Using the SPDIF at 44.1 kHz.

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wouter
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Using the SPDIF at 44.1 kHz.

Post by wouter »

I'm trying to connect the Solaris to my Scope PCI card using the Optical SPDIF connections. At 48 kHz it works but when I switch to 44.1 kHz I can't get any signal from the Solaris into the Scope system. I connected both the inputs and the outputs to my Scope system and I can get an audio signal from the Scope system into the Solaris. But It looks like it keeps sending a signal at 48 kHz because when I connect the Solaris to my T.C Electronic Fireworkx it indicates that a 48 kHz signal it present at the inputs. Is anyone using the SPDIF connection successfully at 44.1 kHz?
John Bowen
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Re: Using the SPDIF at 44.1 kHz.

Post by John Bowen »

Well, this is embarrassing....

I sent another request for more details on this question from Wouter, and now I'm wondering about the 96kHz issue, due to the way he answered...and I asked for more details regarding the testing he had done in the early days of development.

Here's the latest info from the main DSP coder:

"Due to the mainboard hardware, you can not switch the Solaris output sample rate from 48 kHz to 44.1 kHz.
So currently the SPDIF output rate is 48kHz.
The SPDIF input has a samplerate-converter which allows for different input sample rates."

This last sentence makes it sound like no matter what comes in as the input rate, the output is always at 48 kHz. This runs counter to what I had been told back in the early days, so, I've asked him about that as well, and will report here when I get a response.

I'm sorry for the misinformation. I do not have a system set up here to test these things on my own.
Weston Underwood
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Re: Using the SPDIF at 44.1 kHz.

Post by Weston Underwood »

I think you're alright on the 96k John. My Big Ben reports it as 96k.
John Bowen
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Re: Using the SPDIF at 44.1 kHz.

Post by John Bowen »

I see I never reported on the response regarding what I thought we had in the hardware design. It turns out part of my misunderstanding is due to the earlier prototype hardware, which we didn't end up using for production:

"The very first Solaris back in 2007 had different hardware.
With the current hardware the output rate is 48kHz.
Slaving a Scope system to the Solaris SPDIF output is no problem.
Feeding back audio to the Solaris SPDIF input works as well.
Even using a different sample rate applied to the Solaris SPDIF input works because of the sample rate converter."

So, it seems the SPDIF output is fixed at 48kHz no matter what the input rate is, but you should be able to feed the Solaris a different sample rate to slave it.

john b.
niversen
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Re: Using the SPDIF at 44.1 kHz.

Post by niversen »

Is there anything i need to do to get it to sync at 96k? I can't seem to make it happen with my RME UCX set to internal clock, 96k. The Solaris still syncs at 48k and the RME just does SRC on it. Sounds fantastic, but I can't seem to make it flip to 96k using anything i know. Minor, and not critical, just wondering if there is a way.
sam
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Re: Using the SPDIF at 44.1 kHz.

Post by sam »

Try plugging an SPDIF cable from the UCX to the input of the Solaris. From what I gather the Solaris should slave itself to the input rate.
niversen
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Re: Using the SPDIF at 44.1 kHz.

Post by niversen »

Sam, this is what I've done. Set UCX to internal clock @96k sample rate. plug IN and OUT cables to Solaris from RME. RME driver reports signal at 48khz. Sounds fine, but it is not at 96k according to the RME driver. Set up this way, the sync light flashes to indicate a valid signal, but it never goes solid to indicate SYNC, it also never glitches audibly. If I slave the RME to the Solaris, it stays at 48khz, but the sync light is always solid and never flickers.

I've tried reseting the Solaris while the RME is set to 96k to see if it is a bootup thing. Still goes to 48khz. I am not "unhappy" with the Solaris at 48khz. Thing sounds amazing. It was more of a question if I was doing something wrong.

I've read my UCX manual and the Bowen manual, and I can't seem to get it working at 96k. I'm just going to run at 48khz and go make music!

Thanks for suggesting the output cables, but it didn't do the trick for me.
John Bowen
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Re: Using the SPDIF at 44.1 kHz.

Post by John Bowen »

Yes, so, as I state above, I was mistaken in my initial understanding, and probably have it wrong in the User Guide as well. The current hardware only runs at 48kHz. The Solaris output will always be 48kHz, no matter what the input sample rate is (it will convert the input to 48 kHz).
k-Tracker
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Re: Using the SPDIF at 44.1 kHz.

Post by k-Tracker »

Sad note, John. I've just realized that too. Tried to sync Solaris to my set up. Finally I've realized it won't sync at all. Is it hardware design limitation or it can be fixed in FW?
Andrei Kudryavtsev,
http://www.deftaudio.ru
John Bowen
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Re: Using the SPDIF at 44.1 kHz.

Post by John Bowen »

It's a hardware limitation, in that the chip used only allows this situation. We would have to look at a new main board design and see if there's a part that we can use to allow more flexibility.
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