2nd Stage Making Funny Sound

[jrv331]

I have a Scubapro MK11 first stage with the R395 second stage and was doing my AOW class this weekend. While on the surface the regulator would make a strange sound when inhaling but worked perfectly for the dives.
I bought it used and had it serviced before using it, the LDS said it was in exellent condition. It was in the 50's and water temp was 57.

The DM said some regulators make funny sounds when it's cold but the cheap rental units the others were using we're fine. He would have not let me dive if he felt there was a problem with my reg.

Anyone else with this set up have the same issue?
Thanks


John

 

[txtroop07]

My AL Legend will make a funny noise out of the water sometimes too. It goes away as soon as I hit the water, not sure what causes it but my LDS says its normal.

Ryan

 

[Bubbletrubble]

Did you attempt to re-seat the diaphragm in the second stage?
The noise could be caused by resonance with the second stage casing, so changing the position of the diaphragm slightly (rotating it a little inside the case) might be the answer...assuming that nothing else is wrong with the reg, i.e., the reg passes all of its functional pre-dive tests.

 

[TSandM]

My ScubaPro regulators periodically "honk" on the surface. It usually goes away if I keep breathing them, and it definitely goes away in the water. I don't know what makes the noise, but it's of no significance to their function.

 

[jrv331]

No I never tried that. How would I go about reseating it?
Thanks

 

[Bubbletrubble]

No I never tried that. How would I go about reseating it?

Basically, you remove the retaining ring, the case cover, and washer to access the diaphragm. Remove, rotate, and replace the diaphragm. Reassemble.

FWIW, case resonance involving the diaphragm can occur in most makes/models of reg second stages. It's not a Scubapro-specific issue.

If you don't know how a regulator works, please don't attempt to do this on your own. I've seen a few divers turn small reg issues into larger ones by monkeying with stuff they don't understand. Ask a trusted reg tech to do it for you...or better yet have him show you how to do it.

 

[jrv331]

BubbleT,
Thanks but that is way over my head. I can live with the noise as long as I know its not unusual. I was just concerned from a safety standpoint.
Thanks to all
John

 

[Capt.Gene]

Not a safety issue as long as you don't poke a hole in the diaphram working on it.
The material the diaphrams are made of used to be thicker and stiffer and we didn't see the kazoo effect ever.
In atempting to make a regulator "crack" at a lower effort of breathing and score better in a comparison, a thinner softer diaphram is often used.

 

[halocline]

It's just a bit of resonance with the plastic case and the diaphragm as air moves through it. You could think of it as a really bad saxophone, with the diaphragm as the reed. In the water, the diaphragm vibration is dampened by the water because, well, one side of it is touching water, so it can't transfer vibrations to the case. Sometimes re-seating the diaphragm, maybe giving it a little turn, makes it stop, sometimes changing the diaphragm does so, but as everyone else has mentioned, it's nothing to be concerned with and it doesn't indicate anything wrong with the reg. On the 395 there's a plastic ring that sits on the diaphragm around the edge, like sort of a plastic washer, that the case cover presses against when it's screwed in place. Sometimes there's just enough variance of pressure on that ring to allow the diaphragm to transfer vibrations. It seems to be a little hit-or-miss; I've had a couple of G250s that did it, others that did not.

It's always a good idea to do a quick vacuum check on your reg; connect it to a tank, leave the air off, and try to draw some air through the 2nd stages. You should get NONE. If you do, something's leaking, and water will find a way in the 2nd stage. There is an exception to this; if one of the 2nd stages has an automatic seat saver that separates the seat from the orifice when the reg is not pressurized, you'll get a 'leak' if you draw air on the other 2nd stage. That's because air travels in the seat-saver-equipped 2nd stage, up the hose, through the IP chamber of the 1st stage, then back down the other hose to the alternate 2nd. Just one more reason I don't like the seat-saver 2nd stages.

 

[Brian Pasic]

My ScubaPro regulators periodically "honk" on the surface. It usually goes away if I keep breathing them, and it definitely goes away in the water. I don't know what makes the noise, but it's of no significance to their function.

Maybe its the fact that the air is replaced by water when submerged and so your "trumpet" has no air in it to make that sounds..