Noise from laptop

I'm hoping one of you guys knows the answer to this. I am in the process of changing my keyboard rig to a laptop. So far, so good. One issue so far is that I seem to get some noise/hum from the laptop when using a little mini plug into the laptop's soundmax soundcard. The soundcard normally sounds fine, certainly good enough for gigging...and with ASIO4ALL the latency is really low and low CPU. Loving it. But, not sure about the noise. I'm wondering if its the soundcard in the laptop itself or rather the cable I'm using.

Since its a miniplug headphone jack I'm using to feed into the main mixer. I admit I'm an ignoramous when it comes to cables, impedence, etc.. What kind of cable or other attachments would you guess reccomend for running out of the laptop's headphone jack into a mixer line-in? I'm wondering if the cable I'm using now is kinda thin...and getting interference with all the guitars and amps and speakers all over the room, etc.. Anyway, I'm sure some of you must be using a laptop in live situatons, so any feedback you can give me about this would be much appreciated.

Thanks.

If you're running off an AC adapter, see if it gets better when you go to batteries.

If so, you need a ground lifted; maybe run through a direct box or transformer or something similar.

It doesn't like like 60hz hum, but I will try that.

Maybe you could nail down the dominant freq(s) in the noise?

(Record 5 secs. of the noise into a WAV file. Many WAV editors allow you to display the frequency spectrum of the sound.)

See where the peaks are, frequency-wise. That may provide a clue.

Cluedo?? I'll play...

Miss Scarlet with a 60Hz spike in the Studio???

Damn......so close..

Laptop inputs gernerally kind of suck.

The first thing to try is to go into Control panel -> Sounds and Audio Devices -> Sound Recording Volume -> Advanced (under microphone) and be sure +20db Boost is NOT selected.

If that 20db boost was checked you should find a pretty good improvement in the noise by unchecking it.

If that was unchecked or deselecting it doesn't make it fairly decent then you probably have a particularly crappy soundcard or if it's a sort of a crackling sound you may have one that has voltage on the input to run a crappy computer mic kind of like a toy version of phantom power.

The solution to this is to either use a DI box, the transformer won't let the DC voltage pass so it stops the noise, or just get yourself a USB or firewire audio interface.

Soundblaster makes a simple USB device for around fifty or sixty bucks that has RCA line inputs and outputs and sounds a lot better than most laptop cards or if you want to spend more there are all kinds of cool interfaces you can get from companies like M-Audio, Presonus, MOTU, ect. ect...

I had a similar issue with my laptop - went to record bassist's tracks the other night and discovered I forgot my layla pcmcia card, so I tried going through the ESS Allegro on the laptop and the noise floor was so high and sh*tty it was all the way up at -35db! Of course, it was a quick hack setup just for the hell of it, I was pretty sure the tracks werent going to be keepable anyway. Plus, my buddy's house has some power issues - 1930s era house and the AC is notoriously noisy. Had all of the stuff going through a furman rp8, but still ended up with issues. I dont have to deal with that crap when I'm at my own place!

Part of it is the laptop - even with the layla, my noise floor there has still been at almost -60db. (I'd use just the battery, but its mostly dead, not sure it would last a whole track! time for a new laptop, methinks...)