Voice Capture Challenges: The Threshold of the Golden Age of Voice

Voice processing and recognition leading to the development of voice-based personal assistants is one of the decade’s greatest achievements and provides a unique opportunity for the audio industry. Leveraging those sophisticated technologies now available to the consumer electronics industry makes the investment on new designs much more exciting. In this article, Mike Klasco provides an introduction to the voice capture, signal processing and voice recognition challenges. This article was originally published in audioXpress, December 2018.

audioXpress May 2020 Glass Audio/Tube Focus edition is now available. Highlighted on the cover is a review of the RødeTest FuzzMeasure Audio and Acoustic Measurement Software and Ethan Winer's experiments to measure capacitor distortion. For tube enthusiasts, Bill Reeve repurposes an old Shure preamp for line-level duty, and Bruce Heran details how he built his two Mini Blocks tube amplifiers. Mike Rothacher shares an inexpensive MOSFET Follower (MoFo) Class A amplifier project, Richard Honeycutt provides valuable lessons about repairing guitar amplifiers, and there's plenty more audio electronics focused articles. Download now!

Audio Research (ARC) announce important updates to its highest-performance tube phono stage, the Reference Phono 3 Phono Preamplifier with the launch of the Reference Phono 3SE. Following the launch of the recent Reference (REF) 6SE Line-Stage Preamplifier, ARC’s 50th Anniversary product line continues with a special edition update of the Ref Phono 3 Preamplifier. The REF Phono 3SE ($17,000 USD) replaces the REF Phono 3, introduced in 2016.

Audio Media Research (AMR), the company originally founded by Hartley Peavey as a research and development branch of Peavey Electronics, announced the acquisition of the ReValver guitar amplifier modeling software line from Peavey Electronics. AMR is now a stand-alone entity focused on audio software and digital signal processing for the music creation market, specializing in sound emulation with tube, circuit and component level modeling.

McIntosh Labs has been perfecting vacuum tube amplifiers since the 1940s and solid-state amplifiers since the 1960s. From that heritage, McIntosh now announced the MC901 Dual Mono Amplifier, a truly one-of-a-kind monoblock that is also two amplifiers combined into one, with each amplifier boasting differing design philosophies including a 300-Watt vacuum tube amplifier attached to a 600-Watt solid state amplifier on one unified chassis.

This approach to RIAA equalization results in a high-quality phono preamp featuring the high-transconductance 5842 tubes. The author adapts Erno Borbely's project of a transistorized phono preamp with a vacuum tube implementation. These articles were originally published in audioXpress, October 2003 and January 2010. For this repost, we decided to merge the two articles in one single page.

audioXpress December 2019 dives into the latest wireless audio and DSP platforms and solutions in a dedicated Market Update, followed by a review of the latest Audio Precision APx555 B Series audio analyzer. David Logvin shares his experience with the xCORE VocalFusion development platform by XMOS, while Michael Steffes re-confirms a theory that cascaded amplifier + ADC harmonic distortion combine as voltage swings. Christopher Paul explores alternative approaches to the design of a linear current regulator for audio tube amplifiers, Menno van der Veen details an 18 W single-ended valve amplifier using Trans technology, and Richard Honeycutt investigates whether or not swapping out comparable tubes makes any audible difference in a guitar amplifier’s sound. Download your own copy now!

The November 2019 edition of audioXpress is now available with a wide range of technical topics in audio electronics and design. We review the Benchmark LA4 Line Amplifier and the new Hooke Verse Bluetooth Binaural Recording Headphones. Jan Didden proposes an updated version of his High-Voltage Delay for Tube Amplifiers, and Thomas Zarbo, Jr. explains how to build his Tenacious Bass-8 Powered Subwoofer. And, learn more about Data-Over-Sound, MU amplification topologies, and Auverdion’s Aurora open-source DSP platform. Now available!

Allen & Heath has revealed a new stunning new mixing console design. Avantis is the third model to be based on the company's XCVI FPGA engine, allowing 96kHz operation and puts this next-generation technology available across all its 64 channels and 42 configurable busses, with twin Full HD touchscreens, extensive I/O options and processing from the company's flagship dLive mixing system. The new console is also designed with a surprisingly robust all-metal structure inspired by tubular exo skeletons of super-bikes!

Luxman’s new flagship control amplifier, the CL-1000 is the spiritual heir to the legendary C-1000, launched in 1975. Yet even as it salutes the past, the new preamp looks forward with an all-new LECUTA volume control system, a nanocrystal core transformer, Luxman’s proprietary oil-impregnated capacitors and more. “The CL-1000 represents everything Luxman knows about vacuum tube audio,” says Jeff Sigmund, president of Luxman America. “It’s not just our newest preamp, it’s our new benchmark.”