AURALEX LENRD (Low End Node Reduction Device) BURGUNDY. single Size 300mm x 300mm x 600mm (12 x 12 ). This product is now available as a single piece 600mm (2ft) long (picture shows 2 LENRDs). In the world of acoustics, bass frequencies congregate around edges and in the corners of rooms. Corners cause bumps in a room s frequency response, technically known as a Room Node. (Officially a bump is a Mode and a dip is a Node). Mid and high frequencies are easy to control. However low frequencies consists of long wavelengths with high levels of energy. (Compare the size of the cone of a woofer and a tweeter). Long wavelengths can only be absorbed by very thick foam, typically between 1 and 2 metres thick!!. Since that is impractical, another approach is to exploit the fact that low frequencies gather around the edges and in corners.
This is where sonic problems begin. Placing a length of foam between 1 and 2 metres long in a corner will certainly mop up those troublesome frequencies and will not intrude into the working area. LENRDs are triangular shaped, irregularly wedge-cut piece of Studiofoam that give superior broadband absorption, but especially at low frequencies, and perfectly fit room corners and wall/ceiling junctures. LENRDs are the easiest and most cost-effective way to control excess low frequency energy without sacrificing large amounts of cubic space. Note that the foam itself is coloured at the chemical level and not surface painted. Studiofoam conforms to the Californian firecode specification 117 which is more rigorous than UL-94HF1. Colours cannot be guaranteed to be fast as external factors such as humidity, sweat, sunlight, halogen and fluorescent lighting and cigarette smoke will all influence long term colour changes.