Connect Laptop to PA?

[Joy Welsh]

Hi, been reading these threads as I am thinking of moving from playing backing tracks via minidisk player to using laptop via MP3 backing tracks on board. I have winamp software which I use to play the tracks. I am also having a problem connecting laptop to my powered mixing desk/PA. I have read the threads here and as far as I can gather I have 3 optional connections:

 

1: to get an external sound card with RCA/Phono outputs/inputs and with Balanced Outputs (either TRS or XLR).. With this option I connect my computer to the sound card and then connect the ESC to my powered mixer

 

2. to get DI Boxes and with this option connect computer to the DI boxes (do I need 2?) and connect the boxes to my powered mixer.

 

Another 3rd option I have picked up from the thread is to simply use a cable eg 3.5mm stereo jack to 2 RCA Cables (input to line level inputs of Powered Mixer)

 

Which one do I choose? Does anyone know which option is best? Or can give me any more help in this area. Also which output on laptop I should use?:

 

The headphone or Speaker Connection

The microphone connector

or the S-Video TV out Connector and to this I can connect a TV/Digital Audio adapter cable which has 3 inputs 1) S/PDIF digital audio connector, the other two are video input connectors (I have assumed this is not applicable for connecting a laptop?)

 

 

Thanks JOY

[Andrew Edwards]

Let's go backwards with the response...

 

Digital out can be used if your desk has digital in.

 

Straight out of the laptop headphone or speaker output. Depending upon the laptop you may get earth interference when running from mains and questionable audio quality.

 

DI box. You will need 2 if you want stereo. You still may get interference as above.

 

External sound 'card'. Best option if you get a decent one as you describe with balanced connections.

 

HTH.

 

Drew.

[King_Tom]

External sound card is your best option, better sound quality by far, the sound cards built in to laptops aren't great, more functional than anything.

 

You can pick them up fairly cheap, you don't need all the options on them, as long as it has a good output. There are plenty of places on the internet you can pick them up.

 

Avoid the headphone socket, a PA will pick up interference really well, then amplify it. this isn't good.

 

So definitely go USB sound card.

 

Tom

[djandydee]

From experience, even with an external sound card (I have the Edirol UA25) there is still some kind of earth loop. I had to use a pair of isolating transformers to achieve clean sound.

 

This is possibly due to my laptop - Toshiba sat pro and you may not have such problems.

 

good luck

 

 

 

Edit to remove unwise experimentation.

[bassfreak]

How about getting a desk with A USB port on it?

[Sound Man]

I simply use a GROUND LOOP ISOLATOR like this between the headphone out of the laptop and the stereo input of the mixer.

 

David

[Ronus4265]

I simply use a GROUND LOOP ISOLATOR like this between the headphone out of the laptop and the stereo input of the mixer.

 

David

 

What he said. They work GREAT, also you can try this out if you have a two D/I's laying around that have "GND Lift", to my understanding this works similarly in eliminating the ground noise which usually seems to be generated from the power supply and all of the laptop components being in such close quarters, Best of luck! :)

 

~Ryan

[johndenim]

Something like this?

 

I have just gone over to what you mention in your OP, I was advised by Bobbsy to get one.

I did, and the difference between this and the headphone socket is alot.

 

For £44, you can't go wrong short of an external sound card.

[Bobbsy]

Er, John....that IS an external sound card! :)

 

Seriously, there are two separate issues with laptop audio that people sometimes confuse.

 

First off, the sound cards built into laptops are invariably rubbish. The interior of a computer is an electrically noisy space and sound cards in a laptop are very much an afterthought, designed to cost as little money and use as little circuit board space as possible. As John says, even an inexpensive external card like the one he links to will make a huge difference in performance. Spending a bit more on an external card with balanced inputs and outputs is better still.

 

The second issue that crops up frequently is earthing problems when you connect your laptop to a professional mixer. The design of the mains adaptors on many laptops means they're very prone to problems with hum caused by an earth loop. This issue can happen either with the internal card OR with an external card (since a USB external card is powered from the computer and electrically connected to it). Like most hum problems this can usually be cured by something like an isolating transformer or DI box. Or, if your mixer can handle it, an optical connection completely eliminates the problem. It's worth saying that not every laptop suffers from this issue--my old IBM thinkpad was clean as a whistle.

 

Bob

[Chris Beesley]

If you can live with a mono summed output ARTcessories have an interesting little passive unit... AV Direct

[TAG1960]

Here is a brilliant passive ( So no phantom needed ) compact and cheap box. Stereo, 20db pad and of course earth lift

Ckick Here!

I have 2 of these used regularly for corporate events with no problems.

 

Good Luck

 

Neil

[timtheenchanteruk]

in my experience, its USUALLY the laptops that have an earth on the PSU that cause problems, this may or may not be solved by an external card or DIs,

a way that has worked every time so far for me is to use an el-cheepo PSU from Maplin or similar thats double insulated, just a figure 8 type connector.

[J Pearce]

Happy to say my little IBM thinkpad is also lovely and quiet, to the extent I've used its onboard output to drive a large sound rig for background music and had no hiss, fizz or hum.

 

Has anyone tried one of these from CPC?

 

If the sound quality is reasonable they look to be quite promising. What about drivers, do they have ASIO drivers or is ASIO4ALL required?

[onemanband]

Hi, been reading these threads as I am thinking of moving from playing backing tracks via minidisk player to using laptop via MP3 backing tracks on board.

 

Thanks JOY

 

Hi Joy

 

Have you considered any of the Archos range of mp3 players?

I arrange my drumtrax and bass lines on computer and then transfer them to the Archos as either a wav. or mp3 file. I prefer the wav.

The storage is huge and you have a single play option.

I connect my Archos 504 to my mixer via the analouge stereo in chanel, it's reliable and sounds excellent with no noise issues. Might be worth a look.

 

Cheers.............Brian.

[Rob_Beech]

I'd like to throw another spanner in the works and ask the question...... WHY?

 

I'm not saying there isn't a problem, I'd just like to know what the current problem with minidisk is that is making / has made you change to relying on computers?

 

 

Rob