Push-Pull EQ's

[bls]

I'm curious about the concept behind push-pull EQ's. I've been messing with bootsy's channelstrip and I dig it, but I don't really understand the common practice, or consideration for this kind of processing. I'm fine to play around with it till I get something decent, but I'm wondering if someone here can enlighten me with a more traditional approach.

Any insight is appreciated.

[reapercurious]

bump +1

[d.bop]

bummmmmmmmp

I'd like to know, too!


*edit*

Wait a second... I kind of get it now (I think..)

Does it have to do with the different curves that are used for boosting/cutting frequencies?

[timlloyd]

Push-pull refers to the amplification stage of certain analogue EQ designs, most famously the Pultec EQP1a. I can only assume that's what that section of the Bootsy channel-strip is based on.

[dub3000]

the push and pull frequencies aren't aligned, so you get a small bump at the cut frequency or a small cut at the boost frequency. it messes with phasing but also means you can cut or boost less and get a more pleasant effect.

also, that sort of eq usually has very broad curves, they can sound pretty nice on some types of material.

if you want to know exactly what a particular plugin does, go hunt down christian budde's vst analyzer, a free plugin for compression and eq analysis.

[dub3000]

...not to be confused with push-pull amplification stages, which are also known as Class B amp designs (class B has lower power requirements than class A but some crossover distortion where the push/pull stages kick in/out).

[timlloyd]

Originally Posted by dub3000

...not to be confused with push-pull amplification stages, which are also known as Class B amp designs (class B has lower power requirements than class A but some crossover distortion where the push/pull stages kick in/out).

Sorry, my post was misleading. I wasn't meaning to refer to Class B, but rather to the push-pull design of the gain stages of the filters that allows you to boost and cut at the *same frequency*

[bls]

Wow, this was the hientz ketchup of posts.

I'm glad there's finally some dialogue on the subject. It would be cool if anyone familiar felt like sharing a technique or approach.

I did some mixes recently and found some interesting uses for this design.

On bass, for example, it would allow me to use the cut and set the freq where the kick's body was cleared up from any masking. Then I could use the push to bring low end back into the bass while clearing up that space back into the track.

Really though, most of it was a lesson in how much low end could be removed in place of adding high end. So far I'm discovering that to be a great approach for a little more natural sound.

I posted some of the tracks from the session if anyone is interested in giving them a listen. And, as always, suggestions and observations are more than welcome.

[timlloyd]

Originally Posted by bls

Really though, most of it was a lesson in how much low end could be removed in place of adding high end. So far I'm discovering that to be a great approach for a little more natural sound.

+1, negative EQ-ing is often more effective

[rhythmtech]

Originally Posted by timlloyd

+1, negative EQ-ing is often more effective

for problem frequencies definitly but when you want the tone of the actual eq its nicer to drive it up a bit.