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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: John Jackson on April 02, 2014, 05:14:32 PM

Title: Need a 13" spacer between tops and subs
Post by: John Jackson on April 02, 2014, 05:14:32 PM
To get my horns 7' off the ground I need to add 13 inches of space between the top of my subs and my mains. I don't want to use a pole because my mains weigh 99 lbs. each and they sway around on the poll. I thought about putting my two 8-space power amp racks on top of the subs, but that would put the volume controls within reach of dancers - probably not a good idea. I don't want to leave the covers on the amps because I am concerned about heat build-up due to loss of air flow and not being able to see the clip meters.

I am trying to keep the number of items I bring to a gig down to a minimum to fit in a cargo van, so I don't want to build a set of wood 13" x 20" x 18" boxes and paint them black to use as spacers unless I converted them into cable boxes and added side access in case I need to get into them while in use.

Any thoughts or ideas would be appreciated!
Title: Re: Need a 13" spacer between tops and subs
Post by: Dustin Coval on April 02, 2014, 07:11:31 PM
Why not get two matching Amp racks to use as your "spacers" and toss your speaker/ electrical (or whatever) cables in them for transport.  You will then still have "access" in them after setup.
Title: Re: Need a 13" spacer between tops and subs
Post by: TJ (Tom) Cornish on April 02, 2014, 07:13:47 PM
Why not get two matching Amp racks to use as your "spacers" and toss your speaker/ electrical (or whatever) cables in them for transport.  You will then still have "access" in them after setup.
Putting your amp racks on subs is not going to be good for the longevity of your amps. Empty cases would be OK if that is what you meant.
Title: Re: Need a 13" spacer between tops and subs
Post by: Ivan Beaver on April 02, 2014, 07:19:46 PM
To get my horns 7' off the ground I need to add 13 inches of space between the top of my subs and my mains. I don't want to use a pole because my mains weigh 99 lbs. each and they sway around on the poll. I thought about putting my two 8-space power amp racks on top of the subs, but that would put the volume controls within reach of dancers - probably not a good idea. I don't want to leave the covers on the amps because I am concerned about heat build-up due to loss of air flow and not being able to see the clip meters.

I am trying to keep the number of items I bring to a gig down to a minimum to fit in a cargo van, so I don't want to build a set of wood 13" x 20" x 18" boxes and paint them black to use as spacers unless I converted them into cable boxes and added side access in case I need to get into them while in use.

Any thoughts or ideas would be appreciated!
A empty box/case can resonate and cause sonic issues.

It would be best if there are at least 2 open sides to an enclosure.  Or sides with fairly large holes in them.

It could be a cable trunk with holes in it-and then throw a black cloth over it to hide it.
Title: Re: Need a 13" spacer between tops and subs
Post by: Art Welter on April 02, 2014, 07:43:30 PM
I am trying to keep the number of items I bring to a gig down to a minimum to fit in a cargo van, so I don't want to build a set of wood 13" x 20" x 18" boxes and paint them black to use as spacers unless I converted them into cable boxes and added side access in case I need to get into them while in use.
John,

I made cable cases/stack spacers with hinged latching doors for both my systems, no resonating problems with a box of a similar size as yours, and they increase the frontal area of the PA, slightly increasing output while reducing edge diffraction effects.

Feet interlocking into receiver divots are a good idea to keep things in line.

Art
Title: Re: Need a 13" spacer between tops and subs
Post by: John Jackson on April 02, 2014, 08:19:31 PM
Thanks for the replies!

I was thinking that putting amps on top of the subs might be an issue, but what about the amps in powered subs and tops? Wouldn't they get ruined from all the vibration if it was an issue?
Title: Re: Need a 13" spacer between tops and subs
Post by: Brandon Wright on April 02, 2014, 10:26:45 PM
I made spacers that serve two purposes. They are the lids to the boxes I made for the 650s as well as spacers. Works pretty well for setup. Put subs where you want them, lift off the lid and put it on top of the subs, and then put the 650s on top. They are 1.5" thick on the face and well braced on the sides with large holes that work as handles for lifting them. They also have slots cut in them for the interlocking skids on the TH118s.

Title: Re: Need a 13" spacer between tops and subs
Post by: TJ (Tom) Cornish on April 03, 2014, 12:10:17 PM
Thanks for the replies!

I was thinking that putting amps on top of the subs might be an issue, but what about the amps in powered subs and tops? Wouldn't they get ruined from all the vibration if it was an issue?
Vibration is never a good thing for electronics, and therefore if you have an alternative location for your amps than right on your subs, you should use it. 

Powered speakers are designed for the task, and have been adapted to survive additional vibration - components are secured differently, amp modules may be physically isolated, etc.
Title: Re: Need a 13" spacer between tops and subs
Post by: Mike Christy on April 03, 2014, 12:55:01 PM
I made spacers that serve two purposes. They are the lids to the boxes I made for the 650s as well as spacers. Works pretty well for setup. Put subs where you want them, lift off the lid and put it on top of the subs, and then put the 650s on top. They are 1.5" thick on the face and well braced on the sides with large holes that work as handles for lifting them. They also have slots cut in them for the interlocking skids on the TH118s.

That's very similar to what I have for my 3TX's, except they are not lids. I think they are 18x18x18 ply, screwed and glued, back and fronts, no sides, brace in the center between front/back, painted with truck bed paint. I use ratchet straps looped under bottom of sub dolly board and over the top of the mains. they are light.

But Brandon now you have given me an idea to build cases, and obviously make the covers a spacer - Thanks!

Mike
Title: Re: Need a 13" spacer between tops and subs
Post by: Steve M Smith on April 03, 2014, 01:01:10 PM
I would make some dummy speakers with similar grill/cloth to what you already have and in the same style.  I would also make them practical so they could be used to store cables, etc.  No point packing away a box full of air!


Steve.