Last friday show

[uuderzo]

Wow!

Last friday we finally had our show! All went wery well, and i'm really happy

to be a PTE user.

I have only one question, not regarding PTE but the audio system in general.

I admit i'm not a show expert, so I got in trouble when I attached the line out

of the laptop to the tehatre audio system and, when plugged the laptop to the

power plug, an humming noise was heard.

So I had to keep the laptop on batteries, and plug into the power only when

the anchorman was speaking (because there was no music, so I unplugged the

line out from laptop). It happened with 2 laptops, so I think it's not a laptop fault

but something else.

Did someone experienced such trouble? Reading on internet I discovered that

this effect is called "ground loop noise", and there exist "group loop isolator"

filters that claim to solve this issue.

Is it right? How do you solve this trouble?

Thank you... Umberto

[fh1805]

Umberto,

Try using the headphones output jack on the laptop rather than line out. I had a similar experience on Saturday when I got hum on first connecting my laptop to the sound system being used. I simply switched off the sound system's amplifier, unplugged and re-plugged the headphones out jack and then switched the amplifier back on. This solved my problem. Sometimes these problems are caused by bad connections. Removing and re-inserting the connectors can sometimes clear these problems.

My preference is always to use my own equipment or to provide just the exe files on a USB Memory stick and use the hosting organisations equipment.

Whichever option I use, it is always clear who is responsible for sorting the problem out.

regards,

Peter

[Lmoreels]

It is probebly"ground loop noise".

One way to avoid this is working with a audio intrface: http://www.behringer.com/UCA202/index.cfm?lang=ENG

that plugs in a usb conection

It is cheap, about 40 euro and it gifs mutch more sound quality.

specs.: 20hz/ 22khz signal/noise ratio 96 dB!

Luc M

Wow!

Last friday we finally had our show! All went wery well, and i'm really happy

to be a PTE user.

I have only one question, not regarding PTE but the audio system in general.

I admit i'm not a show expert, so I got in trouble when I attached the line out

of the laptop to the tehatre audio system and, when plugged the laptop to the

power plug, an humming noise was heard.

So I had to keep the laptop on batteries, and plug into the power only when

the anchorman was speaking (because there was no music, so I unplugged the

line out from laptop). It happened with 2 laptops, so I think it's not a laptop fault

but something else.

Did someone experienced such trouble? Reading on internet I discovered that

this effect is called "ground loop noise", and there exist "group loop isolator"

filters that claim to solve this issue.

Is it right? How do you solve this trouble?

Thank you... Umberto

[uuderzo]

Hello Luc,

I temporarily solved the "ground loop noise" trouble by plugging the headphones exit to a "ground loop noise" filter for car audio. I paid 10 Euros for this piece and it seems to work well. It has 2 RCA male connectors and 2 RCA famela connectors. Anyway, I don't know if it will work well on every audio system I will plug my laptop into.

The USB interface you are speaking about... what precisely is it?

An external audio card? I see that it has SPDIF output, that should eliminate the ground loop noise I suppose.

After reading something on ground loop noise filters, I understood that the filtering mechanism works by breaking the line with two 1:1 micro transformers (one for each stereo channel).

Does the USB interface work in the same manner or is it totally different mechanism?

Thank you. Umberto

It is probebly"ground loop noise".

One way to avoid this is working with a audio intrface: http://www.behringer.com/UCA202/index.cfm?lang=ENG

that plugs in a usb conection

It is cheap, about 40 euro and it gifs mutch more sound quality.

specs.: 20hz/ 22khz signal/noise ratio 96 dB!

Luc M

[Lin Evans]

Hi Umberto,

My guess is he is referring to this:

http://www.griffintechnology.com/products/imic

And reviews here:

http://www.kenstone.net/fcp_homepage/review_imic.html

http://www.soundadviceblog.com/?p=430

Best regards,

Lin