Please explain Boost/Cut on the same freq setting

dnf777 · #1 12-08-2022, 07:20 PM

Talking about a PulTec style EQP. I get the upper range that has cut and boost ranges for each, respectively.

But the low range has a freq selector for both boost/cut combined. Again, I look forward to playing with this and seeing what shakes out, but in the mean time am interested in hearing the theory and application of a seemingly counterintuitive set up. To this recording Neanderthal, that seems like pressing the accelerator and brake pedal at the same time. (yes, I know the pros actually do that at times!)

TIA,
Dave

jim1960 · #2 12-08-2022, 10:06 PM

I don't know the exact reason why cutting and then boosting the same frequency changes the sound/character of the low end, but I suspect the Q (width of the curve) is different for the boost and attenuate knobs.

This video demonstrates the effect.

DupleMeter · #3 12-08-2022, 10:48 PM

The reason that works is because they frequencies & bandwidth are slightly offset from each other for boost & cut (even though they are supposed to be the same), this is due to the limitations of the design & how the center frequency was detected. This creates a very cool peak/dip relationship that plays with the phase around the center frequency, making any changes more defined.

Often used on the low end (the Pultec Low End Trick) more than the high end, especially on drums or a drum bus. Typically they would select, say 60Hz, then boost to "6" and cut to "3" et voila, super punchy low end that stays really controlled & contained.

A Pultec high end boost was pretty common on the master 2-bus to add some sparkle to a mix, but not often with a cut involved.

dnf777 · #4 12-09-2022, 06:10 PM

Thanks Steve.
And thanks, Jim. I guess there may not be a logical explanation...it just works!

Can't wait to play with the WA version. Will be using it for vocals mostly, so not sure how that will work. I can really begin to appreciate the art form that engineers call upon for audio work. Like so many art forms, any one change may be imperceptible at best, but the final mix is unarguably better because of all those little nuances. Like a Van Gogh or Monet. If you look too closely, its just sloppy heaped up paint. Back up and look at the whole thing, and BAM!!!

min7b5 · #5 12-12-2022, 08:16 PM

The only time I've played around with cutting and boosting the same frequency is with mid/side (sum and difference) processing in Pro Q3 to maybe add a little width in a stereo track. So maybe creating a bell shaped boost at, say, 3K that is sides only. And then the same size bell cutting mids only...

DupleMeter · #6 12-12-2022, 08:40 PM

Quote:

Originally Posted by dnf777

Thanks Steve.
And thanks, Jim. I guess there may not be a logical explanation...it just works!

Can't wait to play with the WA version. Will be using it for vocals mostly, so not sure how that will work. I can really begin to appreciate the art form that engineers call upon for audio work. Like so many art forms, any one change may be imperceptible at best, but the final mix is unarguably better because of all those little nuances. Like a Van Gogh or Monet. If you look too closely, its just sloppy heaped up paint. Back up and look at the whole thing, and BAM!!!

Definitely play with it. It’s a very useful technique. There’s a reason the Pultec has attained legendary status. Not every piece of old gear deserves the veneration it gets, but the Pultec certainly does.