I'd use a second computer (not set up or anything) and substitute it and plug in the USBs and see if you get the same interference. Other wise, check to see if you can try a new power supply in the first computer. I had trouble once hard wiring an analog output of an RME device on a laptop to a mixer but when I used ADAT light pipe to an AD / DA the problem went. There was definitely no way that laptop was meant to be grounded into the audio chain.

Thanks very much for your feedback and ideas guys.

I've just stripped everything down and started bottom up.

The only thing that I haven't done is tried a different computer... the PC I have Dell Dimension 5000 is quite new and a decent model/ spec, though I know that doesn't bring any guarentees about anything. Thew thing I like about it most is its silent operation, you can hardly tell that its switched on.

Heres my findings with all gains mid way on the Tascam DM24 mixer, level sliders at maximum and main volume at maximum. Each unit was tested one at a time seperately whilst all other units totally disconnected.

Roland DS-5 Active Monitors

These hiss slightly anyway without any audio connection.

They produce sigificant hiss when balanced or unbalanced audio cables are connected directly from the mixer (Tascam DM24) main outputs. Theres no power cable cross overs or anything like that, cables are about 1 metre long and have their own space.

Edirol Sound card

Both balanced and unbalanced audio cables tested - drastic hiss.
USB'ed to PC - tried different USB slots, front, back and on additional USB PCI hub. No difference.

Supernova

Both balanced and unbalanced audio connections tested - slight hiss, not too much. Hard to notice through normal useage, though it would be great to have complete silence as all adds up in the final run.

Fantom XR

USB cable doesn't cause any hiss.
Both balanced and unbalanced audio cables tested - significant hiss.


Virus Polar

USB cable causes slight hiss, tried different cables and ports, no difference.
Both balanced and unbalanced audio connections tested - slight hiss.
Hard to notice through normal usage. Though again would be great to reduce to silence.

Korg Triton

USB cable causes significant hiss, tried different cables and ports. No difference.
Both balanced and unbalanced audio connections tested - significant hiss.

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The audio cables used are of good quality. I cant remember the makes but I made sure at the time that I got the best that was going in relation to feedback received in the Sound on Sound forum. Costly buggers.

Theres not much scope for crosstalk in general as the cable runs have plenty of space away from power cables and i've also further sheilded them with plastic tube type corrugation.

Tascam DM24, solid and silent.


What do you see as my options being to reduce the hissy pissyness?

New PC? New USB cables? Are there any specific USB cable types that should be used? Which aspects of what I am dealing with here will the line levellers above help out with?

Thanks a lot, greatly appreciated :idea:

If it is normal hiss, you just need to gate the tracks that arn't playing anything. I had to do that with the Virus b, the TI has way less hiss.

Unfortunately there only way out is to spend a bit of cash. Although a certain level of noise is acceptable - noise to signal ratio.

But if there is too much noise at low levels then I'd be looking for other stuff first.

I'd check for a gain setting on the back of those monitors though. I'm not familiar with them at all, but there could be something. Getting noise with nothing conected isn't great at all. Even gains or room compensation switches shouldn't cause an audible hiss though (specially with nothing conected).

Sound card noise has many variables indeed. I had trouble with a network card once. And my SCSI card always causes noise when it's accessing the sampler. Power suplys, poorly placed cables ect...Pull the sucker appart and put it back together is an idea - vary the positions of cards.

I know you said the levels were mid-way on your mixer, but how about your preamps? If the onboard pre's are cranking then they could put out a bit of noise. Mmmm, but you did say the Tascam was quiet....

How is your grounding? Does your house have properly grounded outlets. Here in Japan I had to run a cable out the window to ground my gear.

Other than this (and everything else that has been brought up), I can't think of anything else.

Hope you get it sorted.

Thanks for your feedback guys.

For the kit items effected by the USB connection I think i'll just pull out the USB cables during recording. Good enough I suppose. :idea:

Changing the Gain on the monitors unfortunately makes no difference. :?

The Soundcard is the bugger. :evil:

I might try an outboard USB hub and see if that makes a difference for the soundcard. :?:

I've no idea about power grounding etc.. with my home, wouldn't know where to look or what to look out for. :?

more or less a brand new PC, perhaps I should have got one of those PC's specific for Music making :?:
http://www.carillondirect.com/clnweb...jsp?country=UK

How does one know when to use balanced or unbalance audio jacks :?:

Read the manuals.

Ok, thanks dude :wink:

Does anyone know if the hum eliminators affect the quality of the sound signal in any way? i.e the sound that you want to keep.

I know that I am kicking the arse out of this here with silly noob like questionings. Please excuse me, and thanks again to you all for taking the time to respond.

Where are you living? Most houses in most countries will have 3 prong power-outlets (here in Japan they don't :? ).

If the outlets have 3 prongs, then chances are the house is grounded (or you'd hope so anyway).

One tip to avoid ground loops (so I've read - I'm no expert), is to run your monitors and your mixer off the same out let. Because I had to make my own grounding setup, all my gear grounds off the same line.

Your soundcard is the biggest problem by the sounds though.

Not sure if eliminators will take something away from the signal - never used them myself.

I'll give that one a try, thanks man.

Unless i've missed it somehow I cannot see any reference in the Ti manual defining wether the Audio connections are balanced or not.

Same with the manuals for:

Triton EX
Fantom XR
Supernova

Anyone? :? :oops: