Noise

[arjepsen]

Hey.
I'm having a bit of a noise problem.
I connected my monitors to the master out on the d8b (xlr jacks), and my keyboard to the mixer.
The monitors are a pair of tannoy reveal 502.
When I start playing, I can hear the noise level increase, and when I hold a chord, After a while the noise level drops, and eventually almost sputters out out the end.
If I connect directly to the monitors, theres no problem. If i use the cr TRS connectors its the same problem.

Anyone else experience this?

[anyhorizon]

This might address your problem.

Peter

[Bruce Graham]

Hi Arjepsen;

In order to give you some thoughts we (specifically me) would need more information as to how you have your d8b "system" installed.
What cards do you have in the mixer?
Is the d8b a master or slave to another digital device or clock?
Is there a recorder, and what recorder?
What version of Mackie d8b software are you using?
Are you using any processing in the d8b or inserted into the d8b?
Basically, how are you using the d8b and how is it connected! it would also help if you can describe the noise as there is all kinds of different sounding noise.
There is a ton of people here who can help we just just need some more info. Thanks.
Of the cuff, it could be a compressor or gate that is in the chain of your keyboard that is enhancing the noise. Just a thought.
Hope that is a start.
Post back.
Bruce

Edit: Peter's came in while I was tying, so I'd start with his as it looks like the issue. Respectfully Bruce

[FrankH]

To answer this: "Anyone else experience this?"
...I can say: yes. Years ago, when I first set up my D8B, I bumped into that exact scenario when I attached a set of Mackie 824 mk1's to the D8B's Master Outs.

Turns out, the TRS plug of each channel's connecting cable (TRS>XLR) was wired unbalanced (Pin 2 wired to sleeve).
Computer "hash" was being modulated by the audio, into the audio stream. I reconfigured the plugs back to balanced and that solved the problem.

I would double-check the plug wiring on your monitor runs just to be sure. That's a quick check (and fix). If it isn't the cause, then what has been suggested above are your next steps. My second best guess is Peter's suggestion.

And one other thing: check to make sure your kybd, mons and D8B are all sharing the same common AC ground.

[arjepsen]

Thanks for the quick replies guys.
Peter was spot on - it was those filters.
I disabled them, and the problem is gone.

[Bruce Graham]

Another problem solved!

Peter,your the man!

FrankH has some very solid points about power (AC) distribution and grounding within an audio system. Even if all the equipment is the same room. Something we all should consider paying attention to. My source was a book written by Philip Giddings called Audio Systems Design and Installation, published by SAMS, 1990. Great reference for Power, Interfacing Unbalanced and Balanced. and many, many other topics of audio interest.

Bruce