Arrggg Leaks!!!

[RyanC]

So I am just finishing my 3 way speakers up only to find out that there are some leaks in between the different chambers!

Now I'm wishing i would have gone with 3 seperate boxes- They are too small to feel with your hand but when I push the big 12" I can see the 8" woofer move- also the tape over my ribbon tweeters moves too (fountek jp2) and they are supposed to be sealed!! I built a chamber for them anyway and alas they all leak!! Is there anything else that could be causing this? How big of a problem is it?

I guess I am just going to run with it for now and start thinking about rebuilding three seperate boxes! I tried using that spray insulation stuff and it did not work so I have very few ideas left!! Any advice here would be helpful- All the cables are cat5 sealed with hot melt glue- they all go straight back through the back (eg no binding posts) The cab seems to be pretty well sealed but not internally- all the boxes are 3/4" MDF and the walls and baffle are two layers thick- all glued and screwed. Anyway thanks again,

Ryan

[BillFitzmaurice]

Instead of glue use polyurethane based construction adhesive, applied with a caulking gun. Polyurethane adhesives expand as they cure to seal all joints. Your only option now is to open the box and caulk all the joints.

[markp]

Make sure that you are not seeing the emf from the woofers voicecoil moving the other driver. This will make it look like there is a leak when there is none. To check this just disconnect the wires to one of the drivers and see if it still moves.
To find real leaks, take a (lit) stick of inscence and hold it over suspected areas and push the big woofer. If there is a leak you will see the smoke move from the breeze right over the leak.

[sreten]

I agree electrical coupling needs to be discounted first.

After that running a line of wood glue along each corner will
sort out the problem, nothing more than this is needed.

sreten.

[johninCR]

If you use silicone caulking to seal the gaps, be sure to allow it to fully cure (at least 24hrs for a thin bead) before remounting your drivers. It releases a nasty little acid that will settle on your drivers otherwise.

Wood glue is too thin and shrinks when it dries, so it doesn't make a very good sealer. You only want to do it once, so do it right and use caulking. You're going to have to use your fingers and your should apply it to every interior corner.

Because it expands in the joints is why I believe polyurethane glue should not be used for furniture, cabinetry, or speakers. It forms an adhesive layer between the 2 pieces and they are each glued to the adhesive. Wood glue on the other hand bonds the 2 pieces of wood together, plus it's the easy to work with and cheap. Afterward seal any possible gaps.

[tiroth]

Both PVA and polyurethane form joints that are stronger than the wood.

[johninCR]

Polyurethane decomposes in air and sunlight over a period of time. A chair glued together with polyurethane won't last. It's messy to work with. Why spend the extra money? To seal gaps that shouldn't be there?

[RyanC]

Thanks guys-

I think it was the EMF thing after all- Got um setup and they are sounding really good- I have a ton of crossover tweeking to do- And I need to figure out why my TC2+'s are demanding so much power (I think I wired them wrong or somthing) but it seems pretty good at this point. Thanks again,

Ryan

[markp]

Originally posted by RyanC
Thanks guys-

I think it was the EMF thing after all- Got um setup and they are sounding really good- I have a ton of crossover tweeking to do- And I need to figure out why my TC2+'s are demanding so much power (I think I wired them wrong or somthing) but it seems pretty good at this point. Thanks again,

Ryan

If you wired the voicecoils out of phase by accident they will be real power hogs. The coils fight eachother and just heat up like crazy so be carefull with this wiring. Also is you crossover coil going from positive to negative or going into the positive on the woofer from the amp? Measure the resistance of the whole speaker with your meter, if less than 2 ohms or so you've got a shorted crossover coil.

[RyanC]

Cool-

So this is an all active system so the speaker is connected directly to the amp- no caps, coils resistors or otherwise (except for the tweeter has a cap up high to protect it)-

I do need to make sure that the coils are wired in phase- How can I test this?? When I turn on my bryston it pulls almost enough current to flip the breaker- and when the speakers are silent you can feel the woofers moving a bit (this could just be the LF noise floor though right???)-

I connected it like this


+ -
- +

The bottom two connect to the amp and the top two connect to each other- should it be the two on one side connect to the amp and the two on the other side connect to each other?? I figured that I would go for the series setup just to have a normal 8 ohm load- Would it be better to go parrallel for a 2 ohm load? thanks,

Ryan