Outboard DSP: Marani Pro MIR260A

The third outboard DSP unit to be examined in this series of currently available outboard DSP processors is from Italian-based Marani Pro Audio, the two in six out Marani Pro MIR260A. MIR stands for Marani Impulse Response, which refers to the proprietary Marani linear (zero) phase Linkwitz-Riley IIR filter, which is described in a white paper available online on the Marani Pro Audio website. The paper is titled “MIR a New Technology for Crossover Filters” by Michael Marani and Simone Castrucci, both from SEED Electronics in Guangzhoe, China. Marani has also added 40dB octave horn-type NXF crossover filters to its selection of filter types. FIR filters are also available with up to 512-taps per channels and up to 120dB/octave slopes.
 
As the name Marani Pro Audio implies, Marani is focused on the pro audio side of the DSP market and makes an entire line of pro audio DSP processors, for a total of 13 models in the Marani FI, A, D, E, and P series DSP processors. While their main application is live sound, Marani processors are equally suited for studio and home audio applications. For the purposes of this article, I will be examining just two models in Marani’s extensive outboard processor lineup, the four in eight out Marani MIR480I featured in the September 2024 issue of Voice Coil, and in this month’s segment, the Marani MIR260A DSP processor.

Besides the Marani line of pro audio-oriented DSP processors, the company also produces rack mixers, matrix mixers, equalizers, power amplifiers, and feedback eliminators. It’s also interesting to note that Marani Pro Audio has partnered with the Danish Class-D pro audio power amplifier company, Pascal, and provides DSP processing boards for Pascal plate amps.
 
The two in six out Marani MIR260A is depicted in Photos 1-4 and is a more cost-effective model than the previously featured MIR480I. And its feature set is extensive:

DSP and AD/DA run at a 96kHz sampling rate.
Functions include input gain, noise gate, PEQ (parametric EQ), compression, delay, polarity, crossover filters selection, peak limiter, auto and dynamic equalization.
A network interface is configured to connect to a PC directly through a network cable. By default, DHCP automatically obtains an IP address. Computer software can control up to 128 processors at the same time via network connections, and can perform unified gain control, mute, PEQ, and polarity via any of the control interfaces (USB, RS485/Ethernet).
FIR filters—each output can have up to a 512 tap FIR filter for total of a possible 3072 taps with a slope range of 21 to 120dB/octave.
IIR filters—Linkwitz-Riley/Butterworth slope: 12/24/36/48dB per octave; NXF (notch filter) slope is 40/45/50/50/55/60/65/70/75dB per octave; Bessel is 12/24dB per octave.
MIR filters—Linkwitz-Riley slope: 12/24/36/48dB per octave NXF slope is 40/45/50/50/55/60/65/70/75dB per octave type; high pass/low pass/band pass/external import.
Taps range: 256 ~ 512.
Critical specifications for the MIR260A are:

A/D dynamic range: 118dB
D/A dynamic range: 118dB
Maximum input level: +20dBu
Maximum output level: +18dBu
Total harmonic distortion: <0.003% (+4dBu 1kHz)
Frequency response: 20Hz~40kHz
Crosstalk: ≦-95dB
Signal-to-noise ratio: ≧113dB (A weighting)
Noise floor: ≦-94dB (A weighting)
Common Mode Rejection Ratio: 60dB

All Marani Pro DSP processors are supplied with a fairly straightforward PC control software that can configure all of the unit’s functions and is compatible with Windows 7-11. You can also configure the MIR260A from the controls on the front panel.
  Besides listing the manufacturer’s specifications, all the outboard DSP units in this series were measured on an Audio Precision flagship AP555B analyzer courtesy of my friends at Audio Precision, with a special thank you to AP engineer Charlene Chow who performed the measurement sequences for this article. Photo 5 and Photo 6 show the basic setup for the series of tests. Test categories that were performed included total harmonic distortion plus noise (THD+N), signal-to-noise ratio (SNR), frequency response at 0dB, crosstalk, and intermodulation distortion (IMD). Starting with THD+N (Figure 1), the 1kHz at +4dBu performance of channel 1 is 90.403dB, and although not shown, the numbers were 87.672 at 10kHz. Figure 2 depicts the SNR graph, which resulted in 116.815dB for channel 1.
 
The Marani MIR260A’s frequency response (Figure 3) indicates the unit is flat 20Hz to 20kHz, and 0.5dB down at 43kHz. This test level was set to reference the result to 0dB. The crosstalk graph (Figure 4) shows channel-to-channel isolation averaged about -97dB across the bandwidth.
 
The last test (Figure 5) compares the IMD response of the Marani MIR260A with the background IMD of the AP555B. Taken all together, the MIR260A exhibited rather good performance when measured with the AP555B. With three outputs per channel, applications for the MIR260A would be for three-way system designs or two-way designs with an external subwoofer, both formats that work well in either home audio or the studio monitor markets. For more information about the Marani MIR260A, visit the Marani Pro Audio website at www.marani-proaudio.com. VC
  This article was originally published in Voice Coil, December 2024