Mbox Pro hissing, crackling, master volume issues

[jonz44]

I have checked the grounding. Still the same issue. As stand alone (when DAW / PC not running) it does not produce any hiss & crackling.

[jonz44]

I tried few things to see where the problem is coming from.

When the firewire cable is removed, the output is absolutely quiet even. The sound starts when I switch on the PC (with FW connected), but much less. When I start pro tools it increases, many variations of swish and small crackle sound while loading PT. Once PT is loaded it is sort of constant.

All this is happening with the main volume knob turned down fully. Also, I tied changing the FW cable. But same effect.

I also did a latency check with DPC latency check and it is showing good results, I feel. All green and average latency is showing 65ms.

I have done all W7 optimization recommended in Aivd website. I am at a loss where to look now.

It is really annoying Avid is not addressing this issue effectively. They should open their software to be used with other better interfaces if they can't fix the issue. Firewire interface is supposed to be good and may be better. But firewire cards in PCs are becoming increasingly up popular and difficult to get. I had to change my initial card avid recommended card which was not available locally (Dubai) and I had to buy it from the manufacturer.

[Southsidemusic]

Originally Posted by jonz44

..... They should open their software to be used with other better interfaces if they can't fix the issue

What do you mean by that statement? Avid "opened" up their software for use of any 3rd party Hardware starting on PT9 and 10 and 11 are fully open to 3rd party interfaces and you don't have to use Avid HW anymore!

[jonz44]

Thanks Southsidemusic.
I obviously were not aware ... fairly new to PT.

[jonz44]

I managed to do some more tests today...
Used another pair of monitors (low end... Samson media1). I could not hear any white noises. Where as my standard Yamaha MSP5 hooked to Mbox it is giving white noises (constant hiss, sounds when mouse is moving and software is loading).

I hooked another Berhinger monitor amp in between Yamaha MSP5 & Mbox Pro. A lot more disturbances... Berhinger amp takes only unbalanced connections. However, Berhinger amp without input from MB Pro is quiet.

This leads me to think that this could be an earthing issue.
Can I have some suggestion how to have correct earthing?

[jonz44]

Thanks for the inputs on this issue so far.
I have done a lot of search and reading in several forums. I will keep on searching and doing some tests and if I get a solution I will share it immediately. However, what I understood from experience of several people is that

• This can happen due to several reasons. It is easy to rectify if this is caused by OS / peripherals setup issue. The grey area is the PC + firewire +interface + amp + monitor combination.

• Almost all experienced no problem when the interface is unhooked from PC

• Some monitors are not giving absolutely any issues. But some are too sensitive.

• Making an earth loop seems too complex for me and some are suggesting to open up Mbox pro which I do not wish to do.

As I though earlier, I do not think my Mbox has some issues. So the only option at present is to live with it and continue searching and testing.

[JoelG]

Perhaps you can look into one of these: http://www.ebtechaudio.com/humxdes.html

Also, double check that the wiring in your house is correct.

Joel

[sunburst79]

Out of curiosity are you using balanced connections between the MBox and the speakers? There have been a huge number of cases over the years where changing the cables from unbalanced to balanced quieted down noisy outputs.

[jonz44]

Thanks JoelG for suggesting Hum X. I will look around and see if I can get hold of one (or two) in Dubai. Do you suggest this for the monitors or Mbox?

sunburst79, I am using balanced XLR cables for all my audio connections.