XLR Microphone into PC

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H

hewo

Member
Joined 2010
1. Does anyone know how to convey the XLR (pin1=ground, pin2=non-inverted, pin3=inverted) into the PC ?

2. the intent is to obtain a digital file.

3. someone told me the PC needs a specialized application in order to generate the digital file.

4. however, the intel board D975XBX features intel's chipset i975X, intel's southbridge 82801GB (ICH7/R), smsc's LPCIO LPC47M182

5. the audio hardware intrinsic to this intel board should be able to do the conversion.

6. the microphone is an XLR output microphone. I am not certain this line level signal is appropriate for the intel board's microphone input. that's because there's two signals (non-inverted and inverted) and only one can be accepted by the PC microphone input, and, the impedance match of the microphone XLR output going into the PC's input might not be proper.

7. any suggestions recommendations are appreciated.

8. i am trying to use this PC to record vocalist tracks which eventually will be blended (mixed together).

thanks
 
B

benb

Member
Joined 2010
hewo said:
1. Does anyone know how to convey the XLR (pin1=ground, pin2=non-inverted, pin3=inverted) into the PC ?

2. the intent is to obtain a digital file.

3. someone told me the PC needs a specialized application in order to generate the digital file.

4. however, the intel board D975XBX features intel's chipset i975X, intel's southbridge 82801GB (ICH7/R), smsc's LPCIO LPC47M182

5. the audio hardware intrinsic to this intel board should be able to do the conversion.

6. the microphone is an XLR output microphone. I am not certain this line level signal is appropriate for the intel board's microphone input. that's because there's two signals (non-inverted and inverted) and only one can be accepted by the PC microphone input, and, the impedance match of the microphone XLR output going into the PC's input might not be proper.

7. any suggestions recommendations are appreciated.

8. i am trying to use this PC to record vocalist tracks which eventually will be blended (mixed together).

thanks
Click to expand...
I presume this is running some version of Microsoft Windows. That will handle all the interfacing between the "mic" and/or "line" inputs and whatever chip sets the PC uses, so chipsets and hardware specifics don't matter as far as getting this thing done.

There are hundreds of "specialized applications" that do this. Windows includes a small app called "sound recorder" but it is too simple and lacks features needed for even the simplest recording job. A commonly used free program is Audacity (available for Windows, Mac and Linux). It's the first two hits when you Google that name.

To point 8, the PC internal sound circuits may not have as good a sound quality as needed. You may need to buy a USB sound interface with an XLR microphone input. This will also supply the voltage needed to use a microphone that runs on phantom power.

It appears you are starting from "ground zero" as far as knowledge about audio recording on a computer. You may be better off hiring someone who is more knowledgable in this area to do the task you want.
 
C

cbdb

Member
Joined 2008
There are many types of microphones, some need phantom power (fed to the mic from the mic preamp) some run on batteries, some dont need power. The non powered ones put out a lot less level ( 20 to 40 db) so you need a quiet pre amp.

Wire the +ve xlr pin of your mic to the +ve input of the mic in and the -ve pin of the xlr to the ground of the mic input, thats it.
 
H

hewo

Member
Joined 2010
XLR microphone into PC

cbdb said:
There are many types of microphones, some need phantom power (fed to the mic from the mic preamp) some run on batteries, some dont need power. The non powered ones put out a lot less level ( 20 to 40 db) so you need a quiet pre amp.

Wire the +ve xlr pin of your mic to the +ve input of the mic in and the -ve pin of the xlr to the ground of the mic input, thats it.
Click to expand...


17August2010:
1. Thanks for all replies to this post.
2. professional vacuum tube condenser microphones are being used.
3. proprietary XLR seven pin cabling from the accompanying power supply floor box must be utilized.
4. but the box's output port is for standard three pin XLR.
5. i am still definition confused about +Ve and -Ve.
6. are you saying +Ve represents XLR pin two non-inverted and -Ve is XLR pin one ground ?
7. if, hypothetically, you are assigning -Ve to XLR pin three inverted signal, it would annihilate +Ve assigned to +Ve, thus yielding nothingness. that's because they are completely out of phase with each other.
8. please clarify on this definition +Ve and -Ve. I assume your symbol "V" represents voltage and the subscript "e" represents "exit" or "effluent", essentially signal leaving the microphone system which is used to drive the house PA, or, in this case, the two conductor input of the intel motherboard's microphone input port.
9. intel's website software package was installed for this particular intel board's onboard audio hardware. an intel application progrom beyond what is furnished default by XP Pro SP3 may be the answer, possibly, creating resolution digital files.
 
P

Pixo

Member
Joined 2003
Here is the typical pin assignment for a 3-pin xlr audio cable:

pin 1 = ground
pin 2 = hot
pin 3 = cold

So for your purpose, connect pin 1 to ground and pin 2 to the signal lead of the left channel Line-in jack of your computer. If yours doesn't have a line-in, then use the microphone jack. But be aware that the microphone jack supplies a small amount of DC bias for regular microphones to work. This may or may not interfere with your equipment.

Keep the cable form the mic box to the computer short - that keeps noise to the minimum.

Pin 3 of the xlr connector doesn't always supply an audio signal. In most mid-end equipment, it is just used to invert the noise present in the line before summing it up at the receiver, thereby subtracting the noise, but keeping the signal at the same level.

But if yours does supply an audio signal, then you can probably connect that to the right channel of the line-in or microphone jack. Now when you do a stereo recording, you'll be recording the signals as a stereo track with both the signals being out of phase to each other.

Once you're done recording, invert one of those signals and sum both up - you should have a noise-free recording. (this assuming that you're using some recording software)
 
J

jaocaetano

Member
Joined 2016
Question: XLR Mic to PC, after 48V power supply

Hi there everybody!
I see there are lots of experts here, perhaps I can get my questions answered.


I have a condenser mic that needs 48V phantom power to work. check.
I've got a 48V phantom power supply. check.
It has a XLR INPUT and a XLR OUTPUT.


Now, my question is:

Can I make a cable (XLR) to (1/8") to connect that OUTPUT into my PC SOUND CARD input (green jack)????


Connecting:
pin XLR-1ground to 1/8"-ground
pin XLR-2hot to 1/8"-left
pin XLR-3cold to 1/8"-right


I will fry my PC????? Or it will get some sound??



In case it works, I have another theory:


Since hot and cold are out-phased in 180º, with Pro Tools if I reverse Cold,
it will get a 2 times boost in the amplitude when I sum both signals.
Also, assuming the noise were the same in hot and cold before I reverse cold... The noise will also be inverted, which would give me a noise suppressor, because the noises are exactly the same in each pin, but out-phased after I inverted, therefore one noise would cancel each other.

Does it work???

Thanks everybody!
 
M

MAAC0

Member
Joined 2010
Jesus .... So simple

Assuming you are connecting mic to xlr in and getting audio from the phantom box xlr out.

For Computer mic input use a mono plug or short ground and sleeve
Computer Bias will be shorted to ground. That's no problem.

pin XLR-1ground to 1/8"-ground
pin XLR-2hot to 1/8"-tip
pin XLR-3cold to 1/8"- ground or sleeve shorted

For line input use a stereo plug

pin XLR-1ground to 1/8"-ground
pin XLR-2hot to 1/8"- tip and sleeve
pin XLR-3cold to 1/8"- ground

Check levels and use line or mic what sounds best.
 
O

Odal3

Member
Joined 2014
...Or you can get a pro-audio USB recording interface. Not sure if you have a mic preamp but you will likely need one plus the internal mic-in/sound card may not be the best. Most route mics via USB or firewire interfaces. Unless you desire top of the line, you can get a used one for $50-150 or a new one for $100-200. I recently picked up a Steinberg UR22mkii, which has 2 mic/line in (XLR - 1/4 combined jacks) with preamp and 48V phantom power, USB2 and two 1/4 outputs. Been very happy with it so far. There are also many other brands such as Focusrite and Presonus.
 
D

dynomike

Member
Joined 2015
Same as above reply... It is basically insane to not use a purpose built audio interface for this.

Problem 1: You need a microphone preamplifier, most importantly, as the output even from a powered tube mic is still microphone level, not line level.

Problem 2: You should make use of the balanced output by having a balanced input to the soundcard. The onboard soundcard does not have this. Shorting the cold pin to ground is not ideal.

Just buy a USB or PCI audio interface that has microphone inputs. Many come bundled with a DAW (digital audio workstation) program like Cubase or Pro Tools (light versions, which will be adequate for your use). If not, there are several free programs available which will do the job.
 
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