New member/first BFhorn/Tuba45

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Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: New member/first BFhorn/Tuba45

#31 Post by Bruce Weldy »

ACUA wrote:
Bruce Weldy wrote:
ACUA wrote:

once my PL sets up and is hard. if i scrap it up with a knife it peals off to reveal the surface between the glue and the work piece and it looks like the glue is highly porous where it is in direct contact with the material i am trying to glue. the little blobs of glue that leak out of the caulking gun even after several days of curing can easily be broken in half the glue never seems to harden to the point of becoming brittle. i will not be in my shop over the weekend so the project will have several days to cure up we will see how it goes come monday. i will try damping the glue joints a little before applying PL and see if it helps.
Where are you located? Must be very dry there.
ya its dry, Arizona!!! 0% humidity and lately it is around 50degrees at night and 90degree high during day. thanks for the support and information all.
That's the problem then......just use a little squirt of water. Not a problem we have here in Texas, but I wish we did.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#32 Post by ACUA »

with my flush trim i cut out the driver chamber access hole, test fit my driver and verified the screw holes were all properly aligned. I believe that I will be using some caulking after i secure the driver to ensure that i get a proper seal between the driver and the cab. will be damping down the work pieces today to see how that reacts to the PL.
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ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#33 Post by ACUA »

found it a bit tricky at first to get the bracing to work for me but with some gentle sanding i got the fit i wanted, i think i ate more PL than made it onto my work piece today :noob: . I notched the internal brace for the driver surround in the event of some high excursions. PL seems to be working out for me and i cant exactly explain it but damping the wood seems to help or at least i will keep doing it i mean it is not hurting it.
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J_Dunavin
Posts: 1260
Joined: Sun Jul 09, 2006 3:13 pm
Location: Appleton WI
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Re: New member/first BFhorn/Tuba45

#34 Post by J_Dunavin »

Man, that LAB12 looks really good in there!
2 - OTop8
2 - T39
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#35 Post by ACUA »

I installed another piece, braced it up, cut and installed the top, used clamps to hold part in place, used some boards to align pieces, i have been filling voids and holes as i go trying to avoid leaks and problems in the future. i discovered that my skill saw can cut up to a 55degree angle that is cool, will work to brace top piece tomorrow,
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ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#36 Post by ACUA »

installed some bracing, the larger the horn throat gets the easier it is to work the bracing in. i am having better luck with the PL now that i am damping the work pieces better, i am getting better at gauging just how much to use i could see after a few builds getting good and being able to make the work look clean, for now i am making a PL mess like a proper noob should, i enstalled another wall and braced it and added the 45degree piece, i am going to sand a bit and wood fill from here on so that when im finished i can paint the inside with out worrying about anything, for the record i have opened up a new tube of PL and i wanna say that this batch of PL is seemingly better, stickier out of the tube and seems to set faster.
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ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#37 Post by ACUA »

i cut and installed the bottom, this tube of PL sets up way better than the other tube i had, and i keep using damp rag over the glue joints its working better for me, the joints dry harder faster i am really happy with it now!!! im getting more comfortable with the expansion rate of the PL and i am making less and less messes, i made my final panel bracing well some of it, i used a flush trim to make two identical braces and nailed them together after that i used my hand held jig saw and cut out the section for the cross brace, i am still rounding over the bracing, at this point its aesthetic, everything fit nice,
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ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#38 Post by ACUA »

final bracing in, i used same method with the cross bracing and it worked great, next will be the side, then router out the access panel, its coming along!!!
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ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#39 Post by ACUA »

i put the side on today, used some heavy batteries to try to ensure a proper tight fit on all of the joints, this part scares me the most because there are joint edges that i have no access to, i made sure and used a lot of PL just for some piece of mind, i had to use some clamps to get the box to square up to the side, its not bad i have had worse out of square situations, next time i may not cut the final side to size but leave maybe a half to quarter inch extra all around and then glue it on that way and just flush trim it to proper fit, the box is not absolutely square but i dont think it will be that easy to notice. PL is setting pretty well by about 5hours at this point definitely better than what was happening when i started.

i wanted to test the strength of the PL as i am new to using it, i took one of my 90degree jig fixtures and put it in a vice, used a pipe wrench and broke the 90degree glue joint apart, picture shows that the first ply of the wood broke off and the plywood adhesive was the weak link, the glue joint tore off the first of the 5 plys leaving the glue joint with PL still intact. i would be a fool not to believe in PL after that :fruit:
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commander_dan
Posts: 461
Joined: Sun Feb 16, 2014 7:19 pm
Location: Perth, Western Australia

Re: New member/first BFhorn/Tuba45

#40 Post by commander_dan »

Coming together nicely :clap: I'm interested to know your finished weight figure at the end of the build. I used marine ply in my T30's and combined with the 3012LF they came in at 36kg each.
Built:
6 T30 (24", 3012LF)
2 OT12 (MA, 3012HO)
2 T24 (18", 3010LF)

Running:
DCX2496
XTi 2002
XTi 4002
TRAKTOR Z2
TECHNICS 1210 Mk5's

ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#41 Post by ACUA »

thanks dan, no clue the weight and i have no way to weigh it exactly, i used my router to cut out the driver panel access panel, i flush trim cut the extra little bits of material off of the final side panel to make it look clean, i also cut the hole for the speakon connector, doors next, some sanding too i suppose...
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ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#42 Post by ACUA »

i decided to stain the cabinet because its cheap and different, i went with a dark jacobean, i installed the feet to the enclosure, man now that i stained it it looks like some 80s psychedelic zebra box!!!! hm oh well i guess i could always paint over it down the road, i like bedliner personally but its pricy.
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ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#43 Post by ACUA »

i counter set my pilot holes for the driver chamber covers and stained them, i soldered my wire to the speakon connector, i installed the speakon connector using both speaker gasket and silicone, i test fit my heavy lab12 driver in place, located my short screw driver and mounted the driver, i took my time and did my best to compress the outer gasket that was pre-mounted to the driver evenly and as much as possible with out stripping the wood with the screws, i placed silicone around the driver enclosure joint area and on the screw locations, it is a mess when the driver has to be removed but i want all the help i can get to ensure a proper seal ya.
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ACUA
Posts: 552
Joined: Sun Sep 25, 2016 6:21 pm
Location: Tucson Arizona

Re: New member/first BFhorn/Tuba45

#44 Post by ACUA »

gaskets on the driver chamber door panels, doors on box complete, some testing and leak detecting then i have wedding friday and a Halloween party next week,

If i set the cab parallel to some direct radiator mains what amount of delay should bet me ball park, 9ft?
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CoronaOperator
Posts: 1648
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: New member/first BFhorn/Tuba45

#45 Post by CoronaOperator »

ACUA wrote: If i set the cab parallel to some direct radiator mains what amount of delay should bet me ball park, 9ft?
It is more important that the tops and subs be "in phase" with each other than perfectly time aligned. That means that the peaks of the waves of the tops and the subs sum together rather than cancel each other out.

The quick and dirty way is to play a sine wave at the x-over frequency over the tops and subs, listen out front in the listening area, then invert the polarity of the sub and listen again. Which ever sounds loudest is the setting you choose.

A more precise way is to play a sine wave at the x-over frequency over tops and subs. Invert the polarity of the subs, then using a "spl meter/app on your phone/rta" measure the loudness out front. Then you adjust the delay until you reach the minimum volume level (maximum cancellation). Then you flip the polarity of the subs back to normal for maximum summation.

An even more precise way is to use Room EQ Wizard or Smaart, etc software to measure the phase and RTA of the tops and subs. You then align them using delay and or changing your x-over slope/type/freqency or adding all pass filters. The reason for this method is that although the above 2 methods will work for the frequency of your sine wave you use, there may be some funky cancellation going on half an octave above or below the x-over frequency and a phase plot will show that. This method is usually for installs at it takes too long for a mobile operator to spend the time on.

The reason I said the phase is more important than time delay is that for low frequency bass you are fine as long as the time doesn't vary by more than 20ms (about 20 feet). Our ears aren't that sensitive to time down that low and if you get into RTA's, neither are they at judging distance in the low frequencies. That and because your subs and tops aren't in the same place the delay between the two will vary depending on where you are in the room so getting it perfect only makes it better for that one spot that you measured. If your DSP can do it then 9 feet delay on the tops is about right if you want to get them close. You still have to do the above phase alignment though because a tape measure can't account for what is going on electrically. Your high pass and low pass crossover filters add delay to the subs as well as the voice coil of the drivers add delay. That electrical delay is also totally frequency dependent. Time aligning a sub is a lot like asking what time the train crosses the road. The front, the middle or the caboose? It is quite common for 35 hz to be 30ms behind 100 hz on a sub. Most people would think that bi-amping a 2-way horn + woofer cabinet, that the woofer should be delayed because the horn is set way back into the cabinet. Believe it or not it is the horn that needs the delay because the x-over and voice coil of the woofer have over delayed the woofer. You have to remember that what happens out front is the sum of the electrical and the acoustical properties and not just one or the other.
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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