Changing sample rates causing loss of inputs..?

[jes]

I'm using a UA Apollo Quad FW on a 2010 Mac Pro. This may be a Pro Tools problem (PT 12.4) or a UA issue, I have never experienced it before using the Apollo as my interface. I assumed that the Pro Tools software would be able to reset the sample rate on the Apollo like it does on other devices, and sometimes this does work, but most times when I've been working in 48khz sessions and then try to open a session at 44.1, I get a dialog in Pro Tools that the I/O layout has been changed by another application (none are open except the UA Meter and sometimes UA Console,) and then it takes forever to close the session, or it's beachballing— it basically kills Pro Tools. If I do get it open again, or force quit while its attempting to close the session and open it again, all inputs from the Apollo are greyed out.
It doesn't matter whether I click close session or save and close session, the close session takes forever—track by track, I've let it sit to see if it will ever get done, but most times I give up.
Not sure what could be causing this, any suggestions? Solution for now is to reboot.

[DJ Hellfire]

I get this issue quite often with my Apollo. I think it's a Pro Tools issue. None of my other audio applications experience this. I have no idea what causes it.

[jes]

Are you using PT 12.4 also? I wonder if it's the same with 12.5.
Annoying.

[JFreak]

This sounds weird. Non-HD systems should have x amount of i/o available, whereas HD systems count voices. And there are different number of voices per different sampling rates. I would surely understand this were we talking about HD system, but for a 3rd party interface it looks like a bug to me...

[JuanPC]

Dude, that's normal.

Let's say you have an ADAT soundcard/interface only...

If you have 4 ADAT physical ports, 2 input 2 output = 8-channels at 48khz per port = 16 channels of I/o.

But if you change sample rate to 88.2KHz or 96KHz,
Channels will half, that's called SMUX,
ADAT laser can't go faster, has a fixed speed...
Today It could but was not designed like that... In 1991 was Top of the line/tip of the spear/cutting edge technology.

It was designed to emulate AES/EBU Double wire, to avoid jitter issues.
Less jitter = Better.
4 ADAT physical ports, 2 input 2 output = 4-channels at 96KHz per port = 8 channels of I/o.

Few sound cards/interfaces can go up to 192KHz, in ADAT.
4 ADAT physical ports, 2 input 2 output = 2-channels at 192KHz per port = 4 channels of I/o.

192KHz is not practical for AD/DA jitter issues, in theory is better but with a perfect clock.

Analog Channels do not half when increasing sample rate, but jitter increases.

If you have a mixed soundcard with ADAT & Analog, some channels half, some don't when increasing sample rate.

If you have AES/EBU and use double wire, channels will half, But jitter does not increase, when increasing sample rate.

MADI is similar to ADAT but has a faster laser, that allows up to 64-channels at 48KHz, but will also half when increasing sample rate.

One sad example is Mytek 8x192, has dual optional card slots... It can have dual ADAT cards with 8-physical ports, 4 I/o, with 8-channels of 192KHz but Firmware was not designed for it, hardware was, but software not.

other converters only have 1-slot, for 1-optional ADAT card with 4-physical ports, 2 i/o, = 4-channels @ 192KHz

[JFreak]

Laser? AES/EBU and MADI are copper-based not optical


Sent from my iPhone using Tapatalk

[jes]

Yes, I understand the resources being tied up and limiting track count by increasing sampling rate, but that's not what's happening here. If I've been working at 48khz and then try to open a 44.1khz session, ProTools reacts saying that the I/O has been changed by another application, then if reopened, has ZERO inputs, but the same number of outputs as before.

I don't think the number of inputs or outputs on the Apollo is in any danger by the difference between 44.1 and 48khz.


Additionally, Pro Tools' dialog box offers "close session" or "save and close", (when nothing would have been changed by simply opening the session so there's no information to save,) and then takes forever to close the session (either selection chosen) track by track. I've let it sit for over an hour to see if it would recover, but even if it does manage to close all the tracks by that point, an iffy proposition, it still is beachballing and has to be force-quit.

[JFreak]

You are correct, there should not be a difference between 44.1 and 48


Sent from my iPhone using Tapatalk

[DJ Hellfire]

Originally Posted by JuanPC

Dude, that's normal.

In my case it happens randomly. Has nothing to do with changing sample rate for me. And I never use anything higher than 48k anyway. It freezes pro tools to the point I have to actually reboot the computer, then reload the session and hope it works. Does not happen in Pro Tools 10. Even when it happens in 12, I can force quit 12 and load the same session in 10 without the problem. It's not normal. Never happened with my 003.

[JFreak]

So perhaps this is a 3rd party interface issue?


Sent from my iPhone using Tapatalk