Preferences - Audio
Master Tune

This lets you adjust the global tuning in Reason. Standard tuning is "middle A" at 440 Hz. You can adjust this by +/- 100 cents.

Audio Card Driver

This menu lists all the available Audio Card Drivers on your system, and lets you select which one Reason should use. Which option to select depends on the audio hardware:

If you are using audio hardware for which there is a specific ASIO driver, you should select this.

With an ASIO driver written specifically for the audio hardware you will get lower latency (see below), support for higher sampling frequencies (up to 96 kHz in 24 bit/32 bit float resolution), and possibly better support for additional hardware features such as multiple outputs.

If there is no specific ASIO driver, you should select the Direct Sound driver for the audio hardware.

This makes Reason communicate with the hardware via Direct Sound (a part of the Microsoft DirectX package). For this to be possible, you need to have DirectX installed on your computer, and there must be a Direct Sound driver for the audio hardware.

If the audio hardware doesn't support Direct Sound (i.e. there is no Direct Sound driver for the audio hardware), select the MME driver for the audio hardware.

This makes use of Windows Multimedia Extensions, the part of Windows that handles audio, MIDI, etc. Using MME often results in larger latency values (see below).

Active Channels (ASIO Only)

This displays the number of audio channels (outputs) the currently selected audio hardware supports. For a regular stereo card, this number will be "2". If your audio card has multiple outputs and an ASIO driver is selected for it, the "Channels" button will be available. By clicking on it, you will be able to select which channel outputs (stereo pairs) should be active. Active outputs will be indicated in the Reason Hardware Interface.

Clock Source (ASIO Only)

If you are using an ASIO driver for your audio hardware, you have the possibility of selecting a Clock Source. This is used for determining the source to which audio playback should synchronize its sample rate. If you have an audio card and a driver that supports it, you can choose to synchronize to external sources.

ASIO Control Panel (ASIO Only)

If you have selected an ASIO driver, this button brings up a control panel window specifically for that audio hardware. This may contain buffer settings, routing options, synchronization alternatives etc.

Sample Rate

This lets you specify the playback sample rate. The options available on this menu depends on which sample rates are supported by your audio hardware.

Play in Background

When this is activated, Reason will not "release its grip" on the audio hardware when another application is active.

The advantage is that Reason will keep playing while you work in the other application.

The disadvantage is that other audio applications may not be able to play any audio, depending on the type of driver used.

Output Latency & Buffer Size

The Output latency 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.

When you select a driver, its latency value is automatically reported and displayed in 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 using a Direct Sound or MME driver, you can adjust the latency value by using the Buffer Size 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 smaller the audio buffers, the lower the latency. Please consult the documentation of your audio hardware and its ASIO drivers for details!

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.

Latency Compensation

This control should normally only be adjusted when synchronizing Reason to external MIDI Clock.

Because of the latency problem, you might need to adjust Reason's playback in relation to the MIDI Clock sync master, so that they are in perfect time. The tempo will not differ between the two, but Reason might play ahead or behind the other application. You might need to adjust this. However, this is something you only need to do once. The setting is stored with your other preferences, so you don't need to adjust it again.

Proceed as follows:

1. Set up the other application so that it generates a solid click, on for example quarter or eighth notes, preferably with a special sound on the downbeat. This click can either come from an internal metronome or from a MIDI source. If you use a MIDI source, make sure you pick one that has solid MIDI timing.

2. Set up Reason so that it plays a similar rhythm as the other application. You might for example use the Redrum drum computer for this.

3. Start the two applications in sync.

4. Make sure you hear both applications at approximately equal level.

5. Open the Preferences dialog in Reason and select the Audio page.

6. Trim the "Latency compensation" setting until the "clicks" from the both sources sound at exactly the same time.

7. Close the Preferences dialog in Reason.