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-   -   Real time SR conversion via spdif - Avid HD IO (http://duc.avid.com/showthread.php?t=402376)

Eric Lambert 12-10-2018 04:50 PM

Real time SR conversion via spdif - Avid HD IO
 
My session is at 48 but an external box is fixed at 44.1 so I'm trying to convert the external box's signal on the way in. I was pretty sure that the Avid HD IOs could convert on-the-fly at the spdif inputs, however, I don't seem to know how to get that working. Selecting sample rate conversion in Hardware Setup doesn't do what I need (the signal still has the incorrect sample rate distortion).

Any ideas? Maybe it won't convert spdif on-the-fly...

Top Jimmy 12-10-2018 05:09 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
As I recall, the real-time SRC only ever worked for inputs to the digital card, not the ones on the enclosure.

If you had an AES-Dsub cable, you might be able to use a balun to adapt the RCA to XLR. But, while this works just fine with many digital input receiver chips, I don't have first-hand experience with doing this on an Avid interface.


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Eric Lambert 12-10-2018 06:06 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Yeah, I've thought about converting to AES but was hoping I could avoid that.

Another option is to use the toslink connectors on the hardware unit and the IO, a connector type which *might* offer real-time conversion in ProTools...? Hopefully?

Top Jimmy 12-10-2018 06:40 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
As long as the output box does ADAT optical you can apply the SRC when using the optical port on the card. Just know, the optical port on the card only does ADAT, it can't be switched to optical S/PDIF.


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albee1952 12-10-2018 06:56 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
What is the "external box"? What are you doing with it? More info might reveal other options, like maybe record the external source to a 44.1K session, then open your 48K session and Import Session Data, and tell PT to apply SRC on import:rolleyes:

Eric Lambert 12-10-2018 07:23 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
It's a UA OX guitar interface (a fantastic box, btw) and it can't output ADAT, only spdif. I could go analog but I'd rather not introduce another D/A and then A/D. I could convert spdif to ADAT with an adapter but that's an expensive product.

This is becoming more of a headache than I expected. My sessions will never be 44.1 -- always 48 or higher -- so something's gotta convert.

Darryl Ramm 12-10-2018 07:45 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
S/PDIF to AES/EBU is likely the easiest path...

Eric Lambert 12-10-2018 08:40 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
That's my thought, too. I just want to verify that the Avid HD IO will do realtime SR conversions if I connect via AES.

YYR123 12-10-2018 08:44 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by Top Jimmy (Post 2508938)
As I recall, the real-time SRC only ever worked for inputs to the digital card, not the ones on the enclosure.


This is true

Eric Lambert 12-10-2018 08:54 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
I don't have the added digital IO card, so... that means I'm out of luck with the realtime conversion idea?

Darryl Ramm 12-10-2018 10:20 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by Eric Lambert (Post 2508974)
I don't have the added digital IO card, so... that means I'm out of luck with the realtime conversion idea?

Oh, yep Eric you are out of luck. No chassis digital connectors support sample rate conversion.

So... you can pick up HD IO digital cards for under $500 on EBay if you have a slot free and then go from S/PDIF to AES/EBU.

Alternately if you have DigiLink capacity, add a 192 IO box which has sample rate conversion on the digital daughter cards as well and you should be able to pick up as a whole 192 I/O with digital (and analog) cards for a few hundred dollars.

Or... you really want a new MTRX anyhow right? (sample rate conversion on AES/EBU as well) :-)

BTW please let us know what you think of the Ox... what a kitchen sink of features (but doh should have had AES/EBU out for pro-studio use)... but UAD themselves just don't do much AES/EBU on their interfaces (a pet peeve of mine).

Darryl Ramm 12-10-2018 11:13 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Oh just in case you have an Omni laying around... they have sample rate conversion on their inputs... including S/PDIF coax and optical.

Omni on EBay... ~$800-$1k?

Eric Lambert 12-10-2018 11:34 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
The OX is fantastic. It's early in the game but it's been exceeding my expectations which have been high for this kind of thing. The only gripe I have at this point is the issue of this thread. Yes, the lack of an AES connection feels like a mistake for this product.

originalscottyg 12-11-2018 10:22 AM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by Eric Lambert (Post 2508999)
Yes, the lack of an AES connection feels like a mistake for this product.

I'd say the lack of any other sample rates than 44.1kHz is the biggest mistake IMO.

Eric Lambert 12-11-2018 11:36 AM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by originalscottyg (Post 2509057)
I'd say the lack of any other sample rates than 44.1kHz is the biggest mistake IMO.

The option for 48, or higher, would be nice.

Eric Lambert 12-11-2018 11:38 AM

Re: Real time SR conversion via spdif - Avid HD IO
 
I compared the digital and analog outs and digital has a slight edge. More detail, faster attacks, more bite. The usual.

Some of this detail would be lost in a 44.1-->48 conversion so I'm not sure which is the lesser of two evils -- analog or a SR conversion -- but I'm going to continue to search for a graceful way to get this signal to 48k.

originalscottyg 12-11-2018 12:01 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by Eric Lambert (Post 2509076)
The option for 48, or higher, would be nice.

My first thought was, why not run it at 48kHz. I had to download the manual to see for myself. The idea that someone would make a new piece of gear with digital outputs that only work at 44.1kHz is mind-boggling to me. I wonder what the reasoning behind that decision was.

Darryl Ramm 12-11-2018 12:56 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by originalscottyg (Post 2509082)
My first thought was, why not run it at 48kHz. I had to download the manual to see for myself. The idea that someone would make a new piece of gear with digital outputs that only work at 44.1kHz is mind-boggling to me. I wonder what the reasoning behind that decision was.

I suspect it is all to do with driving the speaker emulation etc. software. Which may upconvert internally to further complicate things. I expect UAD want to optimize for that/simplify things by supporting one sample rate. Anyhow the decision is likely to be lead by that not just simple digital input/output implementation... there are no reasons there.

IIRC UAD has sample rate conversion on all their interfaces, and only do AES/EBU on their Apollo 16... so I think they blinded themselves to some mistakes here.

Eric Lambert 12-11-2018 01:14 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
So... anyone know of a small, external, high-quality sample rate convertor? ;)

(but seriously, I do need one)

Darryl Ramm 12-11-2018 01:39 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
None of the Avid interface ideas work? The only high-quality converters I have seen in use are the various RMI models, not cheap.

ehaber 12-11-2018 01:42 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
By the way, regarding the post that recommended the MTRX (which is a great unit), for sample rate conversion, the MTRX is similar to the HD I/O; that is the chassis digital I/O that come with the MTRX (16 channel of AES, coax MADI, Dante if you have a Dante card) do not have SRC; while if you separately purchase and install a slot digital I/O AES, MAdi, or (the new) Dante card, those slot I/O cards do sample rate convert.

Eric Lambert 12-11-2018 08:37 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
My HD IO does in fact have a digital card installed into one of the expansion slots. It looks like this:

https://www.google.com/url?sa=i&sour...44675690398949

Shouldn't I then be able to get realtime SRC with that card? I'd try it now, I'm just not currently equipped with the proper DB25 cable nor the spdif-to-AES adapter.

Darryl Ramm 12-11-2018 09:32 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Yes. Edit: Ah but... the photo you link to is a 192 IO digital card, that won't work in a HD I/O. I hope you have the actual HD I/O version of a digital card.

So hoping you have the HD I/O digital card all you need is one of these...

https://www.bhphotovideo.com/c/produ...Data_Link.html I'd much rather do that than try to just use an analog cable with balun in it.

You should be able to wire up a XLR to a DB-25. Much cheaper then buying a cable if you just need one connection.

But here is the cable if you want to buy one... https://www.sweetwater.com/store/det...gisnake-4-foot

If you buy another brand DB-25 cable set make sure it's wired for the TASCAM/Avid standard.

https://www.sweetwater.com/sweetcare...-pinout-guide/

Top Jimmy 12-11-2018 09:41 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by Darryl Ramm (Post 2509127)
If you buy another brand DB-25 cable set make sure it's wired for the Yamaha/Avid standard.


Doesn't Avid use the Tascam pinout?



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Darryl Ramm 12-11-2018 09:43 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by Top Jimmy (Post 2509128)
Doesn't Avid use the Tascam pinout?

Doh I transposed it in my head. Edited my post to fix.

Eric Lambert 12-11-2018 11:07 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Yes, I have the HD IO card.

Rich Breen 12-12-2018 08:13 AM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by Eric Lambert (Post 2509096)
So... anyone know of a small, external, high-quality sample rate convertor? ;)

(but seriously, I do need one)


Hi Eric - not particularly small (1 rack unit), but I've got a Behringer SRC2496 box that's been gathering dust here for as long as I can recall - I bought it for some particular task years ago and haven't used it since - honestly, I'd give it to you free if you picked it up.


best,
rich

Eric Lambert 12-12-2018 11:38 AM

Re: Real time SR conversion via spdif - Avid HD IO
 
Wow, Rich, that's quite generous! I'll email you. Thanks!

dsumich 09-01-2020 04:04 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Hey guys, found this old thread. I have the exact same issue. I have the Digital I/O card installed in my 96 HD I/O, but not sure how to utilize it. Would I just use a cable to run from the s/pdif output of the OX to the optical s/pdif input on the expansion card of the I/O? Something like this?

https://www.banggood.com/CE-LINK-5M-...r_warehouse=CN

If that happens to work, do you have to do anything to kick in the SRC, or does it happen automatically?

dsumich 09-01-2020 04:38 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by dsumich (Post 2576519)
Hey guys, found this old thread. I have the exact same issue. I have the Digital I/O card installed in my 96 HD I/O, but not sure how to utilize it. Would I just use a cable to run from the s/pdif output of the OX to the optical s/pdif input on the expansion card of the I/O? Something like this?

https://www.banggood.com/CE-LINK-5M-...r_warehouse=CN

If that happens to work, do you have to do anything to kick in the SRC, or does it happen automatically?

Never mind this question. I think I understand from Darryl's post above you need the converter from s/pdif to AES/EBU, and then run that into the DB25 digi snake cable that connects to your digital i/o card. I will get the two products linked to above (seems to be about $200 for both these days) and report back how it goes. I am guessing though you still need to turn on SRC in the Hardware Setup Dialog on the Digital tab for which ever channel pair you are i/o'ing on.

Darryl Ramm 09-01-2020 07:19 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
You have me lost here. There is no "Digital I/O card" for a 96 IO. There is no expansion card at all, Avid never made them IIRC. There are chassis digital IO on every 96 IO. And from memory the 96 IO does not support SRC on the chassis digital connectors.

dsumich 09-01-2020 11:31 PM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by Darryl Ramm (Post 2576527)
You have me lost here. There is no "Digital I/O card" for a 96 IO. There is no expansion card at all, Avid never made them IIRC. There are chassis digital IO on every 96 IO. And from memory the 96 IO does not support SRC on the chassis digital connectors.

My bad. I have the HD I/O 8x8x8, not the 96 I/O. Given that info, the solution with those two components linked to from your post should work, shouldn't they?

Darryl Ramm 09-02-2020 02:06 AM

Re: Real time SR conversion via spdif - Avid HD IO
 
Quote:

Originally Posted by dsumich (Post 2576539)
My bad. I have the HD I/O 8x8x8, not the 96 I/O. Given that info, the solution with those two components linked to from your post should work, shouldn't they?

Yes.


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