linuxDSP PEQ-2A Pultec EQ

For anyone who missed this the first time around (and it seems a lot of people did), I think the time has come to remind Ardour users about this little plugin again…

Originally released in January 2012, now at V1.0.3, the PEQ-2A is a vintage Pultec style EQ. Pultec EQs are found in just about every professional studio, and are highly sought-after and valued by engineers for their signature sounds. The PEQ-2A is the only one of its kind designed for linux and a cost-effective alternative to expensive plugins, often requiring DSP hardware, on other operating systems.

The PEQ-2A emulates some of the most sought-after Pultec sounds, in particular the famous ‘low-end trick’ in which the seperate LF Boost and Attenuate controls are used at the same time to provide a tight bass boost without becoming ‘muddy’ or losing mid-range detail.

Try it on e.g. a (Hydrogen) drum track - set the LF Boost and Atten controls to between 6 - 10 and the Low Frequency (CPS) to 30 or 60Hz and hear the effect, then adjust according to taste…

This kind of EQ is definitely not designed as a ‘surgical’ tool for fixing problem mixes (for example, removing room resonances or electrical hum) but more for taking a well recorded track and just making it sound right.

In addition to the famous ‘low-end trick’, another characteristic of this type of EQ, with its passive filters and subtle control interaction, is the ability to add quite large amounts of mid-high boost without the sound becoming harsh or resonant. Once again, seperate boost and attenuate controls mean that the mid-high boost can be tamed if necessary by some HF attenuation, making it possible to open up the sound or add ‘air’ without it becoming sibilant. For anyone (and everyone) unfamiliar with this type of EQ and exactly what makes it such a sought-after, essential addition to any studio / DAW there are some articles here:

specifically about the low-end trick (with some example settings) here:

more detail about the controls and their functions:

And of course there is a technical manual included in the download, which describes the plugin processing and operation in more detail.

Absolutely. It adds a nice sparkle up there. I tend to just add on the high end, but man, this thing fixes low end issues for me all the time. Sometimes the low end will be really muddy, so I will go in with a more surgical EQ (like his MKII Graph, of the open source LV2fil) and pull some low end out, and then add it back in with the PEQ to get that sculpting that I like.

it also works great for sweetening the high end, I achieved great results by attenuating at 10khz while boosting 12khz at the same time…

This plugin is a must have for low end EQing. It’s as simple as that.