Apple Logic Pro /LogicExpress Discussion

Michael,

There are a lot of considerations for your situation without all of the info I will give you my best.

I foresee three scenarios from your description.

1-If they are powered audio monitors and the power cables run 
    along with the digi001 inputs and monitor inputs, 
    then you have induced line hum from the power
    cables being picked up by the inputs of the digi001. 
    or by the monitor inputs for this scenario you need 
    to use shielded balanced cables to your monitors
    and shielded balanced cables to your digi001

2-If you are talking about video monitors and the power 
    cables and digital video cables are run along with your 
    digi001 inputs then you may have digital sync buzz being 
    picked up possibly along with induced line hum 
    for this you will also need to use shielded balanced cables
    for the monitor inputs and the digi001 inputs

3-The third scenario is the worst possible. It would imply that 
    you have a ground loop between your powered monitors 
    and the source of your audio(your computer)? 
    or a ground loop between the power for anything 
    connected to your audio path
    for this you will need to make sure that anything 
    connected to your audio including your computer
    is on a common ground because not all grounded outlets 
    in a home or business are at the same ground potential
    it could be something as simple as this
You have cable TV and you also use your television for monitoring the
ntsc video which you sync to picture everytime you hook up the video 
to the tv everything hums.  discovered the ground loop was the cable tv input to my
monitor. I'm not saying this is the problem but it illustrates the example.
A similar scenario. You have your computer powered from an outlet over here
and you power your speakers from an outlet over there. Try powerring everything from
one source.


If your monitors allow for it, you can use balanced instead of unbalanced cables 
they remove common mode noise (line induced hum) This is a pretty inexpensive 
option. Otherwise you will need very expensive shielded monster cables
and they may or may not completely remove the problem.

Howard
----- Original Message ----- 
From: Michael Tuminello 
To: Logic_Cafe@yahoogroups.com
Sent: 12/28/2004 7:02:46 AM 
Subject: [Logic_Cafe] quick question: monitor hum


Hey again -

I am pretty much forced to run my cables to my monitors along with my 
inputs to the digi001 along one wall in parallel, and I have a hum in 
my monitors as a result.  (the cables are also not the best probably, 
so that may be an additional consideration.)  the distance is 20 feet 
max, probably closer to 15.

thinking of dispatching with this hum once and for all as a birthday 
present to myself.  any advice on the best (and cheapest) way to do so? 
  are there cables that are well-shielded enough to remain silent under 
these conditions, or do I need some kind of hum-cancelling solution?

Thanks -

Michael


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