Axiom Home Page Forums General Discussion Technical Questions Are the demons back JohnK? EP600 strange issue....

Ok, we are down in the basement right now as a severe storm is moving through central Iowa. The kids are in the other room watching something on the extra tv and my wife is sorting stuff in our storage room for goodwill.

I am near the HT area just cruising the internet on my laptop via wireless connection. I have been hearing a faint thump thump about every 10-20 seconds or so and just passed it off for some thunder in the distance.

I looked out the walkout door and there is no activity right now. So I walked over to my ep600 and sure enough, every once in awhile there is a quick thump thump and sometimes more like thumpity thump thumptiy thump thump.

What the heck is going on? All of my AV equipment is turned off. Well, the 600 is always on, but my receiver, sms-1, etc. are turned off.

What the heck could be causing short quick bursts of thump thump? This is two weird.

Randy

Yup, Randy, it's time to call the priest again. By the way, when you ordered the EP600 did you accidentally click on the demon portal option?

Unplug the LFE cable. Does the thumpity thump thump go away?

Well, I did turn the main power switch on the back of the sub off/on and it seemed to have stopped. Almost like energy was stored up and I released it.

I just ran down again, and still hear a very faint thump thump now and then. Is it possible if it is lightning outside that the ep600 could be picking up that energy, or could air preassure because of a storm move the woofer in/out enough to cause a faint thump. It is almost like if you took your finger and tap the driver cone.

Mojo, I'll try the coax cable next...

I just went down there and it still does it when the coax line in is unplugged. If I turn off the amp on the sub it stops.

What is strange is when I first heard it I was like 20feet away and it was much louder. After powering off/on the switch the first time it pretty much went away. I have to get my ear down right in front of the woofer now to hear an occasional bump bump versus the original thump thump.

I hate when I discover these things. argggg

At least you've eliminated conducted or radiated interference on your sub cable. So it appears to be coming from the power outlet.

What other equipment is plugged into that same circuit that is powering the sub? Try unplugging (not just turning off) all equipment that is on that same circuit. Then see if it stops. If it does, methodically turn each piece of equipment on and monitor to see if the thump comes back. This way you may be able to isolate it to a specific appliance.

Yes Randy, they're back and will soon also be at the Odyssey. Again, if your minister doesn't do that sort of thing a priest can perform the exorcism(with a reasonable contribution to the church, of course).

Okay, now I'm not kidding. About a month after I got my EP500 I heard an intermittent thumping sound that I at first thought was coming from the wall or roof. A couple years ago I'd shot a 'coon off the roof, so thinking maybe another one was planning an invasion, I was about to grab one of my guns. In trying to locate the sound better, however, I happened to listen near the sub(the system was off)and discovered that it appeared to be coming from there. So I turned the sub amp completely off and the thumping immediately stopped. Thinking of you, I wanted to immediately sprinkle it with holy water, but had none at the moment, so I kept the sub amp off for maybe 12 hours. When I turned it back on there was no thumping and there's been no repeat for the past 6 months.

I couldn't figure it out, but since it didn't re-occur, I wasn't concerned. Leave yours off for a while to see if some magic occurs.

When I tested the Line-In cable, I reached around the sub and just unplugged it, holding it about an inch away from the line-in connection. Unless sound can jump an inch through the air, I would say that is not it...

I have a dedicated 20amp breaker using 12-2 wire for my HT equipment, so the only other items would be my AV equipment. All the power was shut off by the main switches for everything except the amps that I leave on all the time.

I can test some more later this week. It is just strange that it was so much louder prior to me powering off/on the sub, now it is pretty hard to hear unless your real close, and even then it is very very faint now.

John, just read your post, thanks for the advice. I'm sure our Lutheran Pastor would be glad to stop by anytime.

Your similar description is exactly what I'm experiencing. I leave my 600 on all the time. It was not until tonight during the storm that I heard the louder thump thump from like 20 feet away.

I passed it off for thunder in the distance or the dog upstairs jumping off the bed above the HT area. I soon discovered as you did it was the 600. Just powering it off/on for a few seconds dramatically reduced the thump.

Funny thing, when I first turned the switch off, I heard a loud thump. It was almost like I released some electrical charge that was built up over time.

I'm glad the demons have decided to migrate via the internet to your home from Iowa.

Turning off the switches of the A/V gear doesn't physically disconnect your equipment from the mains. Your equipment may be dumping harmonics onto your AC wiring. Maybe it's the flux capacitors in the Odyssey that are finally broken in . Unplug them instead and play "Sherlock Holmes".

During thunderstorms, electrical systems experience large ground currents and transient voltages. These do make their way to the distribution system. Depending on how the power supply of the 600 is designed, it may be influenced by these transients.

I just re-read your initial post. Was your wife also doing laundry while she was sorting for goodwill?

BTW, Lutheran ministers don't know what to do with demons. You need an Orthodox or Catholic to deal with that. Lutheran ministers will try to counsel the demon whilst Orthodox or Catholic priests will curse it right out of the house .

I guess I would not call it a "pop" like a light bulb blowing, it just sounded similar to the thump or low frequency I was hearing during the storm.

Sounds like John had a similar issue, I may try powering it off for a bit to see if it gets even better. To be honest, tonight is the first time I've heard this before.

ps: just went out with a spotlight to check for coons on the roof.

If unplugging it for a while solves the problem, that's good to know, but yeah, I'm also curious what the real cause of this is.

Yeah Randy, as Mo suggested, maybe you should turn the Odyssey off as well as the EP600 amp. The only thing, if you turn it off the capacitors will have to take another 3 months or whatever to form properly(the ones in my equipment do that in 3-4 seconds from a cold start).

In my occurrance there was no storm going on and no electrical appliances(just lights)were on.

Edit: just read Mo's latest, and this might be a bit specialized. I do have, besides strictly classical, a considerable amount of music from the Eastern Church Liturgy(largely Orthodox). I speculate that if you play one of the CDs that this could possibly do the trick and cheaper than the priest.

Actually, it only takes a few minutes for the amps to stabilize when first turning them on if you decide to turn them off each time, your thinking of the full break in time for the soundstage to open up and place the listener in utopia.

Peter's obviously not around this weekend, but the other day he mentioned that his EP500 does the exact same thing during electrical storms.

The designers of these DSP-based subs may have inadvertantly incorporated a Spiricom circuit.

Randy,

My EP500 does the thump thing during electrical storms. It's happened twice so far and now I just switch it off to avoid the issue. The first time, I thought it was my neighbor (I live in a townhome) banging on the wall.

Iowa.

When will you realize that the common denominator in all your failed (AV) relationships is you?

Quote:

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except the amps

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Whoop! Whoop! Whoop!

Okay, so I can't help. I think John and Mojo have you covered on the actual science and stuff. I'm just comic relief around here anyway.

And, I'm here all week.

Well it is good to know that John and Peter have experienced the same issue. It would be my guess that others just have not come forward.

Anyone from Axiom want to comment on how electrical storms would cause the DSP subs to cause this haunting experience?

No electrical storms where I live. Just snow and rain. I did have the thumpity-thump problem a while back though. One other person did too. An power off/on fixed it and I haven’t had to do that again.

Not really answering your question but I thought I'd mention that I must be much more paranoid than a few of you. There is no UPS or power conditioner, I can certainly afford, to trustingly keep my electronics safe during a lightning storm. If the storm gets close, I unplug my AV gear and my PC. I have even gotten spooked enough to disconnect the leads coming into my invisible fencing transmitter. (Nothing like having an acre & 1/2 worth of lightning rod buried around your back yard.) Any other appliances are fair game.

There are some very good products that get into milliseconds for opening a circuit at risk. I guess I am just am not convinced they were designed to isolate electricity so strong it's arcing from sky to ground.

After I run around unplugging my stuff, I go out on my covered deck to watch the show. Go figure......

Try turning on the closet light. See if that makes it go away

Did you have your cel phone close to the EP600 or your AV receiver when it was doing that noise?

Now that is funny! I almost spit my water out on my keyboard...... ha ha lol

Andrea conducted a poll at Axiom, and to a person none of us have experienced this or even heard of it. Our house gets hit quite often by lightening (which is awesome if you happen to be watching a scary movie at the time and then you see a blinding flash of light actually in the house! Creepy! And then you get the fun of running around and seeing what appliance you lost!) but we have never had the thump come up. Caveat could be that we live in God's country? Tom's away on a Top Secret Axiom Mission right now but I'll follow up with him when he gets back.

Thanks Amie, it is very strange. Now that I've unplugged the sub and plugged it back in, the woofer activity/noise is only noticable if I pratically put my ear within inches of the driver cone.

It will be interesting if the noise gradually builds and gets louder over time..

Here's what Tom Cumberland had to say:

"MoJo is right. The very high power of the amplifier makes it suseptable to line surges. During mid-west and florida lightning storms the AC power lines outside the house are going up and down trying to regulate the line voltage.
This would normally not be a problem as most subs don't go down as flat as ours does. The amp sees these as audio from the point of view as voltage variations, hence the thumping."

Thanks for the explanation. So it's a feature and not a bug, eh?

"Mojo is right"....

Oh no, we don't need his head any bigger than it is now.