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Passive/Active EQs, differences/benefits?
Old 7th June 2006
Here for the gear
🎧 10 years
Passive/Active EQs, differences/benefits?

Hey all, this is my first post on Gearslutz but i've been an avid silent observer for years. Any who i just wondered if any one could explain the difference between an active EQ and a passive EQ and the benefits each displays. Its a subject thats confused me for a while.
Blues Skies
Old 7th June 2006
Gear Maniac
🎧 15 years
following is an excerpt from a tutorial found on

pretty simple but gives an idea....

"Passive and Valve Equalisers

It's worth mentioning in passing here, the subject of passive equalisers.

Most equalisers use circuitry that actively boosts or cuts the sound in the various bands using electronic feedback techniques which can (and often does) introduce audible "ringing" in the circuitry. Passive equalisers on the other hand work by already cutting the sound in all frequency bands to begin with, using simple, unpowered, passive electrical components like resistors, capacitors and inductors. A single, simply-designed amplifier stage after the equaliser usually makes up for the loss in signal level, so that the level is flat when all controls are in their "centre" position. Therefore, on such an equaliser, when you "boost" a frequency, you're not really boosting it at all - you're just allowing it to seep through unhindered by the passive circuitry. Valve equalisers often work in exactly this way.

This gives a much smoother sound. In fact a lot of the "smoothness" attributed to valve equalisers, often has little to do with the fact that they have valves in - it is instead due to the fact that the equaliser circuitry is passive rather than active."
Old 7th June 2006 | Show parent
Gear Maniac
🎧 15 years
That is exactly why I have a custom console based on Auditronics 501 modules:

Passive, inductive coil EQ is my favorite.

Auditronics is NOT my favorite.

I guess I love that EQ enough to completely build a custom console around it.....
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