hi all,

i'm pretty sure this is due to the very weak electrical system in my condo... but i'm at a loss for a solution to avoid it.

whenever i turn on my ceiling fan, there is an audible "thump" from my sub (which is obviously on the same electrical circuit). i cannot plug the sub into another line since my entire living room is on the same circuit. d'oh.

a) can this damage my sub at all in the long term?

b) if so, what possible solution might there be to remedy this?

i have a set of def tech procinema 80 speakers (attached to an outlaw 1050 of course! ). the sub is plugged into a vanilla surge strip and then into the wall socket.

some folks have suggested that i might try a line conditioner (maybe $100 or so to begin... and of course upwards in price from there depending on desired "audiophile exorbitance" factor. )

any tips? thanks!

-e

I'm not sure a decent line conditioner will do the trick. IT can, overtime, possibly damage the sub but others in here will know more then I do.

I would somehow get that sub off the circuit. Can't you run a dedicated one for your theatre? I did this a few months back and it was the best thing I ever did for my theatre Hopefully someone in here can help you more..Good luck

For now...don't turn that fan on, LOL.

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Play it LoUd!!

I have the same issue. The thump I get isn't real loud so I'm not worried.

I can tell you that a line conditioner will probably NOT do anything. I tried a Monster PowerBar ($200) and it didn't do squat. It's a nice looking, quality power strip, but that's about it.

As I really don't want to run a new electrical line at this point, I'm just living with it.

I do wonder if the 'noise suppressors' they use for car audio would work here. I had a thump problem in my car that was completely eliminated by an RCA in-line suppressor ($20). I have no idea what or if this affects the signal quality. Good luck.

[This message has been edited by Slee_Stack (edited July 18, 2003).]

Could be worse, the fans could start pumping out bass.

Hahahahahahahahaha

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Play it LoUd!!

Have you tried a UPS (Uninterruptible Power Supply)? If it's a drop in line voltage that's causing it then that may do the trick.

Keep an eye out, you can usually find them on sale for under $40.

Plus they are better than a plain old line conditioner which can help with over voltage pulses, but can't really do much for under voltage problems.

Unfortunately the problem may not be the actual power. When I first ran my wiring under the floor for my rear speakers they would pop every time the circulator motor came on in my heating system. The wires ran about 10" from the wires to my furnace initially. Moving them about 2' away eliminated that problem. I suspect you are seeing something similar, i.e. not a voltage spike/valley, but an induced signal on the circuit.

Do you use the ceiling fans when using the system? If not, a cheap ( although inconvenient ) solution would be to unplug the sub when the system is not in use.

Just my .02 cents worth.

The ‘sub-thump’ question has come up several times in the Saloon, though the suspected source of trouble is not always related to a ceiling fan. Of the several possible causes, the interfering signal must either be arriving via the input (shielded interconnect or speaker cable, depending on how you get the intended signal to the sub), the power cord, a combination of the two, or even via a ‘broadcast’ by the fan, switch and associated wiring which is being picked up by one or more parts of your system.

You could go through quite a few diagnostic and remedy scenarios, but your main concern seems to be, “Can this damage my sub at all in the long term?”

I would say your chances of this damaging the sub are near zero. Why would I say that? When you play music or movies, aren’t you asking the sub to handle grossly larger signals on a regular basis, some of them quite ‘explosive?’ I would say that playing music and movies through your sub uses much more of whatever capacity your sub has than a slight thump when you turn on your ceiling fan.

My subs use an auto-detect circuit to monitor the incoming signal. When no signal is present for several minutes, the power amp section is turned off while the input is still monitored. When some small signal is detected, the input monitor turns on the rest of the circuitry. If your sub operates similarly, it could be that, even if the rest of your system is off, the small electrical change that occurs when you turn on your ceiling fan is enough to trick the monitoring circuit into going out of standby mode and powering up the sub’s internal amp, hence a little thump made in this process is heard because it is not masked by any incoming music or other intended signal.

As a crude diagnostic tool, tune an AM receiver on the same circuit as the sub to a place on the band where there is no station. Listen for any ‘pops’ in the AM hiss when you turn your ceiling fan on or off. Compare that to what you hear in the hiss when you turn a standard incandescent lamp on or off on the same circuit as the ceiling fan. If the ceiling fan ‘pop’ is much louder than what the lamp causes, it could be minimal arcing in the switch you use to turn the fan on and off.

If you are using speaker cables to a powered sub, try a well shielded interconnect instead. If you are using a shielded interconnect cable, is it at least as good as the ‘radio shack $15’ type, not the $5 type? Also, do what you can to make sure that the physical connections of both the interconnect cable and equipment at either end are good, clean and have a solid grip so that the electrical connections are the best they can be. If you suspect the interconnect cable, try swapping in another cable you know is good from another part of your system to compare results.

Plug the sub into power with the interconnect cable not connected to the sub. Does the sub still thump when you turn the ceiling fan on?

If you decide to put an un-interruptible power supply (UPS) before the sub, make sure it has the capacity to handle the power requirements of your sub.

I wish I could be more concise, but there are quite a few variables involved and quite a few possible solutions.

I hope you find what you need, and that it is one of the more inexpensive solutions!


[This message has been edited by bestbang4thebuck (edited August 10, 2004).]

I had this problem with a ceiling fan switch I had that controls the fan speed from the switch, the med-> high speed selection would always cause a thump from my sub...

it went away once I switched to shielded interconnects