PC soundc cards and CD players are both 16 bit devices and can use same sample rate, but this does not meant the sound quality of those devices is the same. PC soundcards typically have much worse signal to noise ratio (around 80 dB) than CD players (>90 dB), which means that PC soundcards are more noisy. CD players have good straight frequency response form 20 Hz to 20 kHz, but PC soundcards typically have low and high frequencies attenuated noticably.
Signal to noise (S/N) ratio is one of the most important measurements (specs) to look for when purchasing any audio device. It measures the ratio of noise generated by the device, and added to the outgoing signal. Its measured in dBu and the higher the number the better.
A typical problem: I just bought a new soundcard have noticed background hissing after a sound is played. It doesn't appear to be in the speaker system as I ran a portable cd into it.
PC soundcards are cheap consumer electronics and they are built using cheap parts using designs which are not the best possible. This causes that soundcards electronics generate noise and pick up interference from other electronics inside the PC. You hear all this as hising noise in the soundcard output.
The soundcard design has effect how little noise you can get, but usually the reason for most noise is not the soundcard, but how you use it. You can even make the best studio audio system hiss very noticably if you set the settings to very non-ideal values. Soundcards are typically used by people who do not know how to use audio systems properly which causes that they set up the systewm baddly which leads to very poor performance.
Some tips for users of Sound Blaster family of soundcards:
If you you soundcard connected to amplified multimedia speakers or hifi system remember to use line level output connector. Line level output connector typically gives out better sound quality and less noise.
Any sound device distorts when you feed to strong signals to it. Soundcards nowadays typically have many sound generating parts on them (D/A converter for sample playback, syntetizer, etc.) and the sound from all those sources are mixed on the mixer chip.
Mixer chip has gain settings for all of it's inputs and output volume. If you turn up the input gains of the mixer chip too high the mixer can't handle strong signals form that input properly and this causes distortion inside the mixer. If you turn the output volume too high you get the output amplifer easily cause distortion.
For some strange reson some dSB32 rivers from Creative Labs set the gains of input and output amplifiers for x2 position, which causes quite often noise and distortion. Those gain settings can be set using the tools coming with card to x1 and this should stop the distortion. Remeber always to use line level outputs instead of the spaker output when you connect your soundcard to external amplifier (the spaker amplifer adds noise and distortion to the sound).
You have quite propably ground loop problem or bad audio wiring in your system. Check the wiring. If the wiring does not have any fault, then check the ground loop problem. First remove the antenna wire going to you receiver going to your hifi system. If your humming goes away, them you have a ground loop problem caused by antenna wire. This kinds of problems can be most easily solved using antenna cable isolator. For more information about ground loops go to my AV systen ground loop web page.
Typical problem:
Does anyone know why the microphone would work yesterday, and not today?
There have been no changes to the system at all. The microphone works on
other machine, so it isn't the problem??????
Sometimes, the volume mixer doesn't always save its settings. So, you should check to see if the microphone is selected as a recording device and also if the volume is properly set. Check also that the micropone is correct type to for your soundcard. If the microphone has on/off switch make sure that is on.
First check that you have enough gain set in the input setting. If you have the gain set to maximum value and you don't get enough volume the microphone might not be suitable for ypu soundcard. Sound Blasters want electret microphones which give enough high signal levels. Of you connect cheap dynamic microphone to them you don't get enough high signal level for soundcard.
For more information about connectin different microphones to soundcards take a look at Interfacing Microphones to Computer Sound Cards application note from Shure web site.
Try to turn down the gain in the micrphone input using the mixer program which comes with the soundcard. If the microphone input has automatic gain control try to set that off, because AGC turns the gain up when there is no signal coming from the microphone.
Generally the microphone premaplifers in computer soundcards are very noisy and the hissing is quite unvoidable. If you want good samples withou hissing consider getting good soundcard, good microphone, external microphone preamplifer and make sure that there is not noise sources (like your PC) in the same room where you try to record.
Back to home page