Dual subwoofers placement, in real life

[jallejulius]

Hi!

My band have a gig coming and it will be the first time where we will use a dual subwoofer setup.

In total, we will bring 2 Alto tops (TS315) and 2 Alto subwoofers (TS318s).

We play rock covers from the 80-00's and every instrument goes into the PA, we even use electronic drums. Guitars goes into Helix/BossGT units and the bass has a similar setup before going into the PA, we don't need or use any wedges or amps on stage. We also use IEM's for personal mixes.

So now its time for us to decide if we should couple the subs in the middle or place them under the tops.

What I have read so far is that (in theory) its better to couple the subs together in the middle but here is my questions:

1) In real life, in a closed space with walls, ceiling, close to 200 people does it REALLY make a difference with sound bouncing all over the place anyway??

2) If it makes a difference, like gives us a 3 dB gain in the low frequencies, doesn't that mess up the total mix?? If we suddenly add 3 dB below 100 Hz, it must mess upp our mix of drum/bass with the guitars/vox (In theory at least)?

3) If we put the subs under the tops, that will give us:
a better look, more space on stage, less cables running across the stage, less gear to carry (tripods) and it will be an easier to setup overall. Besides that, the DSP is configured to work best with the subs under the tops. How does these benefits compare to the coupling effect?

How would you place the subs?

And btw, here is the venue where we are going to gig.



Thank you very much!

Cheers!

 

[s0c9]

If it were me... I'd just put the subs under the tops and be done with it.
Center clustering won't buy you much in a room that size, but they WILL block folks access to the band.
Just make sure you elevate the tops to get them above peoples heads (or at least head high).
Then set up the DSP's on tops and subs appropriately. I would NOT start with the subs "Extended LF" turned on.
Set Vol at 0db for starters.
Plug your console Left out into left sub and daisy chain sub TO top. Repeat for right side.
You should have plenty of headroom on the system for that room.
have fun!

 

[Wasnex]

Hi!

My band have a gig coming and it will be the first time where we will use a dual subwoofer setup.

In total, we will bring 2 Alto tops (TS315) and 2 Alto subwoofers (TS318s).

We play rock covers from the 80-00's and every instrument goes into the PA, we even use electronic drums. Guitars goes into Helix/BossGT units and the bass has a similar setup before going into the PA, we don't need or use any wedges or amps on stage. We also use IEM's for personal mixes.

So now its time for us to decide if we should couple the subs in the middle or place them under the tops.

What I have read so far is that (in theory) its better to couple the subs together in the middle but here is my questions:

1) In real life, in a closed space with walls, ceiling, close to 200 people does it REALLY make a difference with sound bouncing all over the place anyway??

2) If it makes a difference, like gives us a 3 dB gain in the low frequencies, doesn't that mess up the total mix?? If we suddenly add 3 dB below 100 Hz, it must mess upp our mix of drum/bass with the guitars/vox (In theory at least)?

3) If we put the subs under the tops, that will give us:
a better look, more space on stage, less cables running across the stage, less gear to carry (tripods) and it will be an easier to setup overall. Besides that, the DSP is configured to work best with the subs under the tops. How does these benefits compare to the coupling effect?

How would you place the subs?

And btw, here is the venue where we are going to gig.



Thank you very much!

Cheers!

I agree with @s0c9 . Live audio is about choosing the best compromise. So although there are advantages to center packing the subs, there are also disadvantages. In this case, I think running the subs L/R is the way to go. If you were performing on a stage in a bigger room, it might be better to center pack.

 

[JRA]

s0c9 and Wasnex have you covered, OP! best of luck on your gig! post a gig report!

 

[walterw]

center-coupling subs is cool when the stage layout is right, you get better, more even thump with no "gaps" in the low end out in the room (and no it doesn't mean you have to re-configure your mix all that much).

when you can't do it because the stage layout isn't right then no big deal, in a bar or whatever you're getting so much room gain and bounce-around that the difference isn't night and day, certainly not enough to suffer with blocking the view of the band or anything.

 

[jad]

Indoors with bunch of people who've been drinking I go with tops over subs because they're more secure that way than on stands, and because the cancelations you get are pretty much negated by room reflections (as Walter said). Outdoors I prefer to cluster the subs for increased output and to eliminate interference between them. There is also generally more room at outdoor events, so I'm less nervous about having the tops on stands.

 

[Chad Michael]

Don't care what looks right or is convenient, center them to even the room. I hate power alley.

Better low end sound is noticed by those who really care that live music should sound excellent everywhere ...

Also (comma) listen to the man who lives the obsession, search Dave Rat on utoob

 

[walterw]

Don't care what looks right or is convenient, center them to even the room.

yeah but the band might if there's a low stage (or no stage) and they're half hidden from the crowd behind your subs

ideal sound is not the only consideration to what makes for a good show

 

[jallejulius]

Hi!

Thank you all very much for your help!

I have read a lot on this subject and I can see how the power alleys are created with dead spots around the room and so on when two subs are separated. My issue here is how to weight the pros and cons of coupling the subs vs have them separated in this room.

I can definitely see the benefits of having them separated, but I don't know how to weight this to the cons of power alleys and dead spots around the room.

Would the power ally really be noticeable? Would there even be a noticeable difference at all? I mean the calculations are all made in an open space, with no people, no sound comping from the tops, no walls/ceiling and a constant stream of frequencies, but that's far from what it will be in a gigging scenario.

I'm not here to argue about the coupling effect, I'm just curious about how the theory applies in real life, when there are a lot more to take into consideration (in this scenario).

So far, it seems like its 5-1, even though noone is saying your are wrong @Chad Michael. And thank you for your suggestions about Dave Rat, I have already watch his videos regarding this topic

 

[walterw]

My issue here is how to weight the pros and cons of coupling the subs vs have them separated in this room.

judging by that small hard-floored space, worries about power alley are way down the list!

it looks like you could cover it with one sub, no drum mics except maybe kick, and the snare drum is probably still gonna be too loud

there's no stage to center-pair subs in front of and no need for extra volume to begin with.

(edit: i missed that it was all direct + E-drums + IEMs, so no stage volume to speak of. that certainly makes it easier in that loud reflective room.

if you're trying for extra thump you might try a trick i used to do in small rooms where i would stack my two single 18 subs up on one side with a top box set on top, then use a stand for the other top box on the other side of the stage. i got the benefits of clustered subs without them being in the way of the band. since sub frequencies are mostly omnidirectional it didn't matter as much where the sub was in the room.)

 

[Ggaa]

Friend of mine set up an Alto system for a club. Subs on the bottom of the stacks.

 

[Jack]

We have almost exactly the same system, just the previous generation. We normally have the subs under the tops. For all of the reasons everyone already knows, center clustered is better. 1 per side is more practical.

Venue permitting, we'll often do one side that has two subs and the top all stacked and then the other side with just a top. We have a couple of venues where the stage is off to a side so the subs on one side of the stage is center-clustered as far as the venue is concerned.

 

[Downunderwonder]

yeah but the band might if there's a low stage (or no stage) and they're half hidden from the crowd behind your subs

ideal sound is not the only consideration to what makes for a good show

if a couple of subs is obscuring the punters' view of the performers in a 200 punter room you are playing to a midget convention or your subs escaped from a outdoor arena gig.

 

[jallejulius]

We have almost exactly the same system, just the previous generation. We normally have the subs under the tops. For all of the reasons everyone already knows, center clustered is better. 1 per side is more practical.

Venue permitting, we'll often do one side that has two subs and the top all stacked and then the other side with just a top. We have a couple of venues where the stage is off to a side so the subs on one side of the stage is center-clustered as far as the venue is concerned.

1)
Have no noticed any power alleys or drop of bass when you put the subs under the tops? How much of a difference would you say it make?

2)
Are you happy with the Alto speakers? How much of a headroom would you say we have in this room? How many guests can you usually do without pushing the speakers to hard?

 

[Wasnex]

if a couple of subs is obscuring the punters' view of the performers in a 200 punter room you are playing to a midget convention or your subs escaped from a outdoor arena gig.

It's not necessarily about obscuring the view, it's about creating a barrier. Or perhaps it would be about the view if the lead vocalist has fabulous shoes

Hi!

Thank you all very much for your help!

I have read a lot on this subject and I can see how the power alleys are created with dead spots around the room and so on when two subs are separated. My issue here is how to weight the pros and cons of coupling the subs vs have them separated in this room.

I can definitely see the benefits of having them separated, but I don't know how to weight this to the cons of power alleys and dead spots around the room.

Would the power ally really be noticeable? Would there even be a noticeable difference at all? I mean the calculations are all made in an open space, with no people, no sound comping from the tops, no walls/ceiling and a constant stream of frequencies, but that's far from what it will be in a gigging scenario.

I'm not here to argue about the coupling effect, I'm just curious about how the theory applies in real life, when there are a lot more to take into consideration (in this scenario).

So far, it seems like its 5-1, even though noone is saying your are wrong @Chad Michael. And thank you for your suggestions about Dave Rat, I have already watch his videos regarding this topic

In such a small room, the power alley and comb filtering is unlikely to be a problem. As you alluded to earlier, the sound will be bouncing around off the ceiling, floors, walls, etc and moving in all directions randomly.

Also the relatively narrow spacing between the subs will minimize the comb filtering. The interference patterns are determined by the distance between the drivers and the wavelength. And of course wavelength is frequency dependent. The ramification of this is you can create the same interference patterns at different frequencies by varying the spacing between the drivers.

I have attached a bass array guide that you may find interesting and informative. I suggest you reread the last sentence of the previous paragraph, and then compare figures 42 to 43 and 44 to 45. Note the frequency and spacing between the cabs and the similarity of the dispersion patterns.

Ultimately if you are going to play this room regularly, try it both ways and make an informed decision. Perhaps you should arrive early and play some program material while you move the subs around.



.

 

[Jack]

1) Have no noticed any power alleys or drop of bass when you put the subs under the tops? How much of a difference would you say it make?

Honestly I couldn't say. That band play too loudly in rooms that are too small and not really designed for music. I haven't noticed, that doesn't mean it isn't happening. I think there are too many confounding issues on those kinds of gigs and I can't point to a power alley specifically. There probably have been situations where the better pattern control of center clustered subs would have helped.

2) Are you happy with the Alto speakers? How much of a headroom would you say we have in this room? How many guests can you usually do without pushing the speakers to hard?

Extremely. We have the 2 each of the TS115A and the TS118A and they're great. They're admittedly not the last word in out and out refinement (my other band use a quite nice RCF system and the difference is sometimes noticeable) but they work very well for us: they sound great and they're loud enough. We tend to run indoor gigs of up to around 200 people with them.

We did a party a while back where our guitarist's son sat in for a song or two. Here's a video that mostly focuses on wee Ethan, but at least he's standing next to the PA system! It goes back a long way behind the bar, there's somewhere between 80 and 100 people there. Minimum stage volume, the PA has loads left to give

 

[Chad Michael]

yeah but the band might if there's a low stage (or no stage) and they're half hidden from the crowd behind your subs

ideal sound is not the only consideration to what makes for a good show

Are you stacking double 18's or something?

 

[Chad Michael]

ideal sound is not the only consideration to what makes for a good show

Yes, it is, and should be, if live music is to survive. Video killed the radio star. It absolutely must sound good if you expect return guests.....

 

[Chad Michael]

Put both subs on one side if that makes you feel good about your image.

 

[And I]

do you need both subs to fill the small-to-medium-sized room with bass? put them under the mains for logistics, and only run one of the two subs...