noise cancelling circuit - Electronic Circuits Projects Diagrams Free

bogdanfirst · 28th May 2004, 07:33 PM

hello!
my sound card(actually integrated on the main board) has quite high noise.
my speakers have noise cancelling circuit....but the headphones and wireless headphones...don't.
so is there a solution so that i can reduce the noise?
it would be good if the circuit doesn't need external power suply.
i searched the net, but only found noise cancelling headphones.
can any onehelp?
thanks!

RGBrainbow · 28th May 2004, 09:22 PM

Hi,
what You need is called a 'noise gate'. It is used to mute a signal that is below an adjustable threshold. I don't know how to make one, but 'noise gate' may help You with further search.
regards
joachim

bogdanfirst · 29th May 2004, 08:31 AM

hm, i am not sure that is what i want.
the idea is that if i connect the headphones directly to the computer i hear a noise. the noise doesn't dissappear when the music plays or something else.
i can't hear the same noise in my speakers, because they say that they have noise cancelling circuit.
so...i want to build something similar for my headphones.....

**Nigel Goodwin** · 29th May 2004, 09:22 AM

Quote:

Originally Posted by bogdanfirst

hm, i am not sure that is what i want.
the idea is that if i connect the headphones directly to the computer i hear a noise. the noise doesn't dissappear when the music plays or something else.
i can't hear the same noise in my speakers, because they say that they have noise cancelling circuit.
so...i want to build something similar for my headphones.....

I would sugest it's more likely that the lead to the headphone socket is picking noise up.

bogdanfirst · 29th May 2004, 07:48 PM

nope, i don't think so.
how much can 1.5 meters of wire pick up? they are not active headphones. just simple 32 ohm headphones.
so what do you think i should do?

**Nigel Goodwin** · 29th May 2004, 09:07 PM

Quote:

Originally Posted by bogdanfirst

nope, i don't think so.
how much can 1.5 meters of wire pick up? they are not active headphones. just simple 32 ohm headphones.
so what do you think i should do?

Are you plugging them into the same socket on the PC as the speakers?, or is it a seperate socket? (which was the impression I got).

john1 · 29th May 2004, 09:07 PM

a lot of PC speakers have a headphone socket at the back.
If you try them there,
you could see if the noise is still there.

or maybe you could try the headphone socket
on the front of the CD player,
but that limits you to CDs ....
although it should sound clean.

audioguru · 30th May 2004, 12:30 AM

Your speakers have a noise-cancelling circuit?
What did they do, leave out the tweeters?

Try connecting the headphones in series with 180 ohms resistors, for each channel, like stereo amps do, instead of your speaker connections.

bogdanfirst · 30th May 2004, 04:50 PM

hm....
well, i used reistors for headphones, but they were 160 ohm. don't think it is much difference.
anyway...thanks for the advice...
i'll see what i can do...

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28th May 2004, 07:33 PM	(permalink)
bogdanfirst	noise cancelling circuit hello! my sound card(actually integrated on the main board) has quite high noise. my speakers have noise cancelling circuit....but the headphones and wireless headphones...don't. so is there a solution so that i can reduce the noise? it would be good if the circuit doesn't need external power suply. i searched the net, but only found noise cancelling headphones. can any onehelp? thanks!

28th May 2004, 09:22 PM	(permalink)
RGBrainbow	Hi, what You need is called a 'noise gate'. It is used to mute a signal that is below an adjustable threshold. I don't know how to make one, but 'noise gate' may help You with further search. regards joachim

29th May 2004, 08:31 AM	(permalink)
bogdanfirst	hm, i am not sure that is what i want. the idea is that if i connect the headphones directly to the computer i hear a noise. the noise doesn't dissappear when the music plays or something else. i can't hear the same noise in my speakers, because they say that they have noise cancelling circuit. so...i want to build something similar for my headphones.....

29th May 2004, 07:48 PM	(permalink)
bogdanfirst	nope, i don't think so. how much can 1.5 meters of wire pick up? they are not active headphones. just simple 32 ohm headphones. so what do you think i should do?

29th May 2004, 09:07 PM	(permalink)
john1	a lot of PC speakers have a headphone socket at the back. If you try them there, you could see if the noise is still there. or maybe you could try the headphone socket on the front of the CD player, but that limits you to CDs .... although it should sound clean.

30th May 2004, 12:30 AM	(permalink)
audioguru	Re: Noise in headphones Your speakers have a noise-cancelling circuit? What did they do, leave out the tweeters? Try connecting the headphones in series with 180 ohms resistors, for each channel, like stereo amps do, instead of your speaker connections.

30th May 2004, 04:50 PM	(permalink)
bogdanfirst	hm.... well, i used reistors for headphones, but they were 160 ohm. don't think it is much difference. anyway...thanks for the advice... i'll see what i can do...