The most powerful passive EQ ever! The original hardware Passeq was the first passive EQ to provide three separate frequency ranges for both boost and cut. The Pultec EQ, the famous passive EQ from the 1950’s and 60’s featured just two frequency bands, and had very limited switchable frequencies. SPL’s Passeq has 12 switchable frequencies per band, totaling 36 boost and 36 cut frequencies! Boost and cut frequencies are NOT identical, thus the resultant 72 frequencies per channel offer an enormous choice for the most elaborate EQ curves. The Passeq offers, for the first time, passive filter control possibilities with an unheard of abundance of filter choices.

The fantastic quality of SPL’s Analog Code programming faithfully reproduces the unique sound characteristics of the original hardware Passeq. All the complex interactions between each single filter are faithfully preserved in every detail. One of the unique qualities of passive EQ designs is that the audio signal reacts to the multiple bands as one big filter. Whenever a setting changes, the entire interaction between EQ bands occurs. This provides the unique characteristics and very special sound of these EQs — something that simply does not happen with active EQ designs.

The combination of all this filtering power, mastering grade sonic quality, and advanced M/S processing (a software-exclusive feature!) make the SPL Passeq THE plugin to have for mix busses and mastering.

Download a fully functional 14-day demo today to hear for yourself! (No dongle required!)


  • Includes the standard stereo and a mono version for individual tracks.
  • M/S switch allows for separate processing of M (Mid) and S (Side) signals.
  • Faithful reproduction of the original hardware’s beautiful-sounding interactions between passive filters.
  • 72 filters on three bands per channel.
  • Emulation of input and output transformers.
  • Adds an amazing M/S mode which the hardware doesn´t offer.
  • Four individual “Settings” can be stored for quick A/B comparison, or to automate different settings at different points in the material.
  • Mouse Wheel Control over rotary controls.

Audio Examples

Customer Reviews

  • ★★★★☆
    SPL Passeq
    by Jack
    It takes a while to get good with this comp but when you do the sound can't be beat. Will it do surgical? No. Is it musical? Yes. Even with all controls at neutral there appears to be some gain to… Read More
  • ★★★★★
    by little cloud
    There should be seven stars with five being really really really good because this EQ is the best EQ I've ever used hands down!
    As a software EQ there is nothing that touches it in the passive… Read More
  • ★★★★★
    Musical EQ with M/S
    by Finck von Finckenstein
    I have been using the Passeq plug-in for several years now. I still love it and it is always my first choice for difficult recordings. The selection of frequencies is wise, making this a very musical… Read More
  • ★★★★★
    by Pinellimusic
    In my opinion 90% a mastering tool.
    Very smooth and not for all purposes but extremly gentle sounding.
    A great tool in your arsenal. Exellent !
  • ★★★★★
    Classic plugin
    by Constantin
    Even if you do have another passive eq, this one is still unique.
    The workflow itself lends to interesting results that can't be easily replicated with anything else.
    The sound is perfect… Read More


Supported Plugin Formats
AAX DSP, AAX Native, AU, AAX AudioSuite, Venue 32-bit, VST2, VST3

Supported Operating Systems
Mac OS X 10.8 through 10.12
Windows 7 through 10
Pro Tools 10.3.10 or higher or any VST/VST3/AU-compatible host running on a supported operating system

Intel CPU only (minimum 2 GHz recommended)

Intel-compatible CPU with SSE2 instruction set (Pentium 4 compatible or higher; minimum 2 GHz recommended)

System Requirements
Display resolution: 1440 × 900px or 1280 × 960px or higher
Memory: 2 GB RAM


With the Installation Manager, you can select, download and install just the Plugin Alliance products and formats you need for your system. During this initial release, we at Plugin Alliance look forward to hearing the feedback of our valued customers, as your input will help shape future versions of this utility.