Getting recording levels set

[colmac]

Hi. I'm really a newbie with audio.

I'm having probs with recording through my Line-in Realtek card.

When I start a new tape, I find the recording levels seem to be set at a strange level, and the level is not consistent. I'm recording from tape, and as usual there is a lead-in (approx 14 secs) of silence (obviously there is tape noise etc)

The most common result I'm seeing is that the record level starts at the base of the graph, and then rises steadily (although the playback sound does not). Usually it settles down after a few seconds, but not centered on the 0 level.

I have stopped and started frequently, and eventually, I seem to get a "correct" level, and from then on it is fine till I start a new recording

The image below shows an example of the results I'm seeing.

[waxcylinder]

That looks like a serious fault with your soundcard. You have what is known as "DC offset" - where DC is being added to the signal. The visual indication is that the waveform is not centred on the zero line.

You can correct for this in software in Audacity - immediately after capture, use the Effect > Norrmalize and select the DC Offset removal but do not apply any amplification/noprmalization at this stage.

You may want to consider getting an external soundcard. See this sticky thread: http://forum.audacityteam.org/viewtopic.php?f=27&t=9477

WC

[colmac]

Hi WC

Thanks for such a prompt, detailed and helpful reply. It really is much appreciated.

I do have an external Soundblaster card, so I'll switch to it ASAP.

Thanks again

Colin