It was a pleasure having you guys over. Actually this is sort of a tradition of ours. We call it break-in parties
The whole point is to blast the speakers while nobody gives a hoot about how they sound "raw" because everyone is either too full or too drunk
Trust me it beats a burn in disc everytime!
Mamimili wrote:Hello Jack, a quick question,
Is there a formula for the size and spacing of the wood sound treatment on your side walls?
If not, hey, i have a saw and a drill and i can do that tomorrow
Hi Paul,
Yes there is a computation but I pretty much eye-balled it. The slats are 1"x1" spaced about 2.5" apart. All isn't as it seems however. These are on falls walls that slant and curve away from the listening position. The further away the slats are the smaller the space the "seen" from the pointsource. The slant/curvature of the walls progressively makes the space nonexistent as far as the tweeters are concerned and become in effect a full reflector and not a diffuser as it is closer to the source.
As far as I know I'm the only one who has used this approach. So how does it work? Taking into consideration the left wall for instance: Close to the speaker the slats break the HF sound waves into large ripples, halfway down the beaming frequencies are trapped in what are essentially boxes with open lids 1"x1" within which some but not all the energy cancels out. Further out it becomes almost a flat plane that just reflects. The large ripples of greatest intensity also being farthest away from the listening position aids in localization by breaking up the first and strongest set of first reflections, the second area somewhat cancels out and the third reflects the signal from the near speaker, in this case speaker L to left and behind of the listening position and reflects the signal from the right speaker right and in front of the listening position. Careful positioning of the speakers however are required so as to minimize phase distortions and comb filtering at the listening position.
Notice I said SET of FIRST REFLECTIONS. Conventional wisdom has it that the first reflection point is where you would see the source (tweeter) in a mirror. I on the other hand consider the entire range of points where amplitude is strongest and fall within the confines of the Haas effect (up to five feet of travel distance). I then broke this area into 3. Why 3? I dunno I just like the number 3 I guess. It's small, it's odd and it's a prime number i like better than 2. maybe because I get a buzz at three beers and a headache with only two!
So why slats over absorption? They are prettier. That's all. Now this only helps with frequencies some 900hz and up. Something I had to live with until I could get my hands on midrange centered absorbers that fit the bill. Fortunately I was able to source some ASC panels from FLD in sunny Cebu. Behind the walls is foam in 4 sealed enclosures. The original plan was to take a jigsaw and cut away portions of the wall to later turn the wall into helmholtz resonators. The applied geometry however worked against this plan so it was abandoned in favor of the said panels.
There is also a reason why this approach is not exactly widely used. It is use specific. The Lair is VERY narrow and this approach is only really applicable when the loudspeakers are very close together and very far from the listening position. In other words, it isn't for everyone
In the end it does help BUT there is no substitution for a room with better dimensions, and while the 9's manage to sound open and layered even now, hearing Emperor's pair spaced much farther apart tells me that good as the system is it is not yet at it's full potential.