bad recording quality

[nebojsa]

hello,

i have browsed through all the topics of this type but i haven't been able to find the answer to my problem.
i have been using audacity on my computer for a long time with an okay mic, and the recording quality has been great. however, when i use the same recording technique and means with audacity on my laptop (MSI U123), with the same settings, the recording quality turns out awful, full of weird glitches, grainy and kind of damp. i have recorded a 10 seconds sample of silence in my room and uploaded it so that you can hear what i mean: http://www.sendspace.com/file/4l06qv

i have the same sound card on both my computer and laptop (Realtek HD), with updated drivers, so i guess the sound card isn't the issue. and i have used the same quality settings on both (the default ones):

sample rate: 44100 Hz
sample format: 32-bit float
real-time sample rate converter: High quality Sinc interpolation
high-quality sample rate converter: High quality Sinc interpolation
real-time dither: none
high-quality dither: triangle

i have tried changing the recording device from Realtek HD Audio Input to Microsoft Sound Mapper - Input, but the results are completely the same.

what could be the problem?

________________________
edit: i've just realized i've posted this in the wrong section, hope someone can move it.

[steve]

"RealTek HD" is not a "sound card" as such - the name refers to the audio driver rather than the actual hardware components, and the quality of the hardware components can vary enormously from one machine to another. With good hardware Realtek HD is capable of excellent performance, but unfortunately due to cost cutting it is more usually between poor and rubbish. My laptop is a fine example of how bad recording with an internal sound card can be.

One of the "tricks" that manufacturers use to disguise how noisy the microphone input is, is to use software noise suppression. It's not easy to be 100% certain when listening to an MP3 (a WAV of FLAC sample would have been better), but the "bubbly" sound on that recording is characteristic of aggressive noise suppression.

If you search thoroughly through the sound card settings, you will find a check-box that allows you to switch off the Noise suppression (it may be hidden behind a "spanner" icon). De-selecting the Noise Removal will get rid of the bubbly sound, and you will hear the microphone pre-amp hiss in all its full glory.

Do ensure that your sound card is using the external microphone and not the internal microphone - the internal microphone will be even worse.

This is a recording of "silence" from my laptop (with Noise suppression off).
The first 3 seconds is with an external microphone, followed by one second of real silence, followed by 2 seconds of the internal microphone.

recordingnoise.flac

(234.7 KiB) Downloaded 512 times

For recording I use an external USB sound card.

[nebojsa]

that clears up a lot. so i guess there's no help other than getting an external sound card. in any case, thank you for the informative and quick reply.

[Trebor]

recordingnoise.mp3

(157.58 KiB) Downloaded 639 times

It sounds to me like interference from another process running on your computer.

[kozikowski]

The inside of an electrically noisy computer is a pretty awful place to put an unshielded piece of audio equipment -- a sound card. Macs are the notable exception and most of them don't have microphone connections.

Much better to do all the analog audio steps outside the computer, in an external sound card.

Koz

[bgravato]

The inside of an electrically noisy computer is a pretty awful place to put an unshielded piece of audio equipment -- a sound card. Macs are the notable exception and most of them don't have microphone connections.

Much better to do all the analog audio steps outside the computer, in an external sound card.

Koz

Or having a decent internal sound card properly shielded...