shaping the bottom end on a stereo mix.

[john12ax7]

Regarding pultec style, I often enjoy boosting and cutting the same frequency in the bottom end to make things sit better, program dependent though.

It's the well known springboard effect (exaggerated in the attached graph - done at simultaneous max boost & cut). Boosts LF while cutting low-mids.

Thanks for the graph. I knew it was a common technique, but didn't know the name or realize it could be so drastic. Is that a measurement or a simulation?

 

[abbey road d enfer]

It's a sim. I had the opportunity to compare the sim with actual measurements and they were pretty close. As I said, this is exaggerated; most would apply only a few dB B&C, resulting in a less pronounced dip.

 

[riggler]

Does this effect hold true with the Waves Pultec plugin?

 

[pucho812]

Does this effect hold true with the Waves Pultec plugin?

it should as the waves plugin does mimic the curves of a pultec.

 

[abbey road d enfer]

Does this effect hold true with the Waves Pultec plugin?

From the Waves EQP1 page:
"The Pultec EQP-1A is renowned for its unique ability to boost and cut the same frequencies simultaneously, thereby creating a resonant shelf. "

 

[Biasrocks]

Here's a screen capture of a 2db 60hz Pultec Boost, as you can see it's very broad.

 

[Biasrocks]

Here's a 2db boost along with a 2db cut at 60hz. The cut is very subtle and affect the lowest frequencies.

 

[Biasrocks]

Flat.

 

[0dbfs]

I don't believe "2" is meant as 2dB on the controls. It's just 2 out of a possible 10. The manual states that there is 0-13.5dB low freq boost capable and 0-17.5dB low freq cut available in that 1-10 ranged control.

Anyway, somewhere between 7-10 on the controls will likely show a more pronounced curve on the display.

Cheers,
jonathan

EDIT:
Here is a link to the EQP-1A manual with the cut/boost info:
http://www.recproaudio.com/diy_pro_audio/diy_files/eqp_1a/PultecEQP.pdf

 

[Biasrocks]

I don't believe "2" is meant as 2dB on the controls. It's just 2 out of a possible 10. The manual states that there is 0-13.5dB low freq boost capable and 0-17.5dB low freq cut available in that 1-10 ranged control.

My bad, my point was that Pultec's are pretty subtle tone boosters unless you really crank them.

Here's some graphs with more pronounced curves.

 

[Biasrocks]

And with the same amount of cut.

 

[0dbfs]

A little bit broad like you mentioned

Cheers,
jb

 

[riggler]

Ah, thanks guys!

 

[etheory]

The only thing that hasn't been mentioned here (unless I missed it via a quick re-read) is the massive phase shifts that occur at the boost/cut frequency.
I really don't think that the amplitude effects are the predominant ones here.

Being a largely digital producer, I often insert an 18dB or 12dB VST EQ HPF at sub-sonic frequencies (around 15-25Hz), in order to try and shape the phase response of a bassline so that it sits better in a mix.
In almost all cases, the result sounds "better" (subjectively) than the original. Also the phase change moves higher frequency peaks into areas of the waveform that are "tighter" - in fact, sometimes to the point of literally allowing you to increase the volume of an element in a mix without clipping. This type of shaping is very useful.

Sliding the frequency up and down a little bit of the HPF produces varied phase shifts that can "lock things in" so to speak.

Also, intriguingly, the shapes formed by basslines from digital synths after the HPF are much more like those coming from an analog instrument, than a standard VST. I feel that this is due to the phase response shearing that is more typical of analog gear.

Just worth mentioning - since I think that this is the REAL effect that the engineers are hearing, not the typical amplitude action of the EQ.

 

[Biasrocks]

Just worth mentioning - since I think that this is the REAL effect that the engineers are hearing, not the typical amplitude action of the EQ.

I've tried all sorts of Linear Phase eq's and have never felt the satisfaction that I get from a good old fashioned non-linear phase EQ.

I always ended up boosting huge amounts on the LP EQ's before getting the results I was looking for.

Pultecs, Langs and API's OH MY!

Regards,
Mark

 

[etheory]

I agree 100%
Smear that phase!

 

[abbey road d enfer]

The only thing that hasn't been mentioned here (unless I missed it via a quick re-read) is the massive phase shifts that occur at the boost/cut frequency.

No. The EQP1 is a minimum-phase piece of gear (as most audio equipment); the phase-response is closely related to the frequency response. The LF control circuit are both 1st-order (6dB/octave asymptotes). The attached graph shows the phase-response at max boost and max cut; phase shift nevers exceeds 50°; no one can call it massive by any standards.

Being a largely digital producer, I often insert an 18dB or 12dB VST EQ HPF at sub-sonic frequencies (around 15-25Hz), in order to try and shape the phase response of a bassline so that it sits better in a mix.

Most of my tracks are HPF'ed, but not because of whatever effect it has on phase; I do because I know that anything below 30Hz has 99.9% probability of being garbage, and I don't want this garbage to create havoc with the detectors in compressors or with the loops in reverbs.

In almost all cases, the result sounds "better" (subjectively) than the original.

No doubt about it.

Sliding the frequency up and down a little bit of the HPF produces varied phase shifts that can "lock things in" so to speak.
Just worth mentioning - since I think that this is the REAL effect that the engineers are hearing, not the typical amplitude action of the EQ.

You are entitled to your opinions, but they certainly don't resonate with the most advanced results of scientific research on the subject. The hearing process has no way of perceiving phase of a single signal in the absence of a reference signal i.e. an original non-shifted version of the signal), and even then, the phase difference can be perceived only by the resulting interaction on frequency-response, by a drastic change of peak factor that would trigger non-linearities in the transmission path or by the time-difference in the case of binaural listening.

Also, intriguingly, the shapes formed by basslines from digital synths after the HPF are much more like those coming from an analog instrument, than a standard VST. I feel that this is due to the phase response shearing that is more typical of analog gear.

This is due to the big difference between ADSR in a digital instrument and the natural dynamics of signal when it is produced by a somewhat random combination of fingers, metal, wood, air, analog oscillators...

 

[abbey road d enfer]

This graph is with both Boost and Cut at max.
A frightening 70° phase-shift, consistent with a terrifying 7 dB/octave slope.

 

[Biasrocks]

Phasey-smasey...  8)

Here's max boost @ 60hz.

 

[Biasrocks]

Max cut/boost @ 60hz.