First time OB builder - Page 16

hajj · 18th September 2012, 01:04 PM

This looks gorgeous1
Mind if I use it as inspiration for my ongoing project?

Silent Screamer · 18th September 2012, 01:39 PM

knock yourself out, I'm just spit balling ideas at the moment

rounding off some of the edges on the wood will give it a bit more of a refined look.

studiotech · 18th September 2012, 03:40 PM

Now you've got something original! And when did you sneak up to a 21"? Lol, this is fun! Just make sure you size the tubes so that they are not so long that the first resonance is within their operating range.

Greg

Silent Screamer · 18th September 2012, 10:28 PM

Taking a leaf out of StigErik’s book I would like to get as low as I can using OB, and if I was to use a 21” and a 15” there should be adequate bass there to do the job done, and if there’s not I could always add a single sub for movies.

There is still a lot of refinement work to be done on the current design. To do it in MDF slices would use up quite a number of 8’x4’ boards, so I am also playing with the idea of making clear hexagonal shapes in flat panels.
Figuring 6 x 60 degrees = 360 degrees, and halving 60 degrees is 30 degrees either side of the cut. A 30 degree bevel cutter would be easy to get for the router.

How do I determine the length required?

studiotech · 18th September 2012, 10:52 PM

Doing the tubes in mdf rings? Whoa, that's a lot of waste. Can you get heavy PVC sewer pipe down under? As long as you find a way to make a clean, square cut on the end, it is perfect for your design. Enough heavier than sonotube to actually support the structure that you are proposing.

Greg

Silent Screamer · 19th September 2012, 08:10 AM

Greg I came across you sub build thread today, and decided to go to my local plumbing supplies after work today to see if I could get something like you have in your pics.

They are getting me a price on some 450mm that is about 9mm wall thickness, but they said it will be around $500. So not really looking that flash of an option.

Silent Screamer · 19th September 2012, 10:25 AM

Think this would look kind of funky made out of some 15mm clear acrylic...

studiotech · 19th September 2012, 09:15 PM

That DOES look cool! I wonder about sitting the Raal right on top of the upper hex tube though. You've got a good foot of space for the bottom firing radiation of the Raal to reflect off of. You either have to put a bunch of heavy felt or Bonded Logic up there on the top surface or maybe leave that top portion hollow. Can you mount both woofers together and have the MID/HF module on legs only?

Are you planning to run both woofers in parallel? Not sure if that will work given they may need different amounts of EQ.

studiotech · 19th September 2012, 09:17 PM

You should be able to find it for much less than $500. I got my 10ft piece for $100 on Craigslist. Ask around at a commercial jobsite or roadway construction area. There is always scrap of this that they just throw out after commercial construction.

Silent Screamer · 20th September 2012, 12:07 AM

I was actually wondering about the tweeter, but thought that the foam pads that come with it would stop upward dispersion. I haven’t got the new dipole RAALs yet (getting AM transformers fitted and being air freighted now), but from the PDF description I think they came with foam pads both front and rear. Nothing would stop me putting the top woofer higher or as you suggest opening it up on the bottom side.

If I run two of any size driver I would put them in parallel, if I run odd sized drivers I would probably run them as separate channels. Still need to finish reading up why StigErik went away from this kind of design that he had, to the line array. Don’t want to spend a lot of money only to find that I have followed an inferior design. If I was to put two woofers on the bottom the design goal would be to have the HF/Mid separately mounted.

Kind of like the idea of the clear hex tubes… kind of reminds me of the 70’s electric drum kits. Unfortunately there is no such thing as a bargain in Oz, if it is not commonly used that causes some kind of competition, then they figure that gives them license to rip you off. The internet is great for small items but post on large items like pipe would be crazy.

Got some prices on 10mm clear sheet the other day (2440 x 1220 – 8’ x 4’) $330 + GST for full sheet, $190 + GST for half sheet. Would 10mm be thick enough considering that it isn’t trying to seal the driver?

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18th September 2012, 01:04 PM	#151
hajj diyAudio Member Join Date: Nov 2009	This looks gorgeous1 Mind if I use it as inspiration for my ongoing project?

18th September 2012, 01:39 PM	#152
Silent Screamer diyAudio Member Join Date: Feb 2012 Location: Sydney	knock yourself out, I'm just spit balling ideas at the moment rounding off some of the edges on the wood will give it a bit more of a refined look.

18th September 2012, 03:40 PM	#153
studiotech diyAudio Member Join Date: Jun 2004 Location: Orlando, FLA	Now you've got something original! And when did you sneak up to a 21"? Lol, this is fun! Just make sure you size the tubes so that they are not so long that the first resonance is within their operating range. Greg

18th September 2012, 10:28 PM	#154
Silent Screamer diyAudio Member Join Date: Feb 2012 Location: Sydney	Taking a leaf out of StigErik’s book I would like to get as low as I can using OB, and if I was to use a 21” and a 15” there should be adequate bass there to do the job done, and if there’s not I could always add a single sub for movies. There is still a lot of refinement work to be done on the current design. To do it in MDF slices would use up quite a number of 8’x4’ boards, so I am also playing with the idea of making clear hexagonal shapes in flat panels. Figuring 6 x 60 degrees = 360 degrees, and halving 60 degrees is 30 degrees either side of the cut. A 30 degree bevel cutter would be easy to get for the router. How do I determine the length required?

19th September 2012, 08:10 AM	#156
Silent Screamer diyAudio Member Join Date: Feb 2012 Location: Sydney	Greg I came across you sub build thread today, and decided to go to my local plumbing supplies after work today to see if I could get something like you have in your pics. They are getting me a price on some 450mm that is about 9mm wall thickness, but they said it will be around $500. So not really looking that flash of an option.

19th September 2012, 09:15 PM	#158
studiotech diyAudio Member Join Date: Jun 2004 Location: Orlando, FLA	That DOES look cool! I wonder about sitting the Raal right on top of the upper hex tube though. You've got a good foot of space for the bottom firing radiation of the Raal to reflect off of. You either have to put a bunch of heavy felt or Bonded Logic up there on the top surface or maybe leave that top portion hollow. Can you mount both woofers together and have the MID/HF module on legs only? Are you planning to run both woofers in parallel? Not sure if that will work given they may need different amounts of EQ.

19th September 2012, 09:17 PM	#159
studiotech diyAudio Member Join Date: Jun 2004 Location: Orlando, FLA	You should be able to find it for much less than $500. I got my 10ft piece for $100 on Craigslist. Ask around at a commercial jobsite or roadway construction area. There is always scrap of this that they just throw out after commercial construction.

20th September 2012, 12:07 AM	#160
Silent Screamer diyAudio Member Join Date: Feb 2012 Location: Sydney	I was actually wondering about the tweeter, but thought that the foam pads that come with it would stop upward dispersion. I haven’t got the new dipole RAALs yet (getting AM transformers fitted and being air freighted now), but from the PDF description I think they came with foam pads both front and rear. Nothing would stop me putting the top woofer higher or as you suggest opening it up on the bottom side. If I run two of any size driver I would put them in parallel, if I run odd sized drivers I would probably run them as separate channels. Still need to finish reading up why StigErik went away from this kind of design that he had, to the line array. Don’t want to spend a lot of money only to find that I have followed an inferior design. If I was to put two woofers on the bottom the design goal would be to have the HF/Mid separately mounted. Kind of like the idea of the clear hex tubes… kind of reminds me of the 70’s electric drum kits. Unfortunately there is no such thing as a bargain in Oz, if it is not commonly used that causes some kind of competition, then they figure that gives them license to rip you off. The internet is great for small items but post on large items like pipe would be crazy. Got some prices on 10mm clear sheet the other day (2440 x 1220 – 8’ x 4’) $330 + GST for full sheet, $190 + GST for half sheet. Would 10mm be thick enough considering that it isn’t trying to seal the driver?