Broadcast

 

 

 

Interface (dropdown list common to each I/O channel)

Selects what type of audio driver interface to use for each Input and Output.

Available options:

  • KS: Kernel Streaming is a robust, low level interface. Kernel Streaming bypasses Windows audio subsystem and talks to the hardware driver directly. This interface is the most robust of all.
  • Wave: WaveIn/WaveOut (sometimes called MME) is a legacy interface, but certain professional audio interfaces use this driver interface natively. If KS doesn't work, Wave is the next best choice.
  • DS: DirectSound is the most commonly used audio driver interface in Windows, but despite its name it is heavily abstracted, not very direct. Use only if the above options do not work satisfactorily.

Audio Device (dropdown list common to each I/O channel)

Select the audio interface (sound card) to use for each Input and Output.

Available options:

  • Breakaway Pipeline (1, 2, 3) - a virtual audio driver which allows you to digitally connect other software running on the same PC to Breakaway, without using hardware interfaces. Useful if you're running an automation / playout system on the same machine.
  • Other available options depend on what sound cards you have installed.

 

Input (I/O channel)

Main L/R audio input for Breakaway. Make sure to choose an appropriate sample rate. If you're using the same audio card for Input and Output, select the same sample rate for both.

The input audio device is the master clock for Breakaway, and determines the sampling rate of the audio processing as follows:

Front-end is AGC, Multiband, Limiters.
Back-end is Clippers, MPX generator

Input
sample rate

Front-end
sample rate
Back-end
sample rate 
44100 44100 176400
48000 48000 192000 
88200 44100 176400 
96000 48000 192000
176400 44100 176400
192000 48000 192000

 

RDS Input

RDS / Pilot input for Breakaway. To use an external RDS generator, set it to output both Pilot and RDS. Breakaway will extract both (even from a full MPX signal), synchronize the stereo generator to the Pilot, and mix in RDS at the end. RDS and Pilot stay phase-locked all the way through the output. For a recommended Software RDS generator, look at Airomate.

In the sudden absence of pilot, Breakaway will crossfade to internal pilot. No clicks or glitches are generated during this transition. Breakaway stays on the air in full stereo.

This input has broadcast quality adaptive asynchronous sample rate conversion. Hardware-synchronized audio device is not required.

RDS Input Channels

Choose how many audio channels to request from the audio device, and how to use them. Breakaway's RDS input is mono regardless of the setting -- this affects only how the audio device is opened.

  • 1 will open the sound card as a single channel (Mono).
  • 2 (Mix) will open the sound card as 2-channel (Stereo), but will mix Left and Right and use the signals from both. This is useful for RDS generators which output Pilot and RDS on separate channels.
  • 2 (Left) will open the sound card as 2-channel (Stereo) and use only the Left channel. Right channel is discarded.
  • 2 (Right) will open the sound card as 2-channel (Stereo) and use only the Left channel. Right channel is discarded. 

 

L/R Output

Main audio output. This output can be either de-emphasized or pre-emhasized, depending on the selection in the Settings window.

This output has broadcast quality adaptive asynchronous sample rate conversion. Hardware-synchronized audio device is not required.

 

MPX Output

Built in FM Stereo generator (Composite Baseband, MPX). This output can be fed directly to an exciter, through a capable sound card. Because MPX signals contain frequencies up to 57000 Hz, a sampling rate of 192000, 176400 or 128000 Hz must be used. 96000 Hz or lower is not appropriate.

This output has broadcast quality adaptive asynchronous sample rate conversion. Hardware-synchronized audio device is not required. 

 

Audio Realtime Priority (on/off switch)

ON: Recommended. Audio engine runs in a separate process with Realtime Priority Class (thread priority 31 -- the absolute highest available in Windows). User Interface runs with Normal Priority (thread priority 8). Audio engine is quarantined in its own process, with a watchdog to automatically restart it if the unthinkable should happen.
OFF: Audio engine runs in the same process as the user interface. Audio Engine runs with Time Critical priority (15), User Interface runs with Normal Priority (thread priority 8). Not recommended, unless On causes glitches due to the sound card driver running with lower priority than the audio engine.

 

Buffer Size (drop-down list)

Selects the I/O buffer length to use. Due to the nature of the audio algorithm, algorithm delay itself is roughly 300ms. Thus, it is already too slow for realtime monitoring, so it may not be worth using a small buffer size due to the increased risk of problems. 

Small: Total throughput delay is roughly 400ms (with High Pass Filter OFF).
Medium: Total throughput delay is roughly 600ms (with High Pass Filter OFF).
Large: Total throughput delay is roughly 800ms (with High Pass Filter OFF).
Huge: Total throughput delay is roughly 1000ms (with High Pass Filter OFF).

 

Maximum Quality / Optimize CPU usage (switch)

If your computer is not quite fast enough for Maximum Quality mode, you can gain roughly 30% CPU efficience by sacrificing 5% audio quality and 2% peak control. A worthwhile tradeoff to run on Pentium 4 class machines. For Core 2 Duo class machines, we recommend Maximum Quality, for the absolute cleanest sound possible, with the best peak modulation control possible.

 

Plug-in Effects (on/off switch)

Allows safe, quarantined loading of Winamp DSP plug-in effects. Plug-ins are executed in their own process -- a plug-in crash does not take you off the air.
Effect plug-ins are patched in directly after the Input Sample Rate Converter. Useful for Stereo Enhancers and other effects.

This is the master on/off switch for the effect plug-in subsystem. When enabled, you may select what plug-ins (up to 9) to load on the Settings page. 

 

Plug-in Encoders (on/off switch)

Allows safe, quarantined loading of Winamp DSP plug-ins encoders, for example Shoutcast. Plug-ins are executed in their own process -- a plug-in crash will not affect your on-air signal, and a watchdog will immediately restart the plug-in.
Encoder plug-ins are fed a properly de-emphasized signal sampled at the front-end sampling rate, regardless of the L/R output state.

This is the master on/off switch for the encoder plug-in subsystem. When enabled, you may select what plug-ins (up to 9) to load on the Settings page.

 

Test

Allows you to easily test the I/O configuration. Runs the entire audio engine in bypass mode. Select "Test tone" in the Mode dropdown to internally generate a tone, to verify that the output is free from glitches.