Recording detects sound even though nothing is playing

[BrutalAl]

I've got the Recording Device setting set to my sound software driver (Realtek AC97 Audio) and in the Mixer Toolbar window I've selected "Stereo Mix".

It's my understanding that with these settings Audacity should only record the sound my computer is playing, which also seems to be the case (I can't detect any apparent loss in quality by simply listening to the playback)

Thing is that when I start a recording without playing any sound Audacity indicates there is sound playing in the R stereo channel. I can't hear anything, but it is clearly shown in the Meter Toolbar, the R-meter is moving around -38 db.

What is causing this? Will it result in theoretical quality loss? How do i fix it?

Thanks

[steve]

Use the sound card mixer application to mute the microphone.

[BrutalAl]

Couldn't locate any specific 'sound card mixer application' (which had mic options in it), I did however find my way to the generic "Sound and Audio devices" in Control Panel where I found settings for Audio and Voice Recording, I muted both but the weird behavior in audacity still remains. Weird how it's only in the Right channel that's acting odd, the L channel is stone dead (as it should be).


p.s
to my knowledge there is nothing connected to the computer that is able to pick up sound (webcam cant).

[steve]

Couldn't locate any specific 'sound card mixer application'

There's usually a loudspeaker icon near to the time/date on the Desktop. If you have that icon, then that's it, but you man need to go through all the "Advanced" and "Options" buttons and tabs to find where to mute the microphone.

There does not need to be a microphone attached - the microphone input of on-board sound cards are notorious for creating noise.
On board sound cards are usually fairly noisy even with everything set up correctly, but it should be better than -38 db

[kozikowski]

No. It's worse than that. Your sound card is noisy on one side as compared with the other My sister has that. No matter what she records or captures, it always has this slightly higher noise floor on the right.

You could replace your sound card. If you're using the one built into your system board, there are ways to turn that off and use a more expensive sound card.

This will get a lot more complex if you're on a laptop.

Koz

[steve]

it always has this slightly higher noise floor on the right.

-38dB noise level is not what I'd describe as "slightly" high - I'm not going to argue about upgrading the sound card - the option for laptops that won't break the back is to go for an external USB sound card. ART USB microphone pre-amps have had a lot of good reviews.

[BrutalAl]

There's usually a loudspeaker icon near to the time/date on the Desktop. If you have that icon, then that's it, but you man need to go through all the "Advanced" and "Options" buttons and tabs to find where to mute the microphone.

Apparently the "Sounds and Audio Devices" in Control Panel was connected to that loudspeaker icon (it leads to the same "Master Volume" and "Recoding Control" windows, given you push the right buttons.)
Looking at the menus again I noticed I had missed to mute a "Line In" control. Tried muting it as well, but unfortunately to no avail.

No. It's worse than that. Your sound card is noisy on one side as compared with the other

Oh, in other words it sucks to be me right now, or at least me with my current sound card (which is on board).


Thx for the help all.


P.s. Was the settings, as described in my initial post, the right (and best?) ones (apart from 'wrong' sound card) for capturing streamed audio with minimal/no loss in quality?

[kozikowski]

<<<Oh, in other words it sucks to be me right now, or at least me with my current sound card (which is on board).>>>

One of the disadvantages of "mix-out" is its ability to run two or more sound services at the same time (people normally think this is a grand and glorious thing). The entire playback system is running and then the output data is introduced to the record side and goes through that whole pathway back to a capture program such as Audacity, although it doesn't have to be.

Any damage or disturbance anywhere in any of the pathways gets burned into the show.

Two items: You are trying to do theatrical sound production on a Windows business machine, and nobody on the business side of this equation particularly wants you to succeed at doing this. If they did, there would be a simple clickly for it in both Windows Vista and Windows 7. In fact, this gets progressively more difficult as the versions progress.

Koz

[steve]

Was the settings, as described in my initial post, the right (and best?) ones (apart from 'wrong' sound card) for capturing streamed audio with minimal/no loss in quality?

It's the second best method, but often the best method is not possible.

Depending on what and how the audio is being streamed it may be possible to write "direct to disk". This is the best method. For example, if it is a simple MP3 stream that you can play through WinAmp, VLC player, or similar, then the player can be configured to send it's output to the hard drive instead of to the sound system. The downside of this is that you can't hear it while it is recording, but the benefit is that you get a "recorded" file that is a perfect copy of the audio stream. Increasingly web sites are using "embedded players" that prevent you from doing this, in which case "Stereo Mix" is the best option.

The important thing with Stereo Mix is to mute ALL inputs AND outputs that are not being used (and remember to turn off system sounds or they will also be recorded). This is usually everything except for "wave" (may be called PCM or something else).

As a general point, whatever you are recording, all unused inputs should be muted.

(yes, on-board sound cards on PCs suck)