Latency

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LittlePill

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Once again folks I will have to ask your forgiveness for asking what are probably stupid questions to you, but are great mysteries of the universe to me. I know very little about computer recording but want to learn more so that I can actually, well, do it. I've been reading up on it a bit and one word I keep seing quite frequently is "latency". My question is, what is it (latency)?

I currently record on a Yamaha MD8 but am getting very frustrated with its limitations and am thinking about upgrading to a DAW hopfully in the near future. Therefore I'm probably going to be asking a lot of these types of questions for a while so if you could all just bare with me. I really do appreciate everyone's help!
 
Someone may be able to give you a better or more technical explanation - but essentially latency is the amount of time required to perform certain processing tasks.

For example, if you have an external midi device, latency would be the amount of time from when you press a note until your computer processes the request and responds by playing that note. If you are trying to play along with a pre-recorded track in real time, high latency can result in the midi note being heard "behind" the recorded music.

It can also be exhibited in the amount of time required to change settings. E.g., if you raise a volume slider, how long until the volume actual changes.

There is generally a trade-off between latency and system performance. The lower the latency settings, the more taxing it is on the system.
 
In the context of a sound card, latency is how 'late' the track records compared to the rest of the tune....if you have high latency (bad), you will likely have to manually move your wave track up to match with the rest of the tune, which is frustrating and time consuming....
Most of the higher end Sound Cards (hammerfall, layla, etc) are low latency (hammerfall boasts a 0 latency, while Layla is more like 6ms), which is why they cost so darn much.
 
Latency is a pretty complex area, and I will start by disclaiming any particular expertise. However, I do not believe there is any latency involved in the recording or playback of AUDIO (except when using input monitoring).

I have recorded multiple audio tracks with latency settings as high as 500 ms. The tracks line up perfectly, and I am able to play along/sing along without any problems.

GalacticCelt, if you are having to manually move audio tracks, it is likely because you are using input monitoring which is causing you to hear, and therefore, play things late.

I'd be interested in hearing other comments on this subject, as there seems to be a lot of misinformation going on.
 
What Galactic Celt is refering to is now more commonly called "lag", and is a non-issue with soundcards that provide direct monitoring (just about all of them). In other words, soundcards provide monitoring of the direct input signal before it is processed. The "zero latency" of the RME cards just means that they provide direct input monitoring. The delta cards also provide direct input monitoring.

Now there will be some unavoidable lag in every electronic circuit...I did some tests with my Delta44 and found that the lag was very consistant at about 0.8ms. More expensive cards probably get a little closer to the unreachable 0 limit. Anyway, I haven't found it necessary to move any tracks by hand to compensate for a lag of under 1ms.

Latency, as dachaytnr explained, is the very basically "the amount of time it takes to hear the results of an adjustment after making the adjustment." Let's say you're using a regular consumer soundcard and you're mixing a project. You move the fader to adjust the volume of a track, and 1/2 a second later you hear the results of the fader move. This isn't a fun way to work. Imagine trying to sweep a parametric EQ across a range of frequencies when it takes 1/2 a second to hear each little move! Low latency prosumer soundcards provide much better performance via ASIO or WDM. With a card like something by Echo or M-Audio, you'll see latency times of about 60ms or better (depending on the resolution and number of tracks you're working with, and your system). Anything under 100ms is decent to work with. 50-60ms is wonderful. Less than that is cool, but damn near impossible when you're working on 24 track projects.

Slackmaster 2000
 
I should also mention that latency will be an issue if you choose to do any live input processing. That is, using effects in realtime on an incoming signal (e.g. using your computer as a stomp box). Personally I think that live input processing is a cool idea, but for now it's pretty retarded. Even with the best audio card you're going to have latency of around 10ms or so, maybe a little bit less, when working with just one incoming track. That's enough to throw your playing off. Plus you have to keep your track count very low, which means a lot of painful submixing.

Slackmaster 2000
 
Slackman -

Thanks for confirming my understanding (and explaining it much better than I could).

I think there are a lot of newbies out there who are unecessarily worrying about latency. If you are doing strictly audio work, and have no need for live input monitoring (which as Slack states, is not yet ready for prime time anyway), forget you ever heard the term latency.

On the other hand, if you are using external midi devices and trying to play along with live tracks, you are going to bump your head up against the latency issue big time.

The other area where latency comes into play is in mixing - like Slack explained. However, mixing is generally quite tolerable with 50 - 100 ms latencies, and these are pretty readily achievable with today's soundcards and drivers (even the SB Live :)).
 
Pro Tools! Pro Tools!

(sorry) ;)

But I just thought the fact that the highest latency possible on a Pro Tools LE system is 1024 samples ~ 23 ms (@44.1), coupled with the low latency input monitoring time of 7 samples, deserved a little mention here. Of course, you only get 24 audio tracks... but hey, it performs well. For live inputs, with a fast machine, set your buffer size to 64 or 128 samples, and you get very usable results.
 
well.......I'm glad I stumbled on this site!!!!!!!

Guess I have alot to learn...

My old studio (ha...I can't really call it that, but) was an Athlon 1.2 with the SB Live......which worked fine recording one track at a time....

When I upgraded software on the track of building a real studio (Nuendo) was where I ran into latency (lag...whatever!)...

I just bought the Layla 24, and this hasn't been a problem since then, but thanks to everyone for the education!
 
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