Old sound card (m-audio 2496 from 2002) & too much computer noise with guitar distortion plugins

[kokotron]

Hello everyone!

After a very long time and quite a few computer setups later, I decided to try some guitar fx plugins, such as guitar rig and bias fx. I have the same soundcard since 2002, an mAudio 2496, connected to an 802VLZ3 Mackie mixer for the last few years. No problems whatsoever in recording most kind of stuff. However, when there is a distortion fx in forementioned guitar fx software, I suddenly noticed a TON of computer background noise being overly amplified to the point it makes any use of distortion useless, even with noise gates etc. I'm talking about the electricity noise/interference you get, where you can listen to the motion of the mouse, the starting/stopping of the disk drives etc. So far I lived happily without ever noticing, recording simple things like vocals and keyboards and maybe some clean guitar, however with the use of extra gain and distortion it occurred to me how serious the underlying issue is.

So the question is if the age of my sound card has a role in this (it's been almost 14 years...) , if having a usb3.0 external sound card or a new PCI-express one could eliminate or reduce such an issue, or if I should be looking elsewhere. The computer is a fairly new setup, built in 2015. The noises can be heard through these effects without any input as well, obviously. I assume I shouldn't be listening to this kind of noise even with distortion and gain effects on, or at least it should be low enough that it could be worked out. I also need to say again that I don't notice that noise at all without these kind of effects on.

Cheers!

[nix808]

Could this be a ground loop or several ground loops maybe?
I had such an issue years ago.
You could try lifting the ground on the line-out to mixer?
Or yeah-as you suggest a different sound card.
If the 2496 is wholly compatible with your OS, it is a very reliable card though still,
and most people would find that it would have served without any noise.

This is the kind of device I mean->
https://www.storedj.com.au/products/DAP ... ApO_8P8HAQ

[BertKoor]

The first thing I'd do is to perform some tests with your current sound card with the RightMark Audio Analyser:
http://audio.rightmark.org/manifest.shtml

Start with a simple direct loopback test: connect the inputs directly to the outputs of your sound card. Make sure though that input monitoring on the card is switched off, otherwise you get a direct feedback loop. There are plenty RMAA results published for such a popular card as your M-Audio 2496. A quick google reports that in brand new state it had a noise level of about -95 dB. That is a quite repectable figure, although from a modern card you could expect noise levels below -105 dB. Aging could have added a few dB to your card. If you measure noise levels above -90 dB (so that's in the -80dB range) then for sure it's the card itself that needs replacing.

The next step is to include the mixer into your RMAA test: audio interface output --> mixer channel input --> mixer main output --> audio interface input. I have a Mackie 1604VLZ and I recall it emits a noise level of around -90dB. That's what you can expect from such a mixer, and it should not be a problem.

The noise you hear could indeed be the result of a ground loop. This can occur when there's more than one electrical path for the ground between two devices (PC and mixer, or PC and monitors). Typically there's one path through mains ground and another one through the audio or USB cables. The easiest method to test for a ground loop is to temporary disconnect the mains ground connection of your electrical devices. If the noise goes away when you put some insulation tape on the power plug's ground connector, then you have indeed a ground loop and a possible fix is using a Groundloop Isolator.