Laurence,
I've had similar problems with an external USB soundcard. Depending on
what you connect and disconnect to the PC or if the card was plugged in
during booting the PC either the audio driver of the internal or the
external card was used. So the offsets were different. It gets even more
complex if you disconnect the USB card during a SpecLab instance is
running on this card. Normally you will get an error message then but
after restarting (press start in SL) different drivers may be used.
As an example: It was possible to successfully sample the internal
soundcard at 48k/s although it is normally limited to 41.1 k/s. DHO was
displayed at the right frequency. It seems that the driver of the
unplugged soundcard was still used for the internal card now. But as i
connected a usual USB stick to the USB, SL stopped and i had to restart
and then the actual driver of the internal card was used again.
Another thing: If you start SL on the internal soundcard (external still
unplugged) then the audio source is titled as "use default wave input".
If you then plug in the USB card and start a second SL instance, the new
(=external) card gets titled as the default card. Anyway the first
instance runs on the internal card and titles it as default, until you
restart the instance...
Conclusion: Strange things can happen when unplugging external cards
during a (or several) running SL instance. The best is not to restart
the PC (disable automatic updates) and clearly define the soundcard
type, not just "default". When doing this strictly, there are no
problems. On my LF grabber i even have 2 external soundcards and it
works well :-)
73, GL, Stefan/DK7FC
Am 06.12.2011 21:16, schrieb Steve Dove:
Hi Laurence,
Just a stab: it's unlikely an oscillator is coming up on different
frequencies but it may be that in one 'mode' it's using the USB
device's clock and in the other cuddly Widnows is nicely using it's
sample-rate-converter on you. How to make it stop doing that I don't
know - boot order or such?
Cheers,
Steve
On 12/6/2011 7:51 PM, Laurence KL7UK wrote:
Im using an external 24 bit sound blaster (USB) @ 96k on one of the dell
pc's in Alaska and not sure if its the PC or the card but it
occasionally and annoyingly on PC reboot "moves" 20Hz or so (dang it) -
so here I am looking at DCF39 and in fact its off the scale somewhere
for a couple of days - that and Stefan may have been visible but I was
looking/cal'd in the wrong place.
It apparently flips to one rate or another - checking up what it flipped
to last time comes up with the same cal figure using Argo. Highly
annoying but not being able to physically throttle the devices
(electronically or physically!) Im a bit restrained. As an example in
one state using Argo cal of 1000Hz the offset is 1003.2 and
alternatively 1023.7 Hz - Not sure if anyone else has seen a simliar
issue but its annoying - it appears only to "flip" when the PC is
booted. At the moment its on spec and giving a nice daylight view of
DCF39 or the 137.777 window - Ill move it down to 136.172 and HGA22
windows later
Laurence KL7UK Alaska remotely operated from (freezing cold) Oklahoma
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