SimPhonics, Inc.

FXFXDirectDirect

Audio System for V+Audio System for V+

SimPhonics, Inc.

What Is FXDirect®What Is FXDirect®

• Audio Subsystem Add-on to V+– Currently built-in

• Consists of Objects for Manipulation of Audio– Synthesis/sampling– Mixing

• Audio Subsystem Add-on to V+– Currently built-in

• Consists of Objects for Manipulation of Audio– Synthesis/sampling– Mixing

SimPhonics, Inc.

What Is FXDirect®What Is FXDirect®

• V+ Wrapper Around DirectSound®

• Can be used with advanced hardware (SMx)– FXDirect alone – 4 channels (OTS sound

Cards)– FXDirect with SMx – Up to 50 Channels

• V+ Wrapper Around DirectSound®

• Can be used with advanced hardware (SMx)– FXDirect alone – 4 channels (OTS sound

Cards)– FXDirect with SMx – Up to 50 Channels

SimPhonics, Inc.

• Basic Sampling Theory

• Evolution of Audio Generation

• Sampling Versus Synthesis

• Microsoft DirectX

• FXDirect

• Demo and Hands-On

OverviewOverview

SimPhonics, Inc.

Basic Sampling TheoryBasic Sampling Theory

• “Sampling” is Digitizing Waveforms• Finite sample rate

• Typical 22khz, up to 48khz

• “Sampling” is Digitizing Waveforms• Finite sample rate

• Typical 22khz, up to 48khz

SimPhonics, Inc.

Analog/Digital - Digital/Analog Analog/Digital - Digital/Analog

SimPhonics, Inc.

Bandwidth IssuesBandwidth Issues

• Nyquist Frequency– Maximum Usable Frequency is ½ Sample Rate– Assumes Ideal Conditions

• Nyquist Frequency– Maximum Usable Frequency is ½ Sample Rate– Assumes Ideal Conditions

SimPhonics, Inc.

Bandwidth IssuesBandwidth Issues

• Higher Sample Rates– More samples (memory & processor overhead)– Higher quality

• Lower Sample Rates– Less samples, lower quality of audio

• Typical Industry– CD quality audio is 44.1khz– Telephone quality is 8khz.

• Higher Sample Rates– More samples (memory & processor overhead)– Higher quality

• Lower Sample Rates– Less samples, lower quality of audio

• Typical Industry– CD quality audio is 44.1khz– Telephone quality is 8khz.

SimPhonics, Inc.

Sample Bit DepthsSample Bit Depths

• More Bits Per Sample– Higher Quality (Lower THD)

• Typical Industry– CD quality 16 Bit– Telephone quality is 12 Bit– Up to 24 With Gadget Labs System

• More Bits Per Sample– Higher Quality (Lower THD)

• Typical Industry– CD quality 16 Bit– Telephone quality is 12 Bit– Up to 24 With Gadget Labs System

SimPhonics, Inc.

Sample Rate vs. Control Rate Processing

Sample Rate vs. Control Rate Processing

• Sample Rate– Processor Runs at Sample Rate

– Processor Manipulates Samples

– Very High Overhead

• Control Rate– Processor Runs at 20 – 30Hz

– Processor Manipulates Buffers of Samples

– At 22kHz SR, Buffer Would be 733 Samples, 1 Sec.

• Sample Rate– Processor Runs at Sample Rate

– Processor Manipulates Samples

– Very High Overhead

• Control Rate– Processor Runs at 20 – 30Hz

– Processor Manipulates Buffers of Samples

– At 22kHz SR, Buffer Would be 733 Samples, 1 Sec.

SimPhonics, Inc.

Sample Rate ProcessingSample Rate Processing

• SimPhonics FX-30 System– Manipulate Individual Samples– DSP Iterates at Sample Rate

• SimPhonics FX-30 System– Manipulate Individual Samples– DSP Iterates at Sample Rate

TO HOST PC CPU AUDIO OUTPUT

DSP

Control Rate Processing (30 - 60Hz)

Sample Rate Processing (8 - 50kHz)

Control Data Sample Generation

SimPhonics, Inc.

Control Rate ProcessingControl Rate Processing

• Much Lower Processing Rates – Typically 20 – 30Hz– Samples Are Stored As “Chunks” or Buffers

• Much Lower Processing Rates – Typically 20 – 30Hz– Samples Are Stored As “Chunks” or Buffers

TO HOST PC CPU AUDIO OUTPUT

SOUND CARD

Control Rate Processing (30 - 60Hz)

Sample Rate Processing (8 - 50kHz)

SimPhonics, Inc.

Which Technique to Use?Which Technique to Use?

• Good Question

• PC Technology Can’t Operate at SR– Very Inefficient

• Dedicated DSP is Ideal for SRP– Big Bucks– Non Standard

• Good Question

• PC Technology Can’t Operate at SR– Very Inefficient

• Dedicated DSP is Ideal for SRP– Big Bucks– Non Standard

SimPhonics, Inc.

When to Use SRPWhen to Use SRP

• Mixing Low Latency Audio Input– Delays Using CRP are Unacceptable– Simulating Voice Systems (Intercoms, etc)

• Super Special Stuff– ???

• Mixing Low Latency Audio Input– Delays Using CRP are Unacceptable– Simulating Voice Systems (Intercoms, etc)

• Super Special Stuff– ???

SimPhonics, Inc.

New Technology and Standards Make CRP Work for SimulationNew Technology and Standards Make CRP Work for Simulation

• Before DirectX, No Standard Mixing API

• Intel’s MMX Initiative– Intel and Microsoft Collaborate/Squabble

• Microsoft Launches DirectX®– DirectSound is a Subset of DirectX

• Before DirectX, No Standard Mixing API

• Intel’s MMX Initiative– Intel and Microsoft Collaborate/Squabble

• Microsoft Launches DirectX®– DirectSound is a Subset of DirectX

SimPhonics, Inc.

DirectSoundDirectSound

WAVE FILES

Secondary Buffer

Secondary Buffer

Secondary Buffer

Direct Sound Mixer

Sound Card Channel

Text to Speech

V+ I/O Device

DISComm+ Network

Secondary Buffers

Primary Buffer

SimPhonics, Inc.

Sample Rate ConversionSample Rate Conversion

• Important DirectSound Feature– Different SR Secondary Buffers are Combined– DirectSound Does the SRC

• Quality and Overhead User Configurable– Control Panel, Multimedia Icon

• Important DirectSound Feature– Different SR Secondary Buffers are Combined– DirectSound Does the SRC

• Quality and Overhead User Configurable– Control Panel, Multimedia Icon

SimPhonics, Inc.

Using FXDirect with DirectSoundUsing FXDirect with DirectSound

WAVE FILES

Secondary Buffer

Secondary Buffer

Secondary Buffer

Direct Sound Mixer

Sound Card Channel

Secondary Buffers

SimPhonics, Inc.

Dynamic Control of SoundsDynamic Control of Sounds

• Since DirectSound Performs SRC:– Frequency and Amplitude May be Controlled in Real-Time

• Since Any Waveform Can Be Used:– CRP Can Be Used in Most Cases for SRP.

– I.E. Sine Wave Can Be Synthesized Off-Line and Used as a Secondary Buffer FXDirect Object

• Therefore, Don’t Let Them Tell You:– You can’t Use CRP for Simulation Systems

• Since DirectSound Performs SRC:– Frequency and Amplitude May be Controlled in Real-Time

• Since Any Waveform Can Be Used:– CRP Can Be Used in Most Cases for SRP.

– I.E. Sine Wave Can Be Synthesized Off-Line and Used as a Secondary Buffer FXDirect Object

• Therefore, Don’t Let Them Tell You:– You can’t Use CRP for Simulation Systems

SimPhonics, Inc.

Multiple ChannelsMultiple Channels

Secondary Buffer

Secondary Buffer

Secondary Buffer

Secondary Buffer

Secondary Buffer

Secondary Buffer

WAVE FILES

Secondary Buffer

Secondary Buffer

Secondary Buffer

Direct Sound Mixer

Sound Card Channel

SimPhonics, Inc.

Practical ExamplePractical Example

SimPhonics, Inc.

• FXDirect can use Almost Any Sound Card– Direct Sound Driver for Best Performance– Full Duplex for Voice I/O– WDM Driver Desirable

• FXDirect can use Almost Any Sound Card– Direct Sound Driver for Best Performance– Full Duplex for Voice I/O– WDM Driver Desirable

FXDirect OperationFXDirect Operation

SimPhonics, Inc.

FXDirect OperationFXDirect Operation

Platform Shell Configure Menu Associates FXDirect Channels with Audio Outputs

Platform Shell Configure Menu Associates FXDirect Channels with Audio Outputs

SimPhonics, Inc.

Channels Versus OutputsChannels Versus Outputs

• Multi-Channel Cards are VERY Rare– Most Do Not Use WDM Driver

– Others Do Not Enumerate Channels Properly

• As of Today, Only Two Exist– Gadget Labs With Stage Research and SimPhonics Drivers

– Echo Corporation’s Layla System

• Multi-Channel Cards are VERY Rare– Most Do Not Use WDM Driver

– Others Do Not Enumerate Channels Properly

• As of Today, Only Two Exist– Gadget Labs With Stage Research and SimPhonics Drivers

– Echo Corporation’s Layla System

SimPhonics, Inc.

FXDirect OperationFXDirect Operation

Stereo Channels are Actually 2 Outputs,Left and Right

Stereo Channels are Actually 2 Outputs,Left and Right

SimPhonics, Inc.

FXDirect MessagesFXDirect Messages

• Message Area of the Platform Shell– Run-time and Initialization Messages– Always Look at this Area When There is Trouble

• Message Area of the Platform Shell– Run-time and Initialization Messages– Always Look at this Area When There is Trouble

SimPhonics, Inc.

FXDirect Hands-onand Demo

FXDirect Hands-onand Demo