PT LE and latency.

[bodega.]

Hi all,

Sorry in advance if this has been covered before. but....

I've got a UAD-1 card and know that with a non-latency adjusted sequencer it can be a bit of a nightmare. I used SX 1 for ages with it and it was awful.

Now that I've got SX3 and still hate it (for other reasons) I was thinking of switching to Pro Tools LE, getting rid of the UAD and picking up host-based equivalent plugs. My midi needs are pretty basic and I want to take advantage of the more "pro" (in some cases) RTAS plugs.

My question is this: I know from the UAD board that PT LE is considered pretty primitive because of it's lack of auto delay compensation, but does that play as much of a role with host-based plugs?

ie. for native plugs would I still be setting up delays on every other channel other than the one I've put an effect on like I did with SX 1? To me, even though I'm sick of Cubase's random bursts of full-volume noise, having to adjust timings on 15 tracks in order to see how a delay sounds would disturb my workflow a bit more than I'd like.

Thanks in advance,
Matthew

[bradyvickers]

For the most part latency from RTAS plugins is not an issue, but there are some exceptions. Some RTAS plugins introduce delay that exceed your hardware buffer settings. This can introduce problems like comb filtering, which im sure you're familar with. So unfortunately to answer your question I have to say it depends on what you will be using. To get a quick overview of delay compensation in a host-based Pro Tools system see the following link:


Delay Compensation in Pro Tools LE

[Raw-Tracks]

Don't get rid of your UAD-1 card! It may seem like a pain at first, but if you use UAD's delay comp plugin on all tracks that don't have a UAD plug, there are no latency issues. I use the UAD-1 card with LE and could not part with the card. It adds way too much to my mixes to get rid of.

At the start of a mix, I just add the UAD Delay comp plug to the last insert of the first track. I set that plug for 2 plug-in's worth of delay. I then copy drag that plug to all the other tracks. I set it at 2 since it seems I never use more than 2 UAD plugs on a track. I also set it for the extra Pultec latency (forget what it's called right now). Now I have the delay comp plug on all tracks. It literally takes about a minute to set up the entire session.

Now, when you add a UAD plug to a track, you just remove 1 plug's worth of latency from the Delay comp on that track. The first day I used this method, it seemed like a hassle, but now, it doesn't even make me flinch. It really is not a big deal.

Good Luck!

[bodega.]

So according to that the problem would be, in their words, the "'built-in' hardware buffer" setting, which I would assume would be specific to each MBox or whatever is being used and therefore not be adjustable?

Erick - cheers for the workaround, but I'm going mobile with a Macbook, so I won't have the option anyways. Though, for academic curiosity... if you were to bounce down a mix where all the tracks had 2 plugs worth of delay comp on them, how many ms would that be?

I'd just be wary that if I bounce down a mix, then burn that to cd, that there would be a delay between pressing play on the cd and the audio starting, even if it's cued up flush on the arrange page. I dj my own material using cds often so it's not a minor concern.

[Geert van den Berg]

The start of your CD tracks has nothing to do with any latency within a DAW, that's about how tight you cut off the start of the audio and how you set the indexes on your CD...

Or do you want to run your CD player into PT? And what does that have to do with songs lining up in the arrange page? When you hit spacebar it will almost instanly go into play...

The latency within PT LE is quite easy to deal with because you can see exactly per track how much delay a track has... Offcourse adjusting nudging your audio all the time is not really a joy, but it can be done, only when doing things like parallel compression it's a bit harder, but then you could make a setup with 2 of the same plugins were one isn't doing much to the audio and the other is working...

The software buffersize determines the amount of the data to be processed over a period of time. Smaller buffers create less latency but will let the CPU work harder, bigger buffers create a larger latency...

Some plugins don't report any latency, that's not because they don't have any, but because the calculations can happen within the time the software is buffering and then it won't cause any delays... But when there's A/D/A conversion into the equation gets larger, as then there are several stages of buffering and converter delay and then the total latency gets much worse...

The UAD can't be compensated for by the software buffer because latency is too large and it is so large that it is very noticable, that's why the compensator plugin is necessary.

[Hope209]

erick, what buffer setting are you using while mixing with the UAD delay comp plug-in?

[Raw-Tracks]

Originally Posted by Hope209

erick, what buffer setting are you using while mixing with the UAD delay comp plug-in?

Usually for mixing I use 1024. That helps to lighten the load on the CPU.

[bodega.]

Originally Posted by Geert van den Berg

The start of your CD tracks has nothing to do with any latency within a DAW, that's about how tight you cut off the start of the audio and how you set the indexes on your CD...

You're not getting what I mean. I always cut the start of my audio right up to the first ms of the audio file. If I were to use 2 instances of delay comp, I wonder how far that would be pushed back *within the file*.

Thus, if there is a 20 ms delay across the board due to plugin delay comp, when I burn that to cd and press play, the audio won't start instantly but 20ms later. My timing will be just slightly thrown off while djing. So I'd have to edit the file after bouncing it down, which is another step I'd like to avoid.

Does that make sense? It's kinda hard to explain but it's probably only djs - and dance music djs at that - that will share this concern.

Originally Posted by Geert van den Berg

Some plugins don't report any latency, that's not because they don't have any, but because the calculations can happen within the time the software is buffering and then it won't cause any delays... But when there's A/D/A conversion into the equation gets larger, as then there are several stages of buffering and converter delay and then the total latency gets much worse...

I never monitor through software, always from the audio card (I'm using an RME card at the moment, though that will change as I go portable) so the A/D/A conversion is irrelevant. I'm just talking about applying plugs during mixdown, not tracking.

If I can have, for example, two identical tracks, one with, say, Sony Oxford EQ and a compressor engaged and the other with no plugs at all, and they play at the exact same (phase-locked) time, then I'll be happy. If I have to worry about a few ms here or there, that's not going to work.

I'm assuming, then, that no matter what kind of plug-in I add, there's going to be some audible delay that I'll have to adjust for?

[Geert van den Berg]

Only a few plugins will have such a large latency (20ms), some linear phase EQ plugins...

if you would use just 2 tracks and apply the same plugs on both tracks but one set to flat then there will be no difference between them and maybe the plugins that you choose have almost no latency anyway (latency is usually only a problem on multi-mic'ed sources, like a whole mic'ed up drumkit, one slight delay on one mic can cause the phase to smear.)

I got your point of instant starting audio, but even if there were like 20ms latency you could always make a seperate mastering session or even just cut the head of the bounce in the original session to 1-3 ms. (you can choose to have the bounced file imported on a track after the bounce, where you can zoom in and do some editting and then re-render it/consolidate, if you want to be assured)

[peeder]

What i do is spend busses on UAD-1 latency. I have aux inputs mapped to busses named "0 plugins" "1 plugin" "2 plugins" "3 plugins" etc. if I'm using more.

I put the DelayComp insert on each bus, with the inverse number of plugins from the total. So if I'm using a maximum of 4 plugins for any track, I will set that value for 0 plugins bus, 3 for the 1 plugins bus, 2 for 2, 1 for 3, 0 (no DelayComp) for 4.

Then I simply select the appropriate output for each track depending on how many plugins that track goes through. I use the click plugin to test that i've got everything in synch.

As i've written, Digi knows how to do automatic latency compensation, they do it in TDM. Virtually all DAWs do it now. Digi just feels its a way of defending their breadwinner, TDM, from host-based solutions like LE and M-powered they consider consumer crap. They will eventually capitulate and provide it in LE, but they will charge $200 for the upgrade and provide in-house plugins you will never use as an enticement.

But I still use LE anyway. Drug pusher tactics work, and hooked me young.

[bodega.]

Originally Posted by Geert van den Berg

if you would use just 2 tracks and apply the same plugs on both tracks but one set to flat then there will be no difference between them and maybe the plugins that you choose have almost no latency anyway (latency is usually only a problem on multi-mic'ed sources, like a whole mic'ed up drumkit, one slight delay on one mic can cause the phase to smear.)

I figured that would be the case, as even a non-engaged plugin would still put the track through its buffer. It's in the case of a track with plugs vs a track with no plugs at all (not with non-engaged plugs) that I'm wondering.

[AlexLakis]

The only native plugins you'll have problems with are some beefy linear phase EQs, multiband compressors, and IR reverbs.

If there's too much latency, Pro Tools will tell you how many samples you're exceeding the buffer size by. Simply press ALT-H to nudge your track over that many samples and you're good! I haven't had to do this for quite some time now, tho, even on tracks with 5 inserts of non-digi plugins.

Lack of ADC for plugins in LE is not nearly as big a deal as many people make it out to be.

[bodega.]

Ah, interesting. Cheers everybody for the responses.

[a2dpapi]

I set buffers as low as possible, but with a modest amount of plugins (especially on a master fader), still sucky?!. With direct asio monitoring I have to mute the tracks I'm recording or not send to master? If an 8 year old tdm system doesn't have this problem....why do I have this problem with a Juiced up athlon 270 quad? If I like Pro Tools and want to avoid this an HD core looks like my only solution? Would I have this problem with another format?

[AlexLakis]

Go to the DUC and make sure you follow all the compatibility instructions. Post on the Quadzilla thread with all of your system specs. If you followed any of the recommended builds, you should be able to get some good help.

[doorknocker]

Originally Posted by bradyvickers

Delay Compensation in Pro Tools LE

A Little Background on Delay Compensation
So you may be asking yourself: Why and when do I need to worry about delay
compensation? The truth is, most of the time you don’t need to worry about delay
compensation. In most mixes, the majority of time you’re mixing unique mono and
stereo sources, which typically are not problematic. The only times when problems
can arise is when you’re working with the same or nearly identical signal sources on
separate tracks—e.g., a pair of bass tracks (one signal direct, the other signal from a
mic’d bass amp/cabinet combo).

Problems can arise when two or more separate tracks with the same or nearly
identical signal sources play back out of sync with each other. Identical or nearly
identical audio signals that are not phase synchronous start to cancel each other out,
resulting in comb-filtering effects which can tend to create frequency response
changes. Using delay compensation correctly will ensure that your mixes stay time
aligned and phase accurate.


This is total BS. Why is he talking about phase issues with amp/DI bass tracks and what has this got to do with PLUG-IN DELAY COMPENSATION IN PT????

[nikki-k]

Hi!
PT LE has delay compensation, but only up to the buffer size used. Since there is NO difference whatsoever between mixing at 64 or 1024, it works very well for most mixes.

UAD1 and Powercore would be notable exceptions, since they suffer from immunity to this situation.

As far as tracking latency, it is quite simple: use Low Latency mopnitoring. Plugins shouldnt be a problem...if you HAVE to use something, use outboard...cheap boxes are everywhere. Used properly, life becomes easy.

LE may be a PITA for some things, and Digi's business plan might irk some people. But, at least you dont have to degauss!