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#256649 - 23/05/2005 07:39 last night at the drive-in movie...
bjoern member Registered: 03/04/2002 Posts: 169 Loc: Regensburg, Germany	... I noticed noise on my empeg. They transmit the movie sound through a radio broadcast. I received it through PCATS' radio module and heard some background noise that sounded like static. I paid special attention to ground-loops and such when I installed the empeg, but I only tested with the engne running. Now, in the movie theater, I noticed noise with the engine off. There is no noise with the engine on. Before I get my multimeter out to trace the noise, do you have any idea where I should start looking when I have noise with engine off and no noise with the engine on? Thanks for any hints! _________________________ 32MB, serial: 10101626
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#256650 - 23/05/2005 13:53 Re: last night at the drive-in movie... [Re: bjoern]
tfabris carpal tunnel Registered: 20/12/1999 Posts: 31600 Loc: Seattle, WA	I've noticed something similar with my empeg. Ground loop noise when the engine is off, none when the engine is running. It's still a ground loop, but this time it's due to the change in voltage that happens when the alternator isn't pumping power into the system (I think). Without the engine running, the voltage ends up dropping pretty low. I'll bet that when you turn the engine off and turn the volume up, you also get the occasional blank screen followed by the battery icon, right? _________________________ Tony Fabris
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#256651 - 23/05/2005 21:01 Re: last night at the drive-in movie... [Re: bjoern]
Shonky pooh-bah Registered: 12/01/2002 Posts: 2009 Loc: Brisbane, Australia	I've heard noise due to the drives spinning/seeking (I think seeking more than anything). I doubt it's getting in internally to the empeg's audio circuitry though. I think it's producing some small current fluctuations in the supply lines that are getting into the amps. It's so quiet I've haven't ever bothered about it, but it definitely was there. This was in my old car and I'm not sure the M3 with factory amp has it. I think I remember the old car having it even before my empeg when I had an embedded PC with a 3.5" drive in the boot many years ago. The sound is best described as "fluttering" I think. _________________________ Christian #40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)
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#256652 - 25/05/2005 15:18 Re: last night at the drive-in movie... [Re: tfabris]
bjoern member Registered: 03/04/2002 Posts: 169 Loc: Regensburg, Germany	Quote: I'll bet that when you turn the engine off and turn the volume up, you also get the occasional blank screen followed by the battery icon, right? I'll check that. You mean that pumping electrons into the circuit reduces ground loop effects, becasue the current is "pushed" along lower conductances? I'm having a hard time constructing an image in my mind how that should work, I'm obviously not good enough at electrics... _________________________ 32MB, serial: 10101626
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#256653 - 25/05/2005 15:20 Re: last night at the drive-in movie... [Re: Shonky]
bjoern member Registered: 03/04/2002 Posts: 169 Loc: Regensburg, Germany	Quote: I've heard noise due to the drives spinning/seeking (I think seeking more than anything). That I can hear as well, but given that in radio mode the drives don't spin, the noise is definitely different. A lot more like radio static. I'll do some more testing on different channels and such to see if something changes. _________________________ 32MB, serial: 10101626
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#256654 - 30/05/2005 12:34 Re: last night at the drive-in movie... [Re: tfabris]
bjoern member Registered: 03/04/2002 Posts: 169 Loc: Regensburg, Germany	I double checked everything and paid a little more attention to detail now. It may be that just the signal to nise ratio is worse with the radio module, compared to the player? I need to turn to volume much higher for the same sound level and thus I also increase the noise. I think I just didn't hear the noise when the engine was running. Is the lower signal to noise normal for the radio module? _________________________ 32MB, serial: 10101626
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#256655 - 31/05/2005 17:47 Re: last night at the drive-in movie... [Re: bjoern]
tfabris carpal tunnel Registered: 20/12/1999 Posts: 31600 Loc: Seattle, WA	Quote: I need to turn to volume much higher for the same sound level and thus I also increase the noise. There is a feature in Hijack which allows you to add a config.ini entry to control the relative volume level of the tuner module and the AUX input. [hijack] disable_bassboost_FM=1 volume_boost_FM=-2 volume_boost_AM=-6 volume_boost_AUX=4 Those are from my config.ini. Note that on mine, I've actually had to TURN DOWN the tuner module in relation to the MP3 levels. So I suspect you might have some kind of a wiring problem that is causing your tuner module to put out unusually low volumes. _________________________ Tony Fabris
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#256656 - 01/06/2005 06:33 Re: last night at the drive-in movie... [Re: tfabris]
bjoern member Registered: 03/04/2002 Posts: 169 Loc: Regensburg, Germany	Quote: So I suspect you might have some kind of a wiring problem that is causing your tuner module to put out unusually low volumes. Aw, that sucks! But at least I know there's something I need to check. Thanks for all the help! _________________________ 32MB, serial: 10101626
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