SLA Pro built-in amp options

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Bruce Weldy
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SLA Pro built-in amp options

#1 Post by Bruce Weldy »

Ok, I'm gonna' build a powered SLA Pro 4x6 with the Dayton plate amp.

Planning to put the amp on the outside in the back of the speaker, but it would be nice to actually build it into the speaker without a bump on the back.

In order to put it in the box, it would require moving the two braces between the middle brace and the back. Would it affect the integrity of the box to go with 4 braces (two on each side of the amp cutout? The cutout is 5 1/2 in. wide. That would put the braces 2 1/4 in. from the sides.....would using 4 spread out and replacing the two that are in the middle be an acceptable mod?

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Bill Fitzmaurice
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Re: SLA Pro built-in amp options

#2 Post by Bill Fitzmaurice »

Yes, that's fine. Just be sure to keep the net internal volume of the box the same so it doesn't upset the tuning.

Bruce Weldy
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Re: SLA Pro built-in amp options

#3 Post by Bruce Weldy »

Bill Fitzmaurice wrote: Thu Nov 12, 2020 4:11 pm Yes, that's fine. Just be sure to keep the net internal volume of the box the same so it doesn't upset the tuning.
Thanks Bill.

That amp doesn't have sides or a back. I'm thinking that it won't take up much more space in total than the damping material will. Yes, it's deeper overall, but it's not solid.

There's a picture of the back here.
https://www.parts-express.com/dayton-au ... h--300-798

It would be easy to determine the volume if it was a closed box (211.75 cubic inches), but looking at the picture - it would have to just be a guess with all the open space....

If it was a solid enclosure, adding 3/4" to the depth would be almost exactly the volume of the box....but since it's so open, I'm not sure that it would make much of a difference.

Any thoughts? What would lowering the internal volume of the box do to the tuning? Loss of low end?

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Bill Fitzmaurice
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Re: SLA Pro built-in amp options

#4 Post by Bill Fitzmaurice »

First, damping doesn't detract from the cabinet volume. It doesn't appear that the amp occupies much space, if any, as the case extends back a bit from the mounting flange. If it did occupy space in the cab it would push the cab tuning up.

Bruce Weldy
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Re: SLA Pro built-in amp options

#5 Post by Bruce Weldy »

Bill Fitzmaurice wrote: Thu Nov 12, 2020 6:07 pm First, damping doesn't detract from the cabinet volume. It doesn't appear that the amp occupies much space, if any, as the case extends back a bit from the mounting flange. If it did occupy space in the cab it would push the cab tuning up.
Thanks!

Guess I'll finally own a powered speaker.....

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Re: SLA Pro built-in amp options

#6 Post by Grant Bunter »

Bruce Weldy wrote: Thu Nov 12, 2020 8:02 pm Guess I'll finally own a powered speaker.....
:shock:
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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Seth
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Re: SLA Pro built-in amp options

#7 Post by Seth »

There are practical reasons that make putting the amp in a top a good choice. But, there are also practical considerations for mounting the amp in the sub too. Have you considered that as an option?

Wouldn't have to worry about internal volume and wouldn't have to run an extension cord over to and up the speaker stand. Still just one wire up there, instead of 3-4 (Power, XLR, lead out to sub, lead out to an optional 2nd top (I know you don't use 4 conductor cabling)). Would also allow using different tops. Although, the other configuration (amp in top) would allow you to use different subs, and/or operate without a sub.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Re: SLA Pro built-in amp options

#8 Post by Bill Fitzmaurice »

Having it in a top allows using the top(s) without a sub should the occasion arise. I don't see using a sub without tops.

Bruce Weldy
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Re: SLA Pro built-in amp options

#9 Post by Bruce Weldy »

SethRocksYou wrote: Thu Nov 12, 2020 9:07 pm There are practical reasons that make putting the amp in a top a good choice. But, there are also practical considerations for mounting the amp in the sub too. Have you considered that as an option?

Wouldn't have to worry about internal volume and wouldn't have to run an extension cord over to and up the speaker stand. Still just one wire up there, instead of 3-4 (Power, XLR, lead out to sub, lead out to an optional 2nd top (I know you don't use 4 conductor cabling)). Would also allow using different tops. Although, the other configuration (amp in top) would allow you to use different subs, and/or operate without a sub.
This whole project is designed to do small acoustic type gigs. I'm going to put a top hat in the top of my T24 and let the SLA ride on top. As Bill said, I'll be able to use the SLA on its own if I want to. I can also stick it on top of one of my T39s if the T24 can't keep up. It's also going to wired so that I can use it as a passive speaker in my shop running thru the T24 with the crossover built in powered by my old Peavey XR600. It will be very versatile.

It will be like a pumped-up Bose L1.

The real reason I'm building it? Probably because I'm bored and need a project.....don't necessarily need another speaker cab in my garage - as my wife reminded me.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Seth
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Re: SLA Pro built-in amp options

#10 Post by Seth »

Bruce Weldy wrote: Thu Nov 12, 2020 11:36 pm
SethRocksYou wrote: Thu Nov 12, 2020 9:07 pm There are practical reasons that make putting the amp in a top a good choice. But, there are also practical considerations for mounting the amp in the sub too. Have you considered that as an option?

Wouldn't have to worry about internal volume and wouldn't have to run an extension cord over to and up the speaker stand. Still just one wire up there, instead of 3-4 (Power, XLR, lead out to sub, lead out to an optional 2nd top (I know you don't use 4 conductor cabling)). Would also allow using different tops. Although, the other configuration (amp in top) would allow you to use different subs, and/or operate without a sub.
This whole project is designed to do small acoustic type gigs. I'm going to put a top hat in the top of my T24 and let the SLA ride on top. As Bill said, I'll be able to use the SLA on its own if I want to. I can also stick it on top of one of my T39s if the T24 can't keep up. It's also going to wired so that I can use it as a passive speaker in my shop running thru the T24 with the crossover built in powered by my old Peavey XR600. It will be very versatile.

It will be like a pumped-up Bose L1.

The real reason I'm building it? Probably because I'm bored and need a project.....don't necessarily need another speaker cab in my garage - as my wife reminded me.
Sounds like a good plan.

And, IMO, bored is the best reason to build. Man, could you imagine how much less joy there would be in cabinet building if we HAD to do it? My first couple builds I just wanted to get to the end as soon as possible. But, now I find I get much more enjoyment out of taking my time with each piece, make it my own a little, make it a little nicer than it has to be where no one will ever see it, massage every edge smooth with sandpaper by hand even though no one may ever touch it. I find it to be refreshingly therapeutic and a fantastic, productive cure for boredom.

Looking forward to the build Bruce. :thumbsup:
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Re: SLA Pro built-in amp options

#11 Post by Seth »

Bruce, I was looking at the SketchUp for the SLA Pro and it looks to me that the braces from the center brace to the back are there to brace the back panel and keep it from flexing. If the amp is going to flex, there's not much you can do about that. If I was putting an amp there, I'd think just omitting those two braces would be fine. It seems there isn't much use in the braces if they're moved so close to the sides. I would consider extending the baffle brace all the way across though, so that it ties into the sides too.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: SLA Pro built-in amp options

#12 Post by Bruce Weldy »

SethRocksYou wrote: Fri Nov 13, 2020 1:00 pm Bruce, I was looking at the SketchUp for the SLA Pro and it looks to me that the braces from the center brace to the back are there to brace the back panel and keep it from flexing. If the amp is going to flex, there's not much you can do about that. If I was putting an amp there, I'd think just omitting those two braces would be fine. It seems there isn't much use in the braces if they're moved so close to the sides. I would consider extending the baffle brace all the way across though, so that it ties into the sides too.
More than likely, it wouldn't make much difference at all. But I can get 'em about 2 inches from each edge, so that should give it pretty good rigidity.

I'll do a build thread to show what it looks like....

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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