OT: Home Theater "Noise"

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johann83
Posts: 66
Joined: Sun Aug 03, 2003 6:18 am
Location: Pittsburgh, PA

OT: Home Theater "Noise"

Post by johann83 »

Looking for some ideas here guys/gals. I'm having a problem with what I will call "noise" in my home theater system. The actual symptom is that the sound from the speakers will "skip" when certain electrical appliances are turned on or off. By "skip" I mean the sound will basically be muted for about half a second. It seems more prominent when heavy loads are switched on or off (e.g. refrigerator or clothes washer) but it also happens occasionally with lights as well.

All the components in my system are powered through a Monster Power Home Theater Power Center HTS1000 (power line filter), and are connected to each other using high quality A/V cables. The problem is not isolated to the home theater either as the sound on my computer will do the same thing (it is powered by a UPS). I haven't noticed any other symptoms other than the sound muting, and with the power filter etc, I'm stumped.

I know some of you here are pretty experienced with home theater setups, and I would appreciate any ideas you might have. Thanks.

Matt
jamesgammel
Exile Island Resident
Posts: 394
Joined: Sun Aug 03, 2003 2:48 pm
Location: Gillette, Wyoming

Post by jamesgammel »

What you're experiencing isn't "noise", it's more a factor of taxing circuits. You'll experience virtual brownouts when a heavy load starts up, especially things that take a large current draw when they start up, like compressors (in fridge). In a normal household situation, 220 is brought into the house. That will provide 220 for devices that require it like clothes dryers, electric ranges, hot water heaters, etc. Those will typically be on "double breakers". That's putting half the load on each of the 120 legs: 120+120 (usually really 110)=240 (usually really 220). The rest of the breakers will usually be singles, hopefully half on each 120 main leg. Unfortunatally, despite the sincerest planning, the actual loads don't end up getting evenly distributed.
I'd guess that if the fridge compressor kicking in (they're usually 110 devices) results in a brownout on your stereo, then the outlet your stereo (and pc) are on is the same leg as the fridge is on. Your best solution is to check each outlet and which breaker that outlet is on. Looking in a breaker box, first find which breaker the fridge, and whatever else is doing the most "harm" and see which half of the breaker box those breakers are on, left or right. If, for example those gremlin devices are on the left half, then try and find an outlet that uses a breaker on the right half.
depending on how your house is wired, it may be as "simple" as just using a different outlet in the same room. In tougher ones, it may involve moving to a different room. If that's not feasible, then one could do a simple re-wire job in the breaker box to put the gremlin devices on the other half, so the pc and stereo don't have to be moved. In a severe case, it may involve having a larger service line installed to the breaker box. it may well be that your total current needs because of a lot of devices like A/C, freezers, etc exceed what the current capacity of the house was originally designed for. ie, you have a lot of electrical gizmos.
You may want to consult with an electrician to see about updating/upgrading your electrical service and how it's distreibuted within your house. I suspect a higher amperage service line, and more breakers and some wiring additions may be your best solution. I'd also guess that while the total amperage rating isn't being exceeded, one leg may be getting the heaviest draw, but not quite enough to trip the main breaker. Adding a few more electrical devices may change that in a hurry.
One way to find out just what each breaker contrls is turn on all lights (leave major big appliances OFF), and make sure a small lamp is in every outlet. Then progressively turn off a breaker at a time and note which lights go out. Then note what all is on the left half, and what's on the right half in the box. One thing to remember is that some rooms only see use at certain times of the day. ie. bedrooms more in the late evening/night than the living room which sees more electrical use during the day/early evening. Kitchen heavier use during cooking/meal times, etc.
A typical bedroom has very little electric use during the day, maybe just what little bit runs the clocks, and an occassional light trned on. Thus, during the day, bedroom breakers are almost sleeping.

Jim
bluenose
Posts: 5
Joined: Sat Nov 08, 2003 4:29 pm

Post by bluenose »

You could likely solve your problem with a good UPS of "type 5" or better.

Type 5 means the UPS will shield your equipment from 5 forms of power problems including brownout. Most consumer UPS's are inexpensive Type-3.

This webpage explains UPS differences better than I can:
http://www.et-sales.com/upstypes.htm

Good luck.
usblipitor
Posts: 516
Joined: Fri Oct 10, 2003 10:06 pm
Location: Greenbelt, MD

Post by usblipitor »

The main function of a UPS is to provide uninterupted power when the main power goes out. What you want is a specialized subset of UPS's called a power conditioner. Power conditioners keep "smooth, even power" going to your devices. They are the "Luther Vandross" of UPS's.

I found one power conditioner at surf remote control. You might also look at epinions, google, froogle or maybe even pricewatch to see what else is out there.

Good Luck!
johann83
Posts: 66
Joined: Sun Aug 03, 2003 6:18 am
Location: Pittsburgh, PA

Post by johann83 »

Thanks for the advice gentlemen. I can only assume that Jim is right about the brown-outs, but unfortunately, I am renting this apartment and can do little to fix the potential wiring issues. One thing I did notice is that this building was built in the early 1970's and has aluminum wiring instead of copper. This may or may not be contributing to the problem, but I really have no way to tell. As far as moving items from one outlet to another, the computer is on the second floor far from the home theater (and it has similar problems), so it may not help to move things.

As far as the UPS/power conditioner ideas, I think they are both good ones, but I already have a power conditioner on the home theater (actually, the one usb pointed out). The computer is connected to a UPS, but it is simple "Type-3", and I'm not sure whether the speakers are hooked up to it anyhow. I am going to try an experiment to see if the computer still exhibits the problem when completely disconnected from the line. Unfortunately, if it does, I'll be terribly confused... :(

If anybody has any other suggestions, I'd be glad to hear them.
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