Line array behavior with corner placement

[johninCR]

When placed in a corner (essentially floor to ceiling) would a line array get any 1/8 space loading or just 1/4 space loading ? My guess is 1/4 space only, but I'm hoping for corner loading in the bass frequencies.

[simon5]

Well, you'll get 1/4 loading under some frequency, then you'll get 1/8 loading under the frequency where the wavelength is longer than the height of the ceiling I guess.

[bobhayes]

I would reckon you'de be radiating into considerably less than 1/8 space, if your array had closely spaced drivers from wall to ceiling, as 1/8 space is a single source driving along three surfaces at 90 degrees.
Your theoretical array would be effectively radiating into a more confined space, similar to a very large parallel sided horn flare.
Sounds like a very efficient driver/room coupling strategy to me!

[johninCR]

Originally posted by bobhayes
Sounds like a very efficient driver/room coupling strategy to me!

I didn't want to complicate matters further, but I'm trying to model stacks of corner horns forming a line array with the horn functioning from 100hz down. Then it started to dawn on me that I probably wouldn't get corner loading. I was just hoping for some 1/8 space effect, but I believe that won't occur since line array dispersion is very limited in the vertical axis.

[simon5]

Well, the woofers near the top and near the bottom will get 1/8 and center woofers will get 1/4.

In the end, maybe you'll get about 1/6 so 4 or 5 dB gain instead of 3 or 6 dB.

[johninCR]

Every little bit helps when you are trying to get flat to 30hz and don't have room gain due to an open floor plan.

[Bill F.]

As I understand it, the advantage of a corner line array (having both a ceiling and a floor image) is that it should behave much like an infinitely tall array (= nearfield everywhere), usable up to the frequency where the individual elements decouple.

But an array isn't required for better than 8th-space loading down low. Even just a single sub in a corner should roll on an additional ~6dB up to WL>2x ceiling height due to the ceiling image.

(All this assumes perfectly rigid room surfaces and leaves out reflections from the other two walls.)

[bobhayes]

In which case, making the said system into a three way system with six midrange drivers in a wmmmtmmm array with the woofer at the base would make a really nice speaker eh?
Might make one some day.

[johninCR]

The reason I was asking is that I've been modelling some arrays that are also rear loaded corner horns with upper cutoff of the horn being 100hz. Some of the different drivers showed flat extension down into the 20's with 1/8th space loading, and went high enough to cross to a tweeter. I'm talking about 105db sensitivity from 25hz on up using very little floor space (about 50cm X 50cm in a corner).

The problem with more suitable drivers for deep extension is that they lack the efficiency to keep up with the rest of the array. Otherwise it would be easier to just stick some bass drivers at the top and bottom of the array.

Oh well, back to the drawing board to model in 1/4 space.