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<DIV><FONT size=2 face=Tahoma>Okay. But note when I referred to a
power supply fault, I wasn't necessarily thinking of the PSU unit as such. The
power supply in a computer is generally very 'dirty', so any boards processing
low level and analogue signals will usually have their own power conversion
and/or filtering circutry on the board/in the module. The fault could well lie
in these areas. But given that swapping the power supply itself is very quick
and cheap to do, it may be a good starting point.</FONT></DIV><FONT size=2
face=Tahoma>
<DIV><BR>Alex</DIV>
<DIV></FONT> </DIV>
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style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=admin@londonhuayu.co.uk href="mailto:admin@londonhuayu.co.uk">London
Chinese Radio</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=tlr@gairloch.co.uk
href="mailto:tlr@gairloch.co.uk">Two Lochs Radio</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Cc:</B> <A title=studio@ravensoundradio.co.uk
href="mailto:studio@ravensoundradio.co.uk">Tony Bailey</A> ; <A
title=cma-l@commedia.org.uk href="mailto:cma-l@commedia.org.uk">CMA-L</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, October 31, 2011 1:26
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [cma-l] Audio
crackling</DIV>
<DIV><BR></DIV>Great to get so much support from so many (already busy)
people! CMA rocks!!!<BR><BR>The powersupply is the most expensive part of the
computer!! An Enermax psu, cost me about 85 quid! (although two of these have
already died on me, so not so confident about them...!) <BR>I'm going to
wait until the next song ends, and try playing a CD, thus bypassing a lot of
the computer stuff, see what happens...<BR><BR>...yup the Serbian folk CD I
just put on has no crackling, incl in the stream!!<BR><BR>The plot
thickens.... will keep looking at all the possibilities you have
suggested. (Alex <SPAN class=st>���� </SPAN> - I am in total awe about
what you managed to get from listening to 20s or so audio...!)
<BR><BR>Peter<BR><BR><BR><BR>
<DIV class=gmail_quote>2011/10/31 Two Lochs Radio <SPAN dir=ltr><<A
href="mailto:tlr@gairloch.co.uk">tlr@gairloch.co.uk</A>></SPAN><BR>
<BLOCKQUOTE
style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote><U></U>
<DIV bgcolor="#ffffff">
<DIV><FONT size=2 face=Tahoma>Okay, no that doesn't sound like a buffer
problem at all.</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
<DIV><FONT size=2 face=Tahoma>If the crackle continues during silent
passages i would say it is a hardware problem, most probably a power supply
filtering issue. (It could be, for example, a dried out electrolytic
capacitor that cease to perform sufficient filtering as it gets a bit
warmer.)</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
<DIV><FONT size=2 face=Tahoma>If the crackling disappears or changes greatly
during silent passages, which it sounds like it does, I would say it
was more likely a software problem. It does change a little as the sound
gets louder, but this could happen as power loading changes with the
volume.</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
<DIV><FONT size=2 face=Tahoma>It could also be a 'rectifying contact' -
usually a dirty or tarnished one, or a cracked resistor among many
posibilities.</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
<DIV><FONT size=2 face=Tahoma>There is very distinct almost continuous
series of spikes at 204Hz (4.88ms period) which ought to give a clue, but
doesn't immediately ring any bells, so to speak. </FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
<DIV><FONT size=2 face=Tahoma>
<DIV><FONT size=2 face=Tahoma>If it is software, it might be something
happening at high speed, for example if you are using the card to perform a
sampling rate conversion (eg 44.1kHz to 48kHz), and it is failing to keep up
with the pace, that could possibly produce crackle effects.</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>I don't think your hard
drive is implicated, but it is possible that the crackle is a manifestation
some data issues where the data is passing at a high rate beween the drive
and the system - maybe a problem with DMA interrupts/speed of access, but my
gut feel is that is not the most likely cause - it does sound more like
audio hardware/power problems to me (as i stab in the
dark!).</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
<DIV><FONT size=2 face=Tahoma>Alex</FONT></DIV>
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style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV class=im>
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV style="FONT: 10pt arial; BACKGROUND: #e4e4e4"><B>From:</B> <A
title=admin@londonhuayu.co.uk href="mailto:admin@londonhuayu.co.uk"
target=_blank>London Chinese Radio</A> </DIV></DIV>
<DIV>
<DIV></DIV>
<DIV class=h5>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=tlr@gairloch.co.uk
href="mailto:tlr@gairloch.co.uk" target=_blank>Two Lochs Radio</A> ; <A
title=studio@ravensoundradio.co.uk
href="mailto:studio@ravensoundradio.co.uk" target=_blank>Tony Bailey</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Cc:</B> <A title=cma-l@commedia.org.uk
href="mailto:cma-l@commedia.org.uk" target=_blank>CMA-L</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, October 31, 2011 12:48
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [cma-l] Audio
crackling</DIV>
<DIV><BR></DIV>Hi,<BR><BR>Here is a sample of the audio. As you can see,
it's pretty bad!<BR>It doesn't solve it by disconnecting and reconnecting
the audio stream. But it does sound very software-y.<BR><BR>The HD is an
old IDE drive, but the motherboard, which has mostly SATA ports on it, had
an IDE port, so I installed it. So it could be that... I'm not
properly trained, only find out things by overcoming problems like
this...!<BR><BR>Anyway, I am attaching a small sample from the stream...
<BR><BR><BR>Peter<BR><BR><BR><BR><BR>
<DIV class=gmail_quote>2011/10/31 Two Lochs Radio <SPAN dir=ltr><<A
href="mailto:tlr@gairloch.co.uk"
target=_blank>tlr@gairloch.co.uk</A>></SPAN><BR>
<BLOCKQUOTE
style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote><U></U>
<DIV bgcolor="#ffffff">
<DIV><FONT size=2 face=Tahoma>Does the crackle stop for a while if you
stop and restart the audio stream? If so, that would suggest a small
bite rate mismatch is not being properly handled and is resulting in
repeated buffer overflows, which depending on how well the software
handles dumping the excess data can sound like a crackle or a
'glitch'.</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
<DIV><FONT size=2 face=Tahoma>But the description 'crackle' can cover a
multitude of effects. is it possible for you to post a little audio
sample of it somewhere we can access (or email me a small pice directly
if you want) in case the actual sound triggers any other
thoughts.</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
<DIV><FONT size=2 face=Tahoma>Alex</FONT></DIV>
<DIV><FONT size=2 face=Tahoma></FONT> </DIV>
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style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV>
<DIV></DIV>
<DIV>
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV style="FONT: 10pt arial; BACKGROUND: #e4e4e4"><B>From:</B> <A
title=admin@londonhuayu.co.uk href="mailto:admin@londonhuayu.co.uk"
target=_blank>London Chinese Radio</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=cma-l@commedia.org.uk href="mailto:cma-l@commedia.org.uk"
target=_blank>CMA-L</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, October 31, 2011
10:41 AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [cma-l] Audio
crackling</DIV>
<DIV><BR></DIV>Hi,<BR><BR>I wonder if anyone has had problems with
audio crackling? <BR>I have recently changed to a different streaming
PC, (because it was XP, and I had a Marian marc8 midi sound card which
has 8 ins and outs, but doesn't support Win7), and it was fine for
about a month, until it started crackling. I put all the audio on a
seperate HD, and because they are quite close together, I also fitted
a large fan next to them, which delivers quite an icy blast across the
disks.<BR>It starts crackling after a few hours, and it ruins the
stream. It is solvable by rebooting. I originally thought it could be
something overheating, but since it is solved by rebooting, without
the time for anything to cool down, I don't think that is it.
<BR><BR>System info: <BR><BR>Airmate out into Soundcard in (channels 1
& 2)<BR>mAirlist (6 Channels) and computer audio (2 channels) via
Soundcard outs into Airmate channels<BR>Asus P5K-VM motherboard with
an Intel Core2 duo CPU. (it's a Red Sub computer with a few extra
things I've added) <BR clear=all>The CPU cooler is a bog
standard one but with a funnel that directs the hot air out of a vent
on the side. <BR><BR>Anyway, if you have an idea, I'd really
appreciate any advice. <BR><BR><BR>Peter Vautier<BR>London Chinese
Radio<BR>-- <BR><FONT color=#666666 size=4><SPAN
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