Word Clock Question

Archived from groups: rec.audio.pro (More info?)

Hi, this is my current studio signal flow:

Focusrite Twin Trak Pro>SPIDF in on Delta 1010 PCI card
Focusrtie OctoPre > Analogue input on Delta 1010 Rackmount

This enables me to run ten channels simultaneously. However, I seem to
be getting a tiny bit of background noise with the Twin Trak that
sounds a bit to me like audio when its streamed. Here's a clip anyway
(note: this is normalised silence, so it isn't actually this loud!)

http://www.theshiers.plus.com/crack.mp3

Could this be due to a word clock problem? My Delta 1010 is set to
master at the moment. I originally thought it was my Rode NTK that was
problematic, but since trying an AKG 414 and a range of other mics,
they carry have the same problem, so I'm really just trying to track
down the source.

any help appreciated

Owen

Archived from groups: rec.audio.pro (More info?)

<owenoftheshire@gmail.com> wrote in message
news:1122199708.197159.195190@g14g2000cwa.googlegroups.com
> Hi, this is my current studio signal flow:
>
> Focusrite Twin Trak Pro>SPIDF in on Delta 1010 PCI card
> Focusrtie OctoPre > Analogue input on Delta 1010 Rackmount
>
> This enables me to run ten channels simultaneously.
> However, I seem to be getting a tiny bit of background
> noise with the Twin Trak that sounds a bit to me like
> audio when its streamed. Here's a clip anyway (note: this
> is normalised silence, so it isn't actually this loud!)

> http://www.theshiers.plus.com/crack.mp3

> Could this be due to a word clock problem? My Delta 1010
> is set to master at the moment. I originally thought it
> was my Rode NTK that was problematic, but since trying an
> AKG 414 and a range of other mics, they carry have the
> same problem, so I'm really just trying to track down
> the source.

I've got a 1010 and two 101LTs. They handle SP/DIF input
wonderfully if you set the clocking up right.

When you're recording from the SP/DIF input, there are two
common good good sources of clock, one being the card's
word clock input if its attached to a proper word clock, or
the SP/DIF input itself.

The M-Audio Delta Control Panel is the means you use to set
up the clocking of a Delta interface.

The current Delta 1010 manual can be obtained from
http://www.m-audio.com/index.php?do=support.manuals and is
at

http://www.m-audio.com/images/glob [...] Manual.pdf

Turning to page 23:

"MASTER CLOCK: This section allows you to select the source
of the board's
master clock: Internal Xtal (crystal), S/PDIF In, or Word
Clock. Master clock
operation is outlined in the Synchronization section of this
manual. Internal Xtal
is the default setting. Be sure to select "S/PDIF In" if you
will be recording or
monitoring an S/PDIF stream, or "Word Clock" if you wish to
synchronize your
digital audio with a source device that is Word Clock
capable.

"NOTE: If "S/PDIF In" is selected as the master clock
source, be
sure to supply a valid S/PDIF signal to the board's active
S/PDIF
input. Otherwise, erratic timing and/or improper sample
rates will
be experienced. The same is true for selecting "Word Clock"
as the
master clock setting - make sure there is a valid word clock
signal
present at the Delta 1010's Word Clock In.

In your case, read the note with its sense reversed as
follows:

If you apply a valid S/PDIF signal to the board's active
S/PDIF
input. be sure to select "S/PDIF In" as the master clock
source