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Author Topic: Sub placement to optimize bass output in venue  (Read 4643 times)

austin tam

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Sub placement to optimize bass output in venue
« on: November 29, 2011, 01:03:31 pm »

I'm throwing a NYE part for roughly 350-400 people and would greatly appreciate some help with subwoofer placement.  The link below shows the floor plan I'm working with. 

The venue has 2 subwoofers in each of the rooms (2x in 2nd street gallery and 2x in zappa room).  I'm mainly concerned about 2nd street gallery.  I'm not exactly sure the specs and brand of the subs, but I believe they're sealed, have 3x 12 or 15 inch drivers in each enclosure, and stand roughly 4 ft high.

Currently, there is 1 sub placed in the top left corner (above the dj box in the floorplan) and another between the bar and stage on the lower left.  They're both placed on the floor, which doesn't seem optimal.  The bass response is fine when the room is empty, but becomes nonexistent when it is filled with people.  It doesn't seem the sound waves can penetrate the bodies. 

Would response be better if i were to put both subs on the stage (elevated about 1.5-2 ft)? 

Thanks in advance for the help.


http://www.111minnagallery.com/wp-content/gallery/minna-interior/minna_floor_plan2.jpg
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Paul G. OBrien

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Re: Sub placement to optimize bass output in venue
« Reply #1 on: November 30, 2011, 11:01:49 pm »

  I'm not exactly sure the specs and brand of the subs, but I believe they're sealed, have 3x 12 or 15 inch drivers in each enclosure, and stand roughly 4 ft high.
Sounds like the old EV MT series if you can see the backs of the drivers from the front, but otherwise they could be anything including homebrew boxes. Pics would help.

The bass response is fine when the room is empty, but becomes nonexistent when it is filled with people.
To me that says that the seperate sub locations are working against each other and only reason you get some bass in the empty room is due to surface reflections, when the room fills up the reflections are absorbed and the subs cancel each other out.

Would response be better if i were to put both subs on the stage (elevated about 1.5-2 ft)?
Maybe.. maybe not, placing them together may produce better results but you won't know until you try, it may take some experimentation to find the best arrangement. Also be sure to check that both subs(and all drivers) are wired for the same polarity, if bass output increases when one sub is turned off you have a problem somewhere.
« Last Edit: November 30, 2011, 11:09:20 pm by Paul G. OBrien »
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duane massey

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Re: Sub placement to optimize bass output in venue
« Reply #2 on: December 01, 2011, 01:17:37 pm »

Not familiar with any "name-brand" 3x12 boxes out there, so I'm guessing they might be DIY'ers.
Putting them next to each other will help somewhat, but I suspect there are more fundamental issues going on here. More info on full system, including pics or actual brands/models would be needed before anyone can actually give you useful advice.
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Duane Massey
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Glenn A Williams

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Re: Sub placement to optimize bass output in venue
« Reply #3 on: December 03, 2011, 09:38:47 am »

I'm throwing a NYE part for roughly 350-400 people and would greatly appreciate some help with subwoofer placement.  The link below shows the floor plan I'm working with. 

The venue has 2 subwoofers in each of the rooms (2x in 2nd street gallery and 2x in zappa room).  I'm mainly concerned about 2nd street gallery.  I'm not exactly sure the specs and brand of the subs, but I believe they're sealed, have 3x 12 or 15 inch drivers in each enclosure, and stand roughly 4 ft high.

Currently, there is 1 sub placed in the top left corner (above the dj box in the floorplan) and another between the bar and stage on the lower left.  They're both placed on the floor, which doesn't seem optimal.  The bass response is fine when the room is empty, but becomes nonexistent when it is filled with people.  It doesn't seem the sound waves can penetrate the bodies. 

Would response be better if i were to put both subs on the stage (elevated about 1.5-2 ft)? 

Thanks in advance for the help.


http://www.111minnagallery.com/wp-content/gallery/minna-interior/minna_floor_plan2.jpg

Coupling the subs will get you an extra 6db.....3 from coupling and 3 from having twice the power....THEORETICALLY! In truth perfect coupling is THEORY and if you achieved 4.5 db gain you would be fortunate.

Couple them to two surfaces (floor and wall) will get you another 3 db THEORETICALLY. Less than about 1 ft away

Couple them in a corner which is three surfaces, you will gain another 3 db, THEORETICALLY. As close as you can get them diagonally.

Try the speakers in the corners facing the audience or facing the corner.

These are the tools that you need to understand and experiment with. Try different corners and different wall placements. Other reflective surfaces in the room will affect these placements. The trick is to place them and listen through trial and error.

Start with corner placements since they MAY net you the greatest gain.

Cheers!

FYI: You may find more than one optimum place.
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Brad Weber

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Re: Sub placement to optimize bass output in venue
« Reply #4 on: December 03, 2011, 04:15:11 pm »

Coupling the subs will get you an extra 6db.....3 from coupling and 3 from having twice the power....THEORETICALLY! In truth perfect coupling is THEORY and if you achieved 4.5 db gain you would be fortunate.
What power are you doubling?
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Ivan Beaver

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Re: Sub placement to optimize bass output in venue
« Reply #5 on: December 03, 2011, 04:50:25 pm »

Coupling the subs will get you an extra 6db.....3 from coupling and 3 from having twice the power....THEORETICALLY! In truth perfect coupling is THEORY and if you achieved 4.5 db gain you would be fortunate.

Couple them to two surfaces (floor and wall) will get you another 3 db THEORETICALLY. Less than about 1 ft away

Couple them in a corner which is three surfaces, you will gain another 3 db, THEORETICALLY. As close as you can get them diagonally.

Try the speakers in the corners facing the audience or facing the corner.

These are the tools that you need to understand and experiment with. Try different corners and different wall placements. Other reflective surfaces in the room will affect these placements. The trick is to place them and listen through trial and error.

Start with corner placements since they MAY net you the greatest gain.

Cheers!

FYI: You may find more than one optimum place.
It all depends on the freq and the spacing of the subs.

if you already have 2 subs in the room, then you are neither doubling the cabinets NOR the power.  Or as Brad was implying-you do not have any more power (or any more cabinets)-it/they is already in use , so it does not add anything.

All you can do is choose what sort of compromise you are willing to deal with.

If you put them together, yes there will be less peaks and dips in the room, but the further you move away from them the quieter they will be.  Is that good?  maybe-it depends on the intended application.
If you space them apart, you will generally have more peaks and dips, but the overal level in the room will be more consistant.  Is that what you want?  It depends.

But in reagarding term of loudness, when you go from 1 to 2 subs AND they are close to each other (1/4w/l or less) AND you double the power-or apply the same voltage to each one-you will get 6dB-or really darn close.  But a good bit more than the 4.5dB you state.

Where does that number come from?  My experience say different.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

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ProSoundWeb Community

Re: Sub placement to optimize bass output in venue
« Reply #5 on: December 03, 2011, 04:50:25 pm »


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