Air tight test

Easy Runnin

So I glued the magnets, dynamatted , and installed hurricane nuts on my 1Cs. The original gaskets looked fine so I left them. Unfortunately I slipped on one screw and lost a drive. I am still in search of an original replacement. But anyhow, on the good speaker when I push on the PR I can hear a hiss. I can’t tell for sure but I believe it is coming from all 4 dust caps. When I do a similar test on my monitor 7s I hear nothing. The drivers on the 1Cs also retract a little quicker than on the 7s. Is this normal?

westmassguy

Easy Runnin wrote: »

So I glued the magnets, dynamatted , and installed hurricane nuts on my 1Cs. The original gaskets looked fine so I left them. Unfortunately I slipped on one screw and lost a drive. I am still in search of an original replacement. But anyhow, on the good speaker when I push on the PR I can hear a hiss. I can’t tell for sure but I believe it is coming from all 4 dust caps. When I do a similar test on my monitor 7s I hear nothing. The drivers on the 1Cs also retract a little quicker than on the 7s. Is this normal?

Depends on how long the drivers stay out, 3-5 seconds is normal. The newer woofers have mesh dust caps, while the earlier ones have felt. The felt caps bleed air more slowly than the mesh.

Easy Runnin

That makes sense. What do you mean by “newer”? Is 1987 considered newer? I'll take a closer look tonight.

westmassguy

87 would be considered newer. It's pretty easy to tell the difference

leftwinger57

Dave, I have a different situation w/ my 2Bs. If I do the passive push test on the right side I get just slight movement of the mids and a quick return. Now the left I push w/ equal pressure as I can make it and the mids just have a large throw and return of 2/3 seconds ,no where near 5. I've done mods exactly the same to both w rings, armaflex, retightening screws and added gaskets to the terminal cups when I went w/ the Neutrik connectors. So what exactly is the right response, possibly an air tight right w/ little movement or the left side doing what it's supoosed to. Oh the dust caps are sealed not dented and they sound the same when I use the balance control to shift right to left.

pitdogg2

you should be able to get all mid-woofers to extend out as far as they will naturally go. Little to no movement would mean there is a air leak somewhere. On both SDA1A and SDA2a both mine will stay out a good 7-9 seconds. 4-6 seconds then start to decline back into normal position would be the norm.

westmassguy

Lew, you definitely have leaks somewhere, especially the right one. 2Bs should have mesh dust caps, take a close look. Use a flashlight, off to the side, and you should be able to see the pole piece, and the voice coil former through the mesh. They're not sealed. The early drivers, had felt dust caps, and some I've seen were coated. When they hand applied the clear coating on those early drivers, they might have done the dust caps too.

westmassguy

Here's two examples, an older MW6500 with felt dust cap, and newer 6510 with mesh:

leftwinger57

Looks like from your pix mine is the 1st one. I did your flashligh test and it is the smallest mesh screen I'd ever seen.There does not seem to be any coating on them and the pole I just couldn't see,maybe when it gets darker I'll notice the pole. So the right side w/ little movement would be considered the leakery side. The throw again on the mids of other side does extend pretty damn far but clearly does not take all that long to decompress back. I asked this on anonther thread but you how one does a draft test in your house to see where you have gaps at doors and windows, anyone invent such a test for these speakers so you don't have regasket all the speakers.

F1nut

On both SDA1A and SDA2a both mine will stay out a good 7-9 seconds.

They stay all the way out for that long? Never heard of anyone having that length of time before.

Easy Runnin

Lew, How did you install the Neutrik connection? Is it possible that is your leak?

nooshinjohn

F1nut wrote: »

They stay all the way out for that long? Never heard of anyone having that length of time before.

My 1.2TL's are good for 3 to 4 seconds before they settle. 9 seconds is a very loong time.

pitdogg2

Well they do. I have never used a stop watch per-say but with the rings and Bargmans new gaskets they stand up for a long time before they start their way down. Did I need to mention I get good bass

leftwinger57

Looks like from your pix mine is the 1st one. I did your flashligh test and it is the smallest mesh screen I'd ever seen.There does not seem to be any coating on them and the pole I just couldn't see,maybe when it gets darker I'll notice the pole. So the right side w/ little movement would be considered the leakery side. The throw again on the mids of other side does extend pretty damn far but clearly does not take all that long to decompress back. Just to be clear I have 6511 dd and 6503 sd and of course the new rdo-194s

TennMan

It sounds like you have an air leak. Don't overlook the terminal cup on the back as being the source of the air leak. If you can get the room extremely quiet you can hear the air leak when you press on the passive. Smoke will also reveal where the air is leaking out.

leftwinger57

ER, just noticed your reply. I unlike most of you guys left the orginal sockets in place. Once centered w/ an 1/8'' bit I flipped the cups over and secured them. I drilled the cups at about the 10'o clock high postion and used a gradutated bit to get just the right fit and there was no overlapping or tilting so they just fit perfect. I also used a tiny bit to drill the 2 screw holes and from the back used some black rtv or silicone a very small amount just to be sure. With the spikes in place there is no way I'm moving them again just for a picture that may or may not work w/ my luck posting pixs here. I was thinking why not there be a test like a house draft test w/ the smoke? Then I thought by the time you remove the passive pull the poly out and set the device up you could have regasketed both speakers by then. My distorted logic again at work. I also agree 9 seconds seems like a very long time for the mids to return. Also as said on my efficiency thread I don't know if this is a complaint or not because each and every mod so far has improved the performance noticed easily by me lowering the volume on my pre/amp. Sorry for dp I have no idea what happened there.

F1nut

I unlike most of you guys left the orginal sockets in place.

Why?

Once centered w/ an 1/8'' bit I flipped the cups over and secured them. I drilled the cups at about the 10'o clock high postion and used a gradutated bit to get just the right fit and there was no overlapping or tilting so they just fit perfect. I also used a tiny bit to drill the 2 screw holes and from the back used some black rtv or silicone a very small amount just to be sure.

Never, ever use RTV silicone on any sort of electrical connection.

I suggest you reseal the pin/blade connections on the inside with hot glue as that may be where your air leak is.

leftwinger57

Jesse, it's technically not near any wires at all. Fom back end of the cup laid a very,very small bead w/ an applicator tip just to seal them.Nothing on the front the screws are there. How ever high the the base module is is as far away from any connections which were done w/ stakons crimped and soldered and taped. I do have a hot glue gun, I just never thought of it. Why, if it fit why not the originals are riveted and glued I believe and these fit so I did it and it works and looks ok and you can't see them anyway. My originals were blade/blade. If I absolutly had to I can reach the wires and unplug them then I could tip the speakers on their fronts to see if in fact the cup seal itself is the culprit. This might be my project for today.

Easy Runnin

Never, ever use RTV silicone on any sort of electrical connection.

Could you please explain why? I've used marine caulk to seal a few marine connections in the past and now you have me concerned.

F1nut

Lew, I thought you covered the back of the connector, but I understand what you did now. I'm anal, so there's no way I would have both the original SDA socket and the SpeakOn mounted to the binding post plate. For future reference, removing the SDA socket is easy, just drill out the rivets.

Could you please explain why? I've used marine caulk to seal a few marine connections in the past and now you have me concerned.

RTV silicone is very acidic before it cures, hence the strong odor, which can cause corrosion issues. Not sure what you used, but I doubt it was RTV.

leftwinger57

I'm glad you understod the silicone is nowhere near the connections and I did let it cure before putting them back. As for why I left the originals, chaulk that up to maybe lack of confidence thing and then when I did measure them and they fit w/o overlapping or tiltiing I said go a head. It worked out fine in both position and functuality and I do have an up date on the pressure test. I went and pulled the right side mids and just redid the Armaflex w/ positive results. I'm very happy to say. Early yesterday I got very little movement out of the mids and way less compared to the left sides. After the regasketing and screw down there is a pretty equal displacement of air between the 2 sides now. Quite an improvement. I will say it took 3/4 seconds maybe to return certainly not 7/9 seconds like Pitdogg (he meant nano seconds) but happy w/ the results. I also have these plugs from my alarm installing days to close up knockout holes, drill for a contacts and then not paying for it so like electricians have oversized "goof plates" we had these plugs of all sizes and some in metal most in plastic if any mishap had occoured. Of course they would be black if I needed them here, I did not. (Examples showed are very old and i dug them out of my long stowed stuff)

westmassguy

Lew, glad you got it worked out. 3-4 seconds is about right. Regarding the silicone, glad you used it sparingly, however, for future reference, never use it again for internal sealing. Even though you let it cure for a while, some silicones can take months to fully cure. During that time, acidic off-gas is continually released, and will linger in a sealed cabinet, attacking every exposed metal part.

leftwinger57

Dave I got the message.I would have never thought silicone can be such a detrement. My argument is how long will this take. Don't get me wrong I will not use it but I don't think I would be around be the time any corrosion took place. So what is the best sealer,plastic to plastic to use. Hot glue? I have a gun and sticks and if that's what to use I will from now on for sure. Man I thought silicone was man's 3rd best friend dog,duct tape and silicone. They do sound fantastic but I still want to hear another's set up w/ a ss amp and a spred like mine.

westmassguy

Lew, you can use hot glue, although I despise it personally, and never use it. I use Locktite Power Grab, Clear Acrylic Sealant. It comes in small tubes or gun cartridges. I squirt a little on the connector, and smooth it around with a 1/2" artists brush. It dries clear, and contains no silicone. It cleans up with soap and water. It's also great for re-sealing the inside seams on the cabinets, and gluing the magnet assemblies.

DaveHo

This stuff?

http://www.loctiteproducts.com/p/12/4/pg_ca_all_p_tube_clr_3oz/overview/Loctite-Power-Grab-All-Purpose-Clear-Construction-Adhesive-Squeeze-Tube.htm

westmassguy

DaveHo wrote: »

This stuff?

http://www.loctiteproducts.com/p/12/4/pg_ca_all_p_tube_clr_3oz/overview/Loctite-Power-Grab-All-Purpose-Clear-Construction-Adhesive-Squeeze-Tube.htm

That's the stuff

SciFiTom

F1nut wrote: »

RTV silicone is very acidic before it cures, hence the strong odor, which can cause corrosion issues. Not sure what you used, but I doubt it was RTV.

Correct Sir, but there are other types of silicone adhesive/sealants made for the electronics industry, et al, which use a different chemistry that releases alcohol instead of acetic acid. It's tough to find in regular stores, but I did encounter some in an aquarium store once, as a repair. Watch the warnings on the package. If they mention acetic acid, you don't want it. Dow Corning 3145, as I recall is an example of that class of adhesive, in a viscosity similar to what you get in the store. There is also a much thinner 3140, if you want it to ooze into and under things, and generally run all over. Don't expect to find it for $4.00 a tube, though. More like $30.