Latency & Recording delay Parameter

Hello everyone. I am wrestling with some minor latency problems. Using a G4 Dual 533 with 1.5 Gigs of Ram with Pro Tools 001 interface with Logic Pro 7.1. In the Audio Hardware and Drivers Dialog there are several settings that can affect latency. I have played with the I/O Buffer size from 64Mb and up. This has not completely killed the latency. Lower settings may be introducing "artifacts" (static pops) (I hear them). I even here them at higher I/O Buffer settings! Minor Latency is still with me. I have tried enabling the "Larger Disk Buffer Setting" and still have minor latency. I do not understand what the "Recording Delay" setting does and if it will affect latency. When switching back to OS9.2 and Pro Tools 001 I have zero latency.

Since making the switch to Logic Pro I am enjoying the use of both processors. I am still struggling with getting rid of the latency issues, static pops (see "Note" at bottom of page 378 in Logic Reference Manual).

Can anyone offer some advice on these issues? I am under the impression that my G4 is powerful enough to be able to handle what Logic needs. Due to these issues it is causing me to have to switch back to OS9.2 and PT 001 to do my recording and then bounce the tracks into Logic as a "work-around."

Thank you for your time and opinions.

Ping

I have the same exact issues with Logic Pro 7. I have G4 tower, dual 1ghz, 2GB Ram and have the same exact latency issues when recording with a mic or line input. When I use DP in OS9.2, there's no latency.

Sorry I couldn't help, I just wanted to sympathize and perhaps help both of us out by bringing attention to the problem.

Ditto

Yo Ditto,

Thanks for the company! I did a search for "Latency" and found some interesting threads. One of them mentions that any "Plugins" on the master bus (Output 1&2) will cause out problem of input latency when using a mic. I have yet to fire up Logic and try the solution. Will try today. See if it works for you. Logic does have some alluring features but, there are a lot of things Pro Tools does with a lot less complication. I am sure in time it will all be improved. I just don't like not getting paid for trouble shooting Apple's design flaws.

Ping

Hi guys,

Latency is not only a factor of the software, but the hardware and drivers as well. Unfortunately, the ASIO (OS9) and CoreAudio (OSX) drivers written by some companies are better than those written by others. Personally, I've had good experiences with MOTU and mixed (at best) experiences with Digidesign under OSX (except when using ProTools, where the Digi hardware is supported directly and is obviously solid). Don't rule out a driver issue, particularily with the 001. Just because a certain driver works under OS9 doesn't mean that its OSX counterpart will perform equally well. They are very different systems.

Buffer sizes are measured in samples, so latency is dependant on the sampling rate being used. As a note, here is the latency you should (ideally) expect to get using different buffer sizes at 44.1kHz:

64 samples: 1.45ms

128 samples: 2.9ms

256 samples: 5.8ms

512 samples: 11.6ms

1024 samples: 23.2ms

As you can see, buffer sizes of 256 samples or smaller should give more-or-less imperceptable latency. I use my iBook G4 (IGHz 512mB) live with a MOTU 828 at 256 samples with no issues whatsoever, and either of your machines should be capable of the same. The only way to really eliminate latency is to set up a hardware monitoring solution. If your hardware doesn't include this capability, you can always split the mic output (use an active mic splitter, rather than a y-cable) and mix it with the main outs of the computer to create your monitor feed. If you do this, turn off "Software Monitoring" in the Audio Hardware and Drivers panel.

It is true that some plugins, particularily on busses and the outputs, can increase latency. This is due to the simple fact that you are lengthening the processing chain within Logic. Still, the latency should not be that severe.

Hope this gives you some ideas...

Thanks Northern! I have been wondering about the Digi Driver. Why would Digi go out of there way to make a driver that allows their competitor (Apple) to flourish with their competing software? As I chose to use my 001 as the interface it was simply because I had one sitting around. It was convenient and cost effective. The real question mightr be:

Who makes the most compatible and functionable interface to be mated with Logic 7.1 and above (future)? Anyone want to express their opinion on that one? Who really has the knowledge based on experience? Anyone?

I will say again, Logic is gonna be great and parts of it are great, but as a new user of Logic and one who comes from a Pro Tools (flawless) environment my intitial impression of Logic is that they released it before it was truly ready and Apple is using our frustrating experiences and discoveries to further the development of their product at OUR EXPENSE!

I do take the time to read many of the posts and it is evidenced by the number of posts that Logic users are dealing with a lot of BUGS! Life (and products) are different these days. In the past (way back: ) when you bought a product, it worked. The testing and development was already done and complete. Not so in todays computer world.

So....i digress. What interface will be the best choice for todays Logic and the Logic versions to come?

THANX,

PING

Ping Pong

Its interesting that you say that Logic was released before it was truly ready- it has been under development by Emagic (prior to Apple's buyout of that company) for something like 15 years! Something to keep in mind, however, is that Logic and ProTools approach music production from very different angles, despite their similarities.

ProTools was initially developed as a digital audio workstation, which explains its obvious strengths in this area. Its audio routing is arguably unparalleled. its MIDI support, however, is weak. Totally functional, but weak. Even its software synth support leaves something to be desired, requiring two tracks (one audio or aux, one MIDI) for each instrument.

Logic, on the other hand, was developed as a MIDI sequencer and is brilliant in this regard. Nothing else comes close, especially when you take the flexibility offered by Environment into account. The audio support was added in a very basic form later on and continues to develop. To get an idea of how far it has come, see if you can get your hands on an old copy of Logic Audio Platinum 4 (circa 1998/99), arguably its first "serious" audio implementation. Depending on your state of mind, you'll either laugh or throw the CD and manuals under a speeding train. Still, it was pretty good at the time.

These differences go a long way to explaining the different market segments supported by each application. Studios and engineers tend to gravitate towards ProTools for its live recording capabilities, while composers tend to prefer Logic because it better reflects the musical tradition (through notation and detailed editing capabilities for all types of MIDI data, tempo and time signatures). In time, the differences will probably diminish, but the two programs' distinct histories will still be apparent (Logic still contains features that were effectively obsolete years ago, just for the few composers who are used to having them).

Enough with the history lesson, on to the hardware issues. As previously noted, I have had great experiences with MOTU hardware with Logic. I use an 828 myself, and have a few clients who use the 2408mkIII and HD192 interfaces. All of them are rock solid and sound really good. They also seem to have pretty broad support among Logic users. I have heard great things about RME, but have not had the opportunity to try their hardware with Logic so I'll refrain from making any judgements.

If I may toss in a shameless plug, I've recently authored a three volume series of DVD tutorials for Logic Pro 7 for ASK Video (http://www.askvideo.com). The point of the series is to distill the main reference manual down to an approachable form (and to correct some of its inaccuracies). If you are new to Logic, these should go a long way to explaining it. Volume one should be available within a month, with the others following shortly thereafter.

In the meantime, I'll continue to lurk around the forums and offer all the help I can. Looking forward to seeing how this thread develops...

......Personally, I've had good experiences with MOTU and mixed (at best) experiences with Digidesign under OSX (except when using ProTools......

Agree entirely, NL.

The drivers for the 828 (Mk1 and Mk 2) and for the 896HD are simply the very

best. MOTU "know" how to write audio drivers - simple fact.

And, they care. Their website is always bang up-to-date with drivers and

tech info.

Any musician who can't work with just under 6mS latency either has a

superfast brain from Betelguese or something, or else they are nitpicking

because they know the figures and can't see past them.

A grand piano has over 20mS "latency" and this doesn't appear to faze

Askenazy when he plays the Beethoven Moonlight ...................

Buffer sizes are measured in samples, so latency is dependant on the sampling rate being used. As a note, here is the latency you should (ideally) expect to get using different buffer sizes at 44.1kHz:

 

64 samples: 1.45ms

128 samples: 2.9ms

256 samples: 5.8ms

512 samples: 11.6ms

1024 samples: 23.2ms

Be careful, that's an oversimplification. Latency = A/D converter delay + driver safety offset + CoreAudio input buffer size + Logic input buffer + Logic output buffer + CoreAudio output buffer + driver safety offset + D/A converter delay.

You can roughly quadruple your figures to get realistic results.

So at 256 samples, you are getting around 20ms latency.

Keep in mind that if in your studio, you sit approximately 6 feet from your monitors, you also get a natural latency (the time it takes for the soundwave to travel from the monitor to your ears) of 6ms. Food for thought

David,

Interesting. Thanks for the correction. Still, even 20ms is hardly a problem in practice. Incedentally, I just did a little experiment with a side stick sample and a delay, and it was only at around the 20-30ms area that I could even begin to notice a difference between the attack of the sample and the onset of the delay.

Okay guys,

I was gonna fade out of this discusiion until.....

I was unaware that I might be from Betelguese. I tried NL's "side stick" experiment down to 8ms. Could easily hear the delay/latency. Super easy at 20ms. Even though I may be able to discern these minor latencies it is the Singer that I am currently working with that complains. Evidently for that person the latency is annoying. As the engineer I am merely trying to please the talent to the best of my abilities. But, I can tell you I hear it and it is quite prevelant at 20ms.

I am looking into the MOTU 896HD. Thanx again for everyone's input.

ping

Alright, I'm going to fade out on this one too, but I should clarify myself first. My honor is at stake.

The sidestick experiment, I can hear a difference well below than 10ms, but a great deal of this is due to the comb filtering that starts to set in. What I'm listening for is an obvious difference in the attack that would affect somebody's ability to keep time. Unless the listener is hearing a mix of both the original source and the delayed signal, latency of 20ms or less will be difficult to discern and would not likely affect their rhythmic interpretation of the music.

In the case of your singer, he/she could very likely be more aware of it because the headphone feed would begin to interfere with what he/she hears coming from his/her own mouth. It is a different situation when playing audio instruments of recording a DI'd guitar, when the source is inaudible. Suffice to say, there is still no substitute for the old fashioned hardware monitoring setup. The MOTU firewire interfaces have it built in.

That's it, I'm done!

....... I was gonna fade out of this discusiion until.....

Nah, don't go away, man ! This is an interesting subject.

When you are folding back for a singer, the problem changes profile slightly.

What the singer wants to hear is his/her own voice without latency (for latency,

read "delay" coz it's one and the same). The only way to achieve this reliably and

repeatably in any studio is with cue-mix from the desk or pre's straight to the

singer's foldback amp and cans. When the main thrust of the studio is software-

driven, this remains the only real solution.

Where the recorded vocal ends up in relation to the singer's perception of what

is "happening" in the track at the time they sang the lyric is largely irrelevant in a software-driven environment. The vocal take can be precisely shifted in the

Arrange window to be anywhere you like, temporally, with respect to the rest of the track. For backings/harms etc, obviously you have to shift it properly

before you do the next take, but that's just experience and craft.

There really is no effective substitute for doing it the "old" way and folding back the singer from a desk or even a group of mults carrying the preamp

outs to the A/D.

I am looking into the MOTU 896HD. Thanx again for everyone's input.

You're welcome. The 896 rocks here. Can't fault it with Pro 7.1 and a dual

1gig G4, and the latest drivers, of course

I tried NL's "side stick" experiment down to 8ms. Could easily hear the delay/latency.

I doubt you can hear a latency of 8ms. I think like the other say, you are suffering from doubling of two audio signals that are 8ms apart. That's different, you would suffer from that effect (comb filtering) even if they were 0.2ms apart.

If you play drums, you can hear your kick drum only 5ms after you kick it.

If you play electric guitar, and you stand 10ft from your amp, you can hear your guitar 10ms after you play it.

If you sing live, and stand 8ft from your speakers, you suffer an 8ms latency.

So as you can see, short latencies like that are not a problem "in themselves".

Logic Pro 7, g4 mirrordoor dual 1ghz, Edirol da-2496

OK, sorry guys that I can't contribute more intelligently to this line of thought; I'm no acoustics guru. So maybe this is a stupid question: how does one measure how much latency you're hearing? Is there a device to measure it? A meter in Logic? To me, either you can hear it or you can't. I've been hearing it since buying Logic and it's pretty annoying.

Even with buffer size down to 64 I can hear it, on vocals, on snare, on everything. And I know I've posted this question to you before, David, and I'm sorry to rehash but I tried what you had suggested before and nothing worked. I know, I know, I'm using a slightly inferior D/A converter in Edirol, but it's a PCI card connection and that "no latency" thing was supposed to be a perk, vs. using USB (keep in mind USB was at 1.1 when I bought the Edirol). It's just dumb to me that with DP in 9.2 there was never a latency problem, but there's always been with Logic. Maybe Edirol's driver in OSX just isn't compatible.

PS: Is it wise to connect USB audio equipment through a USB hub? I don't see any other way, whatwith MIDI interface, keyboard, printer, D/A, etc and only 2 USB ports in the back. What's the best brand of USB hub? I had a Belkin 7-port and it died after exactly a year (they've got that 1-year warranty thing down to a science).

DittoDog, did you try switching Software Monitoring OFF in Logic? In Audio > Audio Hardware and Drivers.

Then you can use your Edirol's zero-latency monitoring feature.

Okay, I said I was going to lay off this thread, but I keep getting pulled back in. This time, just to answer a few of Ditto's questions.

PS: Is it wise to connect USB audio equipment through a USB hub?

It is best to connect it directly to a port to make sure the maximum bandwidth is available. This is particularily important if the audio interface is bus powered and/or the USB hub is unpowered. Other peripherals, like the keyboard, mouse, printer and most USB MIDI interfaces use very little bandwidth or power, and can be safely connected to the hub. I use an unpowered 4 port hub for everything but my power-sucking (but otherwise brilliant) Novation X-Station 25.

So maybe this is a stupid question: how does one measure how much latency you're hearing? Is there a device to measure it? A meter in Logic?

Not a stupid question at all. There is no meter or device, but here is a test method that should give a reasonably accurate measurement:

Split the signal, run one line directly to the left channel on a DAT and the other line through Logic to the right channel. Make sure Software Monitoring is turned on and no hardware monitoring is being used. Record something with a sharp attack and short decay, like a hand clap. Transfer the DAT into Logic, take a look at the waveform and measure the time and/or number of samples between the attack on the left channel and the attack on the right channel. If you have a multichannel audio interface, you could use two extra channels in place of the DAT, record straight into Logic and do away with the need to transfer the audio.

A sample signal path:

mic/source>splitter>

splitter out 1>DAT left channel (or interface input 3 into Logic)

splitter out 2>interface input 1 into Logic, mapped to interface output 1>DAT right channel (or interface input 4 into Logic)

If you use two channels in Logic in place of the DAT, switch their outputs off to avoid feedback into output 1. Arm all three tracks and record the test signal.

Hope this helps!

Hello everyone. I am wrestling with some minor latency problems. Using a G4 Dual 533 with 1.5 Gigs of Ram with Pro Tools 001 interface with Logic Pro 7.1. In the Audio Hardware and Drivers Dialog there are several settings that can affect latency. I have played with the I/O Buffer size from 64Mb and up. This has not completely killed the latency. Lower settings may be introducing "artifacts" (static pops) (I hear them). I even here them at higher I/O Buffer settings! Minor Latency is still with me. I have tried enabling the "Larger Disk Buffer Setting" and still have minor latency. I do not understand what the "Recording Delay" setting does and if it will affect latency. When switching back to OS9.2 and Pro Tools 001 I have zero latency.

 

Since making the switch to Logic Pro I am enjoying the use of both processors. I am still struggling with getting rid of the latency issues, static pops (see "Note" at bottom of page 378 in Logic Reference Manual).

 

Can anyone offer some advice on these issues? I am under the impression that my G4 is powerful enough to be able to handle what Logic needs. Due to these issues it is causing me to have to switch back to OS9.2 and PT 001 to do my recording and then bounce the tracks into Logic as a "work-around."

 

Thank you for your time and opinions.

Ping

Maybe time to buy a new computer??