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Recommendations for Sealed Reference System - Page 3

post #61 of 72
Thread Starter 
That's kind of what I figured Jay - I appreciate you running the numbers. My understanding is that the change may move f3 down a couple Hz at the expense of output above that - is that right?
post #62 of 72
Quote:
Originally Posted by HopefulFred View Post

That's kind of what I figured Jay - I appreciate you running the numbers. My understanding is that the change may move f3 down a couple Hz at the expense of output above that - is that right?


The 3 ft3 flat packs really aren't really an optimal volume for the UM honestly. They aren't bad by any means, and of course they're very convenient/well built. With 3.5 ft3 your power handling vs xmax doesn't even drop off until below 10hz, so it isn't an issue, and you gain a db at 20hz.
post #63 of 72
Thread Starter 
Super
post #64 of 72
I would put the driver as close to the floor as possible. With it at the top like in your sketchup drawing it is going to rock back and forth much more due to the added leverage. This results in a loss of output and wasted energy.
post #65 of 72
Thread Starter 
That is probably a good idea. I have conflicting thoughts about driver placement, in that I want to have some easy way to disrupt the primary vertical resonance, but also don't want the driver to be directly behind the head of a listener. The mechanical issue your talking about is another good reason to put the driver at the bottom. Thanks for mentioning it.
post #66 of 72
Thread Starter 
Okay guys, I said I would come back when I had some stuff built. I'm back, but not because it's finished - because I messed it up and need to know if it's recoverable.

I've had some cash flow issues to get straight, so buying drivers got pushed back a little, and PE has the knockdown boxes on back-order for a couple more weeks, so I still haven't received the two kits I bought. In the mean time, I've been building and finishing the two tall cabinets I posted about. Here's the picture of their current status:


The problem is that I'm a dummy and can't manage to read specifications and cut to the right dimensions. The cutouts for the drivers are 15 3/8 inches across - which is too big, even for the the overall dimension given by PE for the UM15-22.
Quote:
Overall Outside Diameter 15.28"
Baffle Cutout Diameter 13.78"

Are these cabinets trash or can I add some supports and shim out the driver? The cabs are a little larger than optimal for Qtc anyway. Don't sugar-coat it. frown.gif
Edited by HopefulFred - 9/17/13 at 7:11pm
post #67 of 72
There are a couple of things you can do to fix it. 1) Remove the finish on the front and cut another baffle. Glue, cut correct opening, and refinish. 2) Cut a ring the correct size ID to fit the driver and OD the inside width of the box. Cut it into two equal halves and glue them to the back of the front baffle. Care will need to be taken in clamping in either case. I have used both methods after messing a couple of boxes up in the same manner.

The first one is the easier method if the depth of the enclosure is not set in stone. The second option assumes the current cutout is larger than the OD of the drivers frame making a recessed mounting flange.
post #68 of 72
Thread Starter 
Quote:
Originally Posted by filtor1 View Post

Cut a ring the correct size ID to fit the driver and OD the inside width of the box. Cut it into two equal halves and glue them to the back of the front baffle. Care will need to be taken in clamping
I was a little panicked and disgusted and couldn't see this solution. I know I can do this - I see it now. Thanks for layout it out like this so I could see it - it's actually not such a big deal, since I have some finish work to redo in a few spots, so adding a few more screw holes will not be the end of the world.
post #69 of 72
Quote:
Originally Posted by HopefulFred View Post

I was a little panicked and disgusted and couldn't see this solution. I know I can do this - I see it now. Thanks for layout it out like this so I could see it - it's actually not such a big deal, since I have some finish work to redo in a few spots, so adding a few more screw holes will not be the end of the world.

I hear you things happen and one can get pretty discusted! Hang in there, looking very nice! cool.gif
post #70 of 72
Quote:
Originally Posted by HopefulFred View Post

I was a little panicked and disgusted and couldn't see this solution. I know I can do this - I see it now. Thanks for layout it out like this so I could see it - it's actually not such a big deal, since I have some finish work to redo in a few spots, so adding a few more screw holes will not be the end of the world.

I am just glad I could help. smile.gif Those cabinets look great BTW!
post #71 of 72
Thread Starter 
Quote:
Originally Posted by steve nn View Post

Hang in there, looking very nice! cool.gif

Quote:
Originally Posted by filtor1 View Post

I am just glad I could help. smile.gif Those cabinets look great BTW!

Thanks guys - I'm cautiously optimistic that I can make this look good in the end. That was the primary goal in design and finish, so I hope that getting the drivers recessed neatly actually improves the results vs the original design. If you're interested, the details of the paint and process I've used are in my dedicated theater build thread - here
post #72 of 72
Thread Starter 
This isn't really a build thread, but I wanted to keep this relatively complete and up to date - insofar as it contains my path to completing this system.

I finally got some partial repairs to my poorly measured cab - only one of two so far. I'm still holding off on amplification, and the repairs I've photographed are not yet finalized - bolted, but not yet glued. I decided to make a more stylistic choice than to go with my initial reaction, which was to make a seamless repair. Instead, I went with carriage bolts. I'll probably buff/sand the numbers off the heads and paint them black, but maybe not.

Anyway, here's the basics of the repair process in pictures.





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