How to play MP3 files into the microphone input

In a chat session, whenever I want the other person to hear a pre-recorded voice, I need to play it on my speakers and use my microphone to capture it. How can I play MP3 files into the microphone input so that whenever I do a voice chat I could play the MP3 file in such a way that I am speaking through the microphone itself?

Operating system: XP Pro sp3

A simpler approach to your problem might be just to record your speakers.

To record anything that comes out of your speakers:

1. Right-click the volume icon and choose "Recording devices".
2. If you don't see "stereo mix": Right-click somewhere in the white area of the recording box, and select "Show Disabled Devices".
3. If you now see "Stereo Mix": Right-click and enable it. Right-click any other recoding devices and select "disable". You should now be able to use any recording software you want.
4. If you still don't see "Stereo Mix": Search for an audio driver on the website of the manufacturer of the audio card. You might be in luck and find a driver that shows "Stereo Mix".
5. If you still don't see "Stereo Mix":

The following thread has many explanations and workarounds :
Missing sound recording option "Stereo Mix" / "Record What you hear" / "Waveout mix".

The problem is that you won't be able to enable the "Wave Out mix" ("Stereo Mix", "Record What you hear") on many computers with built-in sound cards. But you can use software that doesn't need the "Wave Out mix" ("Stereo Mix", "Record What you hear") recording option to record audio from your sound card:

Direct sound recording software allowing to record audio without Stereo Mix/Wave-Out Mix/What U Hear

• Freecorder (Freeware) - sound recording program (Windows 7, Vista or XP),
• Replay Music - shareware sound recording program that can split and tag songs automatically (Windows 7, Vista, XP or 2000),
• Replay AV - shareware stream recorder that is good for scheduling online audio recordings (Windows 7, Vista, XP, XP, Server 2003; x32 or x64),
• Replay Media Catcher - shareware stream recorder that can record audio from your sound card as well (Windows 7, Vista, XP, 2000, Server 2003),
• Ask & Record Toolbar (Freeware) - sound recording program (Windows 7, Vista or XP)
• All Sound Recorder - shareware sound recording program with a scheduler (Windows Vista or 7)

Screencasting software allowing to record video with sound even if you don't have Stereo Mix/Wave-Out Mix/What U Hear

• WM Capture - shareware screen recorder that allows to record both audio and video (Windows 7, Vista or XP),
• Replay Video Capture - shareware screen recorder that allows to record both audio and video (Windows 7, Vista or XP),

Virtual Sound Card software

• Virtual Audio Cable - shareware software that creates a virtual audio device (Windows 7, Vista, XP, 2003; x32 or x64)
• Virtual Audio Streaming - shareware software that creates a virtual sound card (Windows 7, Vista; x32 or x64)

As you can see, the programs work not only in Windows XP, but also in Windows Vista and Windows 7. In fact these programs can be the only way to record audio from your sound card.

Freecorder4, Replay Music, Replay AV, Replay Video Capture, Replay Media Catcher, Ask&Recorder Toolbar, WM Capture use a universal audio driver allowing you to record sound even on those computers that do NOT have a sound card!

If your sound card supports it, you can use the Stereo Mix audio input device to stream what comes out of your speakers to someone. You'd have to go into your application's settings (like Skype's settings) and change the audio input from "Integrated Microphone" (or something similar) to "Stereo Mix".

The most reliable way to accomplish this is to use the Windows Mixer to change your recording source.

1. In Windows XP, open the mixer (Windows+R "sndvol32").
2. Go to Options > Properties.
3. Change the radio button from Playback to Recording. OR, if Recording is grayed out, your sound driver enumerates the recording properties on a different device - change the Mixer Device at the top. On my laptop, it's "Realtek HD Audio input."
4. You should see some options like Line, Mic, Stereo Mix (or "What-U-Hear" if you have a Creative Labs device). Make sure they are all checked.
5. Say OK, and in the mixer, you can now select your recording source with the checkboxes along the bottom.
6. Change it to the Stereo Mix/What-U-Hear/etc. option.

@Rook has a point...but if that doesn't work or suit you, here is what I suggest.

I would take a regular 3.5 mm stereo cable (see here on Amazon.com), plug one end into the headphone jack of your computer (the output) and then plug the other end into your microphone (input) port. Then set the source to be the microphone jack, and just play the MP3 with your favorite music program (Zune software, Windows Media Player, WinAmp, etc) and that should do the trick....

You could also just get your MP3 player, plug one end (output) into the headphone jack of the MP3 player, and the other end into the microphone (input) jack...that will do the same thing...