I wish I was more capable in finding why my T61P will now record through the stereo mixer. I will gladly look at anything that someone could suggest to look at. I just went through the steps I described and I am now able to record audio. Before doing this I was unable to record any audio other than audio input from the external mic port.
One other note......I am still on BIOS 1.26.
Okay, lets walk this through a bit more so we can try to debug (BTW, I've now tried both Audacity v1.26 and beta v1.34 with the same results .... also both with and without installing the plug-ins).
The only difference here between specularious, kubinsky and myself is that specularious has got a T61p vs a X61 and T61 ... but maybe that's enough of a difference and the reason spec is able to record using only Audacity and the inf tweak. I am also still using Lenovo BIOS version 1.26.
First, remove all USB sound devices, headphones, game controllers, etc from all your USB ports.
Then open your Audacity main panel (either v1.26 or the 1.34 beta) and also open the WinXP sound volume panel by double clicking the volume icon in your tray.
Put these two babies side by side and try moving the horizontal recording input slider on the Audacity panel back and forth on the left side. When Stereo Mix is chosen from Audacity, then the Stereo Mix slider also moves on the WinXP recording panel. Switch it to Mic and then the mic slider on the WinXP Recording panel moves. So far so good.
Now when I try to record something off the internet with Audacity using Mic-in, I only get a faint distorted mono recording with the Audacity Mic input slider is moved up full (which also moves the Mic slider full on the WinXP Recoding panel). Again, makes sense.
Now if I select Stereo Mix with Audacity and move the Audacity Stereo Mix slider to max, which also moves up the WinXP recording panel slider, I get nothing. This may be the exact intended result as promoted by intellectual rights advocates.
If I put a small physical jumper between the stereo-out and the mono Mic-in on the T61, I can now record full volume using Audacity Mic as the source, but it is very distorted and of poor mono quality. And still nothing from the Stereo Mix selection.
Well so be it .... I give up.
I'm going to order an Express/54 slot Creative X-fi Notebook card and the 5.1 input connector accessory cable to use my Creative 5.1 P5800 speaker system. Hopefully, that will allow me to record other sources too.
I'm going to chance the possiblilty that a conflict could arise between the new external sound card and the onboard SoundMAX when setting the new card as the default recording and playback device within WinXP. Creative's Support says that can happen on some notebooks. However, they have no known reports of SoundMAX conflicts on new thinkPads ... yet. If that were the case, they recommend disabling the onboard SoundMAX from the ThinkPad Bios.
But guess what? ...... Lenovo has not included this option in any BIOS released so far for the new X/T61s and probably never will.