Mac Pro tower & Studio Monitors > noisy audio at DVinfo.net

Go Back   DV Info Net > Apple / Mac Post Production Solutions > Final Cut Suite

Final Cut Suite
Discussing the editing of all formats with FCS, FCP, FCE


Reply
 
Thread Tools Search this Thread
Old November 10th, 2006, 03:08 AM   #1
Major Player
 
Join Date: Nov 2005
Location: Vittsjö, SKÅNE, SWEDEN
Posts: 266
Mac Pro tower & Studio Monitors > noisy audio

I hooked up a pair of Genelec 8050A monitors (with built in power amplifiers, provided with balanced XLR inputs) to a Mac Pro´s 3.5 mm stereo output on the front using an adapter cable with stereo 3.5 mm mini-tele in one end and dual RCA in the others. Then a RCA to XLR converter.

I got some irritating noise from the loudspeakers. It is not very strong but at a fairly constant level, not affected by the volume control in the computer.

It is mostly some hum and higher friquency hiss but not strong. You don't notice it when playing music but when there should be silence, it is rather irritating.

I also hear the little scroll wheel on top of the mouse when rolled, it produces click sounds in the speakers. Mouse dragging also gives some weak noise.

If I pull the 3.5 mm plug the speakers are dead silent.
If I connect a separate wire between the Mac and the speakers the 50 Hz hum are gone but higher frequency noise is still there and also the scroll wheel and mouse drag sound.

The noise is not audible if I use headphones only.

What is the cure for this? An audio board with XLR outputs?
Anything you could recommend? I will edit HDV video with Final Cut Studio with this setup and have not invested in any video card so far. Could video and audio get out of sync with different boards?

Thankful for suggestions!! /Johan
Johan Forssblad is offline   Reply With Quote
Old November 10th, 2006, 09:26 PM   #2
Inner Circle
 
Join Date: Dec 2005
Location: New York City
Posts: 2,615
That problem is in the new computers? Discouraging.

First try the audio output on the back of the computer. If that doesn't help you might want to invest in a USB to audio adapter. The digital audio out is great but there's nothing economical to hook it up too that I'm aware of.

The hum is either from the RCA-XLR adapter being miswired internally or you have a bad wire.
__________________
William Hohauser - New York City
Edit/Camera/DCP production/Animation
William Hohauser is offline   Reply With Quote
Old November 11th, 2006, 04:06 AM   #3
Major Player
 
Join Date: Nov 2005
Location: Vittsjö, SKÅNE, SWEDEN
Posts: 266
Double posting removed.
Johan Forssblad is offline   Reply With Quote
Old November 11th, 2006, 04:08 AM   #4
Major Player
 
Join Date: Nov 2005
Location: Vittsjö, SKÅNE, SWEDEN
Posts: 266
Don't blame the computer yet!

Dear William, thank you for your answer. I had overlooked the 3.5 mm output on the rear between the many firewire outputs and the ethernet connectors when I first examined the computer.
You were right, the 3.5 mm line-out on the backside is definitely better than the 3.5 mm headphone output on the front! The higher frequency hiss disappeared.
The mouse wheel sound from the speakers are now down to about the same level as the mechanical sound from the mouse itself.
–Hey, this mouse wheel sound disappeared when I later moved the audio wiring further away from the DVI video cable to the LCD monitor.
The 50 Hz hum is low but will almost disappear if I connect a heavy gauge wire directly from the speaker input to the computer.
So overall, with your help it is about as good as I need now. Perhaps using the digital opto output via an adapter to XLR outputs could provide us with an even better output. We will keep our ears open for such stuff.
This community is really appreciated and helps many, thanks Chris Hurd.
Johan Forssblad is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Apple / Mac Post Production Solutions > Final Cut Suite

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 10:00 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network