GUITARPRO2 - LATENCY QUESTION (0ne for the Historians!!)

This is one for the Historians of Cakewalk. I have the good old GTPro2, which I love as its so intuitive to use and I'm a bit of a Computer Luddite (well - lot of one then!) I'm coming back to home recording from a long time away and have noticed that now when I record in, my guitar is ever so slightly out of whack to the backing track. I checked this by loading a pre-recorded metronome track and then recorded my self playing a single note along with it - there is a definite LAG on my guitar track. I'm told by my mate that this is called Latency and something to do with the software being slow to take my signal input and put it onto the track. I didnt used to be like this so what has happened and how do I correct it please? Best regards Ian

He Steve good to know that you are still around in deepest Worcs. The system is Guitar-Effects-Modeller-straight to PC via minijack socket in the back of the PC. Card is Creative Audigy. I previously recorded something early this year and it all seemed fine but now that I have a little time to myself for a change I find I have this odd "latency" problem. cheers ian

  Hi Steve sorry for the delay - been away earning a crust! Audio setting says Effective Latency - 300ms. Should it be more or less? The cursor is in the middle of its range. Number of buffers in playback queue is 4 - whatever that means. Ditto - File Bit Depth - 16 (with an option for 24 ??) cheers ian

 
Good news Ian - glad to hear you're sorted mate.

 
Ian, the buffers are used to temporarily store information - either the sound you hear on playback or more importantly the signal from your guitar that is being recorded into GT. Their main purpose is to ensure there is always information available to be processed - either to your soundcard for listening to your projects, or for GT to record from your soundcard.
 
Think of the buffer/s a little like a header tank in your attic - as long as it's got water in it above a certain level, you'll always get water coming out of your taps. If it runs too low, the flow of water to your tap will be interrupted and then stopped altogether.
 
Taking this analogy over to GT, if your buffers are set too small on playback, the sound will become choppy and tend to stutter - you may even experience a dropout. Much more importantly, when recording, the buffers must always have information from your guitar otherwise you will experience dropouts and the take will likely be unusable.
 
The payoff against having large 'safe' buffer sizes is that it will introduce a delay into the signal chain - in sound recording and mixing terms, this is called 'latency'. Think of the header tank again - if your mains supply is off and the header tank is empty, there will be a definite delay between switching the mains back on and water coming through your taps. Latency is also affected by how efficient the analogue-to-digital (when recording) and digital-to-analogue (on playback) converters and drivers are on your soundcard. The faster they can process the signal, the lower the latency.
 
On playback, this isn't really that important so you can afford to have large buffer sizes - this also has the benefit that your computer won't have to work quite so hard and will free up processing power for playing back large numbers of tracks and using plug-ins and effects.
 
However, when recording, large buffers can create a latency so long that it's impossible to play in time with the metronome, or any other tracks you may have recorded. This is especially noticeable if you record with 'Input Monitoring' or 'Input Echo' switched on. This is because the signal you hear is also sent through any effects you have patched in the track you're recording to - again, this all takes extra time.
 
The key to setting the amount and/or size of the buffers for recording is to get them as low as possible without experiencing drop-outs. Try setting the number of buffers to 2, if you can still record OK then stick with it, if not, try 3 etc.
 
Hope that all makes sense mate!