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Hiss

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Tony Connoly
Hiss
on Nov 11, 2010 at 2:27:42 am

I plugged my Rode NTG-2 into my computer, mainly for the purpose of trying different things with the mic.

I am using an XLR to 1/8" converter.

There is an unbelievable amount of noise/hiss coming through.

The computer has a Realtek sound board. I went into the control panel for the sound board and made sure the microphone boost is set to zero db. The recording volume cannot be set to zero because then nothing is heard at all. But as soon as I increase the volume by just a bit, the hiss goes up a lot. There is a noise suppression button, which removes the hiss but also distorts the sound.

I am using Soundbooth to monitor the sound coming from the mic.

Is the culprit here the mic pre-amp of the sound card, or could there be something else? Shouldn't the mic be able to send some signal that can be recorded without the aid of the pre-amp?


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Eric Toline
Re: Hiss
on Nov 11, 2010 at 2:43:42 am

You'll need 48v phantom power to activate the mic. You don't have it on your computer and even if you did you can't send 48v phantom through an unbalanced cable which is what you have with the xlr to 1/8" adaptor cable.

Get a mixer or a pre-amp that supplys 48vp and send the output of the mixer or pre-amp to the input of your computer, mic level of course.

Eric


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Tony Connoly
Re: Hiss
on Nov 11, 2010 at 3:19:04 am

The mic has a battery. I thought it runs on either the battery or the phantom power equally. No?


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Eric Toline
Re: Hiss
on Nov 11, 2010 at 3:29:39 am

I wasn't sure in the mic had a battery. Now it could be that the xlr to 1/8" cable is not wired properly. Open the XLR end and see how many pins have wires attached to them. If only two pins have wires check to see that pins 1 & 3 are connected together, also if possible open the 1/8" connector and see if there's 2 or 3 wires attached. If the 1/8" is a TRS then there should only be a connection to the shield/ground and the tip/positive. If you had an ohm meter you could do a continuity test. Open them up and report back.

Eric


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Tony Connoly
Re: Hiss
on Nov 11, 2010 at 4:02:59 am

I find the voltage thing pretty confusing. A 1.5 volt battery can take the place of 48 volt power? (I am actually using a rechargeable battery, which is 1.2 volt rather than 1.5 volt).


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Eric Toline
Re: Hiss
on Nov 11, 2010 at 12:27:19 pm

Some electret condenser mics can run on a wide range of voltage. True condensers require 48vp +/- 4v. Think of it like cars that can run ok on any grade of fuel while others require premium fuel for best performance.

Eric


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Tony Connoly
Re: Hiss
on Nov 11, 2010 at 3:33:43 am

This is the XLR connector. I'll see if it's possible to open it up.

http://www.bhphotovideo.com/c/product/589872-REG/Pearstone_8111240_LMT100_L...


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Eric Toline
Re: Hiss
on Nov 11, 2010 at 2:13:14 pm

"This is the XLR connector. I'll see if it's possible to open it up.

http://www.bhphotovideo.com/c/product/589872-REG/Pearstone_8111240_LMT100_L....."

The mini connector is a TRS. Unscrew the outer barrel and see how many wires are connected and where. On the XLR, unscrew the boot and pull the cable to get the connector out so you can see what wires are where. If you have 3 wires on both ends going to 3 seperate points you don't have an unbalanced connection.

Eric


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Ty Ford
Re: Hiss
on Nov 11, 2010 at 1:49:03 pm

Tony,

Is the computer input mono or stereo?

Regards,

Ty Ford

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide






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Tony Connoly
Re: Hiss
on Nov 11, 2010 at 3:03:45 pm

The computer has two inputs: Line-in and Mic-in. They are both stereo.

The XLR to 1/8" adapter I am using is dual-channel mono: it routes the mic to both channels equally.


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Richard Crowley
Re: Hiss
on Nov 12, 2010 at 12:21:26 am

Computer mic inputs (the 3.5mm mini-phone kind with the pink colored jack) are uniformly MONO. Furthermore, they use a special pinout where the tip inputs the (MONO) audio, and the ring terminal sends the ~3V power to the microphone. No computer that I have ever heard of has a stereo 3.5mm mic input jack. Including Mac, AFAIK.

On top of that the "preamp" in a computer sound-card (or built-in to the motherboard) is probably one of the worst preamps you will ever come across. They have high distortion, little dynamic range, and poor signal-to-noise ratio. OK for making Skype phone calls over the internet, but unsuitable for all but the most crude recording project.

There are at least half a dozen solid possibilities why an NTG2 doesn't work in a typical computer mic input. Virtually all of them can be solved by using an external mic preamp with USB connection to the computer.


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Tony Connoly
Re: Hiss
on Nov 17, 2010 at 12:14:36 pm

Ok, the line-in is stereo and I thought the mic-in was stereo because the control panel let me choose the channel. I can test it further. But I was wondering why Ty asked the question--does this affect the hissing sound somehow?


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Ty Ford
Re: Hiss
on Nov 17, 2010 at 12:30:21 pm

Hi Tony,

Strange things can happen when you plug a plug wired for mono into a stereo jack and vice versa, It's difficult to predict exactly what will happen, but it usually isn't good. Hiss would be on the list of not good.

Regards,

Ty

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide






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