Crossover vs EQ

[pktaskes]

What's the difference between what an active crossover does vs. steeply eq'ing the mix (killing all the highs for your subs and all the lows for your top boxes)?

[Square]

An EQ will typically only cut 12db or somtimes 15db.

 

A crossover creates a downward slope starting at the crossover frequency and drops off at the rate set or selected by the crossover (anywhere from 6db to 48db per octave).

 

The thing to note is that while 12db is a significant difference in volume, the crossover will quickly offer a much larger difference and better isolate frequency bands. Where you to use an EQ to act as a crossover for hogh frequency horns, I think you could blow then up quickly as 12db down of low frequencies going to the horns would not be enough to protect them from over excursion and destruction.

 

Also, pushing all the faders up or down on an EQ generally does not result in a flat frequency response.

[agedhorse]

An eq will offer very non-linear response in this mode, lots of bumps and phase shifts, along with a maximum 12-15dB out of band attenuation. Not terribly desireable. A crossover is a single filter, typically with a 24dB/octave slope (meaning that one octave out of band will be 24dB attenuated. 2 octaves out will be 48dB down. Phase response and attenuation rate is smooth and continuous.

 

In an emergency, an eq can helpp you limp by, but is not the tool of choice.

[tlbonehead]

 

Originally posted by pktaskes What's the difference between what an active crossover does vs. steeply eq'ing the mix (killing all the highs for your subs and all the lows for your top boxes)?

A lot, obviously. First of all, most active EQ's are 18/24 DB PER OCTAVE. As mentioned most EQ's only allow for a 12 DB cut. Some Peaveys and others have 12DB boost and 18DB cut. But, the main thing is the "per octave" thing. And EQ is only going to allow a max of 12DB regardless of how far away from your intended crossover you go. So if you crossed over at 120 hz, on the sub side, at 240 hz you would be 18/24 DB down. At 480hz you would be 36/48 DB down. Same with the other side. At 60hz the top cabs would see an 18/24 DB reduction, and at 30hz they would see 36/48 DB reduction.

---Oh,and you only need one crossover as opposed to two EQ's. And the price of a single crossover is about the same as a single EQ.