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PostPosted: Sun Mar 19, 2017 9:32 pm 
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Location: MS Coast
Looks great! Too bad about the first one; I'm curious about how much difference that inch would make acoustically...

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-todd

5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)


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PostPosted: Sun Mar 19, 2017 10:32 pm 
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Location: Littleton, Colorado
ctmullins wrote:
I'm curious about how much difference that inch would make acoustically...
Yeah, I wonder. Maybe somebody who knows will chime in. I resisted the urge to throw it in my burn barrel :wink:

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Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
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PostPosted: Sun Mar 19, 2017 11:21 pm 
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Location: Warren, MI
jdmrivera wrote:
ctmullins wrote:
I'm curious about how much difference that inch would make acoustically...
Yeah, I wonder. Maybe somebody who knows will chime in. I resisted the urge to throw it in my burn barrel :wink:


You could just PL 1" strips, or the cutoffs, back on to save them. PL, wax paper, some wood cauls and some spring=loaded clamps, dampen the joints, lay down the PL, attach the strips, then spring clamps over wood cauls over wax paper. Give it a day or 2 to fully cure (bringing them into the warmer house helps a LOT) then sand and trim.

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I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice


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PostPosted: Mon Mar 20, 2017 2:36 pm 
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Location: Littleton, Colorado
General question about design.
The midrange driver is 6.5" diameter but the horn for it only has a 3.5" opening (less really with the plug) where the driver attaches to the horn. I'm curious how that works with covering up so much of the driver.

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Built:
Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
4 OT12s, 2 Melded Array, 2 Flat Array


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PostPosted: Mon Mar 20, 2017 2:44 pm 
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Location: Medicine Hat, Alberta, Canada
jdmrivera wrote:
General question about design.
The midrange driver is 6.5" diameter but the horn for it only has a 3.5" opening (less really with the plug) where the driver attaches to the horn. I'm curious how that works with covering up so much of the driver.

http://www.centauriaudio.com.au/diy/plugs.html

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Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
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For best results, point the loud end of the array towards the audience


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PostPosted: Tue Mar 21, 2017 10:23 pm 
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Location: Littleton, Colorado
CoronaOperator wrote:
Thanks for the link.
More pics tomorrow. Woofer is breaking in right now. I have midrange and tweeter cutouts done. Midrange horn installed and most internal braces done.
Would do pics tonight but my phone is busy playing 30hz tone for woofer break in.

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Built:
Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
4 OT12s, 2 Melded Array, 2 Flat Array


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PostPosted: Wed Mar 22, 2017 6:09 pm 
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Joined: Sat Mar 04, 2017 12:59 am
Posts: 73
Location: Littleton, Colorado
Latest progress:

Back is cut and here I'm marking the hole locations.
Attachment:
20170322_140015.jpg
20170322_140015.jpg [ 66.22 KiB | Viewed 226 times ]


Back flanges, internal braces and horn installed. I've also installed t-nuts in the flanges to hold the back on.
Attachment:
20170322_164755.jpg
20170322_164755.jpg [ 64.91 KiB | Viewed 226 times ]


View from the front.
Attachment:
20170322_164808.jpg
20170322_164808.jpg [ 56.7 KiB | Viewed 226 times ]
I made one sanding pass to see where are all the spots that need filling with bondo.
After letting the large driver play all night on the bench with a 30hz tone at about 11 volts, I noticed a slight buzz that seemed to be coming from somewhere near the outside edge of the cone. Couldn't really identify exactly where. I'll turn it on again this evening and see if it's still doing it.

_________________
Built:
Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
4 OT12s, 2 Melded Array, 2 Flat Array


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PostPosted: Thu Mar 23, 2017 6:13 pm 
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Location: Warren, MI
jdmrivera wrote:
After letting the large driver play all night on the bench with a 30hz tone at about 11 volts, I noticed a slight buzz that seemed to be coming from somewhere near the outside edge of the cone. Couldn't really identify exactly where. I'll turn it on again this evening and see if it's still doing it.


Do this outside, as far away as you can from buildings and vehicles. 30Hz can cause so many objects to resonate.

_________________
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice


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PostPosted: Thu Mar 23, 2017 8:59 pm 
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Location: Littleton, Colorado
DJPhatman wrote:
Do this outside, as far away as you can from buildings and vehicles. 30Hz can cause so many objects to resonate.

Will do. I also picked up an Inuke NU3000DSP. Will be interesting to see if that makes any difference.

_________________
Built:
Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
4 OT12s, 2 Melded Array, 2 Flat Array


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PostPosted: Fri Mar 24, 2017 10:01 pm 
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Joined: Sat Mar 04, 2017 12:59 am
Posts: 73
Location: Littleton, Colorado
Another noob question. The schematic for the bandpass crossover appears to show the negative end of the 22uf cap connected to the positive input from the amp. The capacitor I bought is polarized. Is there any issue with connecting the negative lead on the cap to positive input?
https://www.parts-express.com/ruby-gold ... r--020-668

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Built:
Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
4 OT12s, 2 Melded Array, 2 Flat Array


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PostPosted: Fri Mar 24, 2017 10:20 pm 
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Joined: Wed Mar 25, 2009 7:07 pm
Posts: 1278
Location: Medicine Hat, Alberta, Canada
Quote:
The capacitor I bought is polarized. Is there any issue with connecting the negative lead on the cap to positive input?
https://www.parts-express.com/ruby-gold ... r--020-668


Have you ever picked a dandelion and then held it in your hand and flicked off the flower? Cause if there is more than 3 or 4 volts going the wrong way through a polar cap that is what happens to the top of it. As audio is AC it gets current in both directions. I don't have the plans in front of me but I would double check to see if a polarized cap is acceptable.

_________________
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience


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PostPosted: Fri Mar 24, 2017 10:47 pm 
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Joined: Sat Mar 04, 2017 12:59 am
Posts: 73
Location: Littleton, Colorado
CoronaOperator wrote:
I don't have the plans in front of me but I would double check to see if a polarized cap is acceptable.


The plans use this capacitor symbol on the schematic which is polarized. the plans don't specifically say polarized or not but they do mention electrolytic which I believe are normally polarized. At least the ones I bought are.
Attachment:
foo1.jpg
foo1.jpg [ 14.35 KiB | Viewed 183 times ]

_________________
Built:
Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
4 OT12s, 2 Melded Array, 2 Flat Array


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PostPosted: Fri Mar 24, 2017 11:48 pm 
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Joined: Sat Mar 04, 2017 12:59 am
Posts: 73
Location: Littleton, Colorado
Quote:
After letting the large driver play all night on the bench with a 30hz tone at about 11 volts, I noticed a slight buzz that seemed to be coming from somewhere near the outside edge of the cone. Couldn't really identify exactly where.
Well it turns out I was being dense - the woofer was face up on my bench and air was moving out from underneath the magnet. When I pick it up - no more buzz!

_________________
Built:
Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
4 OT12s, 2 Melded Array, 2 Flat Array


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PostPosted: Sat Mar 25, 2017 7:48 am 
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Joined: Tue May 02, 2006 5:59 pm
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Crossover caps are never polarized.


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PostPosted: Sat Mar 25, 2017 8:55 am 
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Joined: Sat Mar 04, 2017 12:59 am
Posts: 73
Location: Littleton, Colorado
Bill Fitzmaurice wrote:
Crossover caps are never polarized.
I'm disappointed with parts express. All the caps I bougt from them look like this:
Attachment:
cap.jpg
cap.jpg [ 35.74 KiB | Viewed 165 times ]
Notice the arrow pointing to the negative lead. Guess I should have bought parts from Leland.

_________________
Built:
Omni Tallboy 15 w/3015LF (My BBQ music Machine!)
2 Lab 12 T39s 24" Wide
4 OT12s, 2 Melded Array, 2 Flat Array


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