Outboard DSP: Marani Pro MIR260A

The third of a series of product reviews of outboard DSP hardware, this article explores the MIR260A DSP processor from Marani Pro Audio. Supported with expert measurements performed by Charlene Chow on a flagship APx555B analyzer (courtesy of Audio Precision), Vance Dickason looks at this professional DSP processor with two inputs and six outputs, and a more cost-effective model from Marani.

In his exploration of available Outboard DSP systems, Vance Dickason explores the Marani Pro Audio MIR4801, the company's flagship DSP processor with four inputs and eight outputs. MIR stands for Marani Impulse Response, which refers to the proprietary Marani linear (zero) phase Linkwitz-Riley filter, which is described in a whitepaper titled by Michael Marani and Simone Castrucci, both from SEED Electronics, Guangzhou, China.

The first in a series of reviews of outboard DSP processors available in the market and of interest to loudspeaker engineers, this article explores an extremely versatile and powerful DSP audio processor and DAC, crossover, and control center for any audio system. The dspNexus comes with balanced inputs and outputs, USB, S/PDIF and Bluetooth aptX HD, and processing is handled by a latest-generation Analog Devices SHARC DSP, with Audio Weaver as the programming interface.

In this article, Vance Dickason explores the use of digital signal processing, and specifically Outboard DSP, an increasingly viable solution to create a complete active crossover design, contained in a programmable unit that can be delivered with multiple presets for different usage scenarios or even configured by the user, according to the system in place. This inspired Vance Dickason to begin a series of product reviews of multiple outboard DSP processors, and this article is a preamble for the project.

The new 7.5" coaxial driver from SB Acoustics' prestigious Satori line is built on a rather stylish aluminum-cast frame, totally open below the spider, with a cone featuring SB's proprietary Egyptian Papyrus material with a three-roll coated cloth-type surround, driven with a 1.52" diameter voice coil and neodymium magnet. The 1" tweeter is comprised of a coated cloth-type dome diaphragm, powered by a neodymium motor, which incorporates a resonant back chamber design.

The eagerly awaited Purifi Audio PTT10.0X04-NAB-01 10" Midbass Woofer is the sixth Purifi driver to be examined in Test Bench. This 4Ω woofer features extensive proprietary technology that includes the constant Sd surround, cone edge stiffening ring, and low magnetic hysteresis motor design. The PTT10.0X04-NAB-01 exhibits some very unique engineering that can be finally characterized.

This issue includes a new product review in Vance Dickason’s Outboard DSP series, exploring the miniDSP Flex audio processor. And Dario Cinanni explains how to Enhance Loudspeaker Efficiency and Bl(x) Symmetry with the Virtual Voice Coil software from SpeakerLAB. As scheduled, Mike Klasco and Nora Wong compiled the 2025 Cone and Dome Directory. For this month’s Test Bench, Vance Dickason characterizes the Faital Pro 5PR120 5” Pro Midrange Driver.

The B&C Speakers DE640-16 Compression Driver is a 1.4" exit design, which along with the recent DCM414 midrange and the DE360 models represent a line of two-point suspension ring radiator type compression diaphragms. The DE640-16 features a 65mm (2.6") Polymer diaphragm and neodymium ring magnet and is specified for a recommended crossover frequency around 1kHz, and a 140W continuous power rating. For this Test Bench, the DE640-16 was matched with the Eighteen Sound XT1464 elliptical flare horn.

This Test Bench explores an interesting transducer from Stereo Integrity, a company founded in 2001, targeting the home and automotive audio markets. The Stereo Integrity M3 is a 3.5" carbon fiber midrange driver with neodymium motor, only 52mm (2") in depth. The M3 includes a black woven carbon fiber/paper sandwich curvilinear cone and 1.1 convex dust cap, with suspension provided by a synthetic copolymer surround plus a flat 55mm diameter cloth spider.

The DH450-8 ultra-compact compression driver from B&C Speakers incorporates a 1.7" high temperature Polymer diaphragm driven by a 44mm voice coil wound with aluminum wire on a high Qm Kapton former. Its most fascinating feature is the patent-pending phase plug with a deliberately twisted internal channel, which is intended to improve the overall frequency response. For this characterization, the DH450-8 1" neodymium driver is measured along with the B&C Speakers ME10v2 90x60 hyperbolic cosine flare horn, made from injection-molded ABS. This article was originally published in Voice Coil, August 2024