Turbine Audio Profiles

Normal Audio Profiles

Standard AEC Profile with a few extra filters added to try to minimize the effects on the voice-signal when operating in a standard environment and few non-linearities in the speaker-to-mic feedback signal.

Extra config options can override many of the AEC/NC parameter:

• Conversations modes:
  • Robust-Duplex
  • Half-Duplex-Switching
• Noise Suppresion Levels

Description	Configuration
Echo Tail Length	128	Default is "128 ms". For most cases 128 or 256 msec is enough. Bigger values may slow down the convergence and increasing the CPU load.
Echo Convergence Rate	Fastest	Default is "Fastest". Decides the speed of convergence. Higher value uses more CPU.
Speech Distortion Level	Low	Default is "Low". If hardware is linear enough, set "Low". Bigger values may help if echo is not suppressed enough due to the non-linearity or other damaging factors, however speech quality will degrade.
Use Notch Filter	Off	Default is "Off". Filtering of low frequency components and 50 Hz harmonics. If noise level is very small, NF may be turned off to improve quality
Use High Pass Filter	Off	Default is "Off". filtering of low frequency. If noise level is very small, HFP may be turned off to improve quality.
Use Comfort Noise Generation	Off	Default is "Off". Enables comfort noise generation
Comfort Noise Generation Type	1	Default is "1". quiet1 using fixed spectrum shaping (least MCPS). quiet2, low, load using adaptive shaping
Use Non Linear Processing	On	Default is "On". Affect to suppression of remained echo and noise in single talk conditions (when far-end speaker is active)
Non Linear Processing Threshold	2	Default is "2". Higher values causes better suppression, but lower values causes lower distortion.
Use Automatic Gain Control	Off	Default is "Off". If speech level and environmental noise are very unstable it may be turned on. AGC May cause significant artifacts and can not be recommended for high-quality transmissions.
Automatic Gain Control Speed	0	Default is "0". Selects the speed of the automatic gain control algorithm.
Automatic Gain Control Volume	0	Default is "0". 0..7 corresponds to -20..0 dBm.
Use Noise Cancellation	Off	Default is "Off".
Noise Cancellation Suppression Level	10 dB	Default is "10 dB". Higher suppression removes more noise, but will also cause more speech distortions and more observable musical and metallic noise.
Noise Cancellation Fast Adaption	Off	Default is "Off". Should be turned on in unstable environments (example: streets).
Use Noise Cancellation Fine Algorithm	On	Default is "On". Turning on fine noise cancellation uses more CPU, but results better quality.
Noise Cancellation Musical Noise Suppression Level	0	Default is "0". Higher value causes more metallic voice.
Noise JAM Detector	0	Frequency selective noises (jams) appear in many industrial or harsh environments. For example, they may be produced by instruments, engines, trains, airscrews, etc. Jam detector aids to cancel that jams at very low degradation of nativespeech quality. However, in standard office environments jam detector may be turned off.
Half Duplex Control	Off	Default is "Off". Should be used if open duplex fails due to excessive speaker loudness, microphone overloads or very high nonlinear distortions.
Use Soft Howling Algorithm	Off	Default is "Off". If non-linearity mostly introduced by loudspeakers, special soft howling algorithm may help. It smoothly manages switching between true full duplex and true half-duplex echo cancellation making switching artifacts less noticeable.
Use Fast Howling Speed	Off	Default is "Off".
Use AEC Postfilter	Off	In some environments, AEC is not capable to suppress echo enough. It may be caused by some reasons i.e. resonances in enclosures/mechanical parts, very distorted frequency response, signal clipping, etc. It may look like scrappy or hissing echo or whispering. In that cases, postfilter helps to remove that effects with small degradation of near-end speech.
Use Far-end noise cancellation	Off	Far-end speech with strong noise level may cause degradation of speech quality of speech coming from the near-end. Particularly, you may observe variation of loudness. In the half-duplex mode, strong level of far-end noise may cause more scrappy speech. Normally, VoIP endings already have noise cancellation on their ends and this situation is not occurred. So, in most cases, there is no reason to turn on this feature. But in some cases, this option may help.
Use VBE	Off	Voice bandwidth expansion improves the behavior of echo/noise cancellation in presence of noise of loud far-end speech. Also, it makes the bandwidth of speech perceptually better. Setting of strongest level of VBE is reasonable solution for enviroments with big noises and strong far-end speech levels. However, the setting the strongest level of VBE may cause some small audible artifacts like whispering speech, so if it these effects observing, the strength of VBE should be decreased. Also it should be taken into account, the VBE is computationally intensive algorithm and is not recommended to use if MCPS budget is limited.
Envelope Processor	Off	Compression Type, see Profile selection below.
Envelope Processor Profile	0	You may select 3 possible compression levels or no compression. Compression decreases speech dynamic range at typical levels, so perceptually the speech gets louder. For adaptive compression selects compression profile. Bigger number makes compression stronger. For fixed compression sets fixed gain in 3 dB. steps (3,6,9 and 12)

Normal Profile Override - Duplex Control

Conversation Mode: Half-Duplex-Switching

Set the AEC algorithm in Half-Duplex Switching mode.

Description	Configuration
Half Duplex Control	Half-Duplex	Default is "Off". Should be used if open duplex fails due to excessive speaker loudness, microphone overloads or very high nonlinear distortions.
Use Soft Howling Algorithm	Off	Default is "Off". If non-linearity mostly introduced by loudspeakers, special soft howling algorithm may help. It smoothly manages switching between true full duplex and true half-duplex echo cancellation making switching artifacts less noticeable.

Conversation Mode: Robust-Duplex

This combination turns on some halfduplex-like behavior but only if input signal is strong enough - system remain full-duplex on lower levels of mic input. This protects echo canceller from the negative effects appearing from the mic overflow and corresponding non-linearity.

Description	Configuration
Half Duplex Control	2	Default is "Off". Should be used if open duplex fails due to excessive speaker loudness, microphone overloads or very high nonlinear distortions
Use Soft Howling Algorithm	On	Default is "Off". If non-linearity mostly introduced by loudspeakers, special soft howling algorithm may help. It smoothly manages switching between true full duplex and true half-duplex echo cancellation making switching artifacts less noticeable.

Normal Profile Override - Noise Reduction Level

Noise Reduction Level 0

No Noise Cancellation active. Also resets Half-Duplex Controls that can be set with suppression level 7.

Description	Configuration
Use Noise Cancellation	Off	Default is "Off".
Noise Cancellation Suppression Level	10 dB	Default is "10 dB". Higher suppression removes more noise, but will also cause more speech distortions and more observable musical and metallic noise.
Noise Cancellation Fast Adaption	Off	Default is "Off". Should be turned on in unstable environments (example: streets).
Use Noise Cancellation Fine Algorithm	On	Default is "On". Turning on fine noise cancellation uses more CPU, but results better quality.
Noise Cancellation Musical Noise Suppression Level	0	Default is "0". Higher value causes more metallic voice.
Noise JAM Detector	0	Frequency selective noises (jams) appear in many industrial or harsh environments. For example, they may be produced by instruments, engines, trains, airscrews, etc. Jam detector aids to cancel that jams at very low degradation of nativespeech quality. However, in standard office environments jam detector may be turned off.
Use Comfort Noise Generation	Off	Default is "Off". Enables comfort noise generation
Comfort Noise Generation Type	quiet1	Default is "1". quiet1 using fixed spectrum shaping (least MCPS). quiet2, low, load using adaptive shaping
Half Duplex Control	2	Default is "Off". Should be used if open duplex fails due to excessive speaker loudness, microphone overloads or very high nonlinear distortions
Use Soft Howling Algorithm	Off	Default is "Off". If non-linearity mostly introduced by loudspeakers, special soft howling algorithm may help. It smoothly manages switching between true full duplex and true half-duplex echo cancellation making switching artifacts less noticeable.

Noise Reduction Levels 1-7

It is not guaranteed that higher levels give a higher noise suppression, but levels utilizes different mechanisms like Jam detector and "semi-half-duplex" for handling loud Turbine Speaker Output in Noisy environments.

Level 6 is equivalent to Audio Profile "Noisy Environment"

Level 7 is equivalent to Audio Profile "Very Noisy Environment"

Description	Configuration
Use Noise Cancellation	On	On	ON	ON	ON	ON	ON
Noise Cancellation Suppression Level	10 dB	15 dB	20 dB	30 dB	30 dB	20 dB	20 dB
Noise Cancellation Fast Adaption	Off	Off	Off	Off	Off	Off	Off
Use Noise Cancellation Fine Algorithm	On	On	On	On	On	On	On
Noise Cancellation Musical Noise Suppression Level	0	0	0	0	0	0	0
Noise JAM Detector	0	0	0	0	0	Slow	Aggressive
Use Comfort Noise Generation	Off	Off	Off	Off	Off	On	On
Comfort Noise Generation Type	quiet1	quiet1	quiet1	quiet1	quiet1	quiet2	low
Half Duplex Control	Off	Off	Off	Off	Off	Off	2
Use Soft Howling Algorithm	Off	Off	Off	Off	Off	Off	On

Noisy Environment

Environment with high noise levels but maximum Turbine Speaker level is not required.

• Enhanced Noise filter with Suppression level 15 dB
• Slow Jam detector to handle Frequency selective noises (jams) appearing in many industrial or harsh environments.
• Comfort Noise type "quiet2" to make CNG operation more natural in noisy environments

Description	Configuration
Use Noise Cancellation	On	On	ON	ON	ON	ON	ON
Noise Cancellation Suppression Level	10 dB	15 dB	20 dB	30 dB	30 dB	20 dB	20 dB
Noise Cancellation Fast Adaption	Off	Off	Off	Off	Off	Off	Off
Use Noise Cancellation Fine Algorithm	On	On	On	On	On	On	On
Noise Cancellation Musical Noise Suppression Level	0	0	0	0	0	0	0
Noise JAM Detector	0	0	0	0	0	Slow	Aggressive
Use Comfort Noise Generation	Off	Off	Off	Off	Off	On	On
Comfort Noise Generation Type	quiet1	quiet1	quiet1	quiet1	quiet1	quiet2	low
Half Duplex Control	Off	Off	Off	Off	Off	Off	2
Use Soft Howling Algorithm	Off	Off	Off	Off	Off	Off	On