Audio level from mixer to pc

[IA76]

Hi

 

I need to feed audio from a mixer to the mic/line in of a pc which is 15m away from the mixer. The problems I have is that the sound coming in to my pc is very low in volume. How can I increase the volume?

 

I am currenly using a the main jack out of the mixer to a DI box (which is by the pc) and then from the DI box to the input of the soundacrd.

[peza2010]

Sounds silly but the di box isnt set to attenuate is it?

[Bobbsy]

It's hard to be specific without more details like the make and model of both the mixer and DI box, and the sound card in your computer, but your set up is fraught with potential problems.

 

-The line out of your mixer (unless it's a DJ or other cheapie) is likely a balanced line level feed. Your DI is expecting an unbalanced feed from a guitar at a level sort of half way between line and mic.

 

-Most DI's do attenuate the instrument level feed from a guitar and put it out into a balanced XLR.

 

-The attenuation, since it starts at a higher level than instrument level, will be a non standard level between line and mic.

 

-I assume you have an adaptor cable to go from the XLR on the DI to the 1/8th inch jack on your computer? If so, that'll be balanced at one end going to a PC expecting unbalanced stereo at the other.

 

-If it's a mic/line input, there could well be a sensor on the input which switches in a fixed attenuation pad if it detects levels higher than microphones.

 

On top of all that, you're feeding 15 metres of unbalanced audio so outside interference will always be a worry--you'll be fine at one set up then be parked near an arcing thermostat at the next.

 

Solution? Spend a few pounds on a basic interface like a Lexicon Alpha, feed balanced audio from the mixer to the interface then into the computer via USB.

[IA76]

The DI box is used because without it there is a buzzing noise.Attenuation is off. The mixer is a Behringer 1202FX and the DI bix is a a Stageline DI-100.

 

The mixer doesn't have any balanced outputs? so what is the easiest way of converting one of the mixers unbalanced outputs to balanced?

 

 

Thanks for your help so far.

 

 

[paulears]

The problem is that you are just trying to get decent audio into a PC at line level - which is the best from the signal to noise aspect, but the PC, as with most PCs, has a pretty rubbish sound card, and you get the nasty noises. A DI box will give you the ability to lift the ground which may make it better or worse, and on a cheap one, a transformer to provide electrical isolation, which is what usually brings the best improvement. The snag you are getting is that as Bob says, the entire point of a DI box is to provide a device with a microphone level input - NOT - a line level one.

 

Something like these offer line level isolation, but they are £40 - so Bob's advice to get a proper audio interface that sits outside the electrically noisy environment of your PC is the sensible thing. The Lexicons are available in fairly simple to complex versions with more facilities as they get more expensive. I can confirm they are very good, and you get headphones outputs too. By far the best thing to spend money on. A six hundred quid computer probably has £10's worth of sound card, and all these nasty noises in and out are almost guaranteed.

[Bobbsy]

The DI box is used because without it there is a buzzing noise.Attenuation is off. The mixer is a Behringer 1202FX and the DI bix is a a Stageline DI-100.

 

The mixer doesn't have any balanced outputs? so what is the easiest way of converting one of the mixers unbalanced outputs to balanced?

 

 

Thanks for your help so far.

 

Put the DI at the mixer end of the run so at least the 15 metre run is balanced.

 

I'd still stump up the money for a proper external USB interface. Something like the Lexicon Alpha I mentioned is under fifty pounds--I don't own one but at least one of the other mods does and speaks highly of it. The reason I push the interface is that built in computer sound cards are universally rubbish--noisy, non standard levels, flakey MME drivers instead of ASIO causing high latency (if that's an issue) and so on.

[timtheenchanteruk]

if your really pushed for budget, the behringer UControl is infinitely better for recording purposes than most standard PC cards.

[Oldradiohand]

I've used a Beringer box for a couple of years, they're really very good for the price (£20 to £30) and it's solved a lot of my interface problems. The headphone out isn't bad, either - which is handy 'cos the headphone socket on my mac is nadgered!

 

I also carry a couple of isolating transformers with jack to XLR connectors, they're really useful for breaking hum loops. You sometimes see line level canned transformers on ebay, but mine were the result of some skip dipping when everything went digital and old fashioned analogue kit was just dumped.

[paulears]

Only this week I've stuck in one of the cheaper Lexicons for a friend fed up with the horrible noises from his sound card. They do sound really nice.

[fincaman]

You should be able to feed the line out of a mixer into the line input of your computer (keeping the levels down), I had noise problems doing this some years ago and cured it by disconnecting the earth on the computer. Try connecting the mixer directly to the computer, if you get noise unplug the computer power plug (providing the battery is good) if the noise goes it's an earthing problem. It's also possible that you are overloading the input of the computer because I think (and I'm sure I'll be corrected if I'm wrong) that mic/line inputs on computers switch level depending on what's plugged into them so it's just possible that if the output impedance of your mixer is very low the computer is seeing it as a mic, if this is the case you might try a mmm 2.2k resistor in series with the signal lead. If all this is too much for you the Behringer USB sound card suggested in another post will probably cure your problem, I use one on my netbook all the time.

[david.elsbury]

I had noise problems doing this some years ago and cured it by disconnecting the earth on the computer. Try connecting the mixer directly to the computer, if you get noise unplug the computer power plug (providing the battery is good) if the noise goes it's an earthing problem.

You removed the mains earth, or you removed the signal earth (ground)??

[Bobbsy]

...and, if the mains earth, DON'T DO IT.

 

Be safe. Buy an interface.

[fincaman]

I had noise problems doing this some years ago and cured it by disconnecting the earth on the computer. Try connecting the mixer directly to the computer, if you get noise unplug the computer power plug (providing the battery is good) if the noise goes it's an earthing problem.

You removed the mains earth, or you removed the signal earth (ground)??

 

I removed the earth from the power plug, it was quite common in the 70s and 80s to get rid of hum loops in fact some equipment had earth lift switches.

[GaryNattrass]

I had noise problems doing this some years ago and cured it by disconnecting the earth on the computer. Try connecting the mixer directly to the computer, if you get noise unplug the computer power plug (providing the battery is good) if the noise goes it's an earthing problem.

You removed the mains earth, or you removed the signal earth (ground)??

 

I removed the earth from the power plug, it was quite common in the 70s and 80s to get rid of hum loops in fact some equipment had earth lift switches.

 

It was also quite common in the 70's and 80's for people to get electrocuted from kit that had it's mains earth removed, you need to get an interface box that can ground lift just the audio properly.http://www.blue-room.org.uk/public/style_emoticons/default/ohmy.gif

 

 

 

[Bobbsy]

I had noise problems doing this some years ago and cured it by disconnecting the earth on the computer. Try connecting the mixer directly to the computer, if you get noise unplug the computer power plug (providing the battery is good) if the noise goes it's an earthing problem.

You removed the mains earth, or you removed the signal earth (ground)??

 

I removed the earth from the power plug, it was quite common in the 70s and 80s to get rid of hum loops in fact some equipment had earth lift switches.

 

I've never heard of a piece of gear where an "earth lift" switch is the mains earth. It's the signal earth in my experience.

 

If an item of gear is designed to have a mains earth then that earth is needed for safety reasons. Removing it is risking lives.