QSC KW181 stacking (placement) - NEED ADVICE!

Polarity is relative compared to the incoming signal.

Now that you know both switches are set the same, if you always use the same cables I would check that one of those doesn't have a polarity flip.

Initially if you are setting up by ear I wouldn't worry about a difference of six inches in placement. If you get a signal generator that can do a frequency sweep that would make it easier to hear if something is missing.

I would suggest setting up outside with your crossover in the same configuration/spacing you are going to use and running the sweep to make sure you are producing all frequencies fairly consistently. Then double check by playing your music.

If you have checked outside away from surfaces, when you move indoors and there is a problem and nothing else has changed in the setup then you know it is caused by the room.
 
Re: QSC KW181 stacking (placement) - NEED ADVICE!

Tim Weaver said:
Yes. Your subs will suck up the bass like a hoover.


Here's an article I wrote a while back about getting the most out of a meager system when you don't have the proper tools....
Live Sound: Tuning Without Tools: Working Through A System To Get It Up To Speed - Pro Sound Web
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So I used the crossover and tried running the subs stacked, and they sounded like shit. SO I think I might stick them on the sides of the table with poles and stuff. Usually gets good punch that way. What frequency do you guys suggest I use for the Low/Mid cut? (its technically a low/high cut) on the crossover. I tried 100Hz. What do you guys think?
 
Re: QSC KW181 stacking (placement) - NEED ADVICE!

Matt Gordon said:
I think it might be the crossover since I am sending a full signal to both subs and speakers, since the KW181s don't have a built in crossover or high pass output.

So then from the options, should I just put them coupled side by side, or under each speaker with a pole? I am hoping once I implement the crossover itll fix everything and give it that kick I was hoping for. Low crossover at 100Hz correct?
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Put full-range audio into both the KW181 and the tops. The KW181 has a built-in, full-time 100 Hz low-pass filter. Set the tops to "EXT SUB," which will engage a 100 Hz high-pass filter that complements the sub's filter.

Putting subs on each side gives you the proverbial "Bass Alley" right up the middle (i.e., equidistant between them, where their sound is in-phase at all frequencies) and varying bass response off to the sides. If it's possible to put them tight together, whether side-by-side or stacked, do so. Sometimes, though, physical constraints of the venue require doing left and right subs, and you have to make do with that situation.
 
Bob Lee said:
Put full-range audio into both the KW181 and the tops. The KW181 has a built-in, full-time 100 Hz low-pass filter. Set the tops to "EXT SUB," which will engage a 100 Hz high-pass filter that complements the sub's filter.

Putting subs on each side gives you the proverbial "Bass Alley" right up the middle (i.e., equidistant between them, where their sound is in-phase at all frequencies) and varying bass response off to the sides. If it's possible to put them tight together, whether side-by-side or stacked, do so. Sometimes, though, physical constraints of the venue require doing left and right subs, and you have to make do with that situation.
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It's "power alley".
You get areas of bass and areas of poor bass.
Yes, at equidistant from both sides is good but unfortunately both ears are not in the center of our face, and we don't stand very still. A few inches from center you get comb filtering.

This is not to say that a sub & top on each side doesn't work out ok for some people but the physics say there will be problems which is why it is often suggested to put both sub together.



Sent from my iPad HD
 
Re: QSC KW181 stacking (placement) - NEED ADVICE!

Considering the wavelengths of the sub frequencies, ~ six inches of left-right separation between our ears doesn't actually make a significant difference in the bass alley/power alley (whichever you wish to call it) effect along the equidistant axis between left-right subs. Off-axis, the sub frequency response will vary. Subwoofer-region lobes are quite broad in the near field, which would cover the entirety of many small rooms.
 
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