Test Bench: The AMT100H Driver from Eighteen Sound

The AMT100H driver from Eighteen Sound is the "little brother" of the AMT200P (with the XMT200 horn) air motion transformer (characterized in the November 2021 issue). Features for the AMT100H, include a rectangular throat with a Kapton diaphragm, a neodymium magnet structure, and a net weight of 1.84lb (0.835kg). This driver has a recommended crossover frequency of 1.2kHz at 24dB/octave. This article was originally published in Voice Coil, October 2023.

The February 2024 issue of Voice Coil is now available, and it includes a major resource for all speaker designers and manufacturers, which is our annual Loudspeaker Cone and Dome Manufacturers Directory. In Test Bench, you can find characterizations of the new SEAS Excel T29X001 home audio tweeter, the first transducer to incorporate Composite Sounds' TPCD metamodal technology. The second driver in Test Bench is Eighteen Sound's latest 8NTLS2000 8" high-power handling woofer, for professional audio applications.

In the October 2023 issue of Voice Coil, James Croft reviews an active noise control enclosure system, and Mike Klasco and Nora Wong provide an updated directory of Integrated Electronics for Loudspeakers. Vance Dickason offers three different driver characterizations, starting with the AMT100H driver from Eighteen Sound. Next up, he tests an updated version of the popular TW030WA23/24 tweeter from Wavecor. And finally, measures the Scan-Speak D2008/2010, the revised version of the classic dome tweeter from the Danish brand.

The NSD1095N is a 1" throat compression driver with a compact footprint for “high quality” sound applications in professional audio, from studio monitors or stage monitors to high-power sound reinforcement cabinets. It uses a field replaceable True Piston Motion (TPM) TiN coated titanium diaphragm, extending the frequency response by 25% and incorporates a proprietary phase plug architecture that has been designed to give a smooth coherent wave front at the horn entrance across the whole working frequency range.

The March 2022 issue of Voice Coil offers a complete overview of loudspeaker cabinet design options, plastic enclosure materials, and production techniques, as well as an updated directory of Speaker Enclosure Vendors. This month, in Test Bench, Vance Dickason characterizes the Mundorf U80W from its latest U Series of Air Motion Transformers. And addressing demanding professional audio applications, this issue also includes a Test Bench on Eighteen Sound’s NSD1095N Compression Driver and XT120 Horn. Start reading online. Printed copies are on the way.

This Test Bench article characterizes Eighteen Sound’s AMT200P Air Motion Transformer and accompanying XMT200 6.5” waveguide. This driver is the brand's latest entry into the high-frequency transducer category, specifically designed for the pro sound community. The Eighteen Sound AMT200P includes a rectangular throat with a Kapton diaphragm with a neodymium magnet structure, and is rated for a power handling of 90W AES above 1.2kHz, with a sensitivity of 105dB, and a recommended crossover frequency of 1.2kHz at 48dB/octave. While the AMT200P can be used as a standard planar device it can be also coupled with a dedicated constant directivity horn, the 90°x 20° XMT200, featured in the characterization.

This Test Bench focuses on Eighteen Sound’s latest ND2T, a 1.4” neodymium compression driver, combined for characterization with the XT1464 elliptical-shaped horn, also from Eighteen Sound. This ultra-compact compression driver features a 2.4” diameter edge-wound voice coil wound with aluminum wire on a non-conducting Nomex former with a proprietary treatment. This assembly drives a field-replaceable pure titanium diaphragm and proprietary tangerine radial phase plug design. This article was originally published in Voice Coil, October 2021.

This edition celebrates 35 years of Voice Coil, the Periodical for the Loudspeaker Industry. We discuss a new earphone technology for Balanced Frequency Range, Mike Klasco writes about Subwoofers and Bass, and James Croft reviews a new loudspeaker patent from Tymphany. Finally, Vance Dickason places Purifi Audio’s PTT4.0X04-NFA-01 Home Audio Midbass, and Eighteen Sound’s AMT200P AMT driver and XMT200 waveguide on the Test Bench. Now available in print or download.

The October 2021 edition of Voice Coil discusses "The State of Loudspeaker Magnetics," with an annual overview of these critical industry components and materials for loudspeakers, complemented with an updated industry directory focused on Integrated Electronics. James Croft covers a patent awarded to Coastal Source for the variable waveguide speaker control, while Vance Dickason characterizes the powerful 15DS100 professional subwoofer from B&C Speakers, and Eighteen Sound's latest ND2T 1.4” neodymium compression driver. Now available in print, immediate online access or download.

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.