back ground noise on recording

[keith]

hi i am trying to record from my mixer amp to laptop using audacity software . there is a special connection from my mixer amp to allow recording . I am recording ok but there is background noise ( just like you used to get with vinal records )
does anyone know what im doing wrong or how can i remove this noise .

thanks keith

[gibbo]

Most likely culprit is the soundcard in the laptop, they're notoriously noisy.
Laptop manufacturers don't usually invest much in laptop sound cards because of the native limitations of laptop speakers.
The quickest way to check if this is the problem is to record something on the laptop using the battery mode (ie: disconnect the power supply). Most of the noise seems to be related to interference/hum/snap-crackle-pop from the laptop power supply.
If this is the source of your noise you could try an external sound-card (but try it before you buy it) sometimes the problem persists, it just depends on the particular laptop.

[thingyy]

If it's a earth{ground}hum use battery power or lift the earth off the laptops transformer at the 3 pin plug.
I cut mine off and have used it for a year with no problems.Compaq are renown for this.

[gibbo]

Hey! Don't tell him to do that!
You just moved to Queensland... the home of the Test and Tag Electrical Police! Anything with an earth pin cut off or removed is a complete no-no. If they bust you at a gig it'll be "show's over!"
Now that you've moved to the Sunshine State you should probably check out some of the venue requirements such as testing and tagging of electrical gear.

[thingyy]

Youre kidding right !
The transformer doesn't need the earth. Toshiba and Acer I think only has the 2 pin moulded plug.
So what do you do to overcome the earth hum.Maybe not noticeable in Oz due to lack of dampness to provide an earth.
I'm not there yet next month is the big mve.
I thought I was leaving a facist state,now you tell me.
LOL I might go to Tassie.

[keith]

hi gibb0 i will try that and let you know
keith

[gibbo]

Oh right... next month... well get ready.
No, I wasn't kidding... I know that the transformer doesn't need an earth as such BUT what I meant was DON'T cut off or remove earth pins, if you get checked by an inspector that's an immediate "Failed" tag. (You could buy a non-earth plug and replace the 3 pin by all means.)
Nah, it's not really a fascist state up there, they must've had a spate of electrocutions or something and decided to enforce the already-existing Test & Tag laws. A mate of mine arrived to do a gig in a major club in Q'land, got inspected and failed and; either had to pack up and go home without pay (because Test & Tag is a widely known requirement) or, call an after hours electrician to get everything tested and tagged before he could start! He opted for the latter, needless to say, but it was a rather expensive exercise in "know before you go".
You can check out the law and requirements by Googling "Test and Tag Queensland" or some such variety. Here in Sydney, I know of at least one club that periodically checks your tags before a gig.
It's one of those things that's slowly but surely getting more attention, I guess it's just another case of penalise the majority in order to protect society from the minority! lol

[thingyy]

In the USA they get 3-2pin convertors from Radio Shack.Always a big discussion on this on the solo act newsgroup.
Heres a link to some answers

ask.metafilter.com/20028/Laptop-Audio-Hum
Wow pretty strick there. I cant see why they need earthing as the laptops are made of composit plastic.
Is the electricians fee tax deductable ?

[thingyy]

Just checked it out.All my home made extn leads and reterminated piggy back plugs are gonna have to be tested and tagged.
Thanks for letting me know about that.

[levi2]

try this site might help

www.beststuff.co.uk/xitel_ground_loop_isolator.htm

[gibbo]

Hi Thingy,
Thanks for the metafilter link, there's some good data there and the DC problem is probably the most common cause of that annoying hum in the case of laptops.
There are some good suggestions at metafilter for isolating it.
Yes, the Test & Tag charges are totally tax-deductible. Make sure you shop around for a good price, you can get 'em done for about $2.50 per tag (you basically need to test and tag everything that's connected to the 240v) plus a call-out fee. We do ours every 6 months, as required, and it may be worth your while to consider doing the course to get certified as a Tester, it sounds like you know your 240v stuff. You don't need to be a licensed electrician to get certified and you can always make a few bucks tagging for your lazier mates. BTW, most of the old style piggy-backs are banned now, the only exception are the fully moulded (ie: you can't mis-wire this yourself) version. The self-wire piggy-back got banned after one too many idiots wired 'em up with the pins live... imagine a piggy-back plug being used for the female end of an extension lead... hot pins just waiting to fry someone!
Yep, it's pretty strict but for good reason, I guess.
There are a few other things that are becoming "job requirements" too; stuff like Public Liability Insurance, Workers Compensation etc. especially for the full-timers working the major club circuits. Let me know if you need any further info, I work in NSW but I'm pretty sure Q'land is much the same. Maybe one of the members from Brisvegas can fill you in a bit more on the local scene.

[thingyy]

Thanks for that.I will check it all out when I come over.

[Steptoe]

keith said:

hi i am trying to record from my mixer amp to laptop using audacity software . there is a special connection from my mixer amp to allow recording . I am recording ok but there is background noise ( just like you used to get with vinal records )
does anyone know what im doing wrong or how can i remove this noise .

thanks keith

Not sure about Audacity but on Cool Edit Pro there is a noise reduction function, with it you sample a section of unwanted noise and then cool edit will remove the noise from wave.

[keith]

hi to all thanks for all the information . i recorded using the battery only on my laptop and guess what no background noise at all . i am going to look for better software though . i will try Cool Edit Pro , if they offer a trial download .

thanks keith

[bique]

I HAD A PROBLEM OF VERY LOUD HUM FROM MY COMPAQ LAP TOP, I HAD JUST BROUGHT IT AND THE FIRST TIME I USED IT ON THE JOB I WAS HORRIFIED TO HERE THIS LOUD HUM WHICH WAS UNBEARABLE, BEING AN ELECTRONICS TECHNICIAN, I DISCONNECTED THE POWER SUPPLY, THE HUM DISAPPEARED, I HAD TO RECONNECT THE POWER SUPPLY DURING MY BREAKS TO KEEP THE BATTERY CHARGED, I RANG COMPAQ THE NEXT DAY THEY SENT ME OUT ANOTHER POWER SUPPLY WITH NO EARTH PIN THAT FIXED THE PROBLEM

[a.j.]

I missed this thread first time around.

We encountered a similar problem with a laptop buzzing through the PA, and you're quite correct, we also discovered that it goes away when you run on batteries.

Another solution that we found was to transmit wirelessly from the laptop to the mixer. We run a completely wireless front-line anyway, and just use an old Nady guitar transmitter from the laptop to the mixer.

[thingyy]

Here is the thread you need for earth humming.