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Old 21st March 2011, 08:37 PM   #921
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I'm actually wondering the same thing. It would be my estimate that these replica piezos should have a lower value resistor. Between 33 and 47 Ohms seems like a more optimal value just from experience with other similar piezos. Of course, if you've measured them and calculated 150 Ohms to be the best and confirmed that with listening tests, then I guess it's the right value for those too.
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Old 21st March 2011, 09:42 PM   #922
rubennn is offline rubennn  Denmark
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I didn't test them as I don't have the equipment to do it. But I guess I'll put a 40-50 ohm resistor on them and hope for the best (I think you said somewhere that people often tend to use too low resistor values). If they sound bad, I'll experiment with higher values.
Still, have you figured out what the optimal solution is for the original piezos for the new design when talking about the resistor value?
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Old 21st March 2011, 10:37 PM   #923
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Yes, 33 Ohms.
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Old 23rd March 2011, 11:44 PM   #924
kblnig is offline kblnig  Denmark
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http://www.sperbits.ch/foto.JPG

I am almost finished with my boominator. As mentioned by a lot of other people.. WOW it plays loud - However i might a slight change in the design compared the original design (i regret most of my desissions ).. However i have some questions regarding the drop in performance made from theese dessions/mistakes:

1: i did not make the center brace.. will this affect the sound in a noticeable way or is the purpose of the bracing rather to make the boominator indestructable?

2: i assume i have a lot more airgaps different places around the system.. For instance i did not glue the entire box together but made a removeable lid which i fasten by some hinges as shown on the picture. (i added a gasket between the lid and the box in order to seal it as much as possible). Is this sealing allright and how much does it matter?

3: I painted the tweeters (the routing for the holes on the tweeters were my first routing ever so there was a gap which i fixed with some extra paint and some pollyfilla... that looked horrible so i decided to paint them as well, knowing that i changed the response of the tweeters by adding some mass to them - the layer of paint on the tweeters is rather thin).. is this a major concern.. should i replace them?

the 3 things listed above are my biggest concern for my boominator.. i know my questions are a bit loose.. but some advice regarding where i should try do some damage controll will be much appreciated
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Old 24th March 2011, 06:05 AM   #925
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1. and 2. are related. The point is to make the cabinet as rigid as possible and 100% air tight under all conditions. The very point is that it's the speakers and not the cabinet that's supposed to vibrate and thereby make sound. The more rigid and more airtight the cabinet is the better sound in general, and better bass in particular.

I would suggest immidiately pulling of those hinges off and glue the cabinet together is it's supposed to be, and making sure there's absolutely no other holes or air gaps than the port itself.

3. Your choice. I'm pretty sure that no matter how much paint you've spray on none of it has hit the actual membrane that is in the back.

Last edited by Saturnus; 24th March 2011 at 06:07 AM.
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Old 24th March 2011, 11:36 PM   #926
kblnig is offline kblnig  Denmark
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Ive been thinking all day about how to remove the hinges, and still make the box look somewhat cool. I decided not to remove them since i used so much time in painting the box. Glueing the box furthermore gives me no means of replacing the elctronics !! (the lid is pressed with great force agains the sealing gasket so i guess the problem is not catastrophic???) I will instead build another version of the boominator for a friend, paying more attention the details in your design...

I added some bitumen different places on the inside of the box and then i sealed all small holes on the inside with some sealant rubber... I think it sounds awesome!!, but this is my first audio project ever so i have nothing to compare it to. Even though i decided not to go with your answer, then thank you anyhow. Knowledge for future projects is allways well appreciated. "Copy Saturnus audio knowledge initiate"

Last edited by kblnig; 24th March 2011 at 11:45 PM.
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Old 25th March 2011, 07:54 AM   #927
rubennn is offline rubennn  Denmark
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It will probably still sound very good But as previously mentioned by Saturnus himself, the boominator design is somewhat perfect in all aspects. Changing the design will only degrade quality (even though the project will still sound awesome when superdrunk).
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Old 25th March 2011, 01:32 PM   #928
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It5's not a big deal to add a few big bolts, the kind with plastic knobs on them meant for tightening by hand rather than with a wrench. You just need tio install some blocks of hard plastic or aluminum inside, screwed into the walls, and drill and tap them out to fit the bolts, and also drill matching holes in the lid. With six or so, you can really fasten the lid down quite tightly, but still make it pretty easy to access the inside. If you pick some cool-looking ones (check your surplus outlets), they can even add to the aesthetic. Like this:

McMaster-Carr

--Buckapound
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Old 25th March 2011, 01:56 PM   #929
kblnig is offline kblnig  Denmark
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Quote:
Originally Posted by Buckapound View Post
It5's not a big deal to add a few big bolts, the kind with plastic knobs on them meant for tightening by hand rather than with a wrench. You just need tio install some blocks of hard plastic or aluminum inside, screwed into the walls, and drill and tap them out to fit the bolts, and also drill matching holes in the lid. With six or so, you can really fasten the lid down quite tightly, but still make it pretty easy to access the inside. If you pick some cool-looking ones (check your surplus outlets), they can even add to the aesthetic. Like this:

McMaster-Carr

--Buckapound
is hard plastic a better solution than a rubber gasket? my lid is very tightfully mounted.. but that is just from a "craftsman" point of view (i cannot rock the lid by hand at least)... i got no clue on how airtight it is and i dont know how to test for it either?
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Old 25th March 2011, 02:12 PM   #930
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You can test how tight it is by putting it on full volume and cover the port. If any air leaks out (or in) it's not tight enough.

If you're worried about appearance you might want to turn it over 180 degrees and install the panel from the top in the bottom instead. And then do as Buckapound suggests, with the rubber gasket still in place. Because then any bolts will not be visible, and if you need to, you can just turn it over to get access to the inside.

That's actually the reason why the hole in the electronics compartment Boominator design is on the bottom. Because you practically never have to access it, so you can just as well have it on the bottom where no one can see it. That also have the side effect of should there be spilled water into the venting holes, from rain or just drunk people, it will flow out of the bottom hole without harming anything inside.
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