armboard experimentation


2007-01-12 6:01 pm
Yesterday (well the day before to be completely accurate) I experimented with changing the armboard on my deck for one made from a quite different material. I had been using one made from two skins of phenolic laminate over a 10mm core of MDF; the alternative armboard consisted of two skins of bi-directional carbon fibre over a 10mm core of Nomex (phenolic paper honeycomb). The armboard is bolted at four points and uses a pressure distribution ring (like a very big, square, tapped washer) under the chassis and bolts to a large flange which supports the edge of the armboard on all four of its edges.

This picture shows the carbon fibre board but the other board is very similar in appearance (the chassis material is also a carbon fibre skinned, Nomex construction).

With a bit of careful manipulation it was possible to swap between armboards in about 10 minutes without adjusting any of the arm parameters and using mute on the pre-amp to make certain of the same playback level. The bolt tension was carefully adjusted to be similar in each instance.

The audible (subjective) differences between these two small pieces of material were really quite striking. The carbon fibre laminate had a significantly 'faster' sound with noticeably greater micro dynamic range; voices in particular had a much greater tonal range and sounded quite a bit more 'real'. Macro dynamic was not much different between the two (the absolute difference between loud and quiet) but subtle inflections were definitely (obviously) clearer and more pronounced on the CF item. However, the MDF item did have a warmer (some may say 'richer') tone and mid-bass in particular was fuller. In comparison the CF item seems very lean in this area but with surprisingly deep (and powerful) extension. I could go on a bit more but this post is already long enough. I may try milling a solid aluminium item to compare - or/and a Delrin one.

Has anybody else tried different materials? What were your thoughts or preferences?