Rig Stacking

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Evan F. Hunter

Junior
Jan 11, 2011
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Houston, Texas
I see many threads about getting their speakers up high, people talk about building boxes, scaffolding, road cases etc etc. My new amp rack lids fit my subs width wise perfectly and also make great risers for my tops. (yes it is entirely possible that I have the heaviest amp racks still in use today) This is just a test run in the shop, I will have black straps holding everything down securely. The lids are very sturdy as well. The top of the road case lid is at approx 5ft 8in. I was able to stack this by my self in about 3 minutes as well. Also consider that these speakers also have the 10 degree down angle on the horns, the extra tilt is to keep the sound on the crowd instead of the back wall at a couple indoor venues around town.

More details on the rig: 2 EV QRX153s over 2 JBL SRX 728s I have EV P1250s on the highs and high mids, P3000s on the low mids and subs. QRX 115s are front fills. Its a rocking little rig.

The question: Does anyone see any issues with this rig being stacked this way. In terms of sound quality as well as safety. My two biggest concerns at any event. With a little pushing and shoving on my part it is very solid, Wanted to see what the communities thoughts are.
 

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Re: Rig Stacking

On of the biggest issue is a sonic one. Since the case is closed-it will have a resonant freq (just hit a side and see how it "sounds".

This will cause a "suckout" in the freq response at that freq.

It does exist-but much or how big a deal is up to you. It may not be enough to worry about-or it may be.

It depends on how damped the case it and so forth.

As far as safety-run a strap from the sides-up over the top and back down. Make the speakers a "single unit". It is much harder to tip over them.

Yes I have had more than my share of speakers falling-with the biggest one when a car ran into the scaffolding and it all came tumbling down.

Nobody has ever been hurt :).
 
Re: Rig Stacking

Ivan Beaver said:
On of the biggest issue is a sonic one. Since the case is closed-it will have a resonant freq (just hit a side and see how it "sounds".

This will cause a "suckout" in the freq response at that freq.

It does exist-but much or how big a deal is up to you. It may not be enough to worry about-or it may be.

It depends on how damped the case it and so forth.

As far as safety-run a strap from the sides-up over the top and back down. Make the speakers a "single unit". It is much harder to tip over them.

Yes I have had more than my share of speakers falling-with the biggest one when a car ran into the scaffolding and it all came tumbling down.

Nobody has ever been hurt :).
Click to expand...

Thanks Ivan,
I was curios if it was going to affect the PA at certain frequencies. The inside of that Lid is actually lined with a pretty dense foam, Like a shock mounted rack. You could give it a pretty good smack and there isnt much if any resonance. I also use a lot of moving blankets to try and keep anything without a cover or case looking new, I was thinking of stuffing the inside of the lid with them during showtime. Cloud 9 covers could go in there as well. Might be a good place to store them and help a little with any resonance?
 
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Re: Rig Stacking

There is no more resonance issue with a solidly built case than the other cabinets in the pile, if it does not "boom" when you whack on it, no worries.
If you run a sine wave sweep through the system you will probably find the flip handles are the biggest problem with unwanted noise, you may have to run bungy cords or a rope through them.

As well as the ratchet straps, some form of interlock between cabinets should be used, be it feet in sockets, dowel pins in drilled holes, or skids and slots.

Git 'er up, point 'er down.
 
Re: Rig Stacking

Art Welter said:
There is no more resonance issue with a solidly built case than the other cabinets in the pile, if it does not "boom" when you whack on it, no worries.
If you run a sine wave sweep through the system you will probably find the flip handles are the biggest problem with unwanted noise, you may have to run bungy cords or a rope through them.

As well as the ratchet straps, some form of interlock between cabinets should be used, be it feet in sockets, dowel pins in drilled holes, or skids and slots.

Git 'er up, point 'er down.
Click to expand...

Thanks Art,

Thats a great Idea about running a bungee or rope through the handles. I have some long Nice bungees that will do the trick! Thanks!

The subs are interlocked with feet in sockets, The tops I was planning on hooking together using the flyware on the boxes some how.
 
Re: Rig Stacking

Try it with the QRX153's sitting "flat" on the case lid first and see how the coverage is. I wasn't all that crazy about the down tilt horn on my old qrx212's so I don't know that they'll need all that much more help anyway. It just looks really unstable the way you have it now. Even with ratchet straps I would like to see a more mechanical attachment means to keep the boxes from falling over.
 
Re: Rig Stacking

Tim Weaver said:
It does mean you have to carry both racks to the gig though. It may be time to build 2 amp racks?
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Yep, Im actually getting some designs together to take to a buddies wood shop and build all kinds of cases and caster boards. I will get with you on that actually. On the big gigs with the full rig I dont mind much. In smaller shows I want smaller racks in general but you know the story on these monsters.
 
Re: Rig Stacking

Tom Manchester said:
Try it with the QRX153's sitting "flat" on the case lid first and see how the coverage is. I wasn't all that crazy about the down tilt horn on my old qrx212's so I don't know that they'll need all that much more help anyway. It just looks really unstable the way you have it now. Even with ratchet straps I would like to see a more mechanical attachment means to keep the boxes from falling over.
Click to expand...

I did some pushing them around and they hardly move, and thats without anything holding them down. They are hardly tilted, Back end is raised two inches, I think the pictures exaggerate more than anything. Ive worked on many others rigs when they have used the "audio log" approach to tilt the tops down a bit. The down tilt is for one of the local rooms that is wider and shallow. For deeper venues they will likely sit flat.

I actually love the horns in these. As long as you get them up they do great to cover the crowd even up close.
 
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Re: Rig Stacking

I wouldn't be comfortable with it, personally. Not saying it isn't sturdy if it's in place, but if the case shifted a little bit(it is on thumping subs) during a show it could be disastrous. Also, justifying that setup to insurance in case of an incident might not go over too well.

Something that I would consider if you had a few bucks, is adding another 2x18" to each side to run the subs cardioid. It would be safer(probably still want to ratchet strap) and would add value to the rig.
 
Re: Rig Stacking

After seeing a few cabs fall in my lifetime,I had pole mounts installed in the top of the subs and bottom of the lows,then again in the top of the lows and bottom of the mid/his.I then insert a short piece of pipe in between.They don't move.
 
I've seen much worse:

ImageUploadedByTapatalk1378508019.052973.jpg

Strap the tops together somehow, then strap them to the subs.

I don't see how purchasing two more subs and another amp, and possibly additional DSP, would add much value to a rig at this level.
 
Re: Rig Stacking

Evan F. Hunter said:
Thanks Art,

Thats a great Idea about running a bungee or rope through the handles. I have some long Nice bungees that will do the trick! Thanks!

The subs are interlocked with feet in sockets, The tops I was planning on hooking together using the flyware on the boxes some how.
Click to expand...

I would not trust bungees. They stretch! Use a good, strong ratchet strap.
 
Re: Rig Stacking

Tim McCulloch said:
If you follow up to Art's post (why either quoting every reply or using the THREADED view is better than linear view) you'll see that Art was talking about rattles from the spring-loaded handles.
Click to expand...

You're right, Tim, I missed that in Art's post and was responding directly to Evan. Anyway, strap those bad boys down.
 
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