PAR Studio Review: Ingram Engineering MPA575 Microphone Processor by Russ Long

The MPA575, Ingram Engineering’s foray into the 500 Series format, is the world’s only microphone processor that packs a mic pre, compressor and equalizer into a single 500 Series module.
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The MPA575, Ingram Engineering’s foray into the 500 Series format, is the world’s only microphone processor that packs a mic pre, compressor and equalizer into a single 500 Series module. At first glance, the feature set of the module’s EQ and compressor appear to be quite limited, but in reality it packs a pretty powerful punch without any sonic compromise.

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The MPA575’s mic pre circuit provides from 10 dB to 70 dB of gain and is identical to Ingram’s acclaimed MPA685 rack-mount mic pre. The module has an input impedance selectable between 600 Ohm and 2.4 kOhm and while the exact results will vary from mic to mic, I found that the lower impedance typically yields a darker tone and the higher setting is somewhat brighter. The equalizer consists of just two controls: a continuously variable high-pass filter that has a cutoff frequency ranging from 30 Hz to 400 Hz and a unique combined low/high frequency variable EQ that Ingram Engineering describes as a “frequency response see-saw.” The EQ’s pivot point is set at 1.2 kHz and when turned clockwise, frequencies above 1.2 kHz are boosted and frequencies below are cut and when turned counterclockwise, frequencies below 1.2 kHz are boosted and frequencies above are cut. While this is an extremely simple concept, simultaneous use of the HP filter and EQ control provide fairly extreme tone-shaping flexibility. The high-pass filter and EQ can be independently bypassed when not in use.

The program dependent compressor is also operationally quite simple. The Threshold knob simultaneously controls the compressor threshold, the compression ratio and the make-up gain. The circuit has a soft-knee characteristic with a compression ratio that varies from 1.2:1 to greater than 20:1. The attack and release times are program dependent and are configured automatically. The circuit does an amazing job of adapting to a wide variety of sonic sources and, in my experience, was always usable. The makeup gain is automatically increased for lower compressor thresholds so that a somewhat-constant average program level is achieved.

A second variable see-saw EQ (identical to the EQ in the signal path) is dedicated to the compressor path and used as a side chain filter providing for some creative compression control. The side chain path is also routed to the 500 Series API “Option” or Radial Engineering “Omniport” output allowing an external filter to be used for more intense side chain control. The side chain and compressor path can be bypassed when not being used.

I loved using the MPA575. It’s an incredibly adaptable piece of equipment that works well in practically any recording situation. As someone who almost always tracks with at least some EQ and compression, I never dreamed that I’d be able to confidently record master tracks with a single 500 Series module without feeling I’m compromising the recording quality but the MPA575 has made this a possibility.

During the review period I had the opportunity to use the module with a wide variety of mics on a varied selection of sound sources and the MPA575 never disappointed. Kick drum (AKG D112), snare drum (Heil PR-22) and hi-hat (Royer SF-1A) recorded wonderfully. On occasion, I found that I needed additional EQ (the RTZ PEQ1549 worked perfectly) to attain my desired result on kick drum.

The module did a fantastic job recording bass guitar (Heil PR-40) and electric guitar (Royer 122 on a Vox AC30 and a Fender Twin) also sounded great. The MPA575’s EQ added just the right amount of shimmer to the Royer ribbon while retaining a warm smooth sound. The module is already feature packed but I wish there was a DI input so direct signals could be recorded without the use of an external direct box.

I feel the real strength of the pre is on vocals and acoustic instruments. I recorded male vocals with an MXL Revelation Solo and female vocals with a Sony C-800G and had great results in each instance. On some occasions when I needed more extreme compression, I found that using a Tube Tech CL1B in addition to the onboard compressor worked quite well. I recorded several acoustic guitars and a mandolin through an AEA N22 Nuvo and had great results. In most instances I found that I prefer the lower impedance setting (600 Ohm) on drums and guitars as it is somewhat more “Neve-esque” and I prefer the higher setting (2.4 kOhm) on acoustic instruments and vocals. This wasn’t always the case, but I do love having the ability to switch between the two settings and the module automatically adjusts the gain when the impedance is switched; there isn’t a volume change when switching impedance. The EQ and compressor functions also incorporate this gain matching circuit so when they are switched in and out, the gain stages are automatically adjusted; the module’s gain is constant within a fraction of a decibel.

The MPA575 will be a welcome addition to any studio wanting to expand its audio arsenal yet it is also a perfect “first outboard pre” since it is quite affordable and it includes EQ and compression.
Price: MPA575: $1,200; MPA575-T (with transformer): $1,350
Contact: Ingram Engineering | ingramengineering.net

About Russ

A native of Boulder, Colorado, Russ Long moved to Nashville, Tennessee to attend Belmont University in 1986. Since graduating with a BBA degree in 1988, he has remained in Nashville engineering and producing a wide variety of music and film projects.

Russ’s credits include the hit singles “Kiss Me” and “There She Goes” by Sixpence None The Richer alongside albums by Wilco, Newsboys, Over the Rhine, Relient K, Dolly Parton, Fernando Ortega and Jim Brickman. His film credits encompass the soundtracks to The Sapphires, Girl Interrupted, Here On Earth, Jonah: A VeggieTales Movie, How To Lose A Guy In 10 Days, The Second Chance, Hannah Montana: The Movie, and She's All That. Additionally, Russ has diversified to engineer 5.1 DVD mixes for artists such as Allison Moorer, David Crowder and Mercy Me as well as live sound recordings, having multi-tracked live performances for Switchfoot, Chris Tomlin and Guy Clark.

In 1994, Russ opened his Nashville studio—The Carport—which has played a key role in the majority of his projects. He has been a regular contributor to Pro Audio Review since 1997; as such, he has authored well over 100 equipment reviews and instructional audio production articles to the benefit of the pro audio industry.