Consider Latency When Playing Virtual Instruments

[starise]

This is intended as a help to anyone who might be planning to use software synthesizers or guitar amp sims. 

 

If you've already attempted to play a software synth or guitar amp sim, you're probably  familiar with the delays that you can potentially hear from the time you play a soft synth or guitar sim until the sound gets to your headphones or studio monitors.

 

This is a direct result of something called RTL or round trip latency. Before you hear the sound it needs to go through the audio interface, then into your computer cpu , into the software instrument and back out to the monitors. All of these processes take a small amount of time.The faster the time the less noticeable the delay is.

 

Another term frequently confused with RTL is " zero latency monitoring". Zero Latency Monitoring is simply a direct to interface monitoring solution. In other words, you hear all of the audio in real time as it's being recorded. Almost all recent audio interfaces have zero latency monitoring. If you use zero latency monitoring you aren't hearing the results of the amp sim or software synthesizer. This allows you to hear it in real time. This can be confusing because an interface that has zero latency monitoring might have a bad RTL time. It doesn't help that some manufacturers intentionally market this as a selling point and don't disclose what's really important to the user when recording using vsti's and amp sims.

 

Anything at 5ms and under is considered to be excellent. A common acceptable reported time is 4.5ms. Some configurations report times as low as 3ms. At these times the average person will never notice any delays. 10ms is the equivalent of being about 10ft. away from the source of the sound. More importantly, this is a long time between when you press a keyboard key and hear a sound. Consider that 11ms is a common reverb delay setting.At times this slow it's not really possible to play effectively and keep in time with the other tracks.

 

If you find that you experience these kinds of delays there are a few things you can do to improve the situation.

 

Look in the buffer settings located either in your DAW software under audio settings or in the software that came with your recording interface and try to lower the buffer values. If your system can handle a buffer 512 and lower this is is pretty good. Some engineers using RME and MOTU interfaces report buffers as low as 64 and 128. If you set the buffers too low you will notice crackles in the sound. This is because the system is exceeding it's limitations.

 

Less capable interfaces won't allow low settings  and delays will be noticeable. This is most often the fault of the audio driver and not the hardware. Better written audio drivers process data faster. 

 

A  computer that's not up to the task can also contribute to a long RTL. One way to determine if the problem is the computer is to launch task manager and look at cpu load while recording. If the cpu and memory aren't being stressed chances are the main issue is the audio interface and/or drivers. Your interface will "report" the RTL times. Using both of these methods can determine the main issue. It could be that both the computer and interface are the problem.

 

RTL is a non issue if you only record audio directly into your computer. RTL is VERY important to anyone who makes use of vsti and amp sims. 

 

All DAW software has a monitor button which when pressed passes the audio into and through your effects before you hear it. This can result in a noticeable delay. Most DAW software will attempt to compensate for this using something called " plug in delay compensation". My setup has a global button I can use to disengage effects when I record if the effects are too much of a strain on my computer.

 

The two main ingredients in avoiding high RTL are a computer that isn't bogged down running other programs in the background that's specified to run audio software well, and an audio interface with well written drivers. RME and Motu are known to be good choices. RME is pricey , but I've never heard of anyone who had a problem with one of their interfaces.

 

If you're stuck with a setup that has a high RTL which you are unable to improve on, there are a few workarounds to the problem. Slightly more time consuming, but no less effective.

If recording electric guitar using amp sims. Record the signal dry and add the sim later. This avoids the RTL problem altogether. Recording electric guitar like this can sound rather bland though. If you prefer the sound of an amp, split your signal and run part of it into an amp to get the feel you want, then run the signal dry into your recording interface. 

If recording a midi keyboard that has built in sounds, record the audio from the keyboard into the interface and monitor it with zero latency monitoring, then record a midi track simultaneously from the keyboard midi outs.This way you'll have two tracks, the audio track and a midi track you can send to play a vsti.

 

 

 

 

[Rudi]

great write Tim. IT WOULD MAKE A GREAT ARTICLE !

 

I've had latency problems and one of my songs serves as witness. I'm not sure I 'd know how to go about some of your suggestions, which goes into areas Ive never ventured into. Id like to see this pinned as its good reference material.

[starise]

THANKS RUDI !

 

i! I hadn't thought of it being an article. SS is welcome to use it as such. 

 

 I wanted to try to give those who have had the problem a few potential solutions. I have an older interface and it doesn't have the best RTL specs. If there's any way possible, my next interface will be an RME. 

 

I'll do my best to help you if you're having latency issues. It can be very frustrating trying to play something that has a delay in it and stay in time.

[Richard Tracey]

Tim this is a good post - for anyone using Logic - this is found under Preferences - Audio - General and tick the Low Latency Mode box. Believe me it makes a massive difference.

 

Unfortunately, you have to keep doing this for every new track you do, but it's worth it.

[starise]

Thanks Richard for that info.

 Heads up on a recent development in another DAW which is both mac and PC compatible. Presonus Studio One 3 Professional has a similar thing to what Richard mentions is available in Logic. I have used it with my older interface and it worked wonders in reducing my latency.