...a long threatened 'experiment' comes to fruition...
Just some particleboard scrap utilized to create a vertically aligned pair of drivers; not elegant but suitable. A pair of units, the top with it's cone base connected with a 'sleeve' to a second, upside down. Base to base, to see what would occur.
It's just as I thought....there is no noticeable negative effect with regards to gross cancellations of response, at least in a listening test. If anything, volume/spl seems to be augmented...which IMHO relates as to why GP 'pairs' their DDD units and indicates such in their specs.
Because of the difference in size of the cones of my drivers, there seems to be an 'evening out' of the tonality, much like what we'd experience with different driver sizes with a conventional speaker. If there's anything going on that's perhaps not apparent without 'getting deep', there may be the condition of the cones moving towards each other in the lower frequencies being cancelled out. If the seal between the two was airtight (which it certainly isn't now), any tendency to 'push air' as with a conventional driver might be damped out. Just thinking...
If there's anything noticeable that's a negative, the spatial qualities at the intersection/collar at the bases create a 'null zone' in the near field, say 1~4'. Not surprising, that. The radiation pattern tends to be tilted 'up' from the cones, more or less at a right angle from the cone's angle.
...but fun to play with, none the less....*G*
Next variant: Mount the units reversed from as shown, but spaced apart vertically...think of the lower unit above the upper one, but say 3~4' apart.
Will the created dispersions 'blend' better, much like the interaction of the T/M/W of a conventional speaker? My experience with my little clones says they will....stay tuned.
Just some particleboard scrap utilized to create a vertically aligned pair of drivers; not elegant but suitable. A pair of units, the top with it's cone base connected with a 'sleeve' to a second, upside down. Base to base, to see what would occur.
It's just as I thought....there is no noticeable negative effect with regards to gross cancellations of response, at least in a listening test. If anything, volume/spl seems to be augmented...which IMHO relates as to why GP 'pairs' their DDD units and indicates such in their specs.
Because of the difference in size of the cones of my drivers, there seems to be an 'evening out' of the tonality, much like what we'd experience with different driver sizes with a conventional speaker. If there's anything going on that's perhaps not apparent without 'getting deep', there may be the condition of the cones moving towards each other in the lower frequencies being cancelled out. If the seal between the two was airtight (which it certainly isn't now), any tendency to 'push air' as with a conventional driver might be damped out. Just thinking...
If there's anything noticeable that's a negative, the spatial qualities at the intersection/collar at the bases create a 'null zone' in the near field, say 1~4'. Not surprising, that. The radiation pattern tends to be tilted 'up' from the cones, more or less at a right angle from the cone's angle.
...but fun to play with, none the less....*G*
Next variant: Mount the units reversed from as shown, but spaced apart vertically...think of the lower unit above the upper one, but say 3~4' apart.
Will the created dispersions 'blend' better, much like the interaction of the T/M/W of a conventional speaker? My experience with my little clones says they will....stay tuned.