Firebox Noise

  • Thread starter Thread starter razorbeams
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razorbeams

razorbeams

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I just plugged up my new presonus firebox tonite and there is a lot of hissing. Its wierd because when I move the side scroll in a window it will make a noise. When I took the power cord out of my computer the noise stopped. Anyone ever experience this? Is there a remedy for it? Thanks
 
Sounds like a grounding issue. Try plugging it into a different socket, or maybe a different house all together and see if it still makes the noise. Try getting a power conditioner, that may help too, but I'm not sure if that will fix a grounding issue.
 
BeniRose said:
Sounds like a grounding issue. Try plugging it into a different socket, or maybe a different house all together and see if it still makes the noise. Try getting a power conditioner, that may help too, but I'm not sure if that will fix a grounding issue.
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... You want him to plug his computer in at his house and plug the firebox into someone elses house? :eek::laughings:
 
After looking around on the net, I've found that it might be because im using a 6 to 4 firewire cable. Someone mentioned wrapping the power supply cord around a toroid core (which Ive never heard of). Wonder if this will help..
 
You have a ground loop for sure, what you need is this, you will need one for the audio (2) lines running to the firebox and another for the lines (2) running from the firebox. The little box lifts the earth by isolating the signal with a transformer, there is no loss of quality.

I have exatly the same setup and it fixed the problem, I also take them out with me when live recording off PA systems for the exact same reason.

Cheers

Alan.
 
The only line I have running from the firebox right now is the firewire. Can I make due with just 1 hd400?

And thanks for the answer!
 
If you only have the firewire, how is the audio getting in and out, for example how do you hear the sound? have you only got headphones? If you have a mixer or powered monitors thay would be connected to the audio out.

What have you got connected to the audio in? What are you recording?

Cheers

Alan.
 
witzendoz said:
If you only have the firewire, how is the audio getting in and out, for example how do you hear the sound? have you only got headphones? If you have a mixer or powered monitors thay would be connected to the audio out.

What have you got connected to the audio in? What are you recording?

Cheers

Alan.
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Alan, I'm recording guitar-bass through an sm57 into ART Gold pre into line 3 of the firebox. I only have headphones at the time.
 
At the moment you may only need an hd400 between the ART and the firebox, however I am just curious, if you disconnect the ART completely and plug the bass into say channel 1 of the Firebox, doe the noise go away when listening in on the headphones.

I am asking just to check if it is am earth loop, the loop will be probably be between the computer and the ART. Also are you powering the firebox over the firewire cable or via the external power supply?

If the hd400 fixes the problem, you will nee a second one between the firebox and a set of monitors / external mixer set up.

Cheers

Alan.
 
I am powering the firebox through the external power supply. I tried plugging the firebox into another outlet that the computer was not connected to and the weird noises werent there. Will the HD400 eliminate other unwanted noises in the line?
Thanks
 
I am interested in how you get to solve this problem. I have a similar set-up with my laptop: Four-pin to six-pin firewire cable going from Firepod into laptop. With the alptop's power supply connected, I get to hear all the computer noises, as you do. Disconnect the supply and run off the laptop's batteries, I get blissful silence.

Interestingly, I took this set up to do a live mix and did not experience this problem. Only when I connect it at home does it occur. I haven't done a whole heap of experimentation yet, but I expect to.

For the benefit of Witzendoz, the audio is converted to digital and travels to and from the computer via firewire. Playback and monitoring is done from the interface, so the computer's audio output is not used. Hence there should not be an earthing loop involved (by my way of thinking). However, I may be missing something.

Just to add to the mystery, when the Firepod is connected to the PC instead, there are no noises at all.
 
Hi All,

As I was saying earlier, I have this exact set up, in 2 variants.

1)

In my studio I have the fire box plugged into a PC using the firewire power. I have the left and right outs from the console plugged into line in 3 & 4. I have the main out from the firebox plugged into the 2 track monitor inputs on the console. I always got some amount of digital noise caused by the earth loop, I put a hd400 between the console left / right and inputs 3 & 4 and another hd400 between the firebox main outs and the console 2 track returns and there is complete silence. If the main outs of the firebox are not being used you would only need 1 hd400 before the line ins of the fire box.

2)

Out live, I take a lap top and the firebox, I use the firebox external power supply in this set up. If I am taking a line input from a PA system or a separate external mixer, quite often I get a massive amount of noise from an earth loop that exists between the mixer / PA and the lap top / Firebox. A hd400 placed before the line inputs of the firebox fixes the problem.

I hope I clarified the problem / solution, for a small outlay, the hd400 is very cheap, it's worth trying to see if it fixes the problem for you. It's a handy thing to carry around for fixing earth loops also, all my tech friends carry at least 2 to every gig they are working on.

Cheers

Alan.

p.s this problem with lap tops only came about when the power supply companies decided to connect the mains earth to the low volts earth of the power supply to stop people getting electrocuted by their lap top (when they used it in the bath ha ha), older lap tops did not have this problem.
 
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Well, ever since I plugged the pc and firebox into separate power outlets, I haven't had the hissing. The problem was when I had them both in the same outlet. Not exactly sure why that was happening.
 
razorbeams said:
Well, ever since I plugged the pc and firebox into separate power outlets, I haven't had the hissing. The problem was when I had them both in the same outlet. Not exactly sure why that was happening.
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It is still to do with earth loops, maybe one of the power points is not earthed (I have seen this in houses), or the earth resistance is increased by the extra earth wire length between the 2 power points (remembering that the earth wire may not be the shortest distance between the 2 power points but may run back to the main switchboard) and the extra earth resistance has reduced the earth loop.

In my case the noise I had in the studio with the PC was very small, the lap top set up was unsusable. The 2 earth loops were there but had different behaviour.

Cheers

Alan
 
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