One Sub, Two Tops Advice

My speakers are in the beginner bracket:- 2x Mackie Thump 15a 1x Mackie Thump 18s

The manuals differ from the diagrams on the speakers & I’ve seen several conflicting methods. Up to now, I come out of the Prime 4 & into the tops (with the button set to sub). Out from the tops & into the sub.

I see many coming out from the mixer/controller & into the sub & then out (high pass) into the tops.

  1. Which is most ideal?
  2. Also, anyone else with mackie thumps & if yes, do you set gain to line (10 o’clock) or at midnight unity?
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Don’t know specifically how those speakers work but I personally go into the sub first, use the crossover to cut all the top end from the sub then use the pass through into the monitors, with about 20hz frequency bleed between them.

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As above go into sub first. The crossover in the sub will be better than the crossover in the tops. And its easier to balance.

plus, on the sub you have both the possibility of using a through output or a highpass output.

normally you would use the highpass output, so that you don’t have timing issues between the crossover from the tops and the crossover from the subs. If you use the link out on the tops yuou have 2 seperate crossover networks. On the other hand, a 18 inch subwoofer has different phase response than a 15 inch midwoofer, so the timing is distorted anyway. You could use smaart live to measure this or that, but in the end, as a novice user, not specialized in audio processing, it’s best to rely on the settings given in the manuals from Mackie, rather than believe anyone on this forum.

Oddly enough, indeed, the manual says to go to the tops first, and then to the subs. I admit it is weird, but when you take timing and phasing issues into account as stated above, it could very well be that mackie discovered that this routing gave the best overal phase response…

Google: smaart phase aligment - Google Search

Oh, and PS: well, the volume of your sub is usually adjusted to taste, and thats usually louder than a flat response anyway. But if you read up about phase alignment, ,you discovered that shifting the volume between sub and top shifts the crossover point, and thus the phase alignment. You can only guess for what gain Mackie did their tests, if they did any.

Interesting matter, professional sound reinforcement =D

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Thanks for the comments. I don’t have much understanding in this field & just go by the manuals but as stated, Mackie seem to have conflicting set up guides.

I might try the route of going into the sub from my P4 & then high pass into the tops.