About Latency
At the bottom of the audio page in the Preferences dialog, you will find an indication
of the current Output Latency.
This is the delay between when audio is “sent” from the program and when
you actually hear it. The latency in an audio system depends on the audio
hardware, its drivers and their settings.
If the latency is large, you will notice that the sound is delayed when you play
a device from a MIDI keyboard. You may also notice that reactions are delayed
when adjusting controls on the device panels (for example, if you lower
the volume of a device, you will not hear this immediately but after the latency
time). Therefore, you want to get as low a latency value as possible.
Adjusting the latency
When you select a driver, its latency value is automatically reported and displayed
in the lower left corner of the Preferences-Audio dialog. Depending
on the audio hardware and the driver, you may be able to adjust this value:
➜
If you are running Reason under Windows using a Direct Sound or
MME driver, you can adjust the latency value by using the slider or
the up/down arrow buttons.
The highest and lowest possible values depend on the driver.
➜
If you are using an ASIO driver specifically written for the audio
hardware, you can in most cases make settings for the hardware by
clicking the Control Panel button.
This opens the hardware’s ASIO Device Control Panel, which may or
may not contain parameters for adjusting the latency. Usually this is done
by changing the number and/or size of the audio buffers - the fewer and
smaller the audio buffers, the lower the latency. Please consult the documentation
of your audio hardware and its ASIO drivers for details!
➜
If you are running Reason on a Mac using the Sound Manager Default
Output driver, you cannot change the latency.
OK, so why not just set the latency to the lowest possible value? The problem
is that selecting too low a latency is likely to result in playback problems
(clicks, pops, dropouts, etc.). There are several technical reasons for this,
the main one being that with smaller buffers (lower latency), the average
strain on the CPU will be higher. This also means that the more CPU-intensive
your Reason song (i.e. the more devices you use), the higher the minimum
latency required for avoiding playback difficulties.
For this reason, you should adjust the latency while playing back a test song:
!
If you are using audio hardware with an ASIO driver, and thus need
to adjust the buffers in the ASIO Device Control Panel, you should
make a note of the original settings before changing anything!
1. Pull down the File menu and select Open.
The Reason Song Browser dialog appears.
2. Navigate to the Reason program folder and open one of the songs
in the Demo Songs folder.
The song appears in a new Reason document window.
3. Click the play button on the transport panel at the bottom of the
song window.
Playback starts, and you should hear the song being played back (provided
that you have connected your audio equipment properly).
4. While listening closely for pops and clicks, try lowering the latency
in the Preferences dialog or the ASIO Control Panel.
5. When you get pops and clicks, raise the latency value a bit.
6. Stop playback by clicking the stop button on the transport panel.
Now you have adjusted the latency so that
this song
plays back OK on your
computer. However, you may create more demanding songs, that require
you to raise the latency further.
!
The connection between “demanding songs” (CPU usage) and latency
is especially noticeable if you are using Direct Sound or MME
drivers on the PC. If you are using a specific ASIO driver for the audio
hardware, it may be possible to get very low latency values
(down to a few ms), regardless of the CPU usage. See the electronic
documentation for details about this and general information
