Latency with HD

[mixer]

every disk system has latency..in fact every system has latency

[digi2000]

Yes, there will always be latency but it is very manageable and very unnoticable in most cases. That said, when setting up a recording session try to avoid putting any plug ins on the master fader especially not MAXIM as that way you are guaranteed to get a very prominent latency problem. Found that out the hard way. The only time the latency is really an issue with HD is with certain plug ins depending on the complexity of the processing. Most Pitch Plugs induce very serious latency and nudging is absolutely essential to gettting the audio back in line with the track.

Hope I answered the question.

[pookadilly]

This sort of answers the question but not really. First off, I know about the plugs on the master fader thing. That would only be done when mixing (in my recommendations at least) so it doesn't matter if they introduce latency or not.

The real question here is in native systems you have to set your buffer size and depending on what it is set to you introduce x amount of latency into the audio chain.

For example when I record on a native system I do so with a buffer setting of 256 (128 if there's enough power to work with) to try and make things have very little latency (most of the time absolutely unoticeable to the artist).

The question is does PT HD work the same way? I was under the impression that since everything runs on the cards there was no need for various buffer settings and nudging. I mean if I use a reverb as a send effect and have multiple channels sending audio to that reverb and then use a different reverb somewhere else in the chain, etc. are the tracks going to need to be delay compensated or something?

I thought the whole idea behind PT, especially HD, was to have a near 0 latency solution as compared to the problems of a native setup.

Thoughts?

[pookadilly]

Just out of curiosity I thought I'd pose this one to the group to get the response of multiple engineers working with the new HD systems.

When running HD plugs only is there any latency when recording and/or mixing? The issue that was posed was recording at 88.2khz and being able to completely mix things inside the box.

Apparently some people are asking due to the Powercore/UAD-1 cards used on native systems (don't reply with explanations on the latency regarding these, I already know all about it, I was just stating the reason people were asking me).

So, latency or no latency? What's the verdict?

[digi2000]

Ok in short here is the answer to the question.

The latency on HD rigs is unnoticable (depending on plugs)

It is certainly much beter than Native systems.

[undertone]

The latency during record with ProTools is between 2 and 2.5 milliseconds AFAIK. If you listen to your outputs through a analog or digital mixer, you might have to add somewhere between 1.5 and 2.5 milliseconds. (The best possible latency during record with a fast PC or Mac (with OSX) is around 4 - 5 ms)

[tvent]

I know this has been covered before, but TDM based plugins have their latency measured in SAMPLES, not milliseconds.

I know there are some TDM plugins that have enough samples to actually add up to milliseconds, heck the analog to digital conversion can add up to milliseconds depending on the interface you are using. But most TDM plugs only cost a few samples.

Looking at the stock digirack plugins for example, most all of them have an induced delay of 4 samples. How long this actually is depends on what sample rate you are recording at. The higher the sample rate, the shorter the actual amount of latency you experience.

At 44.1K, one sample equals about 22 microseconds or .02 milliseconds. So 4 samples just cost you right about .88 milliseconds. Just so you know, .88milliseconds is just about how long it takes sound to travel 1 foot. Therefore, having 4 samples of delay is no different than having one of your mic's about a foot back from the other one and this is usually less than the difference in time that music reaches your ears from the left and right speakers in your car.

At 88.2, this phenomenon is cut in half so 4 samples would cost you right about .044 milliseconds or so (but who's counting [img]images/icons/wink.gif[/img]

As far as comparing this to plugins running natively on a host based system - yeah, it seems everyone claims there plugins introduce no added latency to a host based system, BUT - what is the latency of the host based system??? That is where the buffer thing comes in and I find it unusable for truly monitoring and mixing "in the box" regardles of whose software you run on what kind of computer. Even at the lowest buffer setting (128) you are still looking at a few milliseconds (2.9) of delay (not counting the delay introduced by the converters)

Soooo, want to RECORD and MONITOR with software based effects while playing and do it all in the box - currently the only practical way to do this is with a TDM based system. Believe me, I have tried to cheat it. Maybe this audio units thing with OSX will change the game a bit, but I will definitely have to see (hear) it to believe it.

[davip]

There is no buffer setting to reduce the small latency of TDM plugs. Except for a few plugs the latency is so small that it won't be noticed by the artist. In some cases if the artist is tracking and monitoring his own track through plugs as well as directly they may hear a little bit of comb-filtering. To avoid this I usually deactiveate any plugs on the track I'm recording, especially if it's a vocal.

[edhamilton]

Joshua,

The guys were giving you a very technical answer.
In real world use tdm systems do not suffer the latency problems that native systems have to deal with.
No changing buffer setting if you use more plugs, no extra mixer to avoid the slap delay issues, etc.

Powercore adds even more latency than just the native system alone. UAD board is a bit better but niether are in the same league as a tdm system.

I can have a full mix up with 32 eqs 32 comps 4 reverbs and record more tracks while monitoring THRU the mixer while using plugs with NO audible latency.
Cant do that on a native system.

The obvious thing to watch out for is that certain plug ins (waves mastering) do indeed take a lot of time processing and thus there is latency. These plugs typically were designed for applications that are not real time recording (ie mastering).

TDM feels and sounds just like a hardware (mixer/recorder). Its one of the biggest advantages of PT tdm.

hope that helped

[undertone]

it seems everyone claims there plugins introduce no added latency to a host based system, BUT - what is the latency of the host based system??? That is where the buffer thing comes in and I find it unusable for truly monitoring and mixing "in the box" regardles of whose software you run on what kind of computer. Even at the lowest buffer setting (128) you are still looking at a few milliseconds (2.9) of delay (not counting the delay introduced by the converters)

<font size="2" face="Verdana, Arial">The lowest buffer setting in a good system is 64 samples, not 128. But life is different when you record, because not only do you have to double that , and add converter delays, but you also have to check your system for other delays than those that are "supposed" to be found. You will end up with a total latency around just below 4 ms in best cases, unless you use a setup or setting that bypasses the latency all together...

If you check your TDM system for real life behavior during record, you will also find that you can measure the latency in milliseconds, not only samples - even without plugins. The same is true for mixers (Yamaha 02R is supposed to have a 2.5 ms delay from preamp to output, for example).