Thinkpads Forum

dr_st wrote:The mic is not involved.

You are quite correct: the mic is not involved -- but that's not what I said. It is the "mic input" that's involved, and unfortunately the T60 suffers the same issue as the T61.

I don't wish to repeat everything that has already been discussed. I suggest the following: record an audio stream using a T42 and then try the same thing on a T6x/X6x. You will see the difference.

Simply put, muting the speakers should not stop the capturing of the audio stream during recording; if it does, then there is something rotten in Denmark. When one investigates further to find what is really happening, one discovers the "dirty little secret" of audio capture (or lack of it!) on these machines.

In practical terms, you may be able to capture satisfactory YouTube audio, but you will not be able to capture the native resolution audio stream from a CD or DVD.

You are right that muting the speakers does not stop the audio from being recorded on the T42, while it does so on the T60. So they do behave differently.

What you are suggesting is that the Stereo Mix on the T60 is routed to the mic input (internally), which in fact makes the recording mono - do I understand correctly?

However, the T61 seems to lack the stereo mix option at all, and to record one has to result to things like the virtual cable. So in fact we are dealing with separate issues here, or to be more accurate - various degrees of the same issue. Is that so?

Well stated. Correct on both points.

Actually, there are still a couple of things I don't understand.

I don't know what I did wrong yesterday, but I just tried it today again on my T60, and guess what - if "stereo mix" is selected, even if the audio is muted, I can still capture audio that's playing.

I'm not sure if I get stereo or mono, because the only recording tool I have here is the Windows sound recorder, which records in low quality (22KHz). The recorder audio sounds noticeably worse than the original, but I don't know if the hardware or the software is to blame.

One difference is that today the laptop is docked, while yesterday it was undocked. Could that make a difference?

Hmm, but I seem to be able to record playback from WinAmp in stereo. At least when I move balance (in WinAmp) around, I can watch it having correct effect on the left/right channel in recorded sound.

What do you use to record?

Creative WaveEditor, very simple utility which was provided with one of first Sound Blaster Live! cards (still is in my desktop). As recording source selected Stereo Mix in Windows.

And here I was thinking I was untouched by all this audio capture gimping business

I wonder if they're still doing this in the ones after the T61 series?

Actually I also was able to record in stereo - though could it just be a duplicated mono input? I think I was using Cool Edit when I recorded it.

I will investigate it further once I install some real recording software on my T60.

Ok I tried recording (using cool edit) via the stereo mix and got what I believe is a stereo waveform of high if not "original" quality. I then went and set the mic volume to zero (effectively muting it - it was originally set at maximum) and tried recording again. I got the exact same result, no change in amplitude/quality. Only the stereo mix volume affected the recording. I had my T60 docked and was using headphones at the time.

Anyway the general feeling that I've always gotten is that its only the '61 series that is affected (see below).

Mark, on the Lenovo forums, did say that the audio capture was disabled by design on the '61 series. He didn't state anything about the '60 series.

However he appears to differentiate (not too sure) between a loop back function and a 'stereo mix' function. Maybe he's actually trying to equate them...more likely equating.

"The '61 series systems do not have any way to provide the same loopback function or
"Stereo Mix" that previous systems have provided. This is by design of the hardware.
There cannot be any driver update to enable this function as the hardware layer does
not support it."

Verified it on the T60 with the help of the same recording tool Zender used.

Recording is definitely stereo (the waveforms of the two channels are different), and isn't affected by volume/mute of the sound output.

So I'm back to the original claim that stereo mix recording is only disabled on the 61-series, and works fine with the 60-series.

ÒK, the trick with Virtual Audio Cable worked!!

But a question, how do you configure that software to record sound from the Mic-In source, is it possible?