The August 2014 Issue of audioXpress Is Now Online

July 14 2014, 07:38
In audioXpress’s review of OPPO Digital’s new PM-1 Planar Magnetic Headphones and HA-1 Headphone Amplifier, Alex Vlach received an exclusive inside look at the effort and had the chance to experiment with both units. Mike Klasco also provides his exclusive “insider perspective” on OPPO Digital’s decision to enter the headphone market with a ribbon planar headphone and the methodic internal development and test procedures.
In another great feature article, Stuart Yaniger details the amplifier technologies developed and perfected by Powersoft Audio, the Italian company based in Scandicci, Florence. From the introduction of Class-D amplification to the unique company philosophy, Yaniger discusses how Powersoft Audio strived to define the technological edge of its markets rather than follow trends. The article looks at its flagship X and K series amplifiers for the touring market, the Ottocanali series for installation, and the power amp modules for OEM applications. He also examines the technologies involved and how they impact the end user.

In the second article about Cinema Sound, this month we look at the immersive challenge and how the speaker manufacturers are addressing innovation in movie theaters, while aiming to consolidate new audio technologies to reenergize the consumer market. Immersive sound features a 3-D array of loudspeakers and the ability to place sounds anywhere in the theater. It also offers filmmakers more creative freedom in the production of a cinema soundtrack. Instead of thinking about specific 5.1 or 7.1 speaker setups, the audio mix focuses on placing audio in the X, Y, and Z (tridimensional) coordinates. For the exhibitor, it also places greater demands on the entire sound system—especially the surround loudspeakers and amplifiers. In this article, we examine current formats such as Dolby Atmos, Barco Auro 11.1, and the new Multi-Dimensional Audio (MDA) open platform solution, using a DTS proprietary technology, which was submitted to the Society of Motion Picture and Television Engineers (SMPTE).
Continuing with Speakers, Mike Klasco and Steve Tatarunis explore the market for electrostatic and electret speakers. This month, they look at the design aspects of electrostatic panels and the positive attributes derived from their inherently large uniform phase sound radiation. The authors also explore the challenges involved in achieving uniform, wide high frequency coverage and deep bass at high acoustic output with electrostatics and how various designers have addressed these issues.
In this month’s DIY section, we have a great project from Larry Cicchinelli on how to build an Audio Spectrum Display. Using a “real” spectrum analyzer can be helpful if you need to do a detailed analysis of a system’s frequency response. However, during normal audio system usage (e.g., monitoring a PA system console’s output) it can show too much data to be useful. This article describes an Audio Spectrum Display that can be configured for ISO standard frequencies—those that typically are used for graphics equalizers, using sets of 10 LEDs to show the relative amplitudes of bands of frequencies.
In Audio Electronics, Scott Dorsey writes about “Identifying Unknown Transformers.” What do you need to know to identify an unknown transformer? This article is a short guide to determine how to characterize an unknown transformer and use it in our circuits. Also learn how to determine the turns ratio, the optimal load impedance, how wide a range of impedances it can drive without distortion, if it’s a power transformer or a wideband transformer, how much power it can produce before saturating, and how much DC it can accept on the primary.
Richard Honeycutt’s Hollow-State Electronics article is devoted to “Tube Impedance Translators for Capacitor Microphones” looking in detail at the reason why capacitor mics include built-in electronics. In our regular Sound Control section about acoustics, Richard Honeycutt discusses Duran Audio’s Digital Directivity Analysis (DDA) software and explores how DDA and Digital Directivity Synthesis (DDS) technologies are able to help sound system consultants and designers simulate and optimize the directional behavior of Duran Audio’s Intellivox and Target advanced beam-shaping products. After reading this, you’ll better understand why Duran Audio was acquired last year by Harman/JBL Professional.
Finally, in our Book Review article, Chuck Hansen devoted four months to explore all the pages and extra content of Ethan Winer’s, The Audio Expert, Everything You Need to Know About Audio, and shares his thoughts.
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