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trying to understand latency compensation Keyboard Controllers
Old 8th September 2007
Gear Nut

trying to understand latency compensation

I've been reading on this site, and searching about latency compensation. I'm not quite sure if I'm understanding a few things about it.

If I'm mixing in the box (the only outboard gear I have are mic pres), do I have to worry about latency compensation? When I'm bussing to an aux track in the box, should I worry about it?

Or does this latency only come from outboard effects and out of the box mixing?

I just want to make sure I'm not setting myself up for crappy mixes everytime
Old 8th September 2007
Lives for gear
poncival's Avatar
In Pro Tools at least, Delay Compensation is there to make up for the latency imposed by plug ins.

The simplest way to look at it is, if you have no plug ins, no tracks are delayed.

If you insert 1 plug in on 1 track and it has a latency of 50 samples, all the other tracks are delayed by 50 samples so that the 1 track is not late.

If you insert another plug in with a latency of 100 samples on another track, all the tracks are now moved back by 100 samples, except the one with the other plug in on it, which is only moved 50 samples. The track with the 100 sample plug in is not moved at all. If you are using hardware inserts, they may have a latency which the delay compensation should accommodate.

The main reason you would want to do this is to keep the phase relationships the same as they would be without the latency. For example, if you insert a Waves Rennaisance EQ 2 on your "Snare Top" track but not on your "Snare Bottom" track, your snare top track will be delayed by 3 samples relative to the snare bottom.

This may sound ok and heck, might even sound better than it would be if it wasn't 3 samples later, but the bottom line is that it is different, by 3 samples, which is significant enough to cause some comb filtering.

You should try mixing a song with it turned on and get things sounding the way you like them, and then try turning it off and seeing what it sounds like- depending on how many plug ins you are using and how you are using them (and what kind of music etc.), the difference may be pretty drastic.

As far as In the box vs. out of the box, I think you would be most concerned with delay compensation while mixing IN the box, with no outboard gear and only plug ins, which seems to be your situation.

Good Luck!
Old 8th September 2007
Gear Nut

thanks for the detailed response!

Does Pro Tools LE feature delay compensation? Or is it only the HD system?

So if I'm using Pro Tools, I won't have to worry about delaying tracks because it does it for me? For instance, that example you gave about the snare top and Pro Tools, the 3 sample latency would be compensated for, correct?

Just making sure I'm completely clear. thanks!
Old 8th September 2007
Deleted User
LE doesnt have it bro, only HD. You have to MANUALLY shift everything.
Old 8th September 2007
Lives for gear
poncival's Avatar
I work on HD so I am not sure about LE. Maybe someone else can chime in who has experience with this on LE. I do know you have to "turn on" delay compensation as part of the playback engine in HD so maybe you can check that out in LE under "Setup".

If LE doesn't have Delay Compensation (which now that I am thinking about it, I don't think it does), you can do it the old fashioned way...

Make your mix as you usually would but every time you add a plug in, check its latency by apple-clicking in the volume digit window on the mix page (where the green number is which says what the fader is set to. Two clicks will show you the number of samples of latency- check the manual on this one for more info).

Once you find the latency (say 3 Samples as in the above example), select ALL (Apple-A) on the track with the new plug in. Set your "nudge" size to 1 sample and press the minus key on your keypad 3 times (or set "nudge" to 3 and press it once... you get the idea) You may need to chop off some dead air at the beginning of the track to be able to move it towards the left.

This way, the track is actually playing earlier than normal but the latency causes the sound to come out at the right time. This is a simple example but it can get complicated at times. If I do this for this reason (which is rare) I will put a note in the comments for that track about how far I nudged it in which direction and why. If I take off the plug in, I have to nudge it back in order to get things back the way they are supposed to be.

I mostly mix outside the box and don't use too many plug ins other than for special effects etc. so I don't worry about delay compensation too much. But once in awhile I run into a situation where I duplicate a track and put a filter on it and bring it up on the next fader... So I have the "dry" track coming out of one output, and the filtered track coming out the next output.

When I blend these together at the console, there is some latency between these two tracks. Even 3 samples will cause a little comb filtering which will be unpredictable at best. It may "work" but probably not- so why worry? Just fix it so you know the two tracks are in phase. In this situation it may be easiest (at least for a quick test of the effect and to keep things nice and obvious for later recalls etc) to put the same plug in on the "dry" track and put it in bypass. In Pro Tools, at least, a bypassed plug in still has latency.

Another point to all of this is that you mainly need to concern yourself with latency and delay compensation with dynamic processing like EQ's and compressors, filters, that type of thing which doesn't naturally cause the sound to come later like delays, chorus, etc... When the plug in makes the sound come out 10 or 20 ms or more later (and is constantly changing that amount), the 10 or 20 samples doesn't make that big of a difference all of a sudden.

Wow, I can't believe I've actually thought about this stuff this much... Thanks for reading all this! I guess I am really killing some time here. Too bad there's not a "delay compensation" for time spent on Gearslutz- like somehow I get this 1/2 hour back later in the day!
Old 8th September 2007
Gear Maniac

LE has limited delay comp. It works fine for some things and not so fine for others, but it is there.
Old 8th September 2007
Lives for gear
poncival's Avatar
One reason I haven't messed with Delay Compensation in HD too much is every time I have tried it, either my G5 crashes or tracks keep playing after I press stop, etc... So I haven't wanted to use it for a client for fear it would blow up in my face.
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