ADL has long been an advocate of tonewoods: woods used for the making of musical instrument. Our feeling is that musical instrument makers have been experimenting for centuries to get the maximum performance from their instruments and we, as audiophiles, need to closely examine their choices.
One such wood is spruce, a relatively lowly member of the pine family. Spruce, however, is used for the tops of guitars and other stringed instruments, like violins and cellos, and, even more interestingly, used for the soundboards of pianos.
We can think of any acoustical instrument with a wider frequency response than a piano. Even the most expensive pianos: Steinways, Yamaha, Bosendorfers, Faziolis, al use spruce and all consider spruce to be fundamental to their sound.
Curious ,ADL started to experiment with spruce and have found that spruce is an excellent platform for audio components. Particularly on Digital components, it makes them sound so much more analog like, it defies explanation.
Naysayers will claim than any wood platform will inevitably add resonance, and most will declare that resonance is a very bad thing. However, ADL believes that if the resonance is consonant with real music, that resonance can be a blessing. Certainly the use pf spruce under out components has not diminished any detail and actually has enhanced the information we hear: better tonalities and better resolution of ambience. It makes for a much more realistic presentation, in our opinion.
Initial usage of spruce revealed one thing, though. You can not simply place it under a component and expect good results. The way spruce is used for musical instruments is that it is in a cantilevered stress. Spruce soundboards are anchored at the edges and the middle section of the platform both sustains the load and adds the desired resonance.
Using the spruce as a footer is the worse possible way to utilize spruce. Unless cantilevered, the spruce will not sound very good at all. A closer examination of musical instruments using spruce quickly revealed this application.
Also the grain structure is quite important also. Musical grade spruce is always quarter sawn. That is the wood, when looking at the ends, have a vertical grain. The denser the grain structure ( old growth) the higher the natural resonance. Through our friend Loren, we have obtained pieces of a 1901 Steinway’s soundboard as well as pieces from other pianos. A close examination of the Steinway reveals that the grain is quite varied for the Steinway whereas it is more uniform for the other, lesser, pianos. We have dense grain intermixed with coarse grain, probably an explanation for the famous Steinway “ring”.
Finish is also important. Natural seems to have the broadest frequency response. DEvery other finish we have tried seems to either dull the sound or to add high frequencies ( varnish, lacquer, cyanoacrylate).
We have standardized our Spruce planking at 22 inches since that is the nominal width f most racks (19 inch faceplate , plus1 inch clearance on either side, plus an inch more per side for the support structure)
Custom sizes can be made, up to 26 inches wide