LOGIC PRO LATENCY: WE ALL HAVE A PROBLEM

[Lefrançais]

Hi,

I Spent a few hours doing tests on logic pro because after bouncing audio tracks I always had the feeling that my songs' groove was "moving" in a weird way.
Here is how I made the tests:

I choosed an Audio Drum Loop and a Bass Virtual Instrument and made several bounce of each other applying different plugins (Native AU plugins, UAD AU plugins and Logic plugins). I also tried several combination of plugs on audio tracks, bus and master.
The goal is to show how we lose rythm precision when bouncing on logic and proving
the "latency reduction option" we have in Preference -> Audio menu works bad.

Test 1: Drum Bounce with Latency Option "Off".

-Track 1: Drum Loop
-Track 2: Bounce of the Drum Loop with PSP Mixpressor AU Plugin on the audio track.
-Track 3: Bounce of the Drum Loop with Waves Ren Compressor on the audio track.
-Track 4: Bounce of the Drum Loop with Logic Space Designer Reverb on the audio track.
-Track 5: Bounce of the Drum Loop with Logic Space Designer Reverb on the audio track and PSP vintage warmer on the Master Bus.
-Track 6: Bounce of the Drum Loop with Logic Space Designer Reverb on the audio track and Logic Multipressor on the Master Bus.


Test 2: Drum Bounce with Latency Option set on "Audio Tracks, Instruments"

-Track 1: Drum Loop
-Track 2: Bounce of the Drum Loop with PSP Mixpressor AU Plugin on the audio track.
-Track 3: Bounce of the Drum Loop with PSP Mixpressor AU Plugin on the audio track and PSP Vintage Warmer on Master Bus.
-Track 4: Bounce of the Drum Loop with Waves Ren Compressor on the audio track.
-Track 5: Bounce of the Drum Loop with Logic Space Designer Reverb on the audio track.
-Track 6: Bounce of the Drum Loop with UAD 1176 plugin on the audio track.
(What is weird on this track is that the second drum hit is on the right beat position!)
-Track 7: Bounce of the Drum Loop with UAD 1176 plugin on the master Bus.



Test 3: Drum Bounce with Latency Option set on "ALL"
The Drum Loop Audio track is routed to Bus 1.Plugins inserted on Bus 1.

-Track 1: Drum Loop
-Track 2: Bounce of the Drum Loop with Wave ARTS Multidynamics on Bus 1.
-Track 3: Bounce of the Drum Loop with UAD 1176 on Bus 1.
-Track 4: Bounce of the Drum Loop with UAD 1176 and Logic Space Designer Reverb on Bus 1.
-Track 5: Bounce of the Drum Loop with UAD 1176 on Bus 1 and PSP vintage warmer on Master Bus.
-Track 6: Bounce of the Drum Loop with Waves Ren Comp on the audio track, PSP Mixpressor on Bus 1 and PSP Vintage Warmer on Master Bus.



Test 4: Bounce of a Bass virtual instrument (NI Hardcore Bass) with Latency Option Off

-Track 1: Bass, virtual instrument track.
-Track 2: Bounce of the virtual instrument track without plugins inserted on the track.
-Track 3: Bounce of the virtual instrument track with PSP Mixpressor inserted on the instrument track before bouncing.
-Track 4: Bounce of the virtual instrument track with Logic Space Designer Reverb inserted on the instrument track before bouncing.
-Track 5: Bounce of the virtual instrument track with Logic Space Designer Reverb inserted on the instrument track and PSP vintage warmer on the Master Bus before bouncing.


Test 5: Bounce of a Bass virtual instrument (NI Hardcore Bass) with Latency Option set on "Audio Tracks, Instruments"

-Track 1: Bass, virtual instrument track.
-Track 2: Bounce of the virtual instrument track with PSP Mixpressor inserted on the instrument track before bouncing. (Notice that we don't have the first bass note ! bounce made between 5 and 7 bar)
-Track 3: Bounce of the virtual instrument track with Logic Space Designer Reverb inserted on the instrument track before bouncing. (Note 1 is still missing)
-Track 4: Bounce of the virtual instrument track with UAD LA2A inserted on the instrument track.
-Track 5: Bounce of the virtual instrument track with UAD LA2A inserted on the instrument track and PSP vintage warmer on the Master Bus before bouncing.
-Track 6: Bounce of the virtual instrument track with UAD LA2A inserted on the instrument track and UAD PULTEC on the Master Bus before bouncing.

[Lefrançais]

Test 6: Bounce of a Bass virtual instrument (NI Hardcore Bass) with Latency Option set on "All".The Instrument track is routed to Bus 1.
-Track 1: Bass, virtual instrument track.
-Track 2: Bounce of the virtual instrument track with UAD 1176 inserted on Bus 1 before bouncing.
-Track 3: Bounce of the virtual instrument track with UAD 1176 and Mixpressor on Bus 1 before bouncing (Note 1 Bass Missing).
-Track 4: (To avoid bass note missing on beat 1, I did the bounce befor bar 5 and it worked) Bounce of the virtual instrument track with UAD 1176 on the instrument Track and PSP Mixpressor on Bus 1 before bouncing.
-Track 5: Bounce of the virtual instrument track with Logic Space Designer Reverb inserted on the instrument track, UAD 1176 on the instrument Track and PSP vintage warmer on the Master Bus before bouncing.


Do you have this kind of problems on Protools or Cubase ?

[pan]

[Labs]

I think I need bigger screencaps to get the point..

Gustav

[Lefrançais]

Originally Posted by Labs

I think I need bigger screencaps to get the point..

Gustav

Sorry I'm not good in pictures sizing and if I reduce the size you won't read tracks names

[xist]

I'm not sure I get this test. What are the results you got?

p.s: to resize in a easy way, use this widget:
http://www.apple.com/downloads/dashb...geshackle.html

[HEADROOM]

Some plugins create latency, what helps is to freeze the tracks or even bounce them one by one , reimport them an then do the mix bounce ....

[HEADROOM]

my version is pro 7 by the way

[HEADROOM]

Mac g5.. 2,5 ghz doublepr. with 4 gig ram.....what mac are you using....?

[Lefrançais]

Originally Posted by xist

I'm not sure I get this test. What are the results you got?

When you bounce an audio region with a plugin inserted, the result will be at a different time position. You can not evaluate this time shift, it depends on the plugin nature (logic effect, UAD, etc...) and where it's inserted (audio track, bus, master). I choosed only 2 différent files, drums and bass to simplify the test but for example:
If you have each elements of a drum (Kick, snare etc..) all routed to a bus, and if you insert effect on the tracks and/or the bus. Then, when you decide to bounce the whole drums to get stereo reduction, each elements will be in a total different time position...the rythm groove will be changed.

[Lefrançais]

Originally Posted by HEADROOM

Mac g5.. 2,5 ghz doublepr. with 4 gig ram.....what mac are you using....?

Logic pro 7.2.2, G4 2X867, 2Go Ram, but the latency or bugs shouldn't be proportional to the CPU power !

[HEADROOM]

not sure bout the cpu power..... you dont think it could play arole....i dont have this problem.....

[HEADROOM]

just reread your example.....
the univ audio is known to create latency....thisplug in in a bus combined with direct signal........cant work

[Lefrançais]

Originally Posted by HEADROOM

not sure bout the cpu power..... you dont think it could play arole....i dont have this problem.....

Did you do a test ?

Originally Posted by HEADROOM

just reread your example.....
the univ audio is known to create latency....thisplug in in a bus combined with direct signal........cant work

The logic latency option in Pref menu is there for UAD and Powercore users, you can set it on "ALL" or "audiotracks, instruments" or off.

PS, edit your post instead of consecutive multipost, thx

[HEADROOM]

sorry gotta go ill be back to you.....interesting subject

[pan]

Originally Posted by HEADROOM

....i dont have this problem.....

LOL

[adzski]

Logic STILL has the cartoon graphics waveform display in the arranger??????

[u b k]

well, i'd expect verb tracks to start a little later, esp. if there's predelay. also, the space designer has its own button for latency compensation... not sure why, but it's there, make sure it's checked.

the other tracks, though, this is troubling. i've yet to upgrade to 7, i'm mad at apple, but i was thinking i'd cave soon. this may put me off though, can anyone else confirm or deny (with screenshots) whether this is happening to their audio?

it's not clear to me whether this problem is in playback or in the bounce. have you routed a physical output directly back in to your converters and recorded it to see where it lands? that would clear up where the problem is happening.

also, are the results the same with realtime vs. offline bounce? what about the export tracks feature, same deal?


gregoire
del
ubk
.

[Ashermusic]

If you use latency inducing plug-ins like the UAD-1 on busses and auxes etc. you must set Logic's PDC to all. The problem is when you bounce the files they will all have some blank audio created at the beginning of them which is a giant PITA for those of us who work to picture.

All I can say is that the Logic developers are well aware of this issue and the unhappiness of people like myself about it.

Logic Certified Trainer

www.jayasher.com

[Lefrançais]

Originally Posted by u b k

it's not clear to me whether this problem is in playback or in the bounce. have you routed a physical output directly back in to your converters and recorded it to see where it lands? that would clear up where the problem is happening.
.

I'll do the test. But I'm afraid to get new other issues...If all audio moved exactly the same after bouncing, I wouldn't worry, it could be a buffer problem maybe. But the positions are different according to the latency amount the plugin brings.

also, are the results the same with realtime vs. offline bounce? what about the export tracks feature, same deal?

I'll try that. All bounce I made are offline.

[Lefrançais]

Originally Posted by Ashermusic

If you use latency inducing plug-ins like the UAD-1 on busses and auxes etc. you must set Logic's PDC to all.
www.jayasher.com

I know that but by the way, in this case if you have external midi synths, devices, you can't play/playback them without a huge latency ! I didn't found how to calculate this latency, I have to apply manual latency on each midi track to be synchro with audio and instruments tracks....another bug !

The problem is when you bounce the files they will all have some blank audio created at the beginning of them which is a giant PITA for those of us who work to picture

It's a problem for everybody.

[theblue1]

Originally Posted by u b k

[snip]...

it's not clear to me whether this problem is in playback or in the bounce. have you routed a physical output directly back in to your converters and recorded it to see where it lands? that would clear up where the problem is happening.

...[snip]


gregoire
del
ubk
.

This can be a valuable test to make sure your overdubs (or out the box bounces) line up properly.

Of course, you want to make the test as simple as possible, using a previously recorded audio track to do your "loopback" test. (No plugs, VIs, PDC, etc.)

In a perfect world, routing the output of track 1 into the input of track 2 (avoiding source monitoring so as not to set up the feedback loop from hell) would result in a copy of the track that begins on the same, precise sample address. (Use an easily identifiable transient -- even the lead edge of a square wave -- to make it easy to compare.)

But in the real world, many if not most hardware devices and their drivers do not report the precise amount of "alignment compensation" required to get true temporal alignment of existing and new tracks. (Based on a number of anecodotal reports based on loopback testing.)

On my own MOTU 828mkII rig this "misalignment" comes out to about 8 ms (at 44.1) behind -- independent of which of my two DAWs I use. (When I use Mackie Tracktion, it has a calibration and auto-alignment tool that will automatically measure and adjust for this systemic "misalignment." When I use Sonar 5, it does not, and I nudge my tracks forward by the appropriate amount of samples (355). Sonar 6 supposedly has some form of alignment comp. Or something. I've been putting off upgrading 'cause it seems like there's always somewhere else to put my money these days.) [It's my understanding that Cubase's hardware compensation and ping loopback calibration utility can be used similarly to Mackie Tracktion's track alignment utilitiy.]

[pianoman]

Originally Posted by Lefrançais

I know that but by the way, in this case if you have external midi synths, devices, you can't play/playback them without a huge latency ! I didn't found how to calculate this latency, I have to apply manual latency on each midi track to be synchro with audio and instruments tracks....another bug !

It's a problem for everybody.

There's a discussion in the UAD-1 manual, p.44, of the settings for compensating for MIDI. I mention this not as a user but as a prospective purchaser who's trying to get educated before spending $. Also, my screen capture skills aren't quite up to posting with a small enough file size. The gist, though, is that the host application is supposed to compensate for UAD-1 audio delays for audio tracks, but not for send/group/bus. In that event one is supposed to use the "track advance plug-in" which is supposed to act like a reverse delay compensation. At least this is what the manual appears to say....

Is your experience consistent with or different from this statement from UAD? And sorry if I'm muddying the waters as not an experienced user.

[Lefrançais]

I posted this thread in So much gear, so little time because I saw this tread :
PRO TOOLS HD LATENCY VS. LOGIC 7 PRO was not in Music, computer section ....don't know why mine is moved and not this one, maybe mine is less interesting haoouuu

[paddo]

Looking at your sreenshot you made the test with all the plugs on one channel in bypass and popped the plugs in one at a time.Could be some funky shit happens when you do this,i,ve noticed if you do this and dont stop and start the track it doesnt like it.As a rule to avoid any latency problems i always give logic a double click on the stop button and it seeme to be fine.But having looked at your post i will certainly be checking a bit more often.


Cheers paddo.

[arimaka]

Originally Posted by paddo

Looking at your sreenshot you made the test with all the plugs on one channel in bypass and popped the plugs in one at a time.Could be some funky shit happens when you do this,i,ve noticed if you do this and dont stop and start the track it doesnt like it.As a rule to avoid any latency problems i always give logic a double click on the stop button and it seeme to be fine.But having looked at your post i will certainly be checking a bit more often.


Cheers paddo.

VERY TRUE!!!!!

[hbj]

I cannot repeat this.

I've tried running

1) track->plugs->vbus->another track

2) and track->plugs->track bounce->reimport

and I'm getting no latency anywhere.

Am I not doing something right to replicate your results?

[hbj]

Also, a 4 plugin track export I did through the VBus and another I did through a track bounce came back in perfect phase. That's refreshing to know!

I'm glad you got me checking this stuff, because (so far) I'm very, very happy with what I'm seeing. I'd be curious what others' experiences are.

Do let me know if I need to do something different to replicate you results though.

[barryjohns]

This post is confusing!

[Ashermusic]

Originally Posted by hbj

I cannot repeat this.

I've tried running

1) track->plugs->vbus->another track

2) and track->plugs->track bounce->reimport

and I'm getting no latency anywhere.

Am I not doing something right to replicate your results?

It is only a problem if you are using plug-ins that introduce latency like those on DSp cards or Logic's Ad Limiter and with some midi hardware. If all you are using are Logic plug-ins and virtual instruments you will not have a problem.

Logic Certified Trainer

www.jayasher.com