Chipmunk Playback

[mchambers]

Morning all

I have a problem here that is driving me crazy. Whenever I play a normal MP3, CD, Avi etc all is well.

However....

When I record anything via a microphone, whether it be via Windows Sound Recorder or a third party software, the playback is at chipmunk speed! If I manually reduce the speed, it plays normally, but as soon as you make another recording, the playback again is too quick.

Has anyone come across this? I have reinstalled sound drivers (old and new versions), audio codecs, Sound Recorder itself, have changed PCI ports, have even recreated the hardware profile on the machine. But still that chipmunk rattles away.

Any ideas? One thing I havent done is reformat, but I really dont want to consider that just yet. This happens on a whole ICT room of 25 machines.

Help. It's driving me insane.

Thanks Guys

Mark

[Michael]

What soundcards do these machines have? I know with Realtek the software/driver is quite comprehensive allowing you to tweak many sounds settings and effects.

[mac_shinobi]

What soundcards do these machines have? I know with Realtek the software/driver is quite comprehensive allowing you to tweak many sounds settings and effects.

If creative sound card then they have there own utility you can launch to ammend settings with regards to recording / playback as far as sound effects go as well

[mchambers]

Thanks for replies

The machines have a C-Media CMI8738 card in them. The driver comes with a peice of software to play around with the effects settings etc as you suggested, but nothing that makes a slightest bit of difference to the playback speed.

Mark

[Michael]

If possible try installing the sound cards with just the driver and without the software.

[mchambers]

Thanks Michael

Unfortunately, have tried that as early drivers do not come with the software attached.

Tonight I'm going to remove the sound card and re-anable all on board sound and disable the CM card. It's vital to have the PCI sound cards because of audio channels used by certain software, so this is not a solution, but it will give me a better idea of if it is the PCI sound card or a genuine Windows issue.

I'll post results, any other suggestions in the mean time would be grealy appreciated.

Mark

[mchambers]

Forgot to add, the machines are running the RM CC3 system, does it on Admins account though so I know it's not some weird restrictions/permissions issue.

Mark

[Friez]

Sounds like the sound card is recording at the wrong sample rate (e.g. record at 22,050hz then playback at 44,100hz and you have chipmunk mode) Worst case scenario you could try pitching it down to proper levels or playing with sample rates as a post process.

[mchambers]

Can you change the default sample rate of a Sound Card? I didnt think it was possible?

[Friez]

Depends on the soundcard. Quite a few cards don't have such settings, but quite a few M-Audio cards let you (such as the Delta series) and maybe some others do that I don't have experience with.

[mchambers]

Definately no setting in the software for the card, it's a C-Media CM8738 card. I think it's based on a Realtek board, not cannot find anywhere to alter sample rate.

Strange this is, this just 'happened'. No driver updates etc, and has affected 95% of the machines. Really strange.

[mchambers]

Ok, so after some tinkering have discovered that this issue is 100% the sound card.

So now need to work out how to change the sample rate on a C-Media 8738 card. Any ideas? Bundled software does no such thing!

[mac_shinobi]

Ok, so after some tinkering have discovered that this issue is 100% the sound card.

So now need to work out how to change the sample rate on a C-Media 8738 card. Any ideas? Bundled software does no such thing!

if desktop machine assuming spare PCI slot then I would disable onboard audio and use a PCI Sound card whether it be M Audio or creative or whoever.

If laptop then I would still disable onboard audio in bios and get a pcmcia or usb audio external type card and install drivers for that and use that.

[mchambers]

Thanks for reply Mac

The problem card is a PCI card, and the onboard sound is currently disabled. The on board sound works ok, but problem is the C-Media card has 4 channel support which is required for certain software we use.

I may switch PCI ports to see if that makes a difference. I'm sure it's driver or codec based but have installed old and new with no luck.

[mac_shinobi]

Thanks for reply Mac

The problem card is a PCI card, and the onboard sound is currently disabled. The on board sound works ok, but problem is the C-Media card has 4 channel support which is required for certain software we use.

I may switch PCI ports to see if that makes a difference. I'm sure it's driver or codec based but have installed old and new with no luck.

if you have a similiar card from another machine - try that on the same computer and if it fixes it then it may be a duff card ( sound card that is ) if it does the same then may be a software issue just on that computer in which case maybe a re image of the whole machine inc latest sound card drivers and try again with both sound cards.