The skinny on delay compensation...latencies...

[the stranger]

I have always wondered what applications have plug-in delay compensation and which ones don't.

 

Is this a standard by now, or do you really have to watch for this? What got me thinking was the 276 page Pro Review on the Konnect8/24. They had some nice numbers from people testing latencies and Tracktion had some killer numbers.

What sort of advances are being made these days to get digital audio to be as linear as possible when summing at various stages. (If you get my meaning...that all sounds kinda of garbled.)

 

Do you still grin ever so slightly when you use any variation of the term "latent"?

 

That isn't PC, right?

 

And do check out that Pro Review, even if you are not considering purchasing it. That Pro Review has really useful information and makes you see the true potential of that review format. It's awesome. I'm still on page ten.

[blue2blue]

Talking about latency with today's recordists is like putting an elephant, a snake, a tree and spear in a room with three blind men and telling them there's only an elephant...

 

 

There are a lot of interrelated latency issues.

 

There's monitoring latency, the most obvious. But it comes in a number of different flavors: the kind of very short, probably mostly unnoticeable latency of a "near zero latency" digital (DSP) mixer or interface -- that's usually not much more than the time it takes for AD and DA -- probably a ms or two; the latency involved in monitoring through the box... ie, signal from interface, through CPU/DAW software, and back out through the interface -- so the AD/DA latency in addtion to the latency added by a synchronous data transfer buffers in addtion to whatever time it takes the DAW to tranfer data around and process it.

 

Then there's plug in delay latency, which we often try to adjust for by adding an extra delay to other tracks to compensate.

 

Then there's a fairly insidious and, until recently, a widely underrecognized issue of what some call tracking misalignment (new tracks do not line up properly with previously recorded tracks). Sometimes this "latency" is roughly the sum of AD/DA and data transfer buffering -- but devices are supposed to report accurate latency times through their drivers (ASIO supposedly does a better job); unfortunately, most folks I've talked to who actually do a "ping loopback" test to check alignment between existing tracks and new overdubs tend to find that there is an uncompensated misalignment. Happily, more DAWs are offering a way to compensate for this potentially serious problem, whether it's through a semi-automated ping loopback calibration utility (as in Mackie Tracktion and, I think, Cubase/Nuendo) or a simple sample value offset (as in Sonar and Logic, AIUI -- forcing the user to perform his own, hopefully one-time calibration).

 

Hmm... I'm forgetting some stuff...

[Cry Logic]

So it's a minefield?

[blue2blue]

No... it's like an elephant, a snake, and... uh... never mind.

 

 

 

[Cry Logic]

 

"......Happily, more DAWs are offering a way to compensate for this potentially serious problem, whether it's through a semi-automated ping loopback calibration utility (as in Mackie Tracktion and, I think, Cubase/Nuendo) or a simple sample value offset (as in Sonar and Logic, AIUI -- forcing the user to perform his own, hopefully one-time calibration)...."

 

 

How exactly does one perform this calibration in SONAR?

[Jotown]

 

How exactly does one perform this calibration in SONAR?

 

And how exactly does one perform this calibration in Cubase SX3?

 

Thanks in advance.

[blue2blue]

I'm SO tempted to say use the search -- as I've wrestled this particular b

[Anderton]

 

And do check out that Pro Review, even if you are not considering purchasing it. That Pro Review has really useful information and makes you see the true potential of that review format. It's awesome. I'm still on page ten.

 

 

Thanks for that. All the Pro Reviews have some "extras" - for example, the Lynx Aurora pro review has downloadable audio interviews with some of their engineers on the topics of clocking, jitter, and the like. It's fascinating stuff. And in the Discrete Drums pro review, I've included lots of examples including some with their drum libraries doing backing tracks for the Gibson Digital Les Paul. Check 'em out!!!

[Cry Logic]

Thanks Blue for going to all that trouble....

I searched the SONAR help file and found

the info below ... they recommend using the ruler

to calculate the delay......

I was just coming back to post that info but I see you've

already written a very good howto on the subject.

Thanks again

========================================================

 

Record Latency Adjustment (samples)

(From the SONAR 6 help file)

If you loop an audio output back into an audio input, and re-record a track

this way, the audio doesn't line up. For some sound cards, it is off quite

significantly. This record latency adjustment is a compensation for that delay.

 

You can do an approximate measurement of the delay by turning on samples

as the resolution unit in the Time Ruler, and comparing the original track with

the re-recorded track. Then you can enter a value in the Manual Offset field

to compensate.

 

If you use ASIO mode, enter 0 in the Manual Offset field and leave the

Reported Input Latency checkbox checked (this check box only appears in

ASIO mode). This will line up audio in most cases. If you think you can tweak

it closer, use the Manual Offset field.

 

In ASIO mode, the current active ASIO device (remember ASIO can only

have one active at a time) reports its "Input Latency."

You can't edit this value. This supposedly accounts for buffer size, A/D

Conversion latency, etc. The checkbox allows you to use this reported value.

It is checked by default. In any case, the amount entered into the Manual

Offset field will be combined (added to) the reported value if you have it

checked.

[the stranger]

I'm SO tempted to say use the search -- as I've wrestled this particular b

[the stranger]

 

Thanks for that. All the Pro Reviews have some "extras" - for example, the Lynx Aurora pro review has downloadable audio interviews with some of their engineers on the topics of clocking, jitter, and the like. It's fascinating stuff. And in the Discrete Drums pro review, I've included lots of examples including some with their drum libraries doing backing tracks for the Gibson Digital Les Paul. Check 'em out!!!

 

 

Yes, sir!

[blue2blue]

 

(From the SONAR 6 help file) If you loop an audio output back into an audio input, and re-record a track this way, the audio doesn't line up. For some sound cards, it is off quite significantly. This record latency adjustment is a compensation for that delay. You can do an approximate measurement of the delay by turning on samples as the resolution unit in the Time Ruler, and comparing the original track with the re-recorded track. Then you can enter a value in the Manual Offset field to compensate. If you use ASIO mode, enter 0 in the Manual Offset field and leave the Reported Input Latency checkbox checked (this check box only appears in ASIO mode). This will line up audio in most cases. If you think you can tweak it closer, use the Manual Offset field. In ASIO mode, the current active ASIO device (remember ASIO can only have one active at a time) reports its "Input Latency." You can't edit this value. This supposedly accounts for buffer size, A/D Conversion latency, etc. The checkbox allows you to use this reported value. It is checked by default. In any case, the amount entered into the Manual Offset field will be combined (added to) the reported value if you have it checked.

 

 

You know, the funny thing is I dutifully read that when I recently upgraded to Sonar 6 Pro (I waited for the spring sale and saved fifty bucks [thru the end of April, hurry kids!]) ... I didn't even occur to me to cut 'n' paste that in here. D.A. me. (And I don't mean district attorney.)

 

Anyhow... good thing it was fresh in my mind... I think I hit most of the salient parts except the fine points on the ASIO.

 

And, actually, I've now been through it so many times, it's usually easier for me to type out a new explanation than to try to find a previous one.

[the stranger]

Do check out the Pro Reviews, Harmony Central's unique, interactive review format. Even if you are not considering purchasing a particular item under review, the Pro Review format takes audio gear reviews to a new level. How any magazines have thirty-one page gear reviews?

 

In the market for an audio interface? Read a few Pro Reviews and you will be an informed buyer. Find really useful information and see the true potential of this new and exciting review format. It's awesome.

[the stranger]

I'm a latent copywriter.

[Jon Gnash]

 

Hmm... I'm forgetting some stuff...

 

If you want to get really anal - another problem is that sometimes the semiconductor manufactures who make the ADs and DAs do not publish the group delay of their converters. There is nothing the sound card manufactures can do except to try to measure it themselves.