Plan for open baffle Jamo r909 clone

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THWO

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Re: Plan for open baffle Jamo r909 clone
« Reply #120 on: 26 Apr 2012, 10:34 pm »
The rear tweeters on my baffle are firing inwardly with satisfying results.





If you install them flexible, you can test what you like best.

Regards
Till

Rudolf

Re: Plan for open baffle Jamo r909 clone
« Reply #121 on: 27 Apr 2012, 07:47 am »
Jons bullet tweeter doesn't illuminate the hemisphere behind the baffle, but throws a "hot" spot on some part of the wall. I'm not sure if a directive speaker is the best approach in this case.

Rudolf

Poultrygeist

Re: Plan for open baffle Jamo r909 clone
« Reply #122 on: 27 Apr 2012, 12:25 pm »
My hat's off to anyone with the patience and skill to prime, sand and paint MDF.

On my next MDF OB's I'm going to try covering them with heavy pre-pasted wall paper and use molding on the edges.

Lazz

Re: Plan for open baffle Jamo r909 clone
« Reply #123 on: 21 Oct 2012, 08:16 am »
Hello John. I was wondering if you have finished the speakers and how do they sound?

LynX

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Re: Plan for open baffle Jamo r909 clone
« Reply #124 on: 23 Oct 2012, 05:14 am »
My hat's off to anyone with the patience and skill to prime, sand and paint MDF.

On my next MDF OB's I'm going to try covering them with heavy pre-pasted wall paper and use molding on the edges.

I agree with poultry, the last time I put together a MDF cabinet it took forever to sand prime and paint correctly. MDF just soaked up so much primer and when I finally went to paint it the first time some flaws were seen I didn't catch after sanding it multiple times. So back to more priming and sanding then painting. Well in the end I was fairly satisfied. Nope, throw veneer, sanded, stained, poly'd and more than happy.
ps: that mdf dust during sanding is a breathing killer, mask a must. Aw mdf, such an odd material. Pre drill holes or it will crack, heavy and dense but weak and easy to chip.

Also I would like to state these clones look awesome. I always loved those Jamo's thinking that I would create a clone later when I first saw the design as well. A job well done and patience has sure made this go along way. Well done.

Poultrygeist

Re: Plan for open baffle Jamo r909 clone
« Reply #125 on: 23 Oct 2012, 10:47 am »
I too wish for an update from Jon on this interesting build. Since I discovered the ease of active crossovers my OB's has taken on a new life. 

Bob in St. Louis

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Re: Plan for open baffle Jamo r909 clone
« Reply #126 on: 23 Oct 2012, 02:01 pm »
Thanks for the bump guys, I forget all about the build.
I was soooo looking forward to seeing the end results.

I've seen some fells do a brush on "sealer" for the MDF so it'll take paint.

Bob

SteveRB

Re: Plan for open baffle Jamo r909 clone
« Reply #127 on: 23 Oct 2012, 08:21 pm »

I've seen some fells do a brush on "sealer" for the MDF so it'll take paint.


works great. saves time.

jonirvine

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Re: Plan for open baffle Jamo r909 clone
« Reply #128 on: 23 Oct 2012, 08:48 pm »
Hey guys! So as many had predicted, it's much harder to go back an "finish" once I had it all assembled. This is due in part to my summer hobby of motorcycling kicking in and the fact that my air compressor busted right around the same time.  So I'll be picking up where I left off soon as the Portland rainy season is approaching. I have all of the finishing materials (primer, paint, etc) sitting in my garage waiting for me.

I'd be interested to hear more about which MDF sealer people have had success with.  But for now, I've decided to do the following:
  • Seal the edges with a glue/water mix
  • Seal the edges again with wood puddy and sand.
  • Roll a few coats of primer and sand
  • Buy a new air compressor on Craigslist and paint/wetsand x 4 or so coats
  • Polish if necessary

As far as sound is concerned, I'm super satisfied with the results but i think once I get through the finishing process, I'm going to replace the passive C/O's with active C/O amps on the subs and run the TangBand's wide open with my current tube amp.  If that doesn't quite do the job, I may add a miniDSP into the mix and tune each speaker on the front end. 

All summer I've enjoyed them immensely and my friends who have experienced them have also been equally amazed at the clarity and realistic soundstage. If anyone lives in the area, I invite you to come take a listen and let me know what you think!

Jon

Bob in St. Louis

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Re: Plan for open baffle Jamo r909 clone
« Reply #129 on: 23 Oct 2012, 08:59 pm »
I've never (successfully) seal MDF edges myself, but have been witness to the process with buddies.
It's a simple layer/coating of chemical brushed on, then sanded, then painted. After that, it's treated like any other material being painted and sanded. Just don't sand back down deep enough to hit fresh MDF.

Or....Wrap the baffle in speaker fabric, screw the drivers in over the top of the fabric, and call it a day.  :lol:

Bob

SteveRB

Re: Plan for open baffle Jamo r909 clone
« Reply #130 on: 23 Oct 2012, 09:31 pm »

I'd be interested to hear more about which MDF sealer people have had success with.  But for now, I've decided to do the following:


I skipped the water/glue and used a fine drywall filler rubbed into all the seams -- sanded with 220. Wood filler was a little too gritty and not fine enough for the small seams. The best advice I got was to avoid any soft sanding blocks. I used a 6"x12" piece of mdf and a full sheet of sand paper to really smooth everything out.

Then I primed and sealed everything with this rolled on:
http://www.homedepot.com/buy/paint/primers/zinsser-bulls-eye-1-2-3-1-gal-water-based-white-primer-sealer-182407.html#.UIcK3LSxFGE

Again, sand with a large flat sanding block.

Depending on your seams, you may need to repeat the procedure. And remember to let everything dry overnight before sanding anything !

The results I got were fantastic. You can see my current build here:
http://www.audiocircle.com/index.php?topic=109455.0

I'm in the same boat with the weather in Vancouver - next sunny day I'm taking off to do the final spray.

LynX

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Re: Plan for open baffle Jamo r909 clone
« Reply #131 on: 6 Nov 2012, 11:52 pm »
Did you ever finish the project? painted, etc? Finish PICTURES? Just wondering what other inexpensive drivers would go with a project like this besides the alphas.

Thinking about doing a similar project and noticed a couple drivers that might fit the bill. MCMelectronics have a couple new models out. The one I was looking at was  55-2993 with a fs 44hz, qts .53 xmax 6.5mm spl 98 100oz magnet, 4.0" voice coil die cast frame.

Those baffles look really good. You CNC'd them? Did you have this at hand, or did you get it done somewhere else? Where can I get wood cut like that, and how much does it cost?

What inexpensive fullrange driver could be used for the top half besides the TB?