Test Bench: Eighteen Sound NSD1424BTN 1.4” Pro Sound Compression Driver

This Test Bench characterizes an ultra-compact 1.4” compression driver design from Eighteen Sound, the NSD1424BTN, combined with the brand's XT1464 60°x50° horn. This driver is driven by a 62mm diameter edge-wound voice coil, proprietary True Pistonic Motion (TPM) Tin (nitrate compound)-coated titanium diaphragm, 3P phase plug design with short openings and a high flare rate to reduce distortion and improve mid-range detail. This article was originally published in Voice Coil, May 2021.

This Test Bench article characterizes a high-end dome tweeter from Kartesian, a French home audio/pro OEM, founded in 2011 and located near Strasbourg. The Twt28_vMS is a 28mm soft dome tweeter using a proprietary Nylon-coated cloth type diaphragm and surround, with dual N48H neodymium magnets fitted to a low-carbon-content steel motor structure. An extruded polyester damped pole piece venting into a stamped aluminum back enclosure, is complemented by a rear enclosure acoustically linked and tuned to about 670Hz. This article was published in Voice Coil, May 2021.

This article takes a closer look at Polyetherether Ketone (PEEK) and comparisons with the PEI (polyetherimide) or polyethylene naphthalate (PEN) developments, and even standard PET formulas that dominate most cheap earphone and headphone diaphragm applications. The article also references key product implementation and the latest knowledge directly sourced from vendors and patent holders, such as DuPont, Teijin, and Victrex. This article was originally published in Voice Coil, May 2021.

This article illustrates how the latest Klippel Multi-Scanning Workbench solution allows measurements across several domains (acoustical, mechanical, electrical, and magnetic) while working from non-anechoic environments. The author uses a practical characterization of balanced mode radiator (BMR) loudspeakers, which require a more complex approach when compared to conventional cone-based woofers or dome-tweeters. This article was originally published in Voice Coil, May 2021.

In Voice Coil May 2021, Andrew Taylor explains Klippel’s approach to "Comprehensive Transducer Testing in 24 Minutes," Mike Klasco writes about the use of "PEEK High-Performance Film Diaphragms and Cones," and there are two updated directories on MEMS Speakers and Microspeaker Vendors. James Croft reviews Mikhail Dinaburg’s “Speaker with Dual Diffuser” patent, while Vance Dickason characterizes the NSD1424BTN 1.4” compression driver from Eighteen Sound, and the Twt28_vMS high-end dome tweeter from Kartesian in Test Bench. Now available in print and digital.

Our May 2021 Glass Audio Special edition is certain to inform and inspire you. We reveal what is happening at Western Electric's new Rossville Works in Georgia, where production of 300B tubes is ongoing, we explain how to draw tube load lines, and we offer a valuable preamplifier design that enables you to compare the sound of tube and solid-state circuits from the same audio source. There's also a versatile stereo tube amplifier design to build, and plenty more audio electronics theory and practice in this edition. Now available online and in print.