Bose 901 Series ii

@asvjerry 

No. You'll have nothing like a modern line array no matter how many you stack up. A line array is a hell of a lot more that stacking a bunch of crap speakers in top of each other. Line array cabs and drivers are specifically designed for that purpose because the drivers need to be properly aligned from one cabinet to the next. If that proper alignment isn't achieved, you don't have a line array. You have a tall pile of garbage that's going to exhibit severe vertical comb filtering due to the source behaving in an incoherent way. 

kosst, granted....given the 901's design and intent, a stack of them would not be a 'perfect' line array.  It would be louder 'n hell but would exhibit all sorts of warts doing so....

Noting that a concert venue's arrays typically have a curvature, no doubt to minimize if not eliminate combing.  That, and they're meant for coverage and penetration of a large area, much larger than that of a 'typical' suburban listening space.  One might try that with a stack of 901's, but I've got my own predilections to play with and don't really have the desire to follow up on that...;) 

Given your comment, I'd suppose the bulk of 'line arrays' on the market (the tall, thin units with multiple small drivers) could be considered feces.  It would seem that combing would be impossible to avoid with them, which would really appall their owners.  Those who find them attractive no doubt like what they hear. *shrug*

Sets up an interesting conundrum, don'tcha think?  You either like it or you can't stand it.  Starts to sound like a lot of the equipment 'discussions' that become superheated on these pages, IMHO...

...as 'wrongheaded' as they may be...

Not trying to pick a fight with you, BTW.  Just observation and response...

Again, no, line arrays aren't curved to control combing. They're curved to provide fill in the near field. 

The entire definition of a line array is that the column act as a single acoustic source. The goal is to focus the energy and limit vertical dispersion. To do this the acoustic centers of the drivers must be closer together in the vertical plane than the wavelength of the driver's pass band. A primary difference between a common speaker for home or PA use and a line array segment is that the horns in a line array are carefully designed to emulate ribbons as much as possible. In short, having a bunch of domes or cones stacked up a plank of MDF does not a line array even remotely make, regardless of how much DIY'ers and some speaker companies claim it does. 

I'd suggest folks go read some white papers and research on the subject. 

Stacking 901s is not a line array in any shape or form.  However, I wouldn't be worried about comb effect interference from stacked 901s.  The majority of the sound is intentionally bounced off the rear wall making comb effects a non-factor.

Stacking 901's was common in Korea. A hallacious soundstage was the result.  901's are not designed to be pure and accurate - they are designed for musicality and large soundstage.  89% of the sound is reproduced by 8 drivers in the rear at specific angles to reproduce a lively experience. 11% of the sound is directly radiated at the listener.  This is where the amazing soundstage comes from when 901's are placed right. Your HK pre is likely the most limiting component.  I'd sell it and get a good 2/4 channel pre/pro that would match the 901's.  You may consider selling the Carver amp and get a Sunfire amp with 300W or more per channel.  Also comparable would be used Marantz or Denon amps which would be good matches for the 901's.  Bose had a demo room in Hawaii with generic entry-level components and high-end components - the listeners could not differentiate in direct A/B comparisons.