First Build. Titan 48 w Lab 12.

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jmanso
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Location: Lisbon, Portugal

Re: First Build. Titan 48 w Lab 12.

#61 Post by jmanso »

Tom Smit wrote:While building, some people have shone a light at the bottom edge of each panel after it was installed to see if light appeared on the other side.


The rest of the answer is on the top of page 26 in your plans. (my typing finger hurts :mrgreen: )

Thanks ! We broke the driver a while back and in all honesty I hadn't picked that part of the plans in a while.

One thing though, I do this with the access cover off? or simply with no holes for the screws yet and just fitted?

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Tom Smit
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Re: First Build. Titan 48 w Lab 12.

#62 Post by Tom Smit »

Test the cab with the driver installed. Check whatever you can with the access cover off, and correct any failures. Then, install the cover, and recheck everything, correcting any failures.
TomS

Grant Bunter
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Re: First Build. Titan 48 w Lab 12.

#63 Post by Grant Bunter »

jmanso,

How wide is your cab?
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...

jmanso
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Location: Lisbon, Portugal

Re: First Build. Titan 48 w Lab 12.

#64 Post by jmanso »

Tom Smit wrote:Test the cab with the driver installed. Check whatever you can with the access cover off, and correct any failures. Then, install the cover, and recheck everything, correcting any failures.
Cheers. Now I got it. we did some initial testing yesterday and everything seems decent, but we really can't go over 7, 8 v in the studio we're using... the neighbours will have our heads !

We're hoping to have a place to do it this weekend.
Grant Bunter wrote: jmanso,

How wide is your cab?
It's around 52 cm. (50 cm wide plus 2x 12mm from the wood)

which google tells me it's about 20.4724 inches

Grant Bunter
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Re: First Build. Titan 48 w Lab 12.

#65 Post by Grant Bunter »

jmanso wrote:
Grant Bunter wrote: jmanso,

How wide is your cab?
It's around 52 cm. (50 cm wide plus 2x 12mm from the wood)

which google tells me it's about 20.4724 inches
I wish I had asked earlier then.
From what pictures I can see, you have nowhere near enough braces in your cab.

From My plans:
Braces connect the panels. Made of ¼ to ½ inch plywood, they are nominally spaced six to nine inches apart.
For a cab around 20 inches wide, you should have 1 x panel 2-6 brace, 2 x panel 3-5 braces, 2 sets of panel 5-8 braces (4 braces) and 2 sets of panel 9-6 braces with one crossbar.

I know for certain you only have one panel 9-6 brace and crossbar, so I assume you haven't put in the correct amount for the rest of the cab.

You might think that the cab is solid as it is, but any or all of those panels can flex, and when they do, that robs you of 3dB in output.
To give you an example of what losing 3dB means, if you are building 2 cabs and not properly bracing them, that would be the same output as 1 cab properly braced.

If you haven't put your final side on, you can fix this, with difficulty, but the hardest place to fix will be the panel 3-5 braces...
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...

sine143
Posts: 3066
Joined: Sat Feb 06, 2010 3:27 pm
Location: Raleigh NC

Re: First Build. Titan 48 w Lab 12.

#66 Post by sine143 »

The one solace is that this is a lab12 cab with reducers, which should help stiffeb things up a bit. The rear panel needs to be braced more though
Built:
2x Tuba 30s delta12lf loaded (gone)
4x Otop12 d2512 loaded
8x t48s (18, 18, 24, 24, 30, 30) 3015lf loaded
2x AT (1 mcm, 1 gto 804)
2x SLA Pro (dayton pa6, 6 goldwood piezo loaded)
1x bastard XF208

2x OT212 (delta pro 450a loaded, eminence psd)

jmanso
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Location: Lisbon, Portugal

Re: First Build. Titan 48 w Lab 12.

#67 Post by jmanso »

Oh... damn....

You are correct we only have 1 brace of each. We looked to Sketchup for this, and the model that resembles ours 12'' with Reducers AND panel 7 only has 1 of each brace.

I guess I can try to go through the horn to get to the back plate, also can probably fit one through panels 3 and 6.

that being said We've loaded the driver yesterday to start leak testing, and there wasnt a hint of structure failing. we didnt hear a single creak from the wood when we stood the speaker up, nor when we laid it down.

we did find however a leak in the back (top corner where all 3 panels come together and addressed it yesterday. hopefully not many more.

How would the bracing affect if we left the speaker laid on it's side? even if not braced enough for standing upright, will there be a difference if it's on the ground ?

Thanks

jmanso
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Re: First Build. Titan 48 w Lab 12.

#68 Post by jmanso »

a little side note, we ran a 30hz sine through it yesterday. at about 3v from the amp we had to turn it down, because the room we are using for building was just vibrating as if the building might colapse.

If that is about half of a full braced cab, than I can honestly say I may be scared of what actually comes out of a properly built BFM rig !!

:D

PS - Those 3v brought a biiiiiiiiiiiiiiiiiiiiiiiiiiiig smile to our faces! :D
PPS - Gasket arrived today. Gonna try to install it ASAP

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Bill Fitzmaurice
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Re: First Build. Titan 48 w Lab 12.

#69 Post by Bill Fitzmaurice »

jmanso wrote:Oh... damn....You are correct we only have 1 brace of each. We looked to Sketchup for this, and the model that resembles ours 12'' with Reducers AND panel 7 only has 1 of each brace.
The great thing about Sketchup is that you can use the tape measure tool to accurately measure each and every part. If you'd done so with the model with only one brace you'd have found it has 17 inch wide panels. You may not have a problem with only one set of braces, only time will tell.
How would the bracing affect if we left the speaker laid on it's side? even if not braced enough for standing upright, will there be a difference if it's on the ground ?
The bracing has nothing to do with the cabinet position. It's there to prevent the panels from vibrating.

jmanso
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Location: Lisbon, Portugal

Re: First Build. Titan 48 w Lab 12.

#70 Post by jmanso »

Bill Fitzmaurice wrote:The great thing about Sketchup is that you can use the tape measure tool to accurately measure each and every part. If you'd done so with the model with only one brace you'd have found it has 17 inch wide panels. You may not have a problem with only one set of braces, only time will tell.
I understand.
I guess from not having English as our native language, and of course from having zero experience on the matter we didn't understand the importance a few inches would do.
and most important to me we can't visualize inches as we use a metric system and have never been taught imperial measurements so we basically have to go "ask google" whenever we need a measurement.

Is it worth trying to "squeeze" in braces to try and hold the back better ?

Also, if the panels do vibrate will this risk the driver as an air leak does?

And finally, the DBX unit we got (Driverack PX) has a spl mic. Can that be used to determine if panels are vibrating ? Would I see a noticeable drop on the dB level? Can it be done on the DBX or would I require some sort of computer software?
Bill Fitzmaurice wrote:]The bracing has nothing to do with the cabinet position. It's there to prevent the panels from vibrating.
So nothing can be done? adding weight on it, or something ? This is for the internal panels then? not the external ones?

Thx

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Bill Fitzmaurice
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Re: First Build. Titan 48 w Lab 12.

#71 Post by Bill Fitzmaurice »

jmanso wrote:we basically have to go "ask google" whenever we need a measurement.
Or you could just follow the plans:
The Sketchup model that came with your plans is invaluable, and you should refer to it at every step in the construction process. If you need metric dimensions use the Window to open the Model Info/Units tab and change the readout to centimeters, then use the tape measure tool to directly measure the parts on the model.
Also, if the panels do vibrate will this risk the driver as an air leak does?
Vibrating panels waste energy that otherwise would end up as sound. They also can lead to eventual joint failure by placing more stress on the joints.

jmanso
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Location: Lisbon, Portugal

Re: First Build. Titan 48 w Lab 12.

#72 Post by jmanso »

Bill Fitzmaurice wrote:Or you could just follow the plans:
The Sketchup model that came with your plans is invaluable, and you should refer to it at every step in the construction process. If you need metric dimensions use the Window to open the Model Info/Units tab and change the readout to centimeters, then use the tape measure tool to directly measure the parts on the model.
agreed 110%, sorry for making you do the same speech all over :horse: :horse:

But in our excuse, we did use both sketchup and the doc plans to go over the measurements.
We ended up with a lot of stuff like 30,96 cm which is rather precise so we had to scale it to decimal, making it 31cm. I knew that having to do this on almost all of the panels would probably end a bit off but better too much than less.

Having all those measurements we had the ply professionally cut, and we did measure it while we were assembling and everything seemed pretty much like we asked.
Also, if the panels do vibrate will this risk the driver as an air leak does?
Vibrating panels waste energy that otherwise would end up as sound. They also can lead to eventual joint failure by placing more stress on the joints.
Is there a way to test this ? is the cab supposed to slightly vibrate on full volume or it stays completely still?

Are there any joints more prone to damage that we can test and possibly try to reinforce?

thanks

Grant Bunter
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Re: First Build. Titan 48 w Lab 12.

#73 Post by Grant Bunter »

The cab shouldn't vibrate at full volume with proper bracing, it should stay still.

And to help you visualise inches: 10cm is near enough to 4 inches (It's actually 10.1cm).
The acceptable allowance for variation in panel measurements is up to 1/8 of an inch, near enough to 3mm...
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...

billkatz
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Location: San Rafael, CA

Re: First Build. Titan 48 w Lab 12.

#74 Post by billkatz »

Since it appears you have one set of braces half way - rather than cutting them out to put them at the recommended 1/3 and 2/3 - perhaps you could just add two more sets at 1/4 and 3/4. I believe the only downside to 3 sets of braces rather than 2 is weight. If I'm wrong, I'm sure someone will correct me. Without the final side on adding them won't be too difficult. As someone else said, the 3/5 will be the toughest.
Built:
1 Omni-15 Tall Boy
2 DR250s
2 Titan 39s

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Tom Smit
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Re: First Build. Titan 48 w Lab 12.

#75 Post by Tom Smit »

+1
TomS

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