The mad scientists at UnderToneAudio have recreated their legendary (and rare!) MPEQ-1 rack hardware as an affordable plug-in. To understand my excitement, here's some history and context: The original hardware MPEQ-1 was a single-channel-strip Class A mic preamp/DI/EQ, which itself was a standalone version of the channels in the UTA custom mixing consoles. The hardware MPEQ-1 also begat the UTA 500 Series EQs, the UTEQ500 units [Tape Op #161]. All these hardware EQs shared a similar topology and several unique features, including options to blend between peak and shelf EQs and the wild ability to reverse the phase of a particular frequency band (“Vari-Phase” mode). Bonkers. The MPEQ-1 is also noted for using Class A amplifiers at all the gain stages in its circuit design. Many Class A EQs only have one Class A gain stage, usually for the final summing. This hyper-engineered approach, flexible user interface, and killer tone shaping are what led to the MPEQ-1 becoming “unobtainium” in the years after it was discontinued by UnderToneAudio. The hardware can only be found infrequently and always at a premium price, holding its value due to its reputation for quality and its unheard-of feature set.
I had the pleasure of hearing some of the original UTA console EQs at UTA founder Eric Valentine’s Barefoot Recording in Hollywood [Tape Op #45, #133] and was always impressed at the rigor that he and Larry Jasper (co-engineer and genius circuit designer) applied to their testing and development. The UTA team spent years refining the most minute design details of that original EQ, and the result is truly one of the best channel strips ever built. Although the DNA lives on in the UTEQ500, I still get sad that I never picked up an MPEQ-1 strip.
So, fresh off the success of their UTA-D UnFairchild 670M MkII plug-in [Tape Op #165], the time is right for a software version of the MPEQ-1, the MPEQ-1 Super-Parametric Saturation Equalizer plug-in. The MPEQ-1 painstakingly replicates everything the hardware does: variable shapes, selective per-band phasing, adaptable filters, wide-range Q controls, etc. True to form, UTA haven’t stopped there, adding dedicated saturation stages with different distortion characteristics (solid state, smooth, and tube) for each band. This allows you to drive selective frequencies all the way up into pleasant fuzz – I found this feature incredibly useful for individual drum track EQ’ing, as it allowed me to selectively drive the pitch fundamentals of a given drum (snare, kick, or toms) while keeping the other bands clean. Paired with the ability to blend from a peak shape to a shelf shape and options to run any bands in series or in parallel, and baby, you’ve got a stew going! There is also an additional Output Color stage that seems to add very subtle overall saturation when toggled on – I’m guessing this is emulating an output transformer of some kind.
For folks coming from the hardware, it's a boon to have all the modern plug-in amenities like presets, automation, A/B’ing, and undo/redo, plus a fantastic spectrograph display. The plug-in options allow UI customization and scaling, and you can set oversampling to 2x or 4x (or off if you’re running out of compute headroom). In my testing, on an Apple M3 Ultra system, I was able to run over 16 instances of MPEQ-1 at 96 kHz, a buffer size of 128 samples, and 4x oversampling with only a 20 percent CPU load – this is well-optimized software. In a short list of nice-to-haves, I’d like to see a full manual (I’m sure it's in the works) and an opacity setting for the UI, as I like to run it at 100 percent scale with the full spectrum display up, and that eats up a lot of screen real estate. There is a collapsed option, but that spectrograph is hard to sacrifice.
At this price point, this EQ is a no-brainer for me. It sounds flipping great, is thoughtfully designed, and runs well on my Mac. I may never find and buy the unobtainium original, but this doesn’t represent a compromise to me – it's just an iconic EQ, now in software form. That said, it’s probably worth noting that 16 channels of the original hardware would likely run you north of a cool $75,000 (if you can find 16 units that owners would even part with!).