphic EQLogic Graphic EQ

Waves Renaissance EQWaves Renaissance EQ

Concepts of EQConcepts of EQ

In software: NOTCH filtering is a narrow band to pinpoint frequencies

SUBTRACTIVE EQ: Why is that better?Simple HI and LO pass: when are they used?What is OVER and UNDERSHOOT?Adjusting Q: What is it?What is LINEAR-PHASE EQ: Phase shift

introduced that is proportional to the frequency