From: stereobuff07@shaw.ca   
      
   wrote in message   
   news:d17e46a3-5520-4dd0-822a-2ee3d4bad45d@googlegroups.com...   
      
   On Tuesday, May 25, 2004 8:45:45 PM UTC-7, Chu Gai wrote:   
   > A brief discussion on resolving systems with a gentleman who makes   
   > single driver speakers in what appears to be a folded Voigt Pipe   
   > design turned briefly to resonances.  My general contention was that   
   > since he was using alder as opposed to MDF, that it would result in   
   > additional resonances which would color the sound. Some mild umbrage   
   > was taken. The conversation went like this. Am I somehow missing   
   > something here or is this a combination of spin coupled with some   
   > factual errors regarding wood?   
   >   
   > Him: Sure, it will resonate. So will wood, steel, micarta, MDF, and   
   > ANYTHING ELSE that has any mechanical stiffness. How it resonates and   
   > whether it's important depends upon its stiffness, it's internal   
   > mechanical losses, how it's mounted and secured and how it's   
   > mechanically loaded and acoustically excited.   
   >   
   > Me: This should not be interpreted as the intentional use of materials   
   > to impart resonances as opposed to MDF which has a more predictable   
   > nature? In ways, it reminds me of the various woods that can be used   
   > in the construction of guitars where I think MDF, apart from being   
   > heavy, might not make for the most pleasing of sounds.   
   >   
   > Him: No, you have interpreted incorrectly. A common misconception   
   > though. But yes woods do flavor sound, for guitars and speakers. Part   
   > of woods amazing quality is that it can be made to resonate more, as   
   > in the case of a guitar or piano, but that same piano usues wood to   
   > isolate the vibration (the case) so the most energy can be released to   
   > the room (more music)   
   > What solid wood does in the case of my speaker is resonate LESS. I use   
   > solid wood for it's weight vs ridgidity, it is far more ridgid than   
   > mdf. And contributes actually less in the form of self -resonance. In   
   > addition we have have made this speaker from teak, oak, mdf, plywood,   
   > pine, alder, maple and cherry. All have distinct sonic "flavors". The   
   > solid wood particularly the maple extends bass and allows the very   
   > absolute maximum energy transfer from driver cone to port to room   
   > without imparting audible resonance of it's own. The mdf example   
   > sounded muffled and lifeless. My designs pursue maximum energy   
   > transfer from electrical to the room both from the front of the driver   
   > and the rear.. I once made a xylephone from different species of wood,   
   > the keys all the same size as an experiment. 5 octaves were covered   
   > just from locally growing trees.   
   > One really has to integrate decisions about grain orientation,   
   > thicknesses of wood as well as joint strength to carry this discussion   
   > comparing materials to any logical extent as it relates to   
   > speakerbuilding.   
   >   
   > Me: If it's your position that cabinet augmentation is desireable,   
   > then we stand on opposite sides. If you feel that it gives your   
   > speaker a characteristic sound that is pleasing, I can live with that.   
   >   
   > Him: The concept that you propose I subscribe to is incorrect, you   
   > mis-nterpret my intention of reducing resonance through the use of   
   > solid wood. MDf does not eliminate resonance. It reduces it   
   > drastically, such that it also reduces musical content via energy   
   > absorption.   
   >   
   > If you look at speakerbuilding from another angle, the anthropological   
   > veiw, we see that as forests shrank and skilled labor was replaced   
   > with machinery. The square box (usually sealed or ported0 became the   
   > de-facto method of augmenting the bass drivers own free-air resonance   
   > (fs) or limiting it in the case of sealed enclosures. I submit this   
   > has every thing to do with the advent of high powered solid state   
   > amplifiers as equally as declining skills in our labor pool. MDF was   
   > not created for eliminating resonance in speaker boxes but rather to   
   > utilize vast stretches of inadequate lumber stocks. From an acoustical   
   > standpoint MDF is dampening. It absorbs sound due to it's mass and   
   > weight.   
   >   
   > I am trying to allow the energy that would be absorbed by MDF to be   
   > better utilized re-creating acoustical energy in the room. Of course   
   > you do not want your speakerbox to vibrate, but using a "dead" panel   
   > is the easy way out and not neccesarily the best method. ANd I think   
   > Franco Serbelin agrees.   
      
   MDF is the best for creating acoustical energy in any room   
      
      
      
   Try using morning wood.  It might be interesting.   
      
   Shaun   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)