• Registered: 2009-08-04
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Topic: Disappearing Mixer Input Channels 9-16 at 88.2/96kHz

Greetings!

I have an HDSP AES-32 PCIe card, which has been working fine at the lower sample rates.

However, I need to use it at 88.2kHz, and whenever I set the WC input to receive 88.2 clock (from Big Ben) or lock to AES/EBU (on channel 9, for instance)--the input source having come from either a Crane Song Spider's multichannel AES/EBU outputs or a Genex GX-A8 converter's AES-EBU outputs--everything looks fine UNTIL....

Until I actually open Pyramix *or* Sonar 8.5.  As long as either application is set to go at 44.1kHz, the HDSP mixer window stays put, and the meters read appropriately on channels 9-16. 

BUT if either Sonar or Pyramix opens in 88.2 or 96kHz (either set as default, or I instantiate a "new file" at the higher fs), the last eight channels on the top row of the HDSP Mixer promptly disappear, and the window looks a bit lopsided on top!  Both Vista and Windows 7 are affected.

And, strangely, three of the channel inputs (from 9-16) show up on 6-7-8 now--which makes no sense, especially in the case when channels 1-8 were not being fed any digital input at all.

If I'm in Sonar, sometimes going to the Sound control panel and simply clicking on the "record" tab gets the higher channels back, but no input is subsequently passed through the mixer to the application, so "the damage has been done."

I was led to believe that I could have 16 channels of input and output at ALL sample rates, but this behavior seems to indicate that "double the sample rate, halve the number of input channels).

It does this with 3.08.2 and 3.08.3, in Vista and in Windows 7, as I said.  I'm running these applications on a Boot Camped 8-core Mac Pro.  I do not have a multi-channel Mac application (only Pro Tools, which requires different hardware..) to see if the same behavior obtains in Leopard or Snow Leopard, which are also possible operating systems on this "big Mac."

I am using ASIO, of course.

Must I recable my digital inputs, and be resigned to using only the first 8 channels at 88.2kHz?  And/or sticking with 44.1kHz for projects over 8 channels?

I hope I'm doing something wrong!

Thank you!

"Dr. Fred"
Dufay Digital Music
Massachusetts, USA

  • Jeff
  • Jeff
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Re: Disappearing Mixer Input Channels 9-16 at 88.2/96kHz

The channel count does not change at any sample rate, unless you set any clock mode to "double wire" or "quad wire" for compatibility with older devices. Check settings and make sure double speed is set to "single wire".

Regards,
Jeff Petersen
Synthax Inc.

Jeff's Website

  • Registered: 2009-08-04
  • Posts: 21

Re: Disappearing Mixer Input Channels 9-16 at 88.2/96kHz

Yes, I've never changed that setting so, yes, both Double Speed and Quad Speed still read Single Wire.  That's one reason this makes no sense to me.

Thanks!  Next guess?

"Dr. Fred"

4 Reply by MC

  • MC
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  • Registered: 2007-04-06
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Re: Disappearing Mixer Input Channels 9-16 at 88.2/96kHz

The channel count will change when you use the card at double or quad speed but provide only single speed at the input. Obviously then it can only be a double or quad wire signal coming in. The options in the Settings dialog control the output only.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2009-08-04
  • Posts: 21

Re: Disappearing Mixer Input Channels 9-16 at 88.2/96kHz

Thank you, MC, I think...?

But now I'm a a bit more confused.  Jeff wrote that the channel count does not change, regardless of sample rate, but you seem to imply that it does.

So I will ask, simply, can I send the card as input sixteen channels at 88.2kHz via single-wire AES/EBU--or not?  That is to say, can I use the 4 input XLRs belonging to the first DB25 and the 4 input XLRs belonging to the the second DB25 to send 16 channels at the higher sample rates via single-wire mode?  I have no equipment which sends, or receives, or requires double or quad wire (besides my old Genex converters), so I work only at single-wire.  Even at 192kHz, the Crane Song Spider can send its eight channels via four XLRs.  I was my understanding when I purchased this card that I could send it as input *twice* that many channels at 192kHz--i.e. the outputs from *two* Crane Song Spiders.  Is that not possible?

And, if I am still correct (and have merely misunderstood what you wrote about "settings" and double and quad-wire--protocols which do not interest me), then I am still wondering why I lose channels 9-16 immediately when the *system* sample rate (the top row in the HDSP settings window) changes to 88.2kHz--as determined by the application (Pyramix or Sonar).  And why three of those channels reappear, mysteriously, as channels 6, 7, and 8.  As I said, this happens both in Vista and Windows 7.

Thank you!

Fred Bashour

6 Reply by MC

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Re: Disappearing Mixer Input Channels 9-16 at 88.2/96kHz

Why not take a look at that Settings dialog and report the sample rate for any of the AES inputs when the problem occurs?
I bet it says 44 or 48 kHz.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2009-08-04
  • Posts: 21

Re: Disappearing Mixer Input Channels 9-16 at 88.2/96kHz

Matthias, you're a genius!  I'm glad I'm not a betting man..

Your theory--that the HDSP mixer was acting "as if I were in double-wire mode" was correct.  I had come to the same conclusion.  But not for any reason either of us would have normally imagined!

I have now learned that the HDSP settings window has another function--that of a "diagnostic tool."  To answer your question, "Yes, it read 44.1kHz on all four AES/EBU inputs, channels 9-16."

But why?  The Crane Song Spider was clearly set to 88.1kHz.

The answer?  It wasn't receiving data from the Spider!  That was clearly revealed when I changed the Spider to 96kHz, and the HDSP settings window didn't change at all.

Some detective work later...I figured out that..  back last summer, I was very ill for several months (with PMR/severe rheumatoid arthritis) and could hardly walk, let alone bend down and do wiring behind my racks.  Yet I was in the midst of a control room renovation when the illness hit.  So I asked an engineer friend to help me out.  It seems that while wiring the digital outputs from my Crane Song Spider and Genex GX-A8 to the big Z-Systems digital router, he mis-labeled his routings so that, ever since then, when I thought I was selecting the Crane Song, I was actually selecting the Genex, and visa-versa!  I always run two systems in parallel, and *usually* at the same sample rates, so this error went unnoticed until yesterday, when I was using only the Crane Song (or so I thought).  Upon power-up, the Genex defaults to 44.1kHz, while the Crane Song remembers its previous sample rate setting.  And since the same mic preamp feeds went to the same channels in each converter, when the mics came up in the HDSP mixer, the right mics were in the right channels, but they were coming from the Genex (at 44.1kHz) rather than from the Crane Song (at 88.2kHz).

The HDSP settings window "properly" interpreted this as an S/MUX condition (since the software was "looking for" 88.2kHz) and promptly dropped channels 9-16, and put "something" into the corresponding channels of the first eight slots.

So it now makes perfect sense, and I thank the HDSP Mixer and HDSP Settings applications for finding an installation error which had gone unnoticed in this studio for several months!

And I thank you again, Matthias, for asking the trenchant question--which put me on the right track to do the detective work.

All is well now, and I've gained quite a bit of respect for the two RME applications.

Cheers!

"Dr. Fred"
Dufay Digital Music