Possible New Speaker Design???

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Bruce Weldy
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Re: Possible New Speaker Design???

#16 Post by Bruce Weldy »

kjacobs wrote: We do mostly outdoor gigs anywhere from 500-2000 people....relatively sane SPL levels for our family concert series. Audience can be up to 200 ft away, but the 4 DR280s have always done well in this park venue for the past 8 years without having to resort to amplifier overdriving. I have no experience using the DR250. Was actually thinking of a new build of 8X Otop12.....and maybe using the comp driver option.
Here's my suggestion....buy 8 NSD2005 drivers. Put those in the 4 DR280s. If you like 'em, you're done. If not, build the OT12s and put those drivers in there. No waste other than the components to build the new 1.2k crossovers for the DRs.

I think you'll like the smoothness of the comp drivers over the piezos.

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."

kjacobs
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Location: Hood River, OR
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Re: Possible New Speaker Design???

#17 Post by kjacobs »

That sounds like a excellent plan.....except.....I was under the impression that my DR280s, built from 2009 plans, do not have room for compression drivers when using Delta Pro 12-450a speakers. I believe compression drivers only worked with Neo Magnet drivers in that build of cabinet??? I could be mistaken....I have the newer plans as well, but the cabinet plans are slightly different on the front of the box. If I have to replace all the 12s AND buy expensive comp drivers.....that could get quite spendy.
Built
4 X DR280's Delta Pro 12-450A Straight Array

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

Re: Possible New Speaker Design???

#18 Post by Bruce Weldy »

kjacobs wrote:That sounds like a excellent plan.....except.....I was under the impression that my DR280s, built from 2009 plans, do not have room for compression drivers when using Delta Pro 12-450a speakers. I believe compression drivers only worked with Neo Magnet drivers in that build of cabinet??? I could be mistaken....I have the newer plans as well, but the cabinet plans are slightly different on the front of the box. If I have to replace all the 12s AND buy expensive comp drivers.....that could get quite spendy.
My oldest set of plans is from 2009 or 2010 and the NSD 2005 is listed as an option. Go back and check your plans......and it doesn't hurt to do some measuring in the actual cab. The NSD2005 is a neo driver, so it isn't real big or heavy.

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: Possible New Speaker Design???

#19 Post by Bill Fitzmaurice »

The plans should specify the maximum diameter for HF drivers.

kjacobs
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Re: Possible New Speaker Design???

#20 Post by kjacobs »

OK....so I went back and looked through my sets of plans. I have 2 updated sets for the DR280, but the original plans are dated with a creation date of 2006. I had originally ordered the DR290 plans (as they were separate at the time) and then built the piezo version using the DR290 plans. I think all the cabs may have been built in 2008. The plans specifically state not to even use a 12" driver without a Neo magnet. The later plans, of course, show many more options for 12" drivers and is why I replaced the original 2512s with the Delta Pro 12-450a. I had to modify the box framework just to get those Deltas into the box. They all list the NSD2005 for the comp driver. But as tight as that box is with the Delta inside, I am hard pressed to believe the comp drivers will fit. I will have to take a look and some measurements to be sure.....
Built
4 X DR280's Delta Pro 12-450A Straight Array

kjacobs
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Joined: Sat Nov 18, 2006 8:07 pm
Location: Hood River, OR
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Re: Possible New Speaker Design???

#21 Post by kjacobs »

Well....I have done a bunch of measuring to see if comp drivers would fit in the DR280 with the Delta Pro 12-450. I just don't see how it will work with the large frame of the Delta in there. It would push the comp horns almost to the top and bottom of the cab and I am not sure if the horn flares would meet correctly in the middle.

The only other option, besides going back to the piezos, would be trying to doing a column array of Alpha 3-8s down the face....but again I don't know how the spl would compete with the 12". And lack of horizontal dispersion control has been mentioned, though not explained in comparison to the SLA, TLAH, and other column arrays.....
Built
4 X DR280's Delta Pro 12-450A Straight Array

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

Re: Possible New Speaker Design???

#22 Post by Bruce Weldy »

kjacobs wrote:. It would push the comp horns almost to the top and bottom of the cab and I am not sure if the horn flares would meet correctly in the middle.
The horn flares are not symmetrical. If you look at the plans, the drivers are spread to the top and bottom of the horn structure. The center of each driver is about 4 1/2 in. from each end on a 23 inch long driver. Lots of room in the middle.

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."

kjacobs
Posts: 125
Joined: Sat Nov 18, 2006 8:07 pm
Location: Hood River, OR
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Re: Possible New Speaker Design???

#23 Post by kjacobs »

Thanks for the measurement from each end. The comp driver still looks like it will hit the frame of the Delta....at least based on the measurements of the GM500 horn suggested in my old "original" plans from yesteryear. Unless I used a much cheaper, smaller diameter driver which I do not want to do. My first set of updated plans from 2009 still show the GM500 horn flare option. The photos clearly show where the horn driver should sit in the cabinet and I know the woofer frame would be a problem.

My second set of updated plans from 2014 show a built-up horn flare, but will that fit in the older style cabinet? It looks to me like the horn flare is part of the front assembly on the new cabinet. Not sure if it can be built as a separate piece and I do not see a finished size of the horn. Also, what does the vertical dispersion end up at with two 90 deg horns in the vertical plane?
Built
4 X DR280's Delta Pro 12-450A Straight Array

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

Re: Possible New Speaker Design???

#24 Post by Bruce Weldy »

kjacobs wrote:Thanks for the measurement from each end. The comp driver still looks like it will hit the frame of the Delta....at least based on the measurements of the GM500 horn suggested in my old "original" plans from yesteryear. Unless I used a much cheaper, smaller diameter driver which I do not want to do. My first set of updated plans from 2009 still show the GM500 horn flare option. The photos clearly show where the horn driver should sit in the cabinet and I know the woofer frame would be a problem.

My second set of updated plans from 2014 show a built-up horn flare, but will that fit in the older style cabinet? It looks to me like the horn flare is part of the front assembly on the new cabinet. Not sure if it can be built as a separate piece and I do not see a finished size of the horn. Also, what does the vertical dispersion end up at with two 90 deg horns in the vertical plane?
My old set of plans is from April 2009 and it shows the wooden horn that you build yourself. You'd probably have to compare dimensions from the two plans to see if it would fit. Not sure what changes happened between your plans and 2009.....except that they no longer call for an off the shelf horn.

I'm inclined to think that Bill's horn design would be shallower than the GM500, but I can't find a picture and dimensions of one.

Might be worth building a cardboard mockup of the horn and tape it in place to see if there is room for the drivers. I guess you'll need to get an updated set of plans if yours only have the GM500 and not Bill's design.

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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