Operation Manual

AUDIO BASICS
19
What is acceptable?
Normally, hardware synthesizers provide you with a latency of 3 to 7 ms (milliseconds
– thousands of a second), at least if the instrument is targeted towards a “profes-
sional” audience.
On a regular PC, the latency can vary quite a lot. This is an effect of the fact that com-
puters and their operating systems were created for many purposes, not just playing
back audio. For multimedia and games, a latency of a 100ms might be perfectly ac-
ceptable, but for playing a musical instrument it is not!
• PC audio cards with a MME driver (see later in this chapter) might at best give you
a latency of around 160ms.
• The same card with a DirectX driver provides at best around 40ms.
• A card specifically designed for low latency, with an ASIO driver, or the built-in au-
dio controller under Mac OS X can usually give you figures as low as 2-3 ms. This
is just as good as (or better than) dedicated hardware synthesizers!
Reason’s built in sequencer is not affected by latency!
When Reason’s sequencer is playing back a song, the timing between notes is per-
fect! Once playback of a Reason pattern or song is up and running, latency isn’t a
consideration at all. The computer clocks the audio between the steps and does this
with perfect quartz accuracy! The timing is immaculate!
ReWire and Latency
When you run Reason as a ReWire slave, it is the other program, the Rewire master
that is responsible for actually creating the audio and playing it back via the audio
card. This means that it is the master program’s latency you will get as a final result.
! When Reason runs as a ReWire slave, what audio hardware you have,
what driver you use, and settings you have made in the Preferences dia-
log are of no importance at all! All audio hardware settings are then in-
stead done in the ReWire master application!
For information on ReWire, see “Using Reason as a ReWire Slave”.
Reducing latency
There are a few general methods for making sure latency is as low as possible:
D Remove background tasks on your computer.
This might be any background utility you have installed as well as networking,
background internet activities etc.
D Optimize your songs.
You might run into situations where you have to raise the Output Latency setting
to be able to play back a very demanding song on your computer. Another option
would be to actually optimize the song. See “Optimizing Performance” for details.
D Get a faster computer.
This is related to the point above and only required if you find that you need to in-
crease Output Latency because your computer can’t really cope with the songs
you try to play.