Test Bench: Eighteen Sound ND4015BE Beryllium Compression Driver

This Test Bench examines Eighteen Sound's ND4015BE beryllium compression driver, which was mated to an Eighteen Sound XR2064 60° × 40° horn. This compression driver is available in two versions, a 1.5" throat and a 2" throat. This review focuses on the 2" throat model. The ND4015BE has a 4”-diameter edge-wound aluminum voice coil on a nonconducting Nomex former, a 4" pure beryllium diaphragm with a polymer surround. This article was originally published in Voice Coil, February 2014.

The Celestion AN2075 has a 2”-diameter aluminum cone neodymium motor full-range transducer primarily intended for use in line source arrays. The AN2075 is built on a proprietary six-spoke molded-glass reinforced ABS frame. The cone assembly consists of a black anodized aluminum cone with a 19-mm diameter aluminum dust cap and whizzer-type extension. This article was originally published in Voice Coil, February 2014.

For our readers interested in loudness standards, Jon Schorah provides a great article about Loudness Meters and Measurements. If someone has extensive experience both in understanding the norms and cutting-edge implementation of corresponding loudness tools is Jon Schorah, the creative director and co-founder of NUGEN Audio, one of the world’s leading manufacturers of loudness products. Read the full article available online.

Tube life can be extended if you delay the application of high voltage until after the heaters have warmed up and current can flow. This little module does just that: depending on the setting of a jumper, it delays the high-voltage for 40 or 60 seconds after the amplifier is switched on. And the module is available as a kit. This article was originally published in audioXpress, February 2014.