Blip on frequency spectrum

S

Sangram

New member
Hi, I work on a AMD Duron-based computer. The mobo is an Asus AVL series based on the VIA KT133 chipset. Using the onboard sound + Creative Sound card.

The problem is the silence isn't perfect. There's some kind of a signal getting recorded, even with no input.

On a spectrum analyser (Wave tools, downloaded from Maxim), it shows up as a -30 dB signal at the lowest frequency. It also registers on the recording track as a hiss.

The Creative soundcard, on the other hand, gives me a barely noticeable noise floor and equally less noticeable sound. The card sux! The onboard sound is good, but for the glitch in recording.

Please don't hit me, I can't afford better equipment, and I record only for my enjoyment, I'm thinking of a professional sound card a few months later.

Thanks

Sang
 
Maybe?

Is it possibly an unfiltered 50Hz or 60Hz cycle hum (depending of your geographic location). Its the only way some sort of a sound can be getting in if nothing is hooked up.
 
Power supply?

Thanks for the prompt reply. I assume the hum comes in through the power supply, but it's not causing a problem on the other soundcard. My questions are:

1. Is there a way to reliably filter out the hum (the sound is onboard), and how safe would such a mod would be on my computer.

2. Is there any way to take care of the problem in the power supply?

3. Or should I wory about getting myself a brand new soundcard and live with the defect for the time being?


p.s. the signal is almost undetectable in final output. a slight hiss is present, but I'll put that down to the crappy soundcard. To think I've been advising WATYF to not use onboard sound...
 
If its hardly audible in the end, i would imagine you might not actually have a problem? because the noise might be coming out of whatever you are listening to. there is an electrical engineer on the board, i cant remember his name, he i sgood with this stuff, maybe he will pass through this thread.

The whole "hum" thing happens to everyone, its eliminating it is what takes some time, more geear, more hum.. cheaper gear, more hum...

Its a paradigm we live with.
 
I think you answered your own question. It's the crummy noise floor of the cheapo onboard sound. Nothing you can do about it.

What confuses me though, is if the creative card works fine, why are you also using the onboard sound?

Here is a good site on soundcard specs/testing.

http://www.pcavtech.com/soundcards/
 
random thoughts...
high frequency flourescent lights can induce hum
improper grounding of the ac circuit
unbalanced wires that cross each other at right angles

You seem to think its the card.A cheapo card many budget DAW guys get is the Ensonic audio PCI (about $30).I upgraded to 24 bit recently.when you get the bucks,thats the way to go.

Tom
 
Emeric:

I use the onboard sound because it sounds better than the Creative... Go figure! I have absolutely no clue for the reason! Thanks for the soundcard resource.

Tom:

Thanks for the tips, will investigate and get back. Ensoniq ain't available in India. Just Creative and Chinese s**t. I had actually enquired after a Yamaha or an ESS, looks both of them are out, going by what AVTech says about them.

Thanks everybody, I think I'll just have to wait awhile and get someone bring a soundcard for me when they travel abroad.

Laterz

Sang
 
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