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Logic 9 Performance question

iMatt

Member
Messages
366
A have a question for any Logic 9 users amongst you.

Just bought myself Logic 9 having not played around with computer recording for a good few years.

Just giving it a first go today and using Amp Designer I have got 5 tracks running - 4 guitar/bass tracks all running different amp designer "rigs" (picked from the presets) and 1 midi drum track.

My CPU meter is constantly in the red and playback keeps stopping with a warning that either my hard disk is too slow or I have a performance overload.

I am running Logic on a pretty new iMac with 3.06GHz processor and 4GB of Ram. Does it seem reasonable that I am running into problems with so few tracks or does this point to some other issue with my set-up.

Hope someone out there has an answer.
 

stratology

Senior Member
Messages
1,497
Not a Logic user, I use DP. Try to increase the latency, and see if there's an improvement.

Still, even when you use processor intensive plugs, CPU peaks with just 4 channels should not happen on a machine as powerful as yours. Do you have any user log in items, things that run in the background, antivirus SW, Little Snitch, Growl etc? Don't know which audio interface you use, make sure you have the latest drivers.

To isolate log in items etc., you can try a safe boot (hold down the Shift key while booting).

To isolate an issue with your audio interface, play the tracks using the internal sound card only.

It may also be useful to open Activity Monitor (show all processes), to get a better idea where the CPU peaks come from.
 
Messages
3,625
If you are getting warnings re hard driver performance it would suggest you are recording onto the main system hard drive.

It might be worth trying an external hard drive.

For best performance you would want to look at at a fast firewire 800 interface that is a 7200 rpm spin speed.

That would probably help.

Digidesign do not support recording on the system drive under ProTools, so the same logic (bad pun) should apply to Logic.

Cheers

BMF
 

MeMota

Member
Messages
934
I'm only learning myself but hit on this.

I record to my internal drive with no real problems any more.

From memory, what I did to fix was:

Under preferences go to audio
General tab: I have a MOTU ultralite and set buffer size at 128. I think this was the biggest improvement (affects latency)

General tab: play with plug in latency. compensation "all" works for me (have not checked low latency mode)

The apple help built in is frustrating. Google the error message (copy the exact text) and you'll find the answer on dedicated forums with no problems

Good luck!
 

LSchefman

Member
Messages
13,432
There is an incredibly simple fix to try, and it's built into the software. Track freezing in Logic is one of its best features.

Start by freezing the amp designer tracks. Amp modeling software is heavy on computer resources, so that's one thing that will free them up. Track freezing is incredibly simple and fast in Logic.

It IS a good idea to record to a separate disk. Even the midi drum track (if it comes from software on the computer) is trying to operate the drum samples and record to the same disk, at the same time. That's slowing it down, too. I'd freeze that track as well. You can always unfreeze a track and work on it later if things need tweaking.

Definitely record to a separate firewire disk if you can afford one. It will help.

Logic 9 is fairly processor and memory hungry. Five amp models and a midi drum set running at the same time from the same hard disk and CPU is a lot of stuff for a laptop to handle at once. That's why freezing tracks to free up resources is good planning with anything less than a state of the art computer running the latest recording software. And it doesn't hurt a thing.
 

iMatt

Member
Messages
366
Thanks all, I appreciate the time you have all taken to provide some help.

I have not yet explored all of the suggestions. But starting with some of the first suggestions I have identified that the audio interface is indeed making a big difference to the demand on the processor.

I am using a brand new Lexicon I-ONIX U22. When I switch to "Built-in" in-put and out-put the demand on the CPI (desk top iMac by the way) is substantially reduced and I don't get the problem. For this comparison I simply played back the project (since the built in input is not really suitable for getting my guitar signal in), but even when just playing back the difference is very substantial.

I have just downloaded and installed the most up to date driver and that has made no appreciable difference.

Is this a typical experience when using an audio interface? Clearly I don't want to have to rely on the in-built out-put, and certainly not in-bulit input, but at the moment it seems that the only way I could use the Lexicon is by trying some of the other suggestions that have been made to reduce the load on the CPU.

Before I do anything more I would be very interested to hear if other interfaces are so processor hungry. Though I would be very disappointed to have to get rid of the Lexicon (which as I say is brand new and which I understood to be very good quality at its price point - which is not budget) I would do so if that would make a big difference. By the way details of the interface can be found here:http://www.lexiconpro.com/product.php?id=154 (if you check out this unit you will also see it is very desktop and guitar friendly).

What do you think - do I need a new interface or is this type of CPU demand typical??
 

SteveO

Member
Messages
16,888
I have a PreSonus interface, which definitely closer to entry-level as that goes, and I have no latency problems. MacBook Pro, 2.53GHz, 4GB mem, by the way, and I'm not running an external drive.
 

iMatt

Member
Messages
366
Thanks Steve, but I thought I better just clarify its not a latency problem I'm having its CPU overload.
 

SteveO

Member
Messages
16,888
Sorry, shouldn't have specified latency, I'm having no problems with the CPU, either. If you are using Amp Designer as a plug-in effect on each of those tracks, I do believe that you can convert them to straight audio tracks, where no plug-ins are in use at all and the CPU won't have to use as much horsepower.
 

FractalGarden

Member
Messages
1,827
Five tracks should not be overtaxing your CPU. I still use LE 8 with a G5 iMac and can run literally dozens of unfrozen tracks (on my system hard drive, not an external) without problem. So something's not quite right.

Have you tried muting 1 or more of the guitar tracks? Perhaps the effects on the guitar tracks are the culprit? As mentioned above, checking your audio preferences may be a good place to look as well.
 

iMatt

Member
Messages
366
Muting some tracks does help. However, the issue for me at the moment is to try and get to a view on whether using the Lexicon as the output source, to playback the track, should be putting so much more load on the CPU than the MAc built-in output, which seems to be handling the project fine. I just don't have the experience to know whether this is a familiar story with external interfaces, or whether the problem lies with the Lexicon (or something about the way it is set up in device preferences - which are all still on default).
 

OctalSocket

Member
Messages
460
You shouldn't be seeing a problem with so few tracks, and the fact that the problem goes away when using internal sound might indicate that the buffer settings are too low/small. Increasing these will increase you latency, so make small adjustments to see how far you can go.
 

iMatt

Member
Messages
366
Thanks Steve, I will try that.

Just been tinkering some more, and I apologise for the piecemeal way I am laying out the issues, and my ignorance in Logic, but some other things I have found.

When I open up the meters there are two narrow meters side by side and labelled together as "Audio". Next to these is a single wider meter labelled "Disc I/O".

The overload is on the Audio meter, specifically the right hand of the two side by side meters (not sure what the significance of each individual meter is).

Running with the built-in output the right hand Audio meter gets up just past the quarter way point. Running with the Lexicon this peaks into the red causing the problem

I have (following OctalSocket's comment) fiddled with the latency in the device set-up preferance. If I increase the buffer from 64samples to 128 samples I no longer get the overload problem but - "round trip latency" increases to 13.3ms which seems a bit higher than ideal for recording guitar.

However, even if I could live with the higher latency, the fact remains that the built-in output had no problem with the smaller buffer size. In fact with the built-in output I can reduce the buffer to 32 samples (with latency of only 3.2ms - much lower than really needed) without putting any noticeable extra load on the CPU.
 

LSchefman

Member
Messages
13,432
You don't need to reduce the buffer size to levels your computer has difficulty managing to reduce latency while recording. Logic gives you the option of Input Monitoring to solve the problem of latency while recording. On my system there is no latency I can discern with Input Monitoring on.

I use Logic's default buffer size even on my 8 Core Mac Pro (I think the default is 256), and have no problems recording guitar whatsoever. Have you tried that?

Still, you might consider freezing tracks to solve your problem if you feel for whatever reason that you should be sticking with such low buffer sizes.
 

splatt

david torn / splattercell
Platinum Supporting Member
Messages
26,692
you should not be seeing that kinda lack of performance from that machine.

maybe it's a drive-streaming-issue;
try setting recording/playback to a clean external FW800 drive.
(and, move the audio --- in each of yer Logic Projects --- to that drive, from within each Project.....)

as well, it might be useful (for you) to test yer audio system
after having unmounted any irrelevant USB/FW devices.

q's:
how much ram is in this Mac?
which sample-rate are you using?
did you increase the disk-buffer size in Logic preferences?
what's the OS of yer iMac? do ya have the relevant updates for the OS?
which version # of Logic9 is it?
when was the last time you "repaired permissions" & used "disk utility" on the boot drive?
are you using any 3rg party plug-ins?
do you, perchance, have any other audio applications open at the same time as Logic?

etc etc etc

i'd also suggest posing your question at the LogicProHelp forums;
make sure you have a COMPLETE listing of your Mac's specs,
as well as the version #'s / model names of all the relevant audio software & hardware,
& the type & specs of yer recording media (ie, which drives, which connector, which speeds).

dt / spltrcl
 

iMatt

Member
Messages
366
No I have not yet tried input monitoring - | assumed that would not allow me to hear the amp designer at work. I would struggle (or at least imagine I would struggle) for instance to play a high gain lead with a completely unprocessed guitar signal. Nevertheless I will give that a shot.
 

iMatt

Member
Messages
366
Just seen your post thanks Splatt.

4GB ram, 3.06MHZ dual core, latest Leopard update, latest Logic 9 update, latest Lexicon driver.

Not done the repair and disc utililtiy (ever - machine about 6m old).

Not other applications running, and no third party plug-ins.

Sample rate at 64 was giving the problem, at 128 its Ok (with the current number of tracks), but with in-built output even 32 samples is OK.

Can't guarantee I haven't managed to inadvertantly changed the disk-buffer size - but as I check now I can't quite seem to find that in the preferances, if you can give me a pointer I will have another look.

Just now joined the LogicProHelp forum and will post there as suggested. Will have to wait until tomorrow though, off now to play football (soccer in case you are on the other side of the pond) in sub-zero temperatures. Strongly suspect my own performance is going to be suffering some latency.

Thanks again for everyone's help. It is very much appreciated.
 

LSchefman

Member
Messages
13,432
Yes, with input monitoring you will hear the processed signal.

32 is not enough buffer with most systems, certainly not enough with a laptop using an internal drive. As I said, try 256, and try freezing tracks if you're running into CPU problems. You should not hear latency with these settings, unless your ears are somehow more golden than anyone's I know.

Which is possible, but...
 

iMatt

Member
Messages
366
Yes, with input monitoring you will hear the processed signal.

32 is not enough buffer with most systems, certainly not enough with a laptop using an internal drive. As I said, try 256, and try freezing tracks if you're running into CPU problems. You should not hear latency with these settings, unless your ears are somehow more golden than anyone's I know.

Which is possible, but...
Thanks for this.

Having played around further I find that although buffer size and latency are obviously related, the relationship is different depending whether the audio device is set to built in or the Lexicon interface.

Using the Lexicon with the buffer set to 256 I do not get any CPU overload so thats good. The devices box in the audio preferences shows that at this setting the "round trip latency" is 21ms - which I can convince myself I can just about hear/feel if I concentrate (am I imagining that or would you expect to detect latency of that order - I certainly haven't got particular "good" ears).

However, if I set the audio device to "built in", then with the buffer again set to 256 samples, the "round trip latency" is quoted at 13.3ms (compared with 21ms for the same buffer size using the Lexicon). I can't directly test how this feels because I can't get my guitar signal in without using the Lexicon interface. To get the same quoted latency of 13.3ms using the Lexicon I need to drop the buffer size down to 128 samples (at which point I really can't detect the latency).

So, I find two things when comparing the Lexicon with the built-in audio:

1 On playback, and with the buffer set the same in both cases, the Lexicon loads the CPU much more than the built-in; and

2 Regardless of load on the CPU, if the buffer is set the same in both cases the quoted "round trip latency" for the Lexicon is higher than for the built-in audio.

Are these effects related? Is this "normal" when using an outboard USB interface?

Bottom line is that following some of the good advice posted here I can certainly use the Lexicon without any real problem, but it still does not seem satisfactory if there are other interfaces that would not give the same "problem" - enough so that I would swap the Lexicon rather than "work around" the issues.

I have sent an email to Lexicon support today so will see what they have to say, but any further insight you may have would be very welcome.
 




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