I've got some speakers on my computer,
that when I play some music through them, I can hear a sort of clicking or a "tapping"-like sound over the top of the music, this normally happens during peaks in the music.
Is it the speakers doing this, or is it the signal coming from the sound card?.
I haven't got a pair of headphones or another set of speakers, to see what is causing it.
Any ideas?.

Trumpy — A cheap set of headphones would allow you to "split the systems in half" and effectively eliminate the speaker/amplifiers or the sound card as a source of problems.

Does the noise disappear when you turn down the volume control, and thus reduce the level of the peaks? Is it only on one of the speakers or both?

Paul,
It's still there, regardless of how the volume control is set.
Just wondered if it wasn't the speaker cones
vibrating, the speakers are pretty cheap, they were just an "add-on" when I bought the computer.
It affects both speakers, too, BTW.
There is a website URL on one of the speakers, may go and have a look at that.
It's also got a CE mark on it, this may be the problem!.

O.K., I was thinking that if it only happened on peaks when the volume was turned up, it could be a power supply problem (e.g. bad filter capacitor).

I didn't think to ask before, but has this just started, or have these units always sounded that way? Some of the stuff on the market these days is pretty low quality.

I don't know what operating system you're using, but it could be the software. In Win 3.1 you could adjust the sound buffer size to take care of that problem, not sure about more current systems.

kale,
I'm using Windows XP, but I have never heard of this sort of thing happening before.
I think it may be the really cheap set of speakers that came with the computer when I bought it.
I'm not sure what "sort" of sound card I've got though, must check.
Also, can anyone tell me what the output impedance of a sound card is?, is it 8 ohms or is it something different?.
I am looking at building a proper amp and speakers, with better bass and midrange response, anyone know of any good kits for this?.

Trumpy,
The speakers themselves may well be in the region of 8 ohms, but don't forget that these computer "speakers" contain their own built-in amplifier. The output on the sound card is just a normal line-level audio signal.

For kits, have you tried Jaycar Electronics?
www.jaycar.com.au

Paul,
What I meant was, I was wondering if there was a standard output impedance for sound cards, sort of like a figure not to go under with a series-parallel network as in a set of speakers and the odd cross-over.

Paul,
My search has come up with nothing of any real results.
I might have a go at designing and building my own amp and speakers.
I thought about basing the amp on a pair of LM 3876 Amplifier IC's and taking it from there.
I have already bought the speakers and components for the cross-overs.
Just have to work out the circuit for the amp.

Sorry Mike, I missed your post of 4/25/03 before.

I've never bothered to check on the output impedance of computer soundcards, but it's likely to be fairly low. Most modern transistor/IC gear has a fairly low output Z of a few hundred ohms to a couple of K or so.

The input to your amplifier is unlikely to be under about 10K (and that mostly due to the volume control resistance when using op-amp type ICs), so I don't think you need worry about that too much.

Bill,
Thanks for getting rid of them annoying triple posts.
How does this happen?, as I think that I am not the only one that has doubled up on the odd occassion?.
Paul,
I was thinking that the output of a Soundcard was in the tens of Ohms, but there are no published figures to go by, can anyone help??.