Fixed recording problem on vista laptop

I recently downloaded the Beta version of Audacity onto my Toshiba Satellite with Vista. I could not get a good recording no matter which option I used. They were all muffled recordings with more sounds from the room then from the audio I was trying to record. I soon realized that my laptop was recording from a little Mic at the top or my screen. I plugged in an open 3.5 mm jack into the Mic input jack to stop the recording of the room noise but that killed the entire signal. I was obviously not getting an input directly from the sound card.

I did some research on the internet to see if I could somehow patch my Mic to the Spkr jack to get a good recording. I found some information that indicated that it might be possible but that I would have to keep the output level from the speakers down so that it did not overdrive the Mic input. Another problem was that a straight patch of all three conductors (tip, ring, & sleeve) might cause the +5v bias to bang against something that could blow my sound card. Almost everthing I could find said that the 5v would appear on the ring of the jack.

Not having a volt meter but knowing a few tricks I could use with a battery, some wire, a flashlight bulb, and a headset, I determined that the bias voltage was on the sleeve of both the Mic and Spkr jacks on my computer, not the ring. I was also able to determine which wire went to which potion of the male jack cord. The speaker put stereo signals out on the tip and ring and the microphone took its mono input on the tip.

I purchased a 3.5mm male-to-male patch cord on Ebay and cut the ring and sleeve conductors so that only the tips had continuity. I patched the Mic and Spkr jacks together with the cord. That was the only wire I needed because the bias voltage was already standing on the computers female jacks. I then recorded with the Audacity while keeping my speaker output at a low level of 5. My Audacity Audio I/O options were “microphone” for Record and “Microsoft Sound Mapper” for Record. I am now getting a good quality recording of internet radio signals in mono.

I would suggest to anybody that has a similar problem that they verify how their Mic and Spkr jacks are really wired as I did. There is no guarantee that Toshiba wires their jacks the same as any other computer brand. You must also verify the wires of your patch cord to make sure you know what the tip, ring, and sleeve wire colors are.

Not having a volt meter but knowing a few tricks I could use with a battery, some wire, a flashlight bulb, and a headset, I determined that the bias voltage was on the sleeve of both the Mic and Spkr jacks on my computer, not the ring.

Are you certain? I find this hard to believe without seeing it myself.

If true though, it’s very bad practice to go against the standard setup. Bad Toshiba, no biscuit.

I think that computer mics (the small electret condensor types) would still work with the bias voltage inverted, but I would expect that if you plugged a 3-conductor plug in and sent a signal along only one of the conductors (while leaving the ground signal connected) that you would get a big DC offset in your recordings.

What I’d like to know is how you managed to get Audacity to work at ALL on your Vista driven Toshiba … because I can’t even get it to work - none of the posted instructions I find online will work. :neutral_face:

What’s your secret?

<<<Bad Toshiba, no biscuit.>>>

Not yet, please.

Toshiba makes 24,684 Satellites. Which one do you have?

This is how the connectors are wired on almost all sound interface cards…

http://www.kozco.com/tech/audioconnectors/audioconnectors.html

…even the fancy-pants ones that can switch in and out of digital audio. Nowhere is it written, however, that the sleeve/shield has to be connected to laptop ground. On my two PCs, it’s absolutely not and if you connect two computers together they will hum and buzz very badly at you.

And no, standard “computer” microphones will not work with battery on the shield. Under certain circumstances, they will work with battery on the tip. Those sound cards have provision to remove the battery voltage from the sound before digitizing. In those cases, it’s possible to scare the cat with the loud bang if you plug the mic in with the audio system running, one of the reasons they went to battery on the ring.

Koz