I can't even begin to think of a proper title.....But this is very bizarre.

Bob in St. Louis · « **on:** 28 Sep 2009, 06:44 pm »

Sorry for the vagueness of the subject line, but I'm completely and utterly at a loss to what's causing this issue, much less how to create a catchy title.

This has GOT to be the most bizarre thing I've ever seen in this hobby.
Please be patient while I do my best to describe what has occurred. I'll be as quick as I can.

Here's the scenario:
I'm re-wiring my infinite baffle (a quad of 15" drivers). In an effort to make sure the polarity of the drivers is correct, and they're all "pushing" the correct direction, I'm tapping on a 9v battery with the end of the wires that will eventually go to the back of the power amp while watching the cones to ensure they're moving in the same direction (yea, I know the dangers, but the contact time is very minimal). The wiring is isolated from any amps or other equipment. I'm also listening to the system while I'm doing this.

Here's the problem:
When I tap the test leads on the battery, the system audio mutes for about one second.

I'm completely dumbfounded. I'm sure I could give some tidbit of information that might be a clue as far as what's going on, like components being used or which direction my head is tilted, or whatever..But I could fill a page with that and you would have stopped reading by now.

Due to the nature of a 9vDC battery and the drivers, you can imagine I'm not wanting to reproduce the phenomenon any more than I have to, but......

Um....

I just don't know what else to say. I'm speechless.

Any ideas?
Bob

art · « **Reply #1 on:** 28 Sep 2009, 06:55 pm »

I know this isn't going to exactly answer your question, but........

Why not use a AAA cell? Any inductive "kick" which is being produced shouldn't mute your system. Might be easier on the drivers, as well.

A bit O/T............

Many years ago, there was a PCB in the system that did strange things. Eventually, we figured it out. On the top layer, there was a trace that went to a relay. On the bottom trace, directly below it, and parallel for most of its length, was a trace that went to an input of some logic gate.

Whenever the relay changed state, the logic gate would do the same. We cut one of the traces, and re-routed it with a wire.

Might be a clue...........might not.

Pat

AB · « **Reply #2 on:** 28 Sep 2009, 07:41 pm »

Mutes to no sound? Or mutes to a few db or so down?

So... you're rocking out listening, you tap the battery with the woofer leads and immediately there is no sound. Are you in the infinite baffle's infinite baffle or in the listening room? How long does the muting last?

Bob in St. Louis · « **Reply #3 on:** 28 Sep 2009, 09:31 pm »

Hey fellas!

Pat, I suppose I could use a AAA, but are you suggesting that I do that as a test to see if the lower voltage still makes it occur, or simply as a way to not make it happen? If it as a test, then I understand, but if it's the other, then I don't understand the point. Thanks for the reply!!

AB, the system will mute four active channels to zero output for literally about one second. I'm in the dead center of the listening area sitting on the floow behind the center channel speaker, about four feet in front of the IB unit. Which is about 12' in front of the seating position. Maybe a picture of the room would help.

Here's an old photo, the speakers have changed since. But the IB is "center stage" (the big square hole under the screen) and the equipment rack is on the left of the photo:

Thanks guys!

JohnR · « **Reply #4 on:** 28 Sep 2009, 09:56 pm »

You are absolutely positive that the wiring to the IB is fully disconnected from the electronics?

AB · « **Reply #5 on:** 28 Sep 2009, 11:02 pm »

What JohnR said.
Then lets assume it's an effect of the 4 x 15" woofers acting to pressurize your listening room with one loooong wavelength impulse that causes the mother of all room nodes right where you are sitting. Maybe?

Can you try activating the IB from a corner of the room to see if you get the same effect?

In any case that's pretty cool.

Bob in St. Louis · « **Reply #6 on:** 28 Sep 2009, 11:44 pm »

Yea, the only wiring going to the IB would be from the power amp. This is the wire that I've got in my hand, so I know 100% that it's electrically isolated form the rest of the world. I've run "extension cords" on those wires so I can sit in the throat of the IB while tapping on the battery to watch the cones move.

The mother of all room nodes....um....yea...maybe. But that would have to be a room mode for the "papers".
You know what...Right now I'll grab my "extension cords" and my battery and try it again in a different location. Just for the heck of it.
Let's see,...I'll be right back.

.................................

No....that's not a room node. That's a dead silence that continues long after the "thud" from the drivers. I sat in the middle of the floor, perfectly centered in the middle of the room between my center channel speaker and my seating position. This sucker's turning off. That's not a room node.

Now I'm really confused. But like AB said, It is pretty cool.....in a weird sick twisted way.
But cool none the less.
I lust wish it was happening to someone else.

More ideas?

I'd love for one of the STL guys to see this. I'd like to have a witness. aa

Bob

Bob in St. Louis · « **Reply #7 on:** 28 Sep 2009, 11:59 pm »

...................In addition to my above post, I was thinking about what Pat said.
So I tried a brand new "AA" battery. It does NOT mute the audio, but WILL create a small pop through the speakers.

That help?

Bob

art · « **Reply #8 on:** 29 Sep 2009, 12:59 am »

Hmmm...........must be the "mother of all inductive kicks".

The AAA suggestion was for 2 reasons. One is that it might solve your problem. At least we are moving in the right direction.

Pat

wedweb · « **Reply #9 on:** 29 Sep 2009, 01:37 am »

Maybe the infinite baffle is this situation and not the speakers.

Bo

JackD201 · « **Reply #10 on:** 29 Sep 2009, 01:51 am »

Wow Bob, it looks like you found a way to cause an EMP with a 9v battery some wire and a speaker driver

The wires and speaker are electrically isolated from the rest of the system you say? Seriously an EMP is the only thing I can think of.

Bob in St. Louis · « **Reply #11 on:** 29 Sep 2009, 02:57 am »

I was thinking EMP......... but with a 9v battery???????

A taser works with small, low voltage batteries, but.....?

Bob

JackD201 · « **Reply #12 on:** 29 Sep 2009, 03:02 am »

Yeah, nuts right? The driver has a big magnet though so who knows?

JerryM · « **Reply #13 on:** 29 Sep 2009, 03:04 am »

Bob,

I'm taking it that the new transfomer has been installed?

If so, I would call the same cool, knowledgeable guy from the power company back out and say "Check this shit out. This never happened before your transformer was installed. WTF?"

Then I'd enjoy the ride.

Have fun,
Jerry

Bob in St. Louis · « **Reply #14 on:** 29 Sep 2009, 03:06 am »

Jerry, no the transformer has NOT been installed yet. Nothing in the house has changed. Nothing's new with regard to my 'other' electrical issue.

Jack, Very true.
Four very large magnets as a matter of fact.
But I would have never thought of a VC creating an EMP. But I've been wrong before.

Bob

richidoo · « **Reply #15 on:** 29 Sep 2009, 04:12 am »

Call a patent attorney, tell him to make something up, make it good gobbledeegook that a beauracrat will think is sexy but not actually understand. Then get a govt grant for clean energy research, time travel, black holes in Bermuda triangle, anything will work. Then go on Oprah, Time Mag, etc. Milk it man.

Could it be the arc causing EMI? 9V is 6x bigger lightning bolt than AAA. If you have a long speaker leads, try moving as far away from the electronics as possible with the 9V, see if it still mutes. Or opposite, try moving closer to the electronics with the AAA see if you can make it mute. If you find relationship to distance, could be EMI, or RF, lightning is very broadband. Just guessing. Give you something to do so you don't electrocute yourself.

Bob in St. Louis · « **Reply #16 on:** 29 Sep 2009, 05:29 am »

Quote from: richidoo on 29 Sep 2009, 04:12 am

Could it be the arc causing EMI? 9V is 6x bigger lightning bolt than AAA. If you have a long speaker leads, try moving as far away from the electronics as possible with the 9V, see if it still mutes.

Good idea Rich.
I ran around my equipment with a the 9v battery and a razor blade. I "strummed" the razor across the terminals of the battery as I held it close to each piece of equipment.
I got nothing other than a few small sparks. No muting, or popping from the system.

Bob

KenSeger · « **Reply #17 on:** 29 Sep 2009, 10:02 am »

First off if you have those 4 woofers in parallel and each woofer is 8 ohms you are passing 40 to 60 watts, or 10 to 15 watts per woofer but not during the entire time of contact, only after you have overcome the impedance of the coils. Compare this less than a second power pulse to what you pump into woofers when you play War Of The Worlds where less than 10% of the electricity is converted to sound and the rest goes up as heat and that event goes on for minutes or hundreds or thousands of times longer. So burning out your woofers with a 9V battery passing the occasional pulse ain't gonna happen.

So, which of your electronic components that are active in the system during the event in question have a remote control? You've got what, 100 feet of antenna (30 feet of regular wire + 20 feet of remote control) in series with 2 or 4 iron core inductors in really close proximity, if not touching, the other 'antennas' that connect to your bass, midrange, and tweeters and their appropriate amplifiers? It would be interesting to see what a storage osciloscope would see during this event. or better yet a storage spectrum analyzer. And not just in your 9 V amatuer radio circuit, but the 'received' signal in your other 6 antennas.

Ken

P.S. 20 years ago the joke about the government grant would be funny. In today's 'let's poof a trillion dollars into existance and see if that makes things better or not' environment. if one could keep a straight face........

chadh · « **Reply #18 on:** 29 Sep 2009, 02:46 pm »

Bob,

I've devoted quite a lot of thought to your predicament, adopting Sherlock Holmes' principle: eliminate all impossibilities and whatever is left, no matter how improbable, must be the truth. It is clear, then, that one of the following must explain this phenomenon:

(a) Despite your claims, your system is not muted for a second each time you tap the leads to the battery. Instead, it is your EARS that are switching off for a second. If this is the case, I'd check your warranty and see if the ears can be repaired or replaced at the manufacturer's expense.

OR

(b) Your wife is playing a very clever trick on you. If this is the case, you must realize that wives come with no warranty. Repair is impossible, and replacement is inordinately expensive. I'd suggest that you play with the battery for very long periods until she gets bored. And never, EVER mention the curious incident in her presence.

Chad

thunderbrick · « **Reply #19 on:** 29 Sep 2009, 03:06 pm »

Quote from: JerryM on 29 Sep 2009, 03:04 am

Bob,

I'm taking it that the new transfomer has been installed?

If so, I would call the same cool, knowledgeable guy from the power company back out and say "Check this shit out. This never happened before your transformer was installed. WTF?"

Then I'd enjoy the ride.

Have fun,
Jerry