First build: 2x Otop8

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hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#16 Post by hbinderup94 »

ACUA wrote: Sun Mar 17, 2019 10:38 am I built 4 otop12s and 4 t45s. If I could take what I know and do it over I would do what you are doing. The otop8 I do really like and after 2 years of Giging/djing I believe that t48 would have been the better cab for me.

So I think you are off to a great start. I’m all about the driverack or any of those sophisticated dsp units, they solve a great many of the audiophile problems.
Good to hear, thanks for sharing!
I went through numerous of different setups before settling for the OT8 and T48 build. So many that my friend started to get a little too annoyed by me haha! But better safe than sorry :noob:
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: First build: 2x Otop8

#17 Post by Grant Bunter »

I see more than two top hats.
Please tell me you're not planning to put top hats in the subs!

I know you've spent a lot of time lurking in the forum, but have you learnt the sub sticky yet?
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#18 Post by hbinderup94 »

Grant Bunter wrote: Mon Mar 18, 2019 4:33 pm I see more than two top hats.
Please tell me you're not planning to put top hats in the subs!

I know you've spent a lot of time lurking in the forum, but have you learnt the sub sticky yet?
Of course I did! And I also read the sticky about array stacking ;)
Decided to go for double top hats (top and bottom hat I guess you could say..) on these two OTs, then I'll consider the next pair. Better to have the option, and it's quite a cheap upgrade..
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#19 Post by hbinderup94 »

Spend a few hours with the laser cutter today.. And I must say, that I'm quite amazed; being used to 3D printers, this was just a piece of cake.
I had already drawn the models in 2D, but as I'd drawn the models directly from the plan, the models were scaled in inches.. So they were quite small when imported as millimeters...
I then converted everything to millimeters, double checked the scales, and was then ready to lay out the models (you can see the layout on the screen).
54517763_2226166120966688_4655077793846001664_n.jpg
After testing the settings, all we had to do was close the lid, turn on the ventilation and hit the big "start"-button. :chainsaw:
55826172_2296286137312193_4378817976879546368_n.jpg
The 12mm parts were then cut.
54798331_2296125023784536_4963205516529500160_n.jpg
The HF parts were cut in 6mm. Same with mid horn reflectors. Also I checked the hole for the top hats with the 25 degree angle - fits like a charm :hyper:
I added a margin to the sides with angles, why some components might look a little different...
All the parts that were cut with the laser cutter:
all_parts.jpg
Test fitting the woofer spacer - used the dimensions from the datasheet as it fit quite well with the recommended diameter from the plans. The woofer spacer is slightly smaller than the inner frame of the woofer - so it seems spot on.
54800039_414365692441853_5810096599702962176_n (1).jpg
A short video of the laser cutter running:
https://youtu.be/kWmGlM78y-E
The youtube linker doesn't seem to work.. hmm?

So excited to continue the build :cowboy: :cowboy:
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

User avatar
Tom Smit
Posts: 7454
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: First build: 2x Otop8

#20 Post by Tom Smit »

Cool.
I was able to watch the video.
TomS

hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#21 Post by hbinderup94 »

I have some questions:

Question #1: What exactly is attachment screws (maybe language difference, but I can't seem to find anything about these specific screws in Denmark)? I'm thinking the ones to connect the woofer to the baffle.
I suppose that the screws go into the wood and need no bolt on the other side - I can't really see a way to reach around the baffle, when everything is installed - if this is the case.. I also assume that the lock-washers will sit on the woofer gasket then? :confused:

Question #2: When installing the back of the cabinet. Is it same deal as the woofer driver? And do you recommend using an airtight layer around the edges? Have seen some people who use it, and some who don't. The plans doesn't specify it.

Question #3: Assembling the HF horn. The plans say that I can use hot glue to hold the pieces in place. How do I keep the pressure on the parts then? Is hot glue really that strong.. hmm ,,

Question #4: When using jigs; I've seen different methods here - the plans recommend using wax paper. But I've seen people not using it. How does that work? You put the jig, install the part, screw it in place (correct position because of the jig), remove the jig, wait for glue, remove the screw, fill the hole with PU?

Question #5: Painting the horn reflectors with Warnex (EU Duratex) - good idea or not? Have seen people doing duratex on the outer layers of the cabinet, but used a normal paint for the reflectors of the horn. Same goes for the HF horn. Just asking to be sure..

These are the questions that I picked up from reading a hundred build threads + the plans (100 times at least now). I know that there aren't stupid questions, so I'm just asking to be sure! Wood working is still not my strongest skill..

The real build starts this week, hopefully as I'm freaking busy with University, but I'm planning for it.
We did a show this weekend with another sound system, and I really can't wait to bring this setup instead. The next event is in the middle of May, so at least the OT8s should be done by then.. Not so sure about the T48s though - my schedule is pretty tight the next months.. That said the system we use have nice subs (also DIY, not sure about the design.. can upload it here if anyone is curious), so it should be alright.. until we finish the T48s of course! But I'm sure that OT8s will add quite some spice to the sound :chainsaw:
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

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

Re: First build: 2x Otop8

#22 Post by ACUA »

1) wood or drywall screw?
2) weather stripping/ speaker gasket material?
3) hot glue cools in under a minute so you have to hold the part while the hot glue dries but once is cools it holds the parts over night while the pl dries/cures
4) what ever you do you don’t want the jig to get glued into the speaker cabinet!!!
5)I plan to Duratex mine at some point I’m not worried about it.

Good luck
Advanced Concepts Underground Audio

hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#23 Post by hbinderup94 »

ACUA wrote: Mon Apr 01, 2019 6:18 pm 1) wood or drywall screw?
2) weather stripping/ speaker gasket material?
3) hot glue cools in under a minute so you have to hold the part while the hot glue dries but once is cools it holds the parts over night while the pl dries/cures
4) what ever you do you don’t want the jig to get glued into the speaker cabinet!!!
5)I plan to Duratex mine at some point I’m not worried about it.

Good luck
1: so basically just any screw that's made for wood with pilot holes?
2: exactly yes. But I've seen people using it, and also some who don't. Is it necessary with the big surface area from the back mounts?
3: super, thanks!
4: that's what I'm scared of.. gonna find some waxpaper I guess :)
5: I'll do the same then.

Thank you very much :)
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: First build: 2x Otop8

#24 Post by Grant Bunter »

hbinderup94 wrote: Tue Apr 02, 2019 4:06 am
ACUA wrote: Mon Apr 01, 2019 6:18 pm 1) wood or drywall screw?
2) weather stripping/ speaker gasket material?
3) hot glue cools in under a minute so you have to hold the part while the hot glue dries but once is cools it holds the parts over night while the pl dries/cures
4) what ever you do you don’t want the jig to get glued into the speaker cabinet!!!
5)I plan to Duratex mine at some point I’m not worried about it.

Good luck
1: so basically just any screw that's made for wood with pilot holes?

Yes and no. Look up recex screws at www.speakerhardware.com
or robertson screws, you'll get the idea.


2: exactly yes. But I've seen people using it, and also some who don't. Is it necessary with the big surface area from the back mounts?

yes

3: super, thanks!

+1
4: that's what I'm scared of.. gonna find some waxpaper I guess :)

+1

5: I'll do the same then.

You could use some ordinary flat black, it kinda depends on how you're going to finish the front side of the cab, but I use a couple of coats of flat or matt black and then one coat of non textured cab finish, but that's me.
I'm happy to go over the outside as many times as is needed as time goes on for the outside, as time goes by, but I want to do the inside once and once only if possible...

Thank you very much :)
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#25 Post by hbinderup94 »

First day in the workshop!
We decided to go to a public workshop, as it's really close to my place, and also they have a lot of nice tools.
There are professionals who are ready to help. This meant that we spend the first couple of hours getting introduction, and trying out some things.. But of course (as I also expected); Bill's ways are just the easiest.
So we were ready to get going, and first was cutting the top/bottom pieces. The plywood was bought in the workshop, and it's of really nice quality!
55939429_349487282339230_8185029676905791488_n.jpg
We drew it all and made sure that everything had the correct measurements. As some clever board members wrote: measure twice, cut once. We did more like measure 10 times, but yeah, it fits really well.
After drilling the center hole, we found out, that the tophat isn't a perfect cylinder... There was 1mm difference from the top and bottom, that we had to adjust for - easily done with this machine.. (lesson learnt as well):
56119538_852046278470891_3845862219627626496_n.jpg
Time to install the baffles. Went better than expected with jigs and wax paper.
56472512_691046077982837_7165361413853020160_n.jpg
Waiting for the PU to dry, so we cut the rest of the pieces. We now have all the wood and it's all cut out - also the angled 12mm parts.
56673039_323938998475147_7841672506451689472_n.jpg
Installing the braces. We were a little scared to work on the baffle while the PU dried, so we decided to wait a little longer.. This was also the last part we could do before the workshop closed. I'm a little sad that we didn't get to install the other braces, as we have to wait for it to dry before installing the horn sides..
56226044_238270073678800_4688551690914234368_n.jpg
While we waited for the PU, we also started cutting the angles on the 6mm parts. We didn't run into any problems, but also we didn't do the harder parts yet.. We'll see how it goes tomorrow! Can't wait to continue :hyper:

I've cleared my schedule, so we'll go to the workshop tomorrow and Friday as well. The opening hours are limiting us a little, but it's alright. We're not in a hurry, and the build is actually super fun! But tomorrow will be another 6 hours and Friday 5 hours. Then hopefully it'll start looking like an Omnitop :chainsaw:

We use the Sika Bond 545 PU (the one I've seen other Danes use on the forum). We checked the ingredients, and it's very similar to the PL Premium. It also works wonder! Did some tests, and it's just insane how it spreads and expands. So nice! A question: How long do you usually wait before continue working on the glued pieces? The bottle says that the pressure time is 3 hours and hardened time is 24 hours. :feedback:
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#26 Post by hbinderup94 »

Second day in the workshop :chainsaw:
Another set of braces were installed first:
56191278_263631174525282_837370665391620096_n.jpg
As we wanted to make sure that the braces were dry enough to work with, the horn panels were installed a couple of hours later. This was actually a little more complicated than expected. All the panels fit like a charm, but the jigs and gluing was another thing - gravity was not exactly helping..
Well, the panels were installed and kept in place with, maybe not the prettiest, but quite functional jigs. Also there's no warping, so no screws were needed. Only clamps, jigs and plenty of wax paper!
You can see the effect of gravity on the PU on the bottom plate. We'll have to remove that tomorrow. At least it'll be airtight and indestructible.. :fingers:
55954356_401180627347139_6196801294527627264_n.jpg
They look quite nice, and people are very interested in what we're building. Worst was someone asking us if we were building a doll house :lol:
56608885_2578181842211833_3912469702030393344_n.jpg
All the panels follow the edge very smoothly. The jigs worked wonder :hyper:
56514059_2287948638128417_7581098167748263936_n.jpg
As we spend a lot of time waiting for the PU to dry, we also cut angles for throat reflectors and some parts of the diffraction horn.
Also we began doing the handles on the cabinet sides. It's super difficult to get the measurements correctly, as everything is in inches, and we don't use that... so the tools won't have the exact sizes. The holes were made with a 1mm wider diameter.. Hopefully it won't affect the sound that much..

Oh, and after working with the enormous table saw for two days now, we still both count 10 fingers! Even though the small parts for the horn is a little scary to angle.. we also had a professional to show us some tips!

Tomorrow we only have 5 hours of opening, but the goal is to install the sides. Let's see how it goes :fingers:
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: First build: 2x Otop8

#27 Post by Grant Bunter »

hbinderup94 wrote: Thu Apr 04, 2019 5:08 pm It's super difficult to get the measurements correctly, as everything is in inches, and we don't use that... so the tools won't have the exact sizes. The holes were made with a 1mm wider diameter.. Hopefully it won't affect the sound that much..
Not difficult at all!
In sketchup, you can change the default measurement from inches to mm, so you can get your measurements down to the mm.
The tolerance is up to 1/8", or 3.2mm...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

User avatar
Padde298
Posts: 115
Joined: Thu Jun 29, 2017 5:04 am
Location: Denmark

Re: First build: 2x Otop8

#28 Post by Padde298 »

Hej Hans.
Really a great thread. Looking forward to more pics. What do you plan to use as sub for the Otop8's? Love how you use spanners! You can NEVER have too many spanners...
More bass, more bass! :chainsaw: :chainsaw:

2 x TAT

hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#29 Post by hbinderup94 »

Grant Bunter wrote: Fri Apr 05, 2019 4:02 am Not difficult at all!
In sketchup, you can change the default measurement from inches to mm, so you can get your measurements down to the mm.
The tolerance is up to 1/8", or 3.2mm...
That's exactly what I did :)
I think that I have to live with not being able to do it in exact measurements.. we have 1mm off at maximum, and I thought that was a lot.. seems like it's fine.. being used to 3D environments, it's just a lot haha
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

hbinderup94
Posts: 27
Joined: Fri Feb 15, 2019 3:01 pm
Location: Aarhus, Denmark

Re: First build: 2x Otop8

#30 Post by hbinderup94 »

Padde298 wrote: Fri Apr 05, 2019 6:10 am Hej Hans.
Really a great thread. Looking forward to more pics. What do you plan to use as sub for the Otop8's? Love how you use spanners! You can NEVER have too many spanners...
Thank you for following!
We finished for today already, but will upload pictures as soon as I get on my laptop.
Haha, that's my thought as well! The goal is to not use any screws to clamp at all - and so far it's going quite well :chainsaw:

We're gonna use 2x T48 24" with kappalites :hyper:
Built:
2x Omnitop 8; Beta 8 + asd1001 - viewtopic.php?f=30&t=25234

Bought:
2x Titan48, 24"; 18sound 15nlw9300, V-plate (Built by Emanuel)

1x Crown XLS 1502
1x Crown XLS 2502
Driverack PA2

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