VO-BB - 19 YEARS OLD!

brianforrester · Posted: Thu Jun 01, 2006 10:21 pm Post subject: WTF is this!

Hey there fellow Audio geeks... Wink

I'm wondering if you would mind taking a listen to this file and letingt me know if you know what might be causing the wierd rumbling... the level is pretty low, so you may need to crank up the volume a bit.

http://www.brianforrester.com/wtf.wav

The sound bit is only about 10 seconds long, but as time goes by rubmling slows down to a bit faster than a heartbeat. After about 15-minutes, it disapeared all together... now of course I can't seem to replicate the problem.

It suddenly appeard earlier tonight. I've messed with every cable in the signal chain, and the only thing that makes it go away (other than turning the power to the pre-amp off) is to unplug the microphone... but as soon as I plug the mic back in, the sound comes back. Frown

The same is true as soon as I turn the pre-amp back on... back comes the rumble!

Hear's the signal chain that I'm using:

Neuman TLM 103 > Presonus Eureka Channel Strip > Mbox... that's it.

I'm certainly stumped since I've never heard this sound before out of my system. I'm hoping that it's a common problem with a quick fix, but who knows!

Any assistance would be truly appreciated.

Thanks in advance.

Cheers,

Brian
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billelder · Guest

It seems to lower pitch as it progresses. Have you re-wired anything lately, like rewired power or plugged a componant into another power outlet? Is your mic cable rolled or curled? Have you tried another cable? Have you tried the Bypass button on the Compressor and the EQ of the Presonus to see if that changes anything? Is any part of your system where this is plugged in connected to television cable or a componant? Has it only happened this once?

All that wireing can be like a huge radio antenna and pick up all kinds of stuff. It almost reminds me of when you try to listen to an old AM radio in a car with bad wiring. I guess the good news is that it eventually goes away. Sorry for your trouble.

ballenberg · Posted: Fri Jun 02, 2006 6:07 am Post subject:

I could be very far off-base, and I'm no tech guy, but I don't think it's electronic-- Could it be a low-level sound that was being produced outside your house? It's almost a vibration kind of sound, maybe some work being done underground, drilling perhaps?

brianforrester · Posted: Fri Jun 02, 2006 6:19 am Post subject:

Thanks guys...

It's definately coming from somewhere in the signal chain, since the phantom power to the mic was turned off, therefore not picking up any mechanical or man made noises....

As for the cables, things have remained the same for awhile now, however the mic cable is curled into a small loop around itself... I'll undo that and leave the cable in as straight a line as possible.

It's funny Bill, the first thing that I thought of was your previous mention of the tv cable causing wierd noises in your setup... no tv cable plugged in here, in fact no tv cable within about 15 feet.

Thanks again.

Brian
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CWToo · Guest

Have you tried plugging the mic into the Mbox, using the Mbox's phantom power?

I'm assuming you've tried the other inputs on the Mbox.

Bruce · Posted: Fri Jun 02, 2006 6:54 am Post subject:

I vote for ALIENS as the cause.

Have you tried talking back to them?

B
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Bailey · Posted: Fri Jun 02, 2006 7:34 am Post subject: Re: WTF is this!

brianforrester · Posted: Fri Jun 02, 2006 2:40 pm Post subject:

Well guys... I appreciate all of your input!

I'm going with the damn aliens! Those little buggers get me every time... I thought that after I agreed to visit their mother ship and recieve an implant, that this kind of stuff would stop.

Wink

Chris, I actually plugged the line into a completely seperate sound card and still had the same sound...

Bailey, I took a look around the neighbourhood today and couldn't find any towers, even small ones... so I'm not sure.

My thoght at this point is that I have a cable too close to a power source or something. I've tried to keep the cables in as straight a run as possible, and have moved them away from any power supplies etc.. Right now the closest power cable is the one for my pre-amp and it's a good 14 inches away.

As of now, I haven't been able to reproduce the sound, so hopefully the little green guys have gone back to Xenonoville and will leave me alone! Foot in Mouth

Have a great weekend.

Brian
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jrkaiser · Guest

Here it is amplified... it's not 60 cycles... more like 40-45 cycles... it is definitely electrical,,,

Gregory Best

Sounds like something induced from a motor, but the rpm changes. Any fans (particularuy variable speed) nearby or on the same circiut?

Greg

Charlie Channel · Posted: Wed Jun 07, 2006 10:47 am Post subject:

I hear two tones. The high pitched sound (like a whine) is from the MBox pre. I had an Mbox and know that sound.

My guess: the low pitched sound is an artifact from the power source. Since the Mbox is driven by USB power, and USB power is AC converted to DC, my guess is it's noise passed through the USB rectifier circuitry. The slowdown in the low frequency pulse may be due to power supply circuit/capacitance loading when turning something on. That's just my guess.

To test, I'd try plugging the Mbox into another computer to see if there's any change in the low frequency noise.
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