Test Bench: SB Audience 44CDN-PK 1" PEEK Diaphragm Compression Driver

The SB Audience Rosso 44CDN-PK is combined with the H250 90°×60° exponential horn. The driver features a 44.3mm (1.75") diameter voice coil driving a single piece PEEK diaphragm and surround, and including a FEA-optimized neodymium ring magnet motor structure, annular phase plug design, and a cast-aluminum damped rear chamber. This driver has a 60W AES power handling rating (120W maximum), with a 1.8kHz recommended crossover frequency.

This patent, granted to MrSpeakers, the company from San Diego, CA that is now Dan Clark Audio, was granted in the same month that this review was published in Voice Coil. The patent details a headphone driver that should also be of note for the speaker industry. As Croft notes, the patent office initially rejected the claims due to prior patents, eventually accepting the inventor's arguments, in 2016. The review provides the historical context for planar magnetic transducers, and explains why this is an important patent.

This Test Bench focuses on Beyma’s new 1" CD1ND Compact Polyimide Diaphragm Compression Driver, a product oriented for demanding professional audio applications. The 1” throat uber-compact CD1ND compression driver delivers a “high-quality” cost-effective option for studio monitors or stage monitors, as possible examples. The Beyma CD1ND uses a 1” diameter edge-wound voice coil, driving the field-replaceable diaphragm and lightweight neodymium ring magnet motor. This article was originally published in Voice Coil, April 2022.

This article reviews a patent application submitted in 2010 by to two inventors, on behalf of Jazz Hipster Corp. (Taiwan), regarding an improved structure of a speaker using the surround to reduce the resistance of the diaphragm excursion, which helps to generate a more linear diaphragm movement, with less resistance, and reduced distortion. As James Croft noted, the approach had been used in the past, but its use decreased due to the high-performance achieved with well-designed roll-surrounds, at a lower cost. No surprisingly this patent was subsequently abandoned.

As a respected manufacturer of high-quality condensers and crossover components, Mundorf is also capitalizing on the industry's “renaissance” in AMTs and now offers five models in this updated U series, each driver having the same width, but different heights. The U80W AMT model features a 63mm x 19mm pleated proprietary AMT diaphragm, an optimized rear chamber, a flat face plate with an optional secondary aluminum face plate, and is rated for 80W power handling and 94dB sensitivity. The U Series is the fourth in Mundorf's AMT portfolio. This article was originally published in Voice Coil, March 2022.

In this article, James Croft dives in an interesting loudspeaker patent (US20150146910A1), awarded May 28, 2015 to multiple inventors from the Fraunhofer-Gesellschaft Institute in Munich, Germany. The patent describes a diaphragm drive system with a conventional electromagnetic motor and corrective piezoelectric elements that drive the suspension from a sensor that detects the nonlinearity and provides the corrective signal. This article was originally published in Voice Coil, September 2015.

Imagine a new class of speaker diaphragm position sensors that enable audio engineers to reduce distortion and extend bass response from studio monitors, soundbars, smart speakers, and even smartphone microspeakers. With the precision of laser displacement instrumentation, this sensor is located between a stationary component of the speaker and an appropriate moving part to provide an error correction reference signal back to the amplifier. Well, that sensor has already been developed. ​This article was originally published in The Audio Voice weekly email newsletter.

Audiofly added the AF180 to the Audiofly Performance Series of In-Ear Monitors (IEMs). The AF180 offers four expertly tuned balanced armature drivers, and adds crossover circuitry for a sound experience that, according to the company, “redefines the in-ear monitor market”.