Craig: To reduce “power alley” we have to have horizontal directional control at LF. Difficult to do unless the array is large. Possible but complex.
Also RE power alley reduction we need asymetrical horizontal pattern control of the array with LF angled off stage considerably and HF and mids unaffected. Tricky. Steering subs is much easier by simply adding delay to the outer subs and “decorrelating” the summation down the center line.
Moderator: Would it be possible with, say, 8 boxes?
Craig: What 8 boxes? (product?)
Moderator: Any box with 2 front-loaded woofers.
Craig: Assuming 8 (dual 15” vertical placed) boxes a side horizontally placed, then you would get substantial horizontal inconsistency in LF performance. This could be mitigated by frequency shading the outer drivers but then you would lose LF output. You can test this out by down loading the EV Array Show program from the EV site. It’s free and a great education.
Weogo Reed: What about simply placing all subs on one side of the stage? Get rid of power alley and have a little more volume on one side and lower on the other?
Craig: Putting subs to one side would sound pretty weird, I think. Rather steer the beam a little.
yamama3000: If subs are ground stacked you get a +3-6 dB through coupling…is the 6 dB drop part of this equation?
Craig: No, the 3 dB (half-space loading) does not affect the horizontal null at all. You would get the same result with the subs in the air. (Keeping in mind that the stage position would then be asymmetrical to the array null.)
Tucci: To get the subs decorrelated, how much phase change/time are you talking about? You’d want the outer subs to show up “late” at the center line. That could be a significant amount of time, no?
Craig: Time and wavelength are simply two sides of the same coin. The wavelength at 60 Hz is around 16 feet, so if you added 4-6ms of delay you would get significant beam steering.
yamama3000: To the outer boxes only…correct?
Craig: Yes, the outer boxes only. Of course if you wanted to impress the guest engineer, you could align all of the time to point subs at the mix location…
Denny Strauser: What proportion of boxes must be delayed for effective steering?
Craig: Impossible to answer without more info as to the number of boxes, size of boxes, etc.
Tucci: How about doing it the inexpensive way? If 4 ms is 90 degrees at 60 Hz, why not just turn the outer sub at a right angle?? Clever eh?
Craig: Tucci, you jest of course….
Tucci: Yes, of course.
yamama3000: And to add to Denny’s question: Will Smaart help in the equation?