Zulu Posted September 1, 2014 Share Posted September 1, 2014 Hi, all.I'm really a Lampy, but I've got a sound problem to fix. Hope you can help. Our show involves a largish water feature, powered by 2 x 1600W pumps. The pumps need to be switched on and off at certain times during the performance, so, with them plugged into the mains in the wings, one of our techys switches them on and off. As one of the pumps is on a revolve, we are actually plugging/unplugging this one.The Problem: when the switching / plugging of the pumps is done, a loud electrical crackle is amplified through our powered loudspeakers, plugged in nearby. Anyone know how I can make the switching silently, without turning the speakers down, as they are needed for FX during the switching. 2nd problem (less tecnical): the water feature looks fantastic, but the cascading water is louder than anticipated, and becomes distracting after a bit. Any thoughts how to dampen the sound of falling water. Its a 5 tier cascade, with steps at about 1 foot intervals. Many thanks, Zulu Link to comment Share on other sites More sharing options...
dbuckley Posted September 1, 2014 Share Posted September 1, 2014 First thing to try is a snubber across the switch. It's easy to do, but you need someone who knows what they are doing to do it. What sort of pumps are they exactly?? And "water", or '1600w" are not acceptable answers. Makes and models that are googleable. Link to comment Share on other sites More sharing options...
ImagineerTom Posted September 1, 2014 Share Posted September 1, 2014 Falling water makes noise, it's basic physics. The only way you're going to make cascading water "quieter" is to have less of it; there's really nothing significant you can do to dampen the sound down as most of the noise is the sound of droplets of water hitting against water. Link to comment Share on other sites More sharing options...
laolu Posted September 2, 2014 Share Posted September 2, 2014 Could you have someone make a switch using SSRs? That would eliminate or at least minimize the electrical noise from the plugging / unplugging that you have. Norbert Link to comment Share on other sites More sharing options...
top-cat Posted September 2, 2014 Share Posted September 2, 2014 Falling water makes noise, it's basic physics. The only way you're going to make cascading water "quieter" is to have less of it; there's really nothing significant you can do to dampen the sound down as most of the noise is the sound of droplets of water hitting against water. If you can cover the stage with something partially absorptive which can slow the water, you might be able to reduce the noise. I'm not saying you'd be able to silence it, but depending on in what manner the water falls, I think you may be able to reduce the effect with something like a light foam or sponge. Link to comment Share on other sites More sharing options...
Simon Lewis Posted September 2, 2014 Share Posted September 2, 2014 I think you may be able to reduce the effect with something like a light foam or sponge. This is probably the way to go.... You won't achieve absorption in the normal sense, but you could reduce the degree of turbulence and impact noise by using clear material for the water to "fall" or "slide" down and something to break up the impact such as plastic "steel wool"... Link to comment Share on other sites More sharing options...
Richard P-W Posted September 2, 2014 Share Posted September 2, 2014 Can you run the pumps from a couple of dimmer channels? That will depend on the pumps and having dimmers that can handle inductive loads! This could solve both problems - no hard switching on and off and you MIGHT be able to reduce the flow rate, but again that depends on the pumps... Link to comment Share on other sites More sharing options...
dbuckley Posted September 2, 2014 Share Posted September 2, 2014 The idea of dimmers was I was asking about what the pumps are; wrong type of motor and there is going to be damage... Link to comment Share on other sites More sharing options...
Andrew Edwards Posted September 2, 2014 Share Posted September 2, 2014 The stage water gags that I have used (Mother Goose waterfall for example) had that very course 'foam' that comes in pond and fish tank filters. More like a tangled mess of plastic filament than smooth foam. As Simon suggests, plastic steel wool. Along with lowering the noise, it also reduced spray. Link to comment Share on other sites More sharing options...
Robin D Posted September 2, 2014 Share Posted September 2, 2014 Are you starting and stopping the revolve at the same time? Could that be part of the issue? Also, are you plugging/unplugging when the feed is 'hot'. Generally better to make the physical connection before apply power and the reverse. What sort of power switches are you throwing. If those on a standard 13amp socket, you will almost certainly get some noise. Can you move the sound system or these to a separate power circuit? Link to comment Share on other sites More sharing options...
JimWebber Posted September 2, 2014 Share Posted September 2, 2014 If one is available, would connecting the pumps (or speakers) to a socket outlet on different electrical phase help? If you do, just bear in mind that you have 415 (ish) volts between the two bits of kit. This is not inherently dangerous, but if you forget it could turn nasty, "Electricity is safe until you forget that it's dangerous." Jim Hmmmmm. © Ynot..... It seems that Robin got there before me. Link to comment Share on other sites More sharing options...
J Pearce Posted September 2, 2014 Share Posted September 2, 2014 An isolation transformer may be of use, both in reducing emf noise from the inductance of the motors and for safety purposes when dealing with water and electricity onstage. Also a soggy stage (or a stage with the potential to get soggy) is probably one of the few times I would advocate sticking to phase separation. Link to comment Share on other sites More sharing options...
Zulu Posted September 2, 2014 Author Share Posted September 2, 2014 Many thanks, guys. Some great responses. Some answers / comments here:Speaker SpikeNot sure what a snubber switch is. I'll try and get the make/model numbers of the pumps tonight. Dimming might be the solution. I have thyrister based dimmers. (If I "snapped" them to 100% on the dimmers, would that avoid any damage ??)Not sure what an SSR is, or how to make a switch out of one.Regarding the revolve: it is manual, so no drive motors there. Plugging/unplugging hot? Yes and No. We get the same result by swiching at the mains as plugging/unplugging.Power switches? Yes, 13 Amp wall sockets. You're right . . . same noise !Moving Powered speakers to different power circuit? Would this help? Physically, the speaker and pumps are using very close wall sockets. I could run an extension lead to another part of the building, I suppose.Different electrical phase . . . you've lost me. Sorry. Waterfall noisePlastic steel wool or similar sounds good. Maybe with the clear "slope" idea. Sounds v. promising Link to comment Share on other sites More sharing options...
kerry davies Posted September 2, 2014 Share Posted September 2, 2014 Plastic steel wool or similar sounds good. Maybe with the clear "slope" idea. Sounds v. promising I thought at first of that stuff they use on truck mudguards to cut down spray. A sort of stiff, stipply, plastic grass thingy?(Incipient senility kicking in today, someone will have a real word for it.) Link to comment Share on other sites More sharing options...
dbuckley Posted September 2, 2014 Share Posted September 2, 2014 Dimming might be the solution. I have thyrister based dimmers. (If I "snapped" them to 100% on the dimmers, would that avoid any damage ??)Maybe, maybe not. This is why we need to know about the pumps! Link to comment Share on other sites More sharing options...
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