What's the downside to larger jackd buffers?

I usually use a hardware recorder to capture my audio and then I edit it in ardour. Thus I’ve never cared about latency and xruns. As a matter of fact I’ve never really understood what it is. I’ll see some xruns in the jackd terminal window but that doesn’t seem to affect the quality of the exported audio from ardour so I haven’t cared.

Now I’m starting to record some audio directly into the computer and jackrec will halt if there are too many xruns.

The jackd man page says I can decrease the number of xruns by increaseing the -p and -n options. I just did and the xruns seems to be gone.

Now what is the downside to this? What exactly is latency and why is it so important to have low latency?


Doing recording on a home based system going one way into the computer, you probably won’t notice a big difference. However, with larger systems, things get a lot more complicated. With a lot of outboard gear running in and out of the computer at the same time, things can get pretty messy when stuff gets out of sync.

For example, trying to play live, a little latency can go a long way to messing up your groove. Or, in more critical situations, audio and video getting out of sync. A few too many frames off, and you’re on par with Chinese soap operas from the '70s :wink:

But as I said, unless you’re getting paid big bucks for it, it’s probably not a big deal and not that difficult to compensate for.

Latency is the delay between action and reaction. In our case, a low latency is of interest mainly if you want to play a soft-synth or use the pc as an effects box by sending a signal through it.