another distortion problem

[newbie6]

Audacity 1.2.6, Windows Me
Sound card built in on the board so I don't really know what it is; it comes with C-media drivers which have a variety of options. I get the same problem with C-media default and maximum quality settings, and using Microsoft Sound Mapper in default configuration. Input is to line in on the card.
Nero burning software
standard DVD/CD player

When I record a high-quality signal via my TV capture software (Mercury - it uses the sound card for sound input) I get perfect sound both playing direct from the computer and on DVDs. When I record the same signal with Audacity I get mild but clearly audible distortion that sounds like peak clipping, again both direct from the computer and on CDs. Possible clues:
1. in Audacity I have to set the record volume control right at the bottom (0.1, it only goes in steps of .1) to keep peak indicated levels below zero.
2. when I reduce the record level control in Control Panel, it reduces the sound level with the Mercury software but NOT with Audacity - I still have to keep Audacity's record level at 0.1

So at first sight it seems like an Audacity problem. Any suggestions as to how I can identify the precise source of the problem? (And then, of course, fix it.)

[waxcylinder]

A possible workaround: If you can get good quality WAV files out out of your TV capture software - then why not record in that, export the WAV and then import into Audacity for editing.

WC

[newbie6]

"If you can get good quality WAV files out out of your TV capture software - then why not record in that"

it only outputs multiplexed video and when I demux I don't get anything I can figure out how to convert to CD format.

[steve]

in Audacity I have to set the record volume control right at the bottom (0.1, it only goes in steps of .1) to keep peak indicated levels below zero.

I strongly suspect that you are trying to record through a microphone input and not a line level input.
If this is a laptop computer you may need to get an external USB sound card that has a line level input. (I use a Behringer UCA 202, which is cheap and does the job very well).

when I reduce the record level control in Control Panel, it reduces the sound level with the Mercury software but NOT with Audacity

You have not yet found the correct control to adjust. If you have your sound card set to record from "Line-in", then you need to adjust the recording level for "Line in". This setting will be found in either the Windows Mixer, or the sound card control panel - there should be an icon for one of these near to the clock in the lower right corner of the screen.

it only outputs multiplexed video and when I demux I don't get anything I can figure out how to convert to CD format.

If you decide to investigate this route, you will probably find the appropriate tools on the Doom9 forum.

[newbie6]

"I strongly suspect that you are trying to record through a microphone input and not a line level input."

You are right! I finally took the computer apart and checked all the wiring inside. Ever since I got it, the connection to microphone and line in were reversed on the board

The levels are now set with the correct sliders, and Audacity records from Line In as it should. The distortion is gone.

Many thanks for your help.