subwoofer alignment

Shane Presley

Shane Presley

Senior
Jan 12, 2011
909
0
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Ottawa, Ontario, Canada
www.bssproductions.com
So I have a national act in august, and I want to suppliment the low end with dissimilar boxes.... I've asked this question before, and I've gotten every response under the sun, except for something that was helpful.
No I can't sub rent any more Sb's, yes that would be the obvious choice...
No I can't call Clair bros, and get a proper sized rig....
It's just my stuff, and it's a small country fair, and I'm trying to give the BE enough bottom so he doens't complain, or blow up what I do have....
It's an open field, expecting around 1000, 1500 peeps max... 6 KF730 flying over 4 SB1000z.
What I am trying to do is throw my tx-9s in the front, on an aux for kick / bass... Any thoughts on how I can get these two to line up close enough without using SMAART.?
Thanks
SP
 
Re: subwoofer alignment

Shouldn't be too hard to do, as long as you can get a separate send for the tx9's. They're all front loaded cabs, so I imagine a few ms of delay and you'll be rocking. You'll just have to start with everything at 0 and delay the tx9's a ms at a time and listen.



Evan
 
Re: subwoofer alignment

Shane Presley said:
So I have a national act in august, and I want to suppliment the low end with dissimilar boxes.... I've asked this question before, and I've gotten every response under the sun, except for something that was helpful.
No I can't sub rent any more Sb's, yes that would be the obvious choice...
No I can't call Clair bros, and get a proper sized rig....
It's just my stuff, and it's a small country fair, and I'm trying to give the BE enough bottom so he doens't complain, or blow up what I do have....
It's an open field, expecting around 1000, 1500 peeps max... 6 KF730 flying over 4 SB1000z.
What I am trying to do is throw my tx-9s in the front, on an aux for kick / bass... Any thoughts on how I can get these two to line up close enough without using SMAART.?
Thanks
SP
Click to expand...

Shane,

6 KF730 / 4 sb1000 per side? if so this doesn't side like its light on the low end for a country fair...

Without using smaart you can do the tone+ out of phase + db meter trick with the low end to get it to line up. Is that trick as good as smaart? No, but it will get it done....
 
Re: subwoofer alignment

Shane Presley said:
So I have a national act in august, and I want to suppliment the low end with dissimilar boxes.... I've asked this question before, and I've gotten every response under the sun, except for something that was helpful.
No I can't sub rent any more Sb's, yes that would be the obvious choice...
No I can't call Clair bros, and get a proper sized rig....
It's just my stuff, and it's a small country fair, and I'm trying to give the BE enough bottom so he doens't complain, or blow up what I do have....
It's an open field, expecting around 1000, 1500 peeps max... 6 KF730 flying over 4 SB1000z.
What I am trying to do is throw my tx-9s in the front, on an aux for kick / bass... Any thoughts on how I can get these two to line up close enough without using SMAART.?
Thanks
SP
Click to expand...

You could always call someone with a SMAART rig *hint* *hint* :)

Jason
 
Re: subwoofer alignment

Evan Kirkendall said:
Shouldn't be too hard to do, as long as you can get a separate send for the tx9's. They're all front loaded cabs, so I imagine a few ms of delay and you'll be rocking. You'll just have to start with everything at 0 and delay the tx9's a ms at a time and listen.
Click to expand...

Agreed, if using similar types of cabinets over similar bandwidths you can probably just delay based on physical distances. Of course, out on the field you're working in two dimensions, so just delay until it's correct where you want it to be.
 
Re: subwoofer alignment

Bennett Prescott said:
Agreed, if using similar types of cabinets over similar bandwidths you can probably just delay based on physical distances. Of course, out on the field you're working in two dimensions, so just delay until it's correct where you want it to be.
Click to expand...
The problem starts when the phase response of the cabinets is dissimilar.

Simply adjusting the time will allow part of the freq response to be louder (ie work together), but it is very probable that there will be cancellations at other freq. Actual measurements would be the only way to be sure of course.

The problem with doing a simple "tone and cancellation method" is that yes you may get better summation around crossover freq-but there may be notches on either side-that can only be seen during measurement.
 
Re: subwoofer alignment

can you simply use some of the cabs for mid/upper bass and the others for lower/sub bass? Whichever cabs you think are better for lows, cross them over at LP 60 and the rest can do BP 50-100hz?
 
Re: subwoofer alignment

Tim Duffin said:
can you simply use some of the cabs for mid/upper bass and the others for lower/sub bass? Whichever cabs you think are better for lows, cross them over at LP 60 and the rest can do BP 50-100hz?
Click to expand...

It is true that there can be a power advantage to splitting the sub region into two passbands. However, if the OP doesn't have or know how to use a copy of Smaart in order to do something as routine as a sub/mains alignment, I don't think adding another set of crossovers is going to make the problem easier to deal with. We're only talking about an octave or so of bandwidth here anyway, at some point the HPF and LPF begin to interact with each other too much!
 
Re: subwoofer alignment

Bennett Prescott said:
It is true that there can be a power advantage to splitting the sub region into two passbands. However, if the OP doesn't have or know how to use a copy of Smaart in order to do something as routine as a sub/mains alignment, I don't think adding another set of crossovers is going to make the problem easier to deal with. We're only talking about an octave or so of bandwidth here anyway, at some point the HPF and LPF begin to interact with each other too much!
Click to expand...
I wont take that as an insult at all bennett lol
I in fact have two ux8800s which i could route or bandpass whatever i wanted. The fact that i have yet to sit down and figure out the all mighty smaart is well... . Between my sound business and i play in a band myself and i have a 9-5 day job that isnt sound and a wife and... You get the picture. Learning smaart isnt high on my totem pole. Thats why i come here for real world solutions. I dont have 2 hrs in the field to worry if the cabs are turly aligned at 35ms instead of 30. In the ballpark is good enough for me and the other 99.9% of the attendees
 
Re: subwoofer alignment

Trying not to sound like a broken record.
Have you considered a Maxxbass? With that kind of setup, a well utilized unit could give that system the ability to establish quite a solid "Pillow" of low end that will especially go well in your show scenario. Mixed age crowds will not complain and those wanting to feel power will be happy. Great for other than full throttle volume shows.
 
Re: subwoofer alignment

John Chiara said:
Trying not to sound like a broken record.
Have you considered a Maxxbass? With that kind of setup, a well utilized unit could give that system the ability to establish quite a solid "Pillow" of low end that will especially go well in your show scenario. Mixed age crowds will not complain and those wanting to feel power will be happy. Great for other than full throttle volume shows.
Click to expand...

If Shane wants to give that a try he can borrow mine, though he'd want to clear it with the BE. I am a fan of it, but it doesn't work in every situation.
 
Re: subwoofer alignment

Shane Presley said:
So I have a national act in august, and I want to suppliment the low end with dissimilar boxes.... I've asked this question before, and I've gotten every response under the sun, except for something that was helpful.
No I can't sub rent any more Sb's, yes that would be the obvious choice...
No I can't call Clair bros, and get a proper sized rig....
It's just my stuff, and it's a small country fair, and I'm trying to give the BE enough bottom so he doens't complain, or blow up what I do have....
It's an open field, expecting around 1000, 1500 peeps max... 6 KF730 flying over 4 SB1000z.
What I am trying to do is throw my tx-9s in the front, on an aux for kick / bass... Any thoughts on how I can get these two to line up close enough without using SMAART.?
Thanks
SP
Click to expand...

What type music? What you using to power those SB1000's?

Wouldn't 4 properly powered and processed SB1000's handle up to 1500? Would centered subs help?
 
Re: subwoofer alignment

Put the mix position in a spot where you know is a hot zone! Trick the BE into thinking that there is more than there actually is- hopefully that guy will know what happens in a field of low frequency propagation as far there being pockets of voids. Put a tent over his head and tell him it can't be taken down. Hide a single 18" sub under the desk.

Just in case you didn't want to lug more gear out there :)

Even if you didn't have smaart you could set-up the system as normal and watch a simple RTA as you add the subs to be sure that you are being constructive with your additional LF drivers. All jokes aside, the mix position itself will change his or her perception of the low end.
 
Re: subwoofer alignment

Tim Duffin said:
can you simply use some of the cabs for mid/upper bass and the others for lower/sub bass? Whichever cabs you think are better for lows, cross them over at LP 60 and the rest can do BP 50-100hz?
Click to expand...

While that sounds like a good idea-just ask anybody who has tried to do it. When you use REAL cabients, it get quite hard to actually do.

I do that type of thing a good bit. But rarely do I actually low pass the "low freq" box. But rather let the "upper" range be doubled up. With careful alignment-ON SOME CABINES-not all-it can work well.

As usual-it depends.
 
Re: subwoofer alignment

Jamin Lynch said:
What type music? What you using to power those SB1000's?

Wouldn't 4 properly powered and processed SB1000's handle up to 1500? Would centered subs help?
Click to expand...

Qsc pl380 x 4 for 8 subs. I've been playing with placement, I've had them 2 high 4 wide center stage. It loads the stage w low end... I've had them 2 wide 2 high under the array, there are nodes just off center ( which is where this be wants to be, he's not dumb...) so no tricking the B.E. so any suggestions to get more even coverage? Oh yeah type of music is 80's rock.... For you Canadian members... It's Trooper. " here for a good time.... Not a long time"
 
Re: subwoofer alignment

Shane Presley said:
Qsc pl380 x 4 for 8 subs. I've been playing with placement, I've had them 2 high 4 wide center stage. It loads the stage w low end... I've had them 2 wide 2 high under the array, there are nodes just off center ( which is where this be wants to be, he's not dumb...) so no tricking the B.E. so any suggestions to get more even coverage? Oh yeah type of music is 80's rock.... For you Canadian members... It's Trooper. " here for a good time.... Not a long time"
Click to expand...

A little bit of asymmetrical delay can steer power alley a bit :)

Jason
 
Re: subwoofer alignment

Shane Presley said:
Qsc pl380 x 4 for 8 subs. I've been playing with placement, I've had them 2 high 4 wide center stage. It loads the stage w low end... I've had them 2 wide 2 high under the array, there are nodes just off center ( which is where this be wants to be, he's not dumb...) so no tricking the B.E. so any suggestions to get more even coverage? Oh yeah type of music is 80's rock.... For you Canadian members... It's Trooper. " here for a good time.... Not a long time"
Click to expand...

Oh, so 8 SB1000's. You don't think that will cover up to 1500?

Either way, there's going to be trade offs. I'll bet Bennett or Ivan can "steer" you in the right direction for sub placement.
 
Re: subwoofer alignment

Shane Presley said:
So I have a national act in august, and I want to suppliment the low end with dissimilar boxes.... I've asked this question before, and I've gotten every response under the sun, except for something that was helpful.
No I can't sub rent any more Sb's, yes that would be the obvious choice...
No I can't call Clair bros, and get a proper sized rig....
It's just my stuff, and it's a small country fair, and I'm trying to give the BE enough bottom so he doens't complain, or blow up what I do have....
It's an open field, expecting around 1000, 1500 peeps max... 6 KF730 flying over 4 SB1000z.
What I am trying to do is throw my tx-9s in the front, on an aux for kick / bass... Any thoughts on how I can get these two to line up close enough without using SMAART.?
Thanks
SP
Click to expand...

I Shane,
I would have thought unless you wanted an extreme amount of bass, 6 x KF730 with 4 xSB1000’s would be a good match. I don’t see much point in getting more subs unless you get more 730’s.

Anyway if you need more LF you could run the SB1000’s as a center cluster, possibly in a tight packed endfire arrangement if you need to limit the bass on stage or run 4 a side of SB1000s with a center cluster of the TX9s.The delay to align the center cluster is not critical other than how it affects the pattern of the LF, however the outer subs must be aligned with the 730s.

Gunness focusing the 730s from memory takes about 7.5ms in the UX8800 but only 3.13ms for the subs … so if the SB1000’s are physically aligned with the 730s you will need to add 4ms delay to the SB1000s. Getting that right will make a big difference around the sub crossover frequency (100hz)

730s sound really good but don’t go very loud especially when using the UX8800. One trick you can do is run a low pass filter at about 14 or 15Khz on the mid-highs and they will hang together a little better when you push them.

Here are some plots that may be of interest -

The top pair of plots are for 12 boxes - L C R
So you can see how the delay effects the pattern, the RHS plot has the center 4 boxes delayed 5ms while the LHS has no delay .
The other plots are for 8 boxes (all staked 2 over 2)
 

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Re: subwoofer alignment

I used 6 subs center clustered the other night and pulled the middle 2 forward about 18" and the next pair forward about 10" and it reduced the bass on stage very noticeably. There was a corresponding improvement out front too. I suspect a similar thing with 8 subs would work real well.
I would have done it with delay but I only had 2 channels of amp available for the subs.
 
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