G'gay guys i may be bring up an old topic but i just want to know at bit more on sub box bracing for spl?
i did a search on some old forums but haven't found my answer.
My question is : Has anyone build a box, ran it and then decided to insert long, strong threads and nuts to clamp the structure together? Has it gained? Has it lost dB? is their a certain place in placing them?
i really DON'T want to do go through with it to find out it don't work and then have to repair my box from all the tiny port holes that i created Some say that it has improved their scores i think it will disrupt the air flow! (that's why i ask about placments) What's is your guys theorys, opinions and experiences on this?
OR
should i stick to internal bracing?


NOTE: If their is an old post on this that i missed when i did my search on this topic can you give me the link for it please.


Thanks for your help in advance

im not sure as to wether internal bracing rods would affect ur flow, ud have to try and c that one ! but bracing does help ! thats a very proven point ! the stronger the box the better ! they dont fill there cars with concrete in spl for the hell of it !

when using internal bracing there is no sure way of knowing if it will increase/decrease your score.

Yes, you add strength, but u also make the box smaller to.

I say make the box externally strong, so that you dont need bracing inside the box.

I had a 2.5 cu.ft box that you could drive a car onto, with no internal bracing apart from the slot port wall.


For walls its a little different, you have bigger spans of MDF that is more likely to flex, so bracing via steel rods is what most people will do to eliminate flex.

i think blackice might be able to answer this one.


SSS_Hoon

Well yes there is, the most effective place to position your brace is in the actual sub box.

Well sub box bracing does work and it doesnt, example of a working one is BlackIce's festiva, that works, but on the other side of the coin you could have xplod_au braced box, which doesnt work too well, as he broke the box after running 152+Db.......at home.

Does it?

We're waiting to see what the most expensive/"powerful" amp in the world can do.

Phil

ohh sorry i forgot to add the [/sarcasm] at the end of my reply

We're still waiting on the best batteries in the world to run the thing..

You know Phil, just a month ago I was thinking how good it was to see you'd mellowed out, but here you are again with that attitude that we all know and love.

What attitude? I think you're taking what I said the wrong way.

It is the most expensive and powerful amp in the world! We are all waiting to see what it can do, you've never had the oportunity to fully flex it's muscles!

I know you're getting pretty serious with it now, I've been watching your build thread!

Phil

OK, maybe I did flare up so I apologise if you mean it the way you say and not the way it read..

I have a delivery coming on Saturday, hopefully it will unlock the potential.

On the topic. Yes, steel rods will help you to a degree. I've been using them in boxes as well as walls for over 2 years now and gain every time. Even adding M10's to a 2 cube box showed a 0.5dB gain.

The basics are, the weaker the walls being tied together, the greater the effect.
Example: Tie 18mm walls in a 4 cube together with M16 rods and you will gain large (say 0.5dB).
Make the same box with 50mm walls and tie them together with M16, and you'll get little effect (maybe 0.1dB if lucky).

As for position, obviously position has something to do with it. You want the rods in a position to strengthen the weakest part of structure. I always use 3 rods, one next to each sub, and one between them. This is because when you cut the sub holes, the baffle looses a lot of structural strength. The rods are there to help.

You may loose some efficiency with rods, but I doubt it. M16 steel rods are bloody strong and only 16mm thick (M = Metric, 16 = Diameter in mm). Using 2"x4" planks inside would hurt for sure, but not the rods. If it bothers you, sleeve them in tight fitting PVC pipes.

I experienced a 1dB gain in my wall from adding 5 2" x 4" planks (externally), a second backwall (covering planks) and 3 M16 rods. I hope this answers your questions.

Oh one last thing. Rods arent magic. If you build a weak enclosure out of insufficiently thick materials (Eg. a 6 cube box from 16mm MDF), the rods arent going to help much as the structure of the whole box is too weak. The idea of rods is to tie a weak part (Eg, baffle) to a strong part (Eg. back wall) to brace it. Bracing a weak bit to a weak bit wont help much.