What next?

I have already decided that I will build at least one more pair of Asawaris. This time, I want to experiment with fourth-order crossovers at a lower Fc: I'm thinking of 2KHz. I will need to shift to other tweeters: I intend to use the North D25 fabric dome tweeters now, which can comfortably handle a fourth-order crossover at 1600Hz. The current Peerless India TG25 metal domes won't behave well at 2KHz.

The next thing I want to change is the low frequency alignment. I'm thinking of reducing the enclosure volume by 20-25%, to get a more traditional bass reflex alignment, at the cost of a bit of bass extension at the very low frequencies.

The third thing I want to try is 25mm MDF instead of the current 18mm plywood for the outer walls and baffles of the enclosure. The internal bracing will still be 18mm marine plywood -- MDF is pretty useless for bracing of this kind, it's too soft. Why do I want to try using MDF, knowing that the first Asawari sounds quite lovely with an all-ply construction? I don't really know, but I just want to see if it makes any major difference. My front baffles are currently two layers of 18mm plywood, plus one layer of veneer (which, in India, is 4mm thick). With the MDF approach, I will have two sheets of 25mm MDF plus one sheet of veneer.

The fourth thing I want to change is the addition of a separate air-tight tweeter chamber. I want the tweeter to be acoustically isolated from the backwave of the midbass drivers.

I have begun to feel that for designers at my level, the quality of the final speakers depends on three factors in roughly the following ratio:

• driver selection: 10%
  
• making a really dead enclosure: 40%
  
• designing a good crossover and tuning it carefully: 50%
  

Driver selection really doesn't influence the sound as much as the other two factors, provided your drivers don't have obvious problems, like midbass units for passive speakers with a Qts of 1.0, or major cone breakup issues. Making a really dead enclosure is a big challenge, specially if you are building speakers with 4'x2' side panels like the Asawari, where the entire wall becomes a radiating surface. And crossover tuning is so amazing that it's as if the speaker transforms from one beast to another quite different. I am sure that if I had more energy and brains, I could have tweaked the Asawari's crossovers even further.

Wish me luck. :)

(Originally written on 10 Aug 2006)