BillFitzmaurice.info

Bill Fitzmaurice wrote:You have the mouths of the subs and the tops are on the same plane. They never should be set up like that when there's a wall behind them. You'll always have a cancellation caused by the reflected wave off the wall that way. You want the mouths of the subs close enough to the wall so that the cancellation frequency will be above their passband, while the tops need to be far enough away so that the cancellation frequency will be below their passband. The correct way to set them up would be with the T60s aimed at the wall. Once you get the stand situation squared away you can put the T60s sideways against the wall. When you do the local expert 'gear groupies' will ask you why you have your subs set up 'the wrong way'. You then tell them it's to eliminate 1/4 wavelength Allison Effect cancellations, giving them something to Google and ponder.

Agreed 100%. Have faith in one of your young Padawans. I didn't go though all this work to not have them perform their best.

Bill Fitzmaurice wrote:You have the mouths of the subs and the tops are on the same plane. They never should be set up like that when there's a wall behind them. You'll always have a cancellation caused by the reflected wave off the wall that way. You want the mouths of the subs close enough to the wall so that the cancellation frequency will be above their passband, while the tops need to be far enough away so that the cancellation frequency will be below their passband. The correct way to set them up would be with the T60s aimed at the wall. Once you get the stand situation squared away you can put the T60s sideways against the wall. When you do the local expert 'gear groupies' will ask you why you have your subs set up 'the wrong way'. You then tell them it's to eliminate 1/4 wavelength Allison Effect cancellations, giving them something to Google and ponder.

All understood but in the mean time I have to use the tools available to me. My pole mounts broke and plan B came into effect. I mean I was counting on them working out and the in 3 seconds of testing them, snap. Now what do I do? I know I have to get the top boxes over peoples heads and the sub boxes made excellent platforms. I work the field and solutions to the problem always trumps theory.

CoronaOperator wrote: Now what do I do?

Turn the subs around.

To maintain the aesthetic of a front facing sub, consider building a false front and painting in the same style. The top of the fake horn could be used as storage.

Just power one sub (reversed as above) if you don't need the output. Great looking stand, no cancellation.

Bill Fitzmaurice wrote:Turn the subs around.

Tried that, didn't sound as good as that put the mouths in the no go zone.

Chris_Allen wrote:To maintain the aesthetic of a front facing sub, consider building a false front and painting in the same style. The top of the fake horn could be used as storage.

Sounds like I could make my stands quicker than I could do that.

Dale Hammer wrote: Just power one sub (reversed as above) if you don't need the output. Great looking stand, no cancellation.

Tried that, I need the output.


Look, I've worked this room for 25 years and have had many systems come in and out the door, I know what sounds good and what doesn't and locations that work and holes in the room that suck up the bass. Those T60 subs were grouped and wall loaded for an entire year. They sounded great that way, and they sound just as good where they are although at way way less output. If I move those subs 3 feet in any direction the sound goes to crap. They are in magic spots. If have a lot more than rear boundry reflections going on. I have side wall and low ceiling bounces as well. I took my time to make something work out for me temporarily and still sound good. Watch that video I posted when I move locations, there is no interference pattern. The bass is even everywhere.

All this discussion is nonsense anyways as I fully expect to have some stands made up by next Friday. Arguing about ducttape doesn't make any sense to me. Right now this works. If you can't wait until i get something put together, feel free to come down and move them to where you think they will sound better. Those stacks weigh 350 lbs each.

I combed the building last week looking for tables and everything I could think of for make shift stands. I think I just thought of a solution . I have 2 PK Sound rigs in the back room that I let an EDM promoter store. I wonder how this phone call will work out.

Me: "Hey Dylan, can I use your subs for tonight?" - He will, I don't charge him any rent and he always steals my cables.
Dylan: "Haha, you finally came over to the dark side, go ahead dude, you want a hand setting them up and tuning them?"
Me: "setting them up yes, tuning them, no"

30 minutes later...

Dylan: "what do you mean we are not plugging them in"
Me: "I just want to use your subs as speaker stands, haha"
Dylan: " "

Hahahaha

I'm off to work to see if this will go over.

Oh. My. G-O-S-H.

.... and done!

OMG, I can't stop laughing. I called him and he agreed. I had to jump in the shower before I got to work so he beat me there. When I got there he already had my system taken down and his subs in place. He also had dug through all his bins and had all his powercons and xlrs ready to go. All I had to do was lift my tops up on the subs and strap them down (he helped). Then he dug out his driver rack and mixer and I told him we won't be needing those. Then I spilled the beans about my plan. He walked out the door and his driverack and cables are still sitting on the floor. I'll buy him a few beers later to make amends.


Behold my improvised $14,000 speaker stands:



Now before you guys go off on how they will suck up the bass, I already thought of that. I already plugged them in (they self powered) and that should keep the cones steady. I guess we'll see. All I had to do was realign my subs to the tops on the driverack and that was quick.

The beauty of this plan was that he did all the work before I showed up. Sometimes the genius just doesn't stop I tell you.

Ooo, dat bad! LOL.

Sounds like ya' got a little Tom Sawyer in ya'.

Did ya' get him to paint your fence, too?

CoronaOperator wrote: Dylan: "what do you mean we are not plugging them in"
Me: "I just want to use your subs as speaker stands, haha"

Unused speakers will act as Helmholtz resonators, literally sucking up low frequencies. The effect can be minimized with passive speakers by inserting plugs into the cab jacks and shorting the plug poles to each other, but if they're self powered that's not an option. Having the amps powered up with no input might help, but I can't say for sure.

Bruce Weldy wrote:Sounds like ya' got a little Tom Sawyer in ya'.

Did ya' get him to paint your fence, too?

Not yet, lol. I've helped him set up, work and tear down for over 100 of his shows over the years so I figured he owed me one back.

Bill Fitzmaurice wrote:Having the amps powered up with no input might help, but I can't say for sure.

It seems to have worked, there was no lack of bass last night ... or mids or highs for that matter. These DR's are crazy. One of the DJ's last night had the entire crowd huddled against the far wall 100 feet way. I had to tell him that if he wanted people on the dance floor he would have to turn it down some as he was over 105 dBA and that's as far as anyones ears can handle. As soon as he turned down some, the crowd came back over. I measured the voltage going to these stacks just before he turned down - 10 volts !
You guys running 15 volts to a 2 high stack of these are crazy!

I finally got my stand situation figured out. Here is what I came up with:

I started out with the base from the plans, made it a bit taller, added a front and a back, then braced it like crazy:


I didn't want anyone hooking up any ratchet straps to the handles with the hooks as i thought that might tear the box apart so I built a trough all the way through the box. This way they would have to put the strap all the way through the box. It also acts as a brace.


Then I made a base. I quartered a sheet of 5x5 baltic birch, so these are 30" x 30". I made the braces 3.5" high. Yes, these are more torture boxes, except I filled them with sand and added some doublers for casters (1" thick ply in the corners). Just these bases alone weigh around 180 lbs! . I takes 2 guys with some effort just to lift them off the ground.


I made a lower cabinet as well, braced just as heavy as the top cabinet. There is probably more wood you can't see than you can. Then by the power of duratex they turned into these:


I used some window sash locks to hold the 2 cabinets together, they are quick release:


Then some casters to move them around. I also added 2 skids that are only 1/4" off the ground. What these do is make it absolutely impossible to push these off the stage. Try as you might, as soon as one caster falls of the stage the tower only drops 1/4" and that skid digs into the stage so hard that it hits the brakes and everything comes to a stop. All put together these weigh about 350 lbs so it is hard to even get these stands rolling but they wont ever fall on anyone, I made sure of that.

You can also see that I just used 12 screws (3 each side) to hold the bottom cabinet to the base. This way If I ever want to resize the height I don't have to saw away any glue joint.


Then by using the brackets in the plans and some thumb screws that I really liked that I saw hifibob use they assemble into this tower of power!


That thing is solid. Weighs about 350 lbs all together. I would have no problem going 4 boxes high with this stand. Besides the skid safety system, it also has 4 lockable casters and a tether on the top box that I use a 800 lb safety cable to tether it directly to my lighting truss. It's not the DJ's or roadies that I'm worried about as you can find them anywhere but I don't want to hurt any paying customers. They are much harder to find .


It is also on wheels so I can move it around easily, and once I undo those sash locks, I have shorter stands as well. All the angles of the boxes are also adjustable as per the plans as well.

Some more pics: