# Laptop to Sound System Connection



## stryker23 (May 23, 2004)

I don't know all of the hardware specifications, but I was wondering what is the easiest way to interface a laptop computer with a basic High School Auditorium sound system? I know this is kind of a difficult question when you don't know all of the hardware, but I was wondering if there is a general case. Is there a way to connect the laptop to an axillary connection? What kind of connection is needed to connect it to one of the sound board inputs? Thanks!


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## cwwozniak (Nov 29, 2005)

A general case might be to take the stereo headphone output of the laptop and feed it a set of left and right line level (not microphone level) inputs to the soundboard. Radio Shack sells a cable that has a typical mini stereo headphone plug on one end and a pair of RCA Phono plugs on the other end. If the soundboard does not have phono jack inputs you will need some type of adapter plug on the ends of the cable phono plugs to match the soundboard's connector.

You then experiment with the laptop's volume control setting (start low) and the soundboard's input level control to get undistorted sound with minimum noise and hum. If you can not get rid of the hum, you probably need to add a ground loop isolation box (also available from Radio Shack, I believe) to reduce or eliminate the hum.


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## stryker23 (May 23, 2004)

I will just need to find a cable to try it out. Hopefully the feedback hum isn't an issue, but if it's a common problem it will probably definately happen with this setup. Thanks for the suggestion. Any other alternative methods would also be appreciated just in case.


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## cwwozniak (Nov 29, 2005)

The hum isn't feedback. It is related more how AC power fed into the laptop's charger(assuming you are using it to power the laptop during use) and the soundboard (and projector is you are feeding video from a laptop to a projector). If everything is close to each other and plugged into the same set of outlets, you will have less chance of a hum problem than if the laptop is near the stage and you are feeding a soundboard in the back of the auditorium.


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## stryker23 (May 23, 2004)

Alright, thanks for the correction and the tip. I have found an adapter that goes from head phones to rca jack. It's for plugging rca (Is rca the correct name for that type of plug?) headphones into computer jacks. Could I just use this adapter with a straight through rca cable, or do I need a cable that changes plugs?


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## cwwozniak (Nov 29, 2005)

Does you adapter have the same type of plugs and jacks as this one?

http://www.amazon.co.uk/Hama-Cable-...VY2/ref=pd_sxp_grid_i_1_1/203-4971050-6540719

Or does it look more like this?

http://www.radioshack.com/product/i...d=2032058&kw=stereo+adapter&parentPage=search

The first one has a pair of RCA Phono jacks. The second one has a 1/4 inch stereo phone jack.


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## stryker23 (May 23, 2004)

It actually looks like the first one, but it has the same connectors as the second one. I guess they are just called 1/4 stereo jacks. With the adapter I was able to get the computer to work through the head phone jack, and it seems to sound alright. Thanks for the help.


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