All items in category Magazine Articles
Voice Coil Review: Outboard DSP: Marani Pro MIR480I Audio System Processor
by Vance Dickason

Voice Coil Review: Outboard DSP: Marani Pro MIR480I Audio System Processor

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.
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Individual Transfer Curves of Moving Magnet Cartridge Subassemblies
by Hans Polak

Individual Transfer Curves of Moving Magnet Cartridge Subassemblies

A Moving Magnet (MM) phono cartridge can be characterized by its overall transfer function. But the transfer function of the part that generates the signal through magnetic induction has its own transfer function, which can also be measured. By translating the latter into an equivalent electronic circuit, further insight and possibilities for optimization can be obtained. This article explains.
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Outboard DSP: Danville Signal dspNexus
by Vance Dickason

Outboard DSP: Danville Signal dspNexus

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.
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Fresh From the Bench: APL Virtuoso v2 Binaural Renderer for Multichannel and Immersive Audio Formats
by Philipp Paul Klose

Fresh From the Bench: APL Virtuoso v2 Binaural Renderer for Multichannel and Immersive Audio Formats

Originally launched in May of 2023, APL Virtuoso is a culmination of more than 10 years of research into binaural audio and spatial sound, offering users the ability to mix and monitor immersive audio over headphones, without the need for complex loudspeaker setups. The v2 update of APL Virtuoso introduced acoustics emulation and externalization, simulating the experience of listening to loudspeakers in a perfectly tuned room.
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Outboard DSP: An Introduction
by Vance Dickason

Outboard DSP: An Introduction

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.
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Fresh From the Bench: QuantAsylum QA403 32-bit Audio Analyzer
by Jan Didden

Fresh From the Bench: QuantAsylum QA403 32-bit Audio Analyzer

The QuantAsylum QA403, the 4th generation audio analyzer from the company founded by Matt Taylor in 2012, has a lot to offer. In particular when a user gets tips and guidance from someone like Bob Cordell, no less. The QuantAsylum QA403 Analyzer was the result of a complete redesign imposed by the silicon shortages and supply chain disruptions, pre- and post-pandemic. It appears that the efforts made were well worth it. Jan Didden shares his impressions.
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Patent Review: Multiple Path Acoustic Wall Coupling for Surface-Mounted Speakers
by James Croft

Patent Review: Multiple Path Acoustic Wall Coupling for Surface-Mounted Speakers

This article reviews a patent awarded to Paul Wayne Peace Jr. and Derrick Rodgers, on behalf of Harman International Industries. The patent describes a surface-mounted loudspeaker design that mitigates the interference between direct low-frequency (LF) energy and reflected LF energy by breaking the LF energy from an LF driver into multiple paths using one or more of waveguides, driver load plates, and enclosure ports to diffuse the reflected energy and minimize frequency response errors.
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Wireless Audio: Ultra-Low Latency Audio Transmission Over Bluetooth LE Audio
by Jonny McClintock

Wireless Audio: Ultra-Low Latency Audio Transmission Over Bluetooth LE Audio

While Bluetooth technology does not provide a complete solution for live performance audio, it still has a key role to play. In particular, the value of a standards-based approach manifests with the availability of low-cost Bluetooth LE-compatible transceivers from a variety of SoC vendors. Building on these readily available devices, manufacturers can engineer systems that are strongly optimized for live and professional applications. But what latency performance targets should those products meet?
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Fresh From the Bench: RME Audio DPS-2 Power Supply and LNI-2 DC Filter and Stabilizer
by Stuart Yaniger

Fresh From the Bench: RME Audio DPS-2 Power Supply and LNI-2 DC Filter and Stabilizer

When RME Audio released the DPS-2 Power Supply and LNI-2 DC Filter and Stabilizer, it left many of its faithful customers intrigued. The two new solutions are designed to improve the performance of its ADI-2 series of converters in critical applications. One is a super low noise linear audio power supply with a unique µfilter and sensor technology, and the other is an active DC filter with galvanic isolation. Stuart Yaniger explains how these two new solutions improve what is already outstanding.
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Non-Linear Amplitude Modulation of Loudspeakers
by Reinhold Lutz

Non-Linear Amplitude Modulation of Loudspeakers

Even a perfectly linear loudspeaker produces two types of distortions because of the movement of its membrane. First Doppler distortions, a.k.a. Phase Modulation (which the author addressed in his October 2024 article for audioXpress), and secondly distortions stemming from the Nonlinear Amplitude Modulation, characterized in this article. More importantly, this article also addresses how these harmonic and intermodulation spectral line distortions can be minimized and eliminated in loudspeakers.
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