Linear Phase EQ and Latency?

Do you have plug-in delay compensation on?

PDC is currently set to Audio tracks and instruments.
If I set it to 'All,' things get even weirder.
Inserting the LPEQ isn't an issue anymore, but
playing any audio instrument exhibits massive
latency.

this is normal. if you've got a linear phase EQ on anything, and you set PDC to 'all' or even to audio tracks and insts, then your audio instruments will play live with huge latency.

but where are you using the linear phase EQ? on an audio track, bus or master out?

well yes you can use it that way.. but you'll just have to start toggling it on/off and changing PDC settings when you want to continue playing audio instruments. PITA, but not impossible. otherwise, why not use a different EQ, like the highly recommendable sonalksis SV517.. very good sound, and being as the english lads that design sonalksis plugs are actually timelords from dr who, none of their plugs ins introduce any latency at all. it's actually not that hard, given the 11 dimension postulate underpinning quantum mechanics. I mean for pete's sake, do no other plug in manufacturers even bother to implement this stuff??

I found the same problem with the Linear Phase Time-Shifting EQ.

Hi all,

This weekend I am posting results of Plugin latency tests on my website.

I have already tested the Linear Phase EQ,and it did NOT exhibit ANY latency.Under any I/O buffer settings.So I think some of the myths and unknowns about the Logic plugin latencies will be laid to rest when I'm done testing.

I am desgingin another test which will include different audio material,not just a click.I am planning to include pink and white noise,and different short complex audio materials too.Like 5 seconds of a full mix,and a full frequency sweep.

So the latency problem the OP posted,is probably due to changing the songs' latency handling.This is a HUGE no-no. It has bitten my butt a couple of times in the past.I now have the latency compensations ALWAYS set the same,ALWAYS,and I NEVER change it,especially after having recorded audio in the song.This guarantees me that if there is timing issues,it is not because of latency compensation.

Cheers

I do have to say that after I read a different post where Brent praised the sound of the linear EQ, I tried it out on a bunch of tracks I was working on and it added lots of latency to my kick...almost enough to be considered a slap back delay. Bypassed and it was gone.


It does sound nice though.....
X

noeq,

OK, would you have time to do this test to check something out about the linear phase EQ?

track 1 = audio region + Sample Delay (link=on)
track 2 = audio region + Linear Phase EQ + Gain Plug (set for out-of-phase)

(levels, pannings, outputs the same)


TEST#1
• Set all plugs to bypass except the gain/phase rev. plug
• Play back the tracks. They should cancel. Do they?


TEST#2
• unbypass the Linear Phase EQ
• Play back the tracks. Do the tracks still cancel? If not, do Test #3


TEST #3
• Play back the tracks, sample delay = unbypassed. Click/hold on the numerical value (not the slider) and drag the mouse to increase the value until the tracks cancel. What's the value?


-=iS=-

Hi iSchwartz,

I'm going to devise a test whereby we can in fact tell whether there is the latency in the plugins or not.

The OP said he was experiencing latency with audio instruments,so I am thinking of adding that to my test as well.
And I will still record out and back in,to make sure there is no latency due to other factors (Record Latency,etc...)

I will post on my website EXACTLY how to reproduce the test,as well as Logic song files,etc...it will take me some time,but it will end up debunking myths and misconceptions about latency once and for all,at least that's what I hope.

I notice different posters use different Latency Compensation settings.
I will experimtent on a few of the tests wiht the different settings,but only after going through the setting of compensating for ALL,which is what I always use.This way I will have One benchmark,and then I can start in on the overall changes when Latency is NOT set to "all".

After this is all done,I will drink liberal amounts of Tequila,and rejoice.

Cheers

Thanks for the input, noeq.

You're weclome Brent

For the record, the latency issue started before
changing any settings. There's also no recorded
audio in the session file, all of it is soft-synths
and samplers.

I am devising a test for the synths only...without any audio in the session.I'll keep you posted on what I find.

Are you suggesting that PDC should be off to avoid
the latency issue?

At this point I am not suggesting ANYTHING.so please don't change your setup until you can find out exactly why the latency happens.By Sunday I'll have results of my tests for you to look at.

I don't think it's just my issue or a myth,
especially since tbird, iS and X all posted as having
the exact same issue with the LPEQ.

I'll be looking into this.So far with my only test,to determine default latency of Logic Plugins only,I have found it to be the case that the GuitarAmp Pro and the Space designer reverb DO have different latencies,after all other latencies have been accounted for.The Linear Phase EQ in this particular test,came out to have no latency.

Perhaps it will be a different result when I do the synth-only test.

But until I do the test,I cannot know.

Here is one of my favorite quotes,from aristotle:

"We suppose ourselves to possess unqualified scientific knowledge of a thing, as opposed to knowing it in the accidental way in which the sophist knows, when we think that we know the cause on which the fact depends, as the cause of that fact and of no other, and, further, that the fact could not be other than it is. Now that scientific knowing is something of this sort is evident-witness both those who falsely claim it and those who actually possess it, since the former merely imagine themselves to be, while the latter are also actually, in the condition described. Consequently the proper object of unqualified scientific knowledge is something which cannot be other than it is.”
— Aristotle, Posterior Analytics (Book 1 Part 2)

Cheers