Tuba 60 Outdoor Wall Loading

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5meohd
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Tuba 60 Outdoor Wall Loading

#1 Post by 5meohd »

Screenshot_20230429_153246_Maps.jpg
I'm considering trying to get extra output from using that brick wall to the left in the image.

Otherwise the plan would be 4 15" LAB loaded T60s horizontally across the ground facing the photographer of this image. At least 12' from the left wall. About right where the Google Map icon is, mouths in plane with the green fencing (that would be temporary peeled back).

I think using the wall could get us more output, but I'm always a little confused by how to place them.

Thanks in advance for any input.

Happy Saturday!
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Re: Tuba 60 Outdoor Wall Loading

#2 Post by Bill Fitzmaurice »

Place them as a block of two above two no more than 2.5 feet from the wall.

5meohd
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Re: Tuba 60 Outdoor Wall Loading

#3 Post by 5meohd »

Thank you Bill!

Which of these would be best? I do not really understand the concept, so your description left a lot of room for imagination with my ignorance involved.

Quick sketch. X signifies mouth of T60.

A:
Screen Shot 2023-04-30 at 1.32.00 PM.png
B:
Screen Shot 2023-04-30 at 1.30.41 PM.png
C:
Screen Shot 2023-04-30 at 1.29.25 PM.png
Attachments
Screen Shot 2023-04-30 at 1.30.32 PM.png
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Re: Tuba 60 Outdoor Wall Loading

#4 Post by Bill Fitzmaurice »

Aiming at the wall may work slightly better. The main thing is having them close enough to the wall.

Fastskiguy
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Re: Tuba 60 Outdoor Wall Loading

#5 Post by Fastskiguy »

The second and 4th pictures look the same to me....is that ideal?

Joe

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Re: Tuba 60 Outdoor Wall Loading

#6 Post by 5meohd »

Fastskiguy wrote: Sun Apr 30, 2023 5:15 pm The second and 4th pictures look the same to me....is that ideal?

Joe
Yes, they are the same. The 4th image is the "attachments" window. I may be using the forum incorrectly. I was just trying to upload the first 3 images in-line.
4 T60's
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Ashley Protea
QSC PLX2
Crown CDi

5meohd
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Re: Tuba 60 Outdoor Wall Loading

#7 Post by 5meohd »

One interesting thing about this wall loading is that our audience is so used to be right up on the subwoofers and only the depth of the woofers being between them and the DJ. Placing them near the wall will be quite a change.

What do you think the estimated gain will be? Compared to using the 2 x 2 stack about ~ 12' from that wall facing the crowd as normal?
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Re: Tuba 60 Outdoor Wall Loading

#8 Post by Bill Fitzmaurice »

You may gain as much as 6dB. That's the equivalent of doubling the cab count to eight. There's absolutely zero benefit in aiming them at the crowd. The output pattern is 360 degrees below where the summed mouths are less than a wavelength in dimension. A wavelength at 100Hz is 11.25 feet.

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Re: Tuba 60 Outdoor Wall Loading

#9 Post by Fastskiguy »

1st a question

as long as the mouth is within 11 feet of the wall he’s good to 100hz? No matter the direction? He could have the stage (or dj stuff) close to the wall and maybe make it.

Then a comment

It just seems like the direction the mouth is firing should matter. I’m not a disbeliever (or whatever you call it….maybe science denier?) but it would “make sense” that the sound comes blasting out of the mouth like with higher frequencies.

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Re: Tuba 60 Outdoor Wall Loading

#10 Post by Grant Bunter »

Fastskiguy wrote: Sun Apr 30, 2023 10:06 pm 1st a question

as long as the mouth is within 11 feet of the wall he’s good to 100hz? No matter the direction? He could have the stage (or dj stuff) close to the wall and maybe make it.
Not quite.
The subplacement sticky mentions the prime directive.
Being that the mouth of the cab is less than 2 feet or more than 8 feet from a boundary.

Nearing 100Hz probably won't be affected, but down near the bottom end of that cabs response will suffer due to frequency cancellation...
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Re: Tuba 60 Outdoor Wall Loading

#11 Post by Bill Fitzmaurice »

Fastskiguy wrote: Sun Apr 30, 2023 10:06 pm as long as the mouth is within 11 feet of the wall he’s good to 100hz?
No. When the mouth is 1/4 wavelength away the reflection will be 180 degrees out of phase, causing a cancellation. When it's more than 1/4 wavelength away you don't full boundary loading. Therefore you want to be closer than 1/4 wavelength. At 100Hz that's 2.8 feet, so 2.5 feet is safe.
it would “make sense” that the sound comes blasting out of the mouth like with higher frequencies.
It would make sense if sound waves worked the same way that light waves do. They don't. People who have not learned how sound waves work (and you have to be taught, because it's not the least bit intuitive) set up speakers as if they were lights, under the mistaken assumption that speaker dispersion patterns work like lights. This fundamental flaw in their understanding of the physics of sound is responsible for the two most common errors in speaker placement: Tops placed side by side, and tops placed over subs. It doesn't help that the speaker industry panders to their desires with trapezoid tops for outward splaying and sockets atop subs for pole mounting mains above them. Neither of those features should have ever been offered, but rather than educating their customers as to what they really needed they took the money and gave their customers what they wanted. :roll:

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Re: Tuba 60 Outdoor Wall Loading

#12 Post by Fastskiguy »

Ah OK, I get it, less than *1/4th* wavelength so less than 1/4th of 11.25 feet or shoot for 2 1/2. Hopefully the crowd will appreciate the sound and accept the new layout :)

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5meohd
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Re: Tuba 60 Outdoor Wall Loading

#13 Post by 5meohd »

Screen Shot 2023-05-03 at 8.06.20 PM.png
What do you think of this layout?

Won't it feel weird with so much level on the left side?

Tops are Danley Sh69 for anyone wondering.
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Re: Tuba 60 Outdoor Wall Loading

#14 Post by Bill Fitzmaurice »

It would feel weird if you could tell where the subs are, but you can't. They're not directionally locatable. For that to happen there has to be a significant phase difference as the wave arrives at each of your ears. There isn't, the wavelengths are too long.

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Re: Tuba 60 Outdoor Wall Loading

#15 Post by Grant Bunter »

5meohd wrote: Wed May 03, 2023 8:07 pm Screen Shot 2023-05-03 at 8.06.20 PM.png

What do you think of this layout?
Can you tell us if the areas with what looks like mesh in your rendering is actually mesh, or solid wall with dressing?
To get boundary loading you need a solid wall, not part solid wall(s) with openings in spots, is why I'm asking.

There's no dimensional figures, so hard to know, but your Danley tops look to be too low...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

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