Yes, Marco you can look here for the plans(in metric, and INSIDE DIMENSIONS).
http://kosat.consultit.no/~ketil/lowther/voigtpip.html
Those are the original Lowther Club of Norway plans, and are the correct ones. Stick with those. The only beneficial mod to make, is to use my "swinging door" mods on the sides of the baffle-board, to extend the width for eliminating baffle-step losses that are common to narrow cabinet designs. Makes the bass much better. They do not ever swing forward of the baffle face, but can be angled backwards to reduce the bass augmentation for certain records. Contact me if you are going to make these.
IMO, these with either Fostex or Lowther, on your 300B will have those "twin dishwashers" permanently in the storage room.
Here's the rationale. Basically, when you remove the crossover from the speaker system, you are then achieving the same result as "active" speakers. You directly control the driver from the amp, with nothing in between. Big difference. Also, the traditional problems with crossovers and driver overlap are eliminated. Another big difference. Especially since the LaScala crosses over right in the middle of the vocal midrange. Third, you will get just as much top end extension(with Lowthers) and the (40Hz)bass will go lower than your LaScala's. Efficiency is very close, with the Lowthers doing about 100db/watt in the Voigt Pipe cabinets. And, there is a certain technical "synergy" between the SET amp and single driver speaker, that is just unmatchable with any other type of speaker on a SET. They are "made for each other", and you won't ever hear your SET better than on a pair of fullrange single-drivers. This is where the "magic" is.
One caveat: Lowthers and other single drivers take a VERY long time to break in. At the start, the bass is poor. They are stiff, and tight tolerances, so you have to start at low volumes, and then increase SPL over the first 30-50 hours. They don't come into their own till after 100-200 hours, and are not fully broken in until after 500 hours. This is very real, and not a "psychological effect".
http://kosat.consultit.no/~ketil/lowther/voigtpip.html
Those are the original Lowther Club of Norway plans, and are the correct ones. Stick with those. The only beneficial mod to make, is to use my "swinging door" mods on the sides of the baffle-board, to extend the width for eliminating baffle-step losses that are common to narrow cabinet designs. Makes the bass much better. They do not ever swing forward of the baffle face, but can be angled backwards to reduce the bass augmentation for certain records. Contact me if you are going to make these.
IMO, these with either Fostex or Lowther, on your 300B will have those "twin dishwashers" permanently in the storage room.
Here's the rationale. Basically, when you remove the crossover from the speaker system, you are then achieving the same result as "active" speakers. You directly control the driver from the amp, with nothing in between. Big difference. Also, the traditional problems with crossovers and driver overlap are eliminated. Another big difference. Especially since the LaScala crosses over right in the middle of the vocal midrange. Third, you will get just as much top end extension(with Lowthers) and the (40Hz)bass will go lower than your LaScala's. Efficiency is very close, with the Lowthers doing about 100db/watt in the Voigt Pipe cabinets. And, there is a certain technical "synergy" between the SET amp and single driver speaker, that is just unmatchable with any other type of speaker on a SET. They are "made for each other", and you won't ever hear your SET better than on a pair of fullrange single-drivers. This is where the "magic" is.
One caveat: Lowthers and other single drivers take a VERY long time to break in. At the start, the bass is poor. They are stiff, and tight tolerances, so you have to start at low volumes, and then increase SPL over the first 30-50 hours. They don't come into their own till after 100-200 hours, and are not fully broken in until after 500 hours. This is very real, and not a "psychological effect".