DR280's

[wallywally]

Before I start....sorry no pics my camera was broken.

I recently built 2 DR280's, 22 piezo melded, 2512 loaded, small chamber, full back, Duratex. I wanted a speaker that would go down to 80hz so I could run aux fed subs. I also didn't want it to weigh alot.

I used arauco ply for all the 1/2" stuff. Sanded 1/4" pine for the horn mouth sheaths and back. Anything that was supossed to be 1/8" I substituted .026" aluminum sheet. I also used aluminum instead of PVC for the reflectors.

I dadoed the mouth sheathes, reflectors and butt cheeks into the top and bottom panels. This required a different order of assembly but it assured me a good seal. I also rabbeted the throat horn and mouth sheaths so the reflectors could overlap and still sit flush. Again to ensure a good seal.

If you are going to use sheet metal in your build make sure you use pl premium. Do NOT use Gorilla glue it bonds very well, BUT, has very little tensile strength!!

I also cut holes in the throat horn divider and side braces to reduce weight.

The finished speaker weighs 55 lbs. I do not believe this speaker could be built any lighter without the use of more exotic materials. Although the large chamber version would weigh about 3 lbs less.

Now to the sound.....
These are replacing 2 Celestion R1520 15" direct radiator with compression driver cabinets that weigh 51lbs each. I have always been very happy with the sound of the Celestions. I cannot even begin to compare the DR' and Celestions. Spanked....no.. smoked....no...eaten alive....no......I can't emphasise enough how far apart these cabinets are. It' like a top fuel dragster and a yugo racing.....no contest.

When I first fired the DR's up I cranked them up to ear bleeding levels and checked the voltage being fed....15volts. But they sounded distorted, I checked everything again, all was good except for distortion. I decided to get back and take a listen. Then I found the problem... the speakers were crystal clear but my hearing was distorting. These things are stupid loud! At the same time they are detailed, articulate, and refined. They sound more hifi than my home stereo speakers. Positively the best sounding pro audio cabinet I have ever heard.

Practice was on saturday... 5 hour session...very little ear fatigue and we were very loud!! Unbelivable.

[Greenman]

I'm happy for you. I hope my 280 sound the same.

[Randall Dibble]

I'd like to hear more about the alternate materials and construction methods.

Maybe over in the DR Forum.

The Use of aluminum sheet is interesting.

[DAVID_L_PERRY]

Great pa cabs...

I dadoed the mouth sheathes, reflectors and butt cheeks into the top and bottom panels. This required a different order of assembly but it assured me a good seal..

I did the same on my last pair of DR280 for the rear butt cheaks but used large dia plastic pipe. Worked a treat and meant the top and btm panels are one piece, so no infill pieces to sort out....



shot of the inside plastic pipe rear butt:-



It was during this build and discussions with Leland and Harley where Harley came up with the aluminium option.

Having built the standard DR method and rebated top and btm panels Its probably no quicker but to me the best part was having a one piece top and btm panel and not the infill bits to fill and sand flush as you can see here:-



Dave[/img]

[Chris_Allen]

Dave,

Where did you get the large plastic pipe from and is there anything suitable for a 200?

Chris.

[DAVID_L_PERRY]

Dave,

Where did you get the large plastic pipe from and is there anything suitable for a 200?

Chris.

My brother worked for plastics supply company at the time so I got some 'ahem' damaged warehouse offcuts. Its normally pretty expensive stuff as its such a large dia. I see bits lying around all the time on housing sites I inspect on as its used for drainage.

It is fairly heavy though, so for lightweight I would probably use the ply option or aluminium.

Dave