PT Native TB Question

[Darryl Ramm]

Originally Posted by lukeyy

hey craig
could you explain what DSP for I/O means?

I´m noticing that recording with plugins and delay compensation turned on on a old HD3 system is much easier than on a new protools 11 (not HDX) system and I was wondering if a native HD comes close to what I can do with the HD3 because of the DSP for I/O?

basically what is much better on the old HD3 is that I never have any issues with timing of tracks as long as delay comp is on - on the non HD system I can´t do that without getting pretty serious timing problems even with dleay comp on..
thx for your help

I already tried to correct this misinformation, but let me try again, with Pro Tools HD Native there is no "DSP for IO". Non, nada, zilch. There is no DSP for anything. There is a hardware mixer on the HD Native card that provides low-latency monitoring. That is it.

Latency and delay compensation with Pro Tools with a third party CoreAudio or ASIO interface works the same as with HD Native/Digilink interface. You may have more or less hardware latency and able to run at higher/lower IO buffer sizes depending on the exact interface. Again there is no DSP involved with HD Native.

We don't know what your "timing problems" are, and nobody here can really guess. If you want help maybe you could describe them. One big difference in HD/DSP/TDM land was unless you were going out to RTAS plugins, you never dealt with a software IO buffer and associated latency.

More often than not problems come down to just the complexity of what is going on. Needing to worry about all of: what IO buffer size you are trying to use, what exact signal routing you have through Pro Tools (including AUXes, busing etc.), what high-latency (if any) plugins you have in use, if delay compensation is actually turned on, and if all the automatic delay compensation settings are correct (what are they? can you manually change them to get them correct?). Most delay compensation issues are solved by carefully working through the signal paths, reducing things as simple as possible to start with, checking whether the compensation is correct etc. and yes there are cases where Pro Tools appears just broken. If you can't fix your problem, try to work it down to a simple test case and describe that on DUC.

EDIT: and although you mention delay compensation, since the problem you are having at all is not descended it's not clear if you have a simple input delay issue for monitoring (which ADC can never fix) or if it's a downstream ADC issue where things are getting out of whack (for want of a better technical term).

[Craig F]

DSP PIs vs using the CPU for PIs
and the interface type

[Craig F]

Darryl, mixing in the Digital Domain is Digital Signal Processing

[Darryl Ramm]

Originally Posted by Craig F

Darryl, mixing in the Digital Domain is Digital Signal Processing

That is a rather useless pedantic statement when people are confused and are asking for help and you make statements like the HD Native has "some DSP for I/O handling " which is wrong at worst or confusing at best (it's only for monitoring paths) and leads people to more confusion, as we've just exactly seen.

[albee1952]

FWIW, here is my own experience(there should be no difference between HDN TB and HDN PCIe). I moved from using an 003 with PT10 HD software, to using HDN(with HD IO boxes) on the exact same computer(custom built PC i7 quad core). I absolutely noticed an improvement in performance overall, plus better latency performance(because the PCIe bus is much faster than FW). What that means for me is this, on the old system(003) at a 64 buffer, I had to make high-latency plugins inactive during tracking and overdubs to avoid noticeable latency in the headphones. With the HDN system, I could have plugins with modest latency(like 64 samples) with a 64 buffer setting and get no complaints about latency from players. Now that I have moved to a more powerful 6 core PC, I can actually track with plugins that have upwards of 1100 samples of latency(any UAD stuff with my Quad card), and by dropping the buffer to 32(which I could not do with the 003), I can still track and overdub. For me, its been a very positive experience

[lukeyy]

Originally Posted by Darryl Ramm

I already tried to correct this misinformation, but let me try again, with Pro Tools HD Native there is no "DSP for IO". Non, nada, zilch. There is no DSP for anything. There is a hardware mixer on the HD Native card that provides low-latency monitoring. That is it.

Latency and delay compensation with Pro Tools with a third party CoreAudio or ASIO interface works the same as with HD Native/Digilink interface. You may have more or less hardware latency and able to run at higher/lower IO buffer sizes depending on the exact interface. Again there is no DSP involved with HD Native.

We don't know what your "timing problems" are, and nobody here can really guess. If you want help maybe you could describe them. One big difference in HD/DSP/TDM land was unless you were going out to RTAS plugins, you never dealt with a software IO buffer and associated latency.

More often than not problems come down to just the complexity of what is going on. Needing to worry about all of: what IO buffer size you are trying to use, what exact signal routing you have through Pro Tools (including AUXes, busing etc.), what high-latency (if any) plugins you have in use, if delay compensation is actually turned on, and if all the automatic delay compensation settings are correct (what are they? can you manually change them to get them correct?). Most delay compensation issues are solved by carefully working through the signal paths, reducing things as simple as possible to start with, checking whether the compensation is correct etc. and yes there are cases where Pro Tools appears just broken. If you can't fix your problem, try to work it down to a simple test case and describe that on DUC.

EDIT: and although you mention delay compensation, since the problem you are having at all is not descended it's not clear if you have a simple input delay issue for monitoring (which ADC can never fix) or if it's a downstream ADC issue where things are getting out of whack (for want of a better technical term).

the problem with low latency monitoring is that you can´t use any plugins on that channel - I like to record with plugins on all channels to get some kind of a vibe how the track will sound mixed.. and as well on the tracks I´m recording for example vocals I like to add compression and eq - when I turn off DC I obviously get into problems with this setup but I had problems with DC on as well on a native system
so here´s the setup:

- ADC is turned on
- the delay display is green which means protools is able to compensate for all the delays in the session
- I´m playing back tracks with plugins and recording tracks with plugings on them
- playbackbuffer size is 512 or 1024
- I´m using VI´s as well
- I´m monitoring trough protools which means I´m using sends for my headphone mixes

using this setup an a HD3 system works perfectly with no issues and on a native system I´m getting problems when I record like this - is this only me and you guys dont have problems at all with timing (which means overdubbing and having the overdubbed tracks not in time) on a native system?

[JFreak]

Use lower buffer. I've found you rarely have trouble with 256 buffer (@48k) or 512 buffer (@96k). Divas are an exception to this.

[Darryl Ramm]

Originally Posted by lukeyy

the problem with low latency monitoring is that you can´t use any plugins on that channel - I like to record with plugins on all channels to get some kind of a vibe how the track will sound mixed.. and as well on the tracks I´m recording for example vocals I like to add compression and eq - when I turn off DC I obviously get into problems with this setup but I had problems with DC on as well on a native system
so here´s the setup:

- ADC is turned on
- the delay display is green which means protools is able to compensate for all the delays in the session
- I´m playing back tracks with plugins and recording tracks with plugings on them
- playbackbuffer size is 512 or 1024
- I´m using VI´s as well
- I´m monitoring trough protools which means I´m using sends for my headphone mixes

using this setup an a HD3 system works perfectly with no issues and on a native system I´m getting problems when I record like this - is this only me and you guys dont have problems at all with timing (which means overdubbing and having the overdubbed tracks not in time) on a native system?

You will of course have real-time monitoring latency as you have a large IO buffer and are software monitoring through Pro Tools. And delay compensation does nothing for real time latency of monitored channels, all it can do is slow down other things to time align them. Green ADC should means Pro Tools thinks things are OK, but ADC can still be wrong. And be aware that Pro Tools 11.2.1 fixed bugs with delay compensation.

If things are not time aligning you need to systemically debug what is going wrong. Start by looking for any plugins with real latency, disabling all plugins playing with measuring latency differences through different signal paths with clap tests or click clack, you may need to manually correct any wrong delay compensation times.

If you want to monitor through plugins you may also need to get your IO buffer smaller, how much smaller depends on what you are doing and how sensitive the talent is to latency. All this is identical to regular (non HD) Pro Tools, the HD native card does nothing for you here directly, except it and it's driver efficiency can often help you set a smaller IO buffer than some other interfaces. Wether you can run things like certain heavy plugins or VIs at the small buffer you need is something you need to experiment with. Make sure your computer is fully optimized, all plugins up to date, etc. You may need to do things like print VI tracks or print effects on existing audio tracks to allow operation at extreme small IO buffer size. You can also just bus lots of existing content to a track and print it to see if delay compensation works OK with that much simpler set up.

And that you cannot run plugins on a low latency monitoring path goes to my point of trying to emphasize there is no DSP on the HD Native card. But the hardware mixer on the HD native card is what is providing that low-latency monitoring.

Make sure you are chasing the right problem: ADC problems or high real-time latency. What exact version are you on?

[lukeyy]

I will do some testing soon and get back here with my results - at the moment working with low buffer size (64) works except getting 6000something errors from time to time...

[Darryl Ramm]

Great you are making progress.

We'll know/be able to help a lot more if you tell us the exact AAE Error numbers/messages

If you are getting delays that don't seem to make sense, can you post a screenshot showing all your mix window (at least with a test session if not a full session) and/or draw a diagram that shows the channel/bus routing and attach that.