Interference from laptop USB using USB sound card

PostmanPot · 2008-11-17T14:02:05+00:00

Hi all Well got the Rokit 6s (drool!) and Audiophile USB this morning. Problem now is that there is interference coming from the boy's laptop's USB connect...

Interference from laptop USB using USB sound card

AlanRatcliffe

Could be any one of a number of things. You'll have to do a bit of detective work to narrow down where the problem is coming from. Try these things:

* Reboot - preferably a "cold boot" (not just restart from the shutdown menu - turn off completely, then restart).
* Uninstall then reinstall the sound card drivers.
* try different music apps like Windows Media Player and your recording software to see if it's only from one program. Also try different source material to make sure it's not a distortion on the recording.
* try the speakers on another source to see if it is the speakers or the computer/interface
* Listen closely to each speaker to see if it is coming from only one or both speakers
* If it is from a specific speaker, swap left and right speaker cables to see if the problem changes sides. If it changes sides it's not the speaker, if it doesn't change sides, it's is.
* If it's a speaker, try identify which driver is the problem or if it's both by listening to each up close (most likely the tweeter in this case).
* If it is a driver, swap the driver with the other speaker's equivalent (it's a few screws and the wires use terminals - just make sure to match positive wire with positive terminal). If the problem changes sides again, it's the driver, if it doen't it's the crossover.
* If it's the driver, ask your supplier to get you a replacement under warrantee - you can swap it out yourself when you get the replacement. If it's the crossover, you'll have to take the speakers back for replacement or repair.

I had this with my KRK V8s - one tweeter would distort at a particular frequency. I emailed the distributor directly and they sent me a replacement by courier and I popped it in myself. Two days to get a replacement, I got to use the speakers while I was waiting and it only took 5 minutes for the swap.

PostmanPot

Thanks Alan, but what confuses me is that when the laptop's PSU isn't connected the speakers play normally?!

PostmanPot

Ah, the Legend is online and viewing this topic/thread... ?

PostmanPot

Jinxed it. ?

AlanRatcliffe

Very strange that would happen. Clipping (distortion) happens when something runs out of headroom and I would think if anything a laptop should be less likely to clip on the PSU - unless the PSU is underpowered. Is the PSU the correct one for the laptop? I think the next step would be to try another PSU to see if it helps - maybe your PSU is faulty and not supplying the correct voltage or current.

That's all I've got...

AlanRatcliffe

PostmanPot wrote: Ah, the Legend is online and viewing this topic/thread... ?

LOL! Yeah - contrary to popular opinion, I don't live here and actually do sleep occasionally. ?

PostmanPot

The laptop is from Australia and the PSU was changed to one with a South African plug when the boy came back from Aus. I'm sure it's an original Toshiba cable, should be fine...

I'm going to take my whole PC over there tomorrow and test the speakers and sound card with it. Hopefully everything works, and then I can just sort the kid out with a new PC.

PostmanPot

Alan Ratcliffe wrote:
PostmanPot wrote: Ah, the Legend is online and viewing this topic/thread... ?
LOL! Yeah - contrary to popular opinion, I don't live here and actually do sleep occasionally. ?

PostmanPot

Do you think I should make a new thread in the mean time while I wait to take my PC over there?

Title would be "Speakers clipping when laptop runs off AC, no clipping when running off battery"

AlanRatcliffe

Interestingly enough, my father has had problems with three PSUs for his laptop in the last year - the first two were OEM models the last a clone. I've also got his desktop machine here with a dead PSU. I suspect that the local power situation over the last year or so has been hard on power supplies.

PostmanPot

Alan Ratcliffe wrote: Interestingly enough, my father has had problems with three PSUs for his laptop in the last year - the first two were OEM models the last a clone. I've also got his desktop machine here with a dead PSU. I suspect that the local power situation over the last year or so has been hard on power supplies.

I can vouch for that myself... Lost a PC last year. Thanks goodness for insurance!

AlanRatcliffe

PostmanPot wrote: Do you think I should make a new thread in the mean time while I wait to take my PC over there?

Title would be "Speakers clipping when laptop runs off AC, no clipping when running off battery"

Sorry - almost missed this one. Yes, go for it - it might pull in a few folk who looked at this thread earlier and might still have something to add on the new problem.

PostmanPot

Set up everything on my PC and there was no problem. Kinda given up now, testing the laptop with another PSU will probably give distortion, and I wouldn't be able to de-ground it as it would probably be someone elses cable.

Just going to have to get him desktop PC. Will be much better any way. ?