Now all the 3.5 mm cables I have seen have three contacts. I suppose one is for a microphone.
When I plug a headphone into cable like adapters or in line volume controls I may get one channel or no channels. When I insert it part way I can hear one channel. When I insert it deeper I get the other channel.
By moving it in and out carefully I will get both channels. If I accidentally pull on the cable I have to reset it.
These are
not cheap headphones
not the cheapest connectors but I can get better (does price equate to better performance, though not audiophile quality)?
not the cheapest cables but I can get better (does price equate to better performance, not though audiophile quality)?
Now all the 3.5 mm cables I have seen have three contacts. I suppose one is for a microphone.
Nope! If your computer has a combination microphone/headphone jack you need a 4-conductor [u]TRRS[/u] plug to make the microphone connection. (Regular-old headphones with the 3-conductor TRS plug work normally.)
With a normal 3-conductor connection the 3 connections are left, right, and ground.
These are
not cheap headphones
not the cheapest connectors but I can get better (does price equate to better performance, though not audiophile quality)?
not the cheapest cables but I can get better (does price equate to better performance, not though audiophile quality)?
If your headphones are not working properly (ignoring the microphone) you may have a bad jack on the computer.
(does price equate to better performance, not though audiophile quality)?
“Audiophile” cables are 90% B.S. Assuming you’ve got good shielding, all that matters is that you make a connection. And with headphones or speakers (high-level low impedance) you don’t need shielding. With long speaker runs a heavier gauge wire may be needed (for low cable resistance) but it doesn’t require exotic materials or exotic construction. Audio pros buy good quality rugged cables… They don’t buy “audiophile” cables.
But not your headphones or headset assembly, right? They work fine?
I have seen have three contacts.
Not counting the shield. If you have a modern, single-socket laptop, you need to count the shield because it’s important.
They were doing so well, too…
So you need to seriously dig in your instructions so see what you have.
Please note in all those variations, there is ever only a single microphone connection. It’s going to be mono no matter what you do. If you pull the connection partly out, you may get two sound channels, but it’s a very safe bet it’s still mono because you have the same sound on both channels. Watch the Audacity sound meters. They bounce exactly the same, right?
If your goal is a simple stereo in and out, you’re far ahead with a device designed to do this. That’s a Behringer UCA202 stereo USB adapter.
If your computer has a combination microphone/headphone jack you need a 4-conductor 
