C/E/X PA Flat to 30 (FT30) PA TH Awesomeness

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#325
m R g S r said:
Yes it does. If someone else doesn't jump on this I might be the first to build it within the next couple weeks!
Martin any chance you wanna make this reallyyyyy easy and include a cut sheet as well? (well cut sheets) 😉
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Make sure your bracing is enough (and made well) cause that thing gets "swollen cheeks" :gasp: (and that is going to cost you a couple of dB's). The problem I brought up in post # 309 was caused by bracing that came loose.
 
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#327
m R g S r said:
I will! Is it better to run a single thicker brace through the center of the horn path or should i run two thinner parallel braces?
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One in the middle but use my second suggestion as guideline cause it can use support over the whole length at the back (don't forget to cut out the wholes). Btw, you would be the first as ours are not the same as Xoc1's (ours are similar and -3dB at 36Hz but 2dB in SPL lower 🙁 )
 
#328
Martin any chance you wanna make this reallyyyyy easy and include a cut sheet as well? (well cut sheets)
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Maybe -
Can you give me some guidance on what allowance you think is reasonable for the saw cuts.
Would you be cutting the mitres with the saw bench?
Also I take it that you are happy with a simple glued and screwed box and you are not rebating the sides?
This is one of the problems with providing a cut sheet, different people have different ideas, skills, and techniques for construction.
It would be very easy for instance to generate some DXF files to allow the sides to be rebated with a CNC Router.🙂
That would probably be my choice!
Thanks for all the positive comments from everyone, I am very busy at the moment and it looks like that might be the case for at least another couple of months. However I am very happy to continue to develop these designs within the forum.
The current design is based on the inputs of many forum members and as such I am not really in a position to claim ownership of any part of it. I,m enjoying bringing all the different knowlege skills together.😱
m R g S r when you are ready to build let us know and we can start a new thread and get all the relevant information together in one place!😀
 
#329
I would love to Use the Cnc router that I don't have lol so yes glued and screwed is the only way for me to do it.
For cutting allowance, it doesn't really matter as the design isn't single sheet based. So whatever the allowance is is fine with me.
All I have is a table saw and a router drill press hole saws etc. No crazy, expensive, Computer driven tools.
 
#331
Djim said:
One in the middle but use my second suggestion as guideline cause it can use support over the whole length at the back (don't forget to cut out the wholes).
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Yes, hollow your braces by quite a good amount - the more 'solid' they are, the more low corner you sacrifice.

Djim said:
Btw, you would be the first as ours are not the same as Xoc1's (ours are similar and -3dB at 36Hz but 2dB in SPL lower 🙁 )
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What are you referring to when you say, "ours" by the way?
 
#334
External Bracing

Hi Y'all,

Bracing can work really well when applied from the outside. I once did this to a poor Altec A7 rattletrap, and the next owner added pipes between the braces at the back corners as handles. Also protects the box when lugging it around.

Regards,
 

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#335
That only helps for the outer panels, the inner planels which are all 535mm wide would still be unbraced. If you don't care about weight, then sure go crazy and add steel plates to the outside of the box lol but for something that is supposed to be "semi" portable i think metal bracing would add a bit too much weight....


For initial construction, i think that adding the internal bracing along the entire length of the path down the center seems like a good option. I will add as many holes as possible without weakening the braces too much. Then in the future I could always add to the outside. Or I could use 1" ply for the outter panels and 3/4" (sorry..err..18mm) for the inners
 
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#336
Crescendo, our cab is based on an extra folding to Jbell's concept (see one sheet challenge) and kept everything as symmetric as possible for easy building.

MrGsR, going full inch panels doesn't make a big difference as the structure of the Beechwood isn't more dense. If really want something dead you need sandwich/layering style of panelling with a thin layer of bitumen in between. For instance 9mm multiplex beech + 1mm Bitumen + 9mm multiplex of another kind of wood.
(Btw, we sometimes 'paint' the insides with liquid rubber which doesn't smell if the cab is standing in full sun)
 
#338
4pyros said:
Does that work in a TH?
I tryed some rubberized under coating in my mids and it didnt seem to do much, I still had to add padding.
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I think you are mixing a few things:
1.) Padding works by absorption of soundwaves trough air. The absorption material(s) transfer the energy from the sound waves into heat (friction). Exception; if pressurise padding between two solid materials it becomes also a contact absorber.
2.) Rubberising works by absorbing internal contact sounds trough materials. Sheets of wood start to vibrate like a membrane. To suppress this vibration you can use several techniques. It wont work as good as the 'sandwitch' method but yes it does make a difference.
 
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#340
Often these 'specialised' coatings for audio are way to expensive, in my opinion. Old fashion solutions like bitumen, liquid rubber and silicones work all fine but yes, I agree, they don't come in such fancy labelled cans 😉
 
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